Scientific American Supplement, No. 455, September 20, 1884
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Title: Scientific American Supplement, No. 455, September 20, 1884
Author: Various
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Language: English
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*** START OF THE PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPPLEMENT, NO. 455, SEPTEMBER 20, 1884 ***
[Illustration]
SCIENTIFIC AMERICAN SUPPLEMENT NO. 455
NEW YORK, SEPTEMBER 20, 1884
Scientific American Supplement. Vol. XVIII, No. 455.
Scientific American established 1845
Scientific American Supplement, $5 a year.
Scientific American and Supplement, $7 a year.
* * * * *
TABLE OF CONTENTS.
I. CHEMISTRY AND METALLURGY.--Gallisin, an Unfermentable
Substance in Starch Sugar.
The Combining Weights, Volumes, and Specific Gravities of
Elements and Compounds.
Analysis of Zinc Ash and Calcined Pyrites by Means of
Ammonium Carbonate.
II. ENGINEERING AND MECHANICS.--Petroleum as a Fuel in
Locomotive Engines.--By THOMAS URQUHART.--Spray
injector.--Driving locomotives.--Storage of petroleum.
Improved Gas Light Buoy.--2 figures.
Project for a Roadstead at Havre.--With map and views of
different breakwaters.
Improved Catch Basin.--2 figures.
Water Power with High Pressures and Wrought Iron Water
Pipe.--By HAMILTON SMITH, JR.--Methods of conducting water
and transmitting power.--Texas Creek pipe and aqueduct.--4
figures.
Parachute Hydraulic Motor.
Improved Shafting Lathe.--1 figure.
Power Straightening Machine.--1 figure.
Hydraulic Mining in California.--By GEO. O'BRIEN.
III. TECHNOLOGY.--Emerald Green: Its Properties and
Manufacture.--Use in wall paper.--ROBERT GALLOWAY.
Charcoal Kilns.--Extra yield.--2 figures.
IV. ARCHITECTURE--Entrance, Tiddington House, Oxon.--An
engraving.
V. ELECTRICITY, LIGHT, HEAT. ETC.--The Temperature of the
Earth as shown by Deep Mines.
New Arrangement of the Bichromate of Potash Pile.--3
figures.
The Distribution of Electricity by Induction.--1 figure.
Electricity Applied to the study of Seismic Movements.--Apparatus
for the study of horizontal and vertical seismic
movements, etc.--8 figures.
New Accumulators.--3 figures.
Industrial Model of the Reynier Zinc Accumulator.
The History of a Lightning Flash.--By W. SLINGO.
Researches on Magnetism.
VI. NATURAL HISTORY.--The Giraffe.--With engraving.
VII. MEDICINE, AND HYGIENE.--The Treatment of Cholera--By
Dr. H.A. RAWLINS.
Temperature. Moisture, and Pressure, in their Relations
to Health.--London deaths under 1 year in July, August,
and part of September.
Consumption Spread by Chickens.
New Method of Reducing Fever.
VIII. MISCELLANEOUS.--The Crown Diamonds of France at the
Exhibition of Industrial Arts.
A New Mode of Testing the Economy of the Expenses of
Management in Life Insurance.--By WALTER C. WRIGHT.
* * * * *
THE GIRAFFE.
The spirited view herewith presented, representing the "Fall of the
Giraffe" before the rifle of a sportsman, we take from the _Illustrated
London News_. Hunting the giraffe has long been a favorite sport among the
more adventurous of British sportsmen, its natural range being all the
wooded parts of eastern, central, and southern Africa, though of late
years it has been greatly thinned out before the settlements advancing
from the Cape of Good Hope.
[Illustration: THE FALL OF THE GIRAFFE.]
The characteristics of this singular animal are in some particulars those
of the camel, the ox, and the antelope. Its eyes are beautiful, extremely
large, and so placed that the animal can see much of what is passing on
all sides, and even behind it, so that it is approached with the greatest
difficulty. The animal when full grown attains sometimes a height of
fifteen to seventeen feet. It feeds on the leaves and twigs of trees
principally, its immense length of legs and height at the withers
rendering it difficult for the animal to graze on an even surface. It is
not easily overtaken except by a swift horse, but when surprised or run
down it can defend itself with considerable vigor by kicking, thus, it is
said, often tiring out and beating off the lion. It was formerly almost
universally believed that the fore legs were longer than the hinder ones,
but in fact the hind legs are the longer by about one inch, the error
having been caused by the great development and height of the withers, to
give a proper base to the long neck and towering head. The color varies a
good deal, the head being generally a reddish brown, and the neck, back,
and sides marked with tessellated, rust colored spots with narrow white
divisions. Many specimens have been brought to this country, the animal
being extremely docile in confinement, feeding from the hand, and being
very friendly to those who are kind to it.
* * * * *
An experiment has been made in Vienna which proves that even with
incandescent lights special precautions must be taken to avoid any risk of
fire. A lamp having been enveloped with paper and lighted by a current,
the heat generated was sufficient to set fire to the paper, which burnt
out and caused the lamp to explode.
* * * * *
THE TEMPERATURE OF THE EARTH AS SHOWN BY DEEP MINES.
At a recent meeting of the American Society of Civil Engineers,
observations on the temperature of the earth, as shown by deep mines, were
presented by Messrs. Hamilton Smith, Jr., and Edward B Dorsey. Mr. Smith
said that the temperature of the earth varies very greatly at different
localities and in different geological formations. There are decided
exceptions to the general law that the temperature increased with the
depth. At the New Almaden quicksilver mine, in California, at a depth of
about 600 feet the temperature was very high--some 115 degrees; but in the
deepest part of the same mine, 1,800 feet below the surface and 500 feet
below sea level, the temperature is very pleasant, probably less than 80
degrees. At the Eureka mines, in California, the air 1,200 feet below the
surface appears nearly as cool as 100 feet below the surface. The normal
temperature of the earth at a depth of 50 or 60 feet is probably near the
mean annual temperature of the air at the particular place. At the
Comstock mines, some years since, the miners could remain but a few
moments at a time, on account of the heat. Ice water was given them as an
experiment; it produced no ill effects, but the men worked to much better
advantage; and since that time, ice water is furnished in all these mines,
and drunk with apparently no bad results.
Mr. E.B. Dorsey said that the mines on the Comstock vein, Nevada, were
exceptionally hot. At depths of from 1,500 to 2,000 feet, the thermometer
placed in a freshly drilled hole will show 130 degrees. Very large bodies
of water have run for years at 155 degrees, and smaller bodies at 170
degrees. The temperature of the air is kept down to 110 degrees by forcing
in fresh air cooled over ice.
Captain Wheeler, U.S. Engineers, estimated the heat extracted annually
from the Comstock by means of the water pumped out and cold air forced in,
as equal to that generated by the combustion of 55,560 tons of anthracite
coal or 97,700 cords of wood. Observations were then given upon
temperature at every 100 feet in the Forman shaft of the Overman mine,
running from 53 degrees at a depth of 100 feet to 121.2 degrees at a
depth of 2,300 feet. The temperature increased:
100 to 1,000 feet deep, increase 1 degree in 29 feet.
100 to 1,800 feet deep, increase 1 degree in 30.5 feet.
100 to 2,300 feet deep, increase 1 degree in 32.3 feet.
A table was presented giving the temperatures of a large number of deep
mines, tunnels, and artesian wells. The two coolest mines or tunnels are
in limestone, namely, Chanarcillo mines and Mont Cenis tunnel; and the two
hottest are in trachyte and the "coal measures," namely, the Comstock
mines in trachyte and the South Balgray in the "coal measures." Mr. Dorsey
considered that experience showed that limestone was the coolest
formation.
* * * * *
GALLISIN, AN UNFERMENTABLE SUBSTANCE IN STARCH SUGAR.
C. Schmitt and A. Coblenzl have made a careful investigation of the
unfermentable substances found in commercial starch sugars, and have
succeeded in isolating a definite compound, to which they give the name
gallisin. The method of separation and purification which they made use of
is as follows: 5 kilogrammes of commercial starch sugar were allowed to
ferment. At a temperature of 18-20° C. and with a solution containing 20
per cent. the fermentation was complete in five to six days. It was
filtered; the perfectly clear, almost colorless, liquid evaporated as far
as possible on the water-bath, and the sirup while still warm brought into
a good-sized flask. The sirup was then well shaken with a large excess of
absolute alcohol, when it became viscous, but did not mix with the
alcohol. The latter was poured off, replaced by fresh alcohol, and again
shaken. When this shaking with alcohol has been repeated several times,
the sirup is finally changed to a yellowish-gray mass. This is now brought
into a large mortar, and rubbed up under a mixture of alcohol and ether.
After some time the whole mass is transformed into a gray powder. It is
quickly filtered off with the aid of an aspirator, washed with alcohol and
then with ether, and brought under a desiccator with concentrated
sulphuric acid. In order to purify the substance, it is dissolved in water
and treated with bone-black. The solution is then evaporated to a sirup,
and this poured into a mixture of equal parts of anhydrous alcohol and
ether. In this way the new compound is obtained as a very fine, pure white
powder which rapidly settles. It has much the appearance of starch. Under
the microscope it is perfectly amorphous. In the air it deliquesces much
more rapidly than ignited calcium chloride.
Treated with dilute mineral acids or oxalic acid on the water-bath
gallisin is transformed into dextrose. It does not ferment when treated in
water solution with fresh yeast. The analyses led to the formula
C_{12}H_{24}O_{10}. When treated under pressure with three times its
weight of acetic anhydride at 130-140° it dissolves perfectly. From the
solution a product was separated which on analysis gave results agreeing
with the formula C_{12}H_{18}O_{10}(C_{2}H_{3}O)_{6}. The substance
appears therefore to be hexacetylgallisin.
Physiological experiments on lower animals and human beings demonstrated
clearly that gallisin has neither directly nor indirectly any injurious
effect on the health.--_Berichte der Deutschen Chemischen Gesellschaft,
17, 1000; Amer. Chem. Jour._
* * * * *
THE COMBINING WEIGHTS, VOLUMES, AND SPECIFIC GRAVITIES OF ELEMENTS AND
COMPOUNDS.
Under the title of "Figures Worth Studying," Mr. William Farmer, of New
York, read a paper before a recent meeting of the Society of Gas Lighting,
from which the _American Gas Light Journal_ gives the following:
I have prepared the following table, which contains some of the elements
and compounds, with their combining weights, volumes, and specific
gravities. When the combining weight of any of these elements and
compounds is taken in pounds, then the gas or vapor therefrom will always
occupy about 377.07 cubic feet of space, at 60° Fahr. and 30 inches
barometer. If we divide this constant 377.07 by the combining weight of
any of the substances, then the quotient will be the number of cubic feet
per pound of the same. If we divide the combining weight of any of the
substances given in the table by 2, then the quotient will give the
density of the same, as compared with hydrogen. If we divide the combining
weight of any of the substances by the constant 28.87, then the quotient
will be the specific gravity of the gas or vapor therefrom, as compared
with air. All the calculations are based on the atomic weights which are
now generally adopted by the majority of chemists.
-------------------------------------------------------------------
| | |Cub. Ft.| |
| | | per | |
| Combi- |Cub. Ft.| Combi- |Specific|
| ning | per | ning |Gravity |
|Weight. | Pound. |Weight. |Air = 1.|
------------------------------+--------+--------+--------+--------|
Hydrogen (H_{2}) | 2.00 | 188.53 | 377.07 | 0.0692 |
Carbon vapour (C_{2}) | 23.94 | 15.75 | 377.07 | 0.8292 |
Nitrogen (N_{2}) | 28.06 | 13.43 | 377.07 | 0.9719 |
Oxygen (O_{2}) | 31.92 | 11.81 | 377.07 | 1.1056 |
Chlorine (Cl_{2}) | 71.00 | 5.31 | 377.07 | 2.4593 |
Bromine (Br_{2}) | 160.00 | 2.35 | 377.07 | 5.5420 |
Flourine (F_{2}) | 38.00 | 9.92 | 377.07 | 1.3162 |
Iodine (I_{2}) | 253.20 | 1.48 | 377.07 | 8.7703 |
Sulphur (S_{2}) | 63.96 | 5.89 | 377.07 | 2.2154 |
Phosphorus (P_{4}) | 123.84 | 3.04 | 377.07 | 4.2895 |
Carbonic oxide (CO) | 27.03 | 13.50 | 377.07 | 0.9674 |
Carbonic acid (CO_{2}) | 48.89 | 8.59 | 377.07 | 1.5202 |
Water vapour (H_{2}O) | 17.06 | 20.99 | 377.07 | 0.6221 |
Hydrogen sulphide (H_{2}S) | 33.08 | 11.09 | 377.07 | 1.1770 |
Ammonia (H_{2}N) | 17.03 | 22.14 | 377.07 | 0.5898 |
Sulphurous oxide (SO_{2}) | 63.90 | 5.90 | 377.07 | 2.2133 |
Sulphuric oxide (SO_{3}) | 79.86 | 4.72 | 377.07 | 2.7662 |
Cyanogen (C_{2}N_{2}) | 52.00 | 7.25 | 377.07 | 1.8011 |
Bisulphide of carbon (CS_{2}) | 75.93 | 4.96 | 377.07 | 2.6300 |
Ethyl alcohol (C_{2}H_{6}O) | 45.90 | 8.21 | 377.07 | 1.5898 |
Ethyl ether (C_{4}H_{10}O) | 73.84 | 5.10 | 377.07 | 2.5576 |
Methyl alcohol (CH_{4}O) | 31.93 | 11.81 | 377.07 | 1.1059 |
Methyl chloride (CH_{3}Cl) | 50.47 | 7.47 | 377.07 | 1.7482 |
Carbonyl chloride (COCl_{2}) | 98.93 | 3.81 | 377.07 | 3.4267 |
Phosphine gas (PH_{3}) | 33.96 | 11.10 | 377.07 | 1.1769 |
Hydrochloric acid (HCl) | 36.50 | 10.33 | 377.07 | 1.2642 |
Methane (CH_{4}) | 15.98 | 26.61 | 377.07 | 0.5531 |
Ethane (C_{2}H_{6}) | 29.94 | 12.50 | 377.07 | 1.0370 |
Propane (C_{3}H_{8}) | 43.91 | 8.58 | 377.07 | 1.5209 |
Butane (C_{4}H_{10}) | 57.88 | 6.51 | 377.07 | 2.0048 |
Ethene (C_{2}H_{4}) | 27.94 | 13.49 | 377.07 | 0.9677 |
Propene (C_{3}H_{6}) | 41.91 | 8.99 | 377.07 | 1.4516 |
Butene (C_{4}H_{8}) | 55.88 | 6.74 | 377.07 | 1.9355 |
Ethine (C_{2}H_{2}) | 25.94 | 14.53 | 377.07 | 0.8985 |
Propine (C_{3}H_{4}) | 39.91 | 9.44 | 377.07 | 1.3824 |
Butine (C_{4}H_{6}) | 53.88 | 6.98 | 377.07 | 1.8662 |
Quintone (C_{5}H_{6}) | 65.85 | 5.72 | 377.07 | 2.2809 |
Benzene (C_{6}H_{6}) | 77.82 | 4.84 | 377.07 | 2.6955 |
Styrolene (C_{8}H_{8}) | 103.75 | 3.63 | 377.07 | 3.5936 |
Naphtalene (C_{10}H_{8}) | 127.70 | 2.95 | 377.07 | 4.4232 |
Turpentine (C_{10}H_{16}) | 135.70 | 2.77 | 377.07 | 4.7003 |
Dry air | 28.87 | 13.06 | -- | 1.0000 |
* * * * *
EMERALD-GREEN: ITS PROPERTIES AND MANUFACTURE.[1]
[Footnote 1: This substance is also known by the name Schweinfurt green.]
By ROBERT GALLOWAY, M.R.I.A.
The poisonous effects of wall-paper stained with emerald-green
(aceto-arsenite of copper) appears to be a very favorite topic in many
journals; it is continually reappearing in one form or another in
different publications, especially medical ones; there has recently
appeared a short reference to it under the title, "The Poisonous Effect of
Wall-paper." As some years ago I became practically acquainted with its
properties and manufacture, a few observations on these subjects may not
be without interest.
In the paragraph referred to, it is stated that the poisonous effect of
this pigment cannot be _entirely_ due to its mere mechanical detachment
from the paper. This writer therefore attributes the poisonous effects to
the formation of the hydrogen compound of arsenic, viz., arseniureted
hydrogen (AsH_{3}); the hydrogen, for the formation of this compound,
being generated, the writer thinks probable, "by the joint action of
moisture and organic matters, viz., of substances used in fixing to walls
papers impregnated with arsenic." In some of our chemical manuals, Dr.
Kolbe's "Inorganic Chemistry," for example, it is also stated that
arseniureted hydrogen is formed by the _fermentation_ of the starch-paste
employed for fastening the paper to the walls. It is perfectly obvious
that the fermentation of the starch-paste must cease after a time, and
therefore the poisonous effects of the paper must likewise cease if its
injurious effects are caused by the fermentation. I do not think that
arseniureted hydrogen could be formed under the _conditions_, for the
oxygen compound of arsenic is in a state of combination, and the compound
is in a dry solid state and not in solution and the affinities of the two
elements--arsenic and hydrogen--for each other are so exceedingly weak
that they cannot be made to unite directly except they are both set free
at the same moment in presence of each other. Further, for the formation
of this hydrogen compound by the fermentation of the starch, or by the
growth of minute fungi, the _entire_ compound must be broken up, and
therefore the pigment would become discolored; but aceto-arsenite of
copper
(3CuAs_{2}O_{4}+Cu(C_{2}H_{3}O_{2})_{2})
is a very stable compound, not readily undergoing decomposition, and is
consequently a very permanent color. It has also been not unfrequently
stated that the injurious effects of this pigment are due to the arsenious
oxide volatilizing from the other constituents of the compound. This
volatilization would likewise cause a breaking up of the entire compound,
and would consequently cause a discoloration of the paper; but the
volatilization of this arsenic compound is in every respect most
improbable.
The injurious effects, if any, of this pigment must therefore be due to
its mechanical detachment from the paper; but has it ever been
conclusively proved that persons who inhabit rooms the wall-paper of which
is stained with emerald-green suffer from arsenical poisoning? If it does
occur, then the effects of what may be termed homoeopathic doses of this
substance are totally different from the effects which arise from larger
doses. During the packing of this substance in its dry state in the
factory, clouds of its dust ascend in the air, and during the time I had
to do with its manufacture I never heard that any of the factory hands
suffered, nor did I suffer, from arsenical poisoning. If there is any
abrasion of the skin the dust produces a sore, and also the delicate
lining of the nostrils is apt to be affected. It is in this way it acts in
large doses; I am therefore very skeptical as to its supposed poisonous
effects when wall-paper is stained with it.
Different methods are given in works on chemistry for the manufacture of
this pigment, but as they do not agree in every respect with the method
which was followed in English color factories some years ago, it will be
as well, for the full elucidation of the manufacture of this substance, to
briefly recite some of these methods before describing the one that was,
and probably is still, in use; and I will afterward describe a method
which I invented, and which is practically superior to any other, both in
the rapidity with which the color can be formed, and for producing it at a
less cost.
It is stated in Watts' "Dictionary of Chemistry" that it is "prepared on a
large scale by mixing arsenious acid with cupric acetate and water. Five
parts of verdigris are made up to a thin paste, and added to a boiling
solution of 4 parts or rather more of arsenious acid in 50 parts of water.
The boiling must be well kept up, otherwise the precipitate assumes a
yellow-green color, from the formation of copper arsenite; in that case
acetic acid must be added, and the boiling continued a few minutes longer.
The precipitate then becomes crystalline, and acquires the fine green
color peculiar to the aceto-arsenite." I do not know from personal
knowledge, but I have always understood that the copper salt employed in
its manufacture in France is the acetate. This would account, in my
opinion, for the larger crystalline flakes in which it is obtained in
France than can be produced by the English method of manufacturing it.
Cupric acetate is never employed, I believe, in England--the much cheaper
copper salt, the sulphate, being always employed.
In "Miller's Chemistry" it is stated it "may be obtained by _boiling_
solutions of arsenious anhydride and cupric acetate, and adding to the
mixture an equal bulk of _cold_ water." Why it should be recommended to
add _cold water_, I am at a loss to understand.
In Drs. Roscoe and Schorlemmer's large work on "Chemistry," and in the
English edition of "Wagner's Handbook of Chemical Technology," edited by
Mr. Crookes, the process as described by Dr. Ehrmann in the "Ann. Pharm.,"
xii., 92, is given. It is thus stated in Wagner's work: "This pigment is
prepared by first separately dissolving equal parts by weight of arsenious
acid and neutral acetate of copper in boiling water, and next mixing these
solutions while boiling. There is immediately formed a flocculent
olive-green colored precipitate of arsenite of copper, while the
supernatant liquid contains free acetic acid. After a while the
precipitate becomes gradually crystalline, at the same time forming a
beautiful green pigment, which is separated from the liquid by filtration,
and after washing and carefully drying is ready for use. The mode of
preparing this pigment on a large scale was originally devised by M.
Braconnot, as follows: 15 kilos. of sulphate of copper are dissolved in
the smallest quantity of boiling water, and mixed with a boiling and
concentrated solution of arsenite of soda or potassa, so prepared as to
contain 20 kilos. of arsenious acid. There is immediately formed a dirty
greenish-colored precipitate which is converted into Schweinfurt green by
the addition of some 15 liters of concentrated wood-vinegar. This having
been done, the precipitate is immediately filtered off and washed."
As I have already stated, the copper salt used in the manufacture of this
pigment in England is the sulphate, and it is carried out pretty much
according to Braconnot's method as described by Dr Ehrmann; but any one
would infer, from reading his description of the manufacturing process,
that the compound, aceto-arsenite of copper, was formed almost immediately
after the addition of the acetic acid, a higher or lower atmospheric
temperature having no effect in hastening or retarding the formation.
Furthermore, it is not stated whether the compound forms more readily in
an acid or neutral solution, or whether it can or cannot be formed in a
neutral one; now both these points are important to notice in describing
its manufacture. As regards the former I shall notice it presently, and,
as far as my knowledge extends, the pigment will not form when the
solution is neutral.
The operation is conducted in the following manner in the factory: The
requisite quantity of sulphate of copper is placed in a large wooden vat,
and hot water added to dissolve it; the requisite quantity of arsenic
(arsenious anhydride) and carbonate of soda, the latter not in quantity
quite sufficient to neutralize the whole of the sulphuric acid set free
from the sulphate of copper on the precipitation of the copper as
arsenite, are placed in another wooden vessel; water is then added, and
the formation of the arsenite of soda and its solution are aided by the
introduction of steam into the liquid. When complete solution has been
effected the arsenic solution is run off into the vat containing the
solution of the sulphate of copper, arsenite of copper being at once
precipitated. The necessary quantity of acetic acid is afterward added. In
_warm_ weather the formation of the aceto-arsenite soon commences after
the addition of the vinegar; but, even in that case, it takes a week or
more to have the whole of a big batch of arsenite converted into the
aceto-arsenite; and perfect conversion is necessary, as the presence of a
very minute quantity of unchanged arsenite lowers very much the price of
the emerald pigment, and a by no means large quantity renders the pigment
unsalable, owing to its dirty yellowish-green color. In cold weather a
much longer time is required for its complete conversion; even at the end
of a fortnight or three weeks there frequently remains sufficient
unconverted arsenite to affect seriously the selling price of the color;
when this occurs the manufacturer generally removes these last traces by a
most wasteful method viz, by adding a quantity of free sulphuric acid. The
acid of course dissolves the arsenite, but it dissolves in very much
larger quantities the aceto-arsenite; and this costly solution is not
utilized, but is run into the factory sewer.
By my method of manufacturing it, it can be produced in winter as well as
in summer in one or two hours, and the quantity of free acid required for
its formation is reduced to the lowest amount. I proceed as follows: After
having dissolved in hot water the requisite quantity of cupric sulphate, I
decompose one-fourth of this salt by adding just sufficient of a solution
of carbonate of soda to precipitate the copper, in that quantity of the
sulphate, as carbonate. I then add just sufficient acetic acid to convert
the carbonate into acetate. I have now got in solution--
3CuSO_{4} + Cu(C_{2}H_{3}O_{2})_{2},
and I have to transform it into--
3CuAs_{2}O_{4} + Cu(C_{2}H_{3}O_{2})_{2}.
It is at once seen that I have got the requisite quantity of acetate
formed. I next dissolve the requisite quantity of arsenious anhydride in
an amount of carbonate of soda _rather less_ than is sufficient to
neutralize the acid in the remaining cupric sulphate, and I then bring the
solution to or near the boiling-point by introducing steam into it; the
arsenic is dissolved not in the same vessel as the copper salt, but in a
separate one. When the arsenic solution is fully heated, a small current
of it is allowed to flow into the vat containing the copper salts, and
brisk stirring is kept up in the vat. The emerald green is at once formed;
but if there should be the slightest formation of any arsenite, the flow
of the arsenic solution is at once stopped until every trace of the
arsenite has been converted; the arsenic solution is then allowed to flow
in again, with the same precautions as before; in this way a large batch
of emerald-green can he formed in one or two hours, without containing the
slightest trace of the arsenite. I keep the arsenic solution near the
boiling-point during the whole of the time it is flowing into the other
vessel. By varying the proportions of water I could either make it coarse
or fine, as I wished, which is an important matter to have complete
control over in its manufacture.
Two points of interest occurred to me during the time I was occupied with
the research, which I had not time to complete; one was whether the
aceto-arsenite can be formed, adopting the old method for its formation,
if there is more than a certain quantity of water; from some experiments I
made in this direction I was inclined to the opinion it could not. I have
already stated that emerald-green is soluble to a certain extent in acids,
and that it is formed in a more or less acid solution; consequently a
varying amount of the pigment is always lost by being dissolved in the
supernatant liquid. To prevent to a certain extent this loss I
precipitated the copper from it as arsenite; but I was not successful in
the few experiments I had time to make on this part of the subject of
reconverting the copper arsenite thus obtained into the aceto-arsenite by
the addition of acetic acid.--_Jour. of Science._
* * * * *
ANALYSIS OF ZINC ASH AND CALCINED PYRITES BY MEANS OF AMMONIUM CARBONATE.
In a recent issue of the _Chemiker Zeitung_ Dr. Kosmann has reported an
analytical method for the examination of zinciferous products; according
to this report, the ash and flue dust produced by the extraction of zinc
from its ore comprise:
1. Zinc dust, from the distillation of zinc,
2. Flue dust, condensed in chambers of zinc furnaces with Kleemann's
receivers,
3. Zinc ash, of various assortments, from iron blast furnaces.
Of these, zinc dust is the only ready product which is, as color or
reducing agent, employed in analytical and technical processes. Its value,
when serving the latter purpose, is determined by the percentage of finely
divided metallic zinc and cadmium contained therein; of equal reducing
power is cadmium, generally associating zinc; injurious, and therefore
uneffective, are zinc oxide and oxides of other metals, also metallic
lead.
Flue dust, condensed in chambers of zinc furnaces with Kleemann's
receivers, is employed with zinc ores in the extraction of zinc, and in
small quantities as substitute for zinc white; its commercial value is
similarly estimated as that of zinc ores.
The various modifications of zinciferous flue ashes from blast furnaces
are an object for continual demand, being both a valuable material for the
production of zinc and, in its superior qualities, a desirable pigment. In
the regeneration of zinc the presence of foreign substances is of some
concern; detrimental are lead, sulphur, and sulphuric acid in form of
lead, zinc, and lime sulphate.
The chemico-technical analysis of these products has until recently been
confined to the volumetric determination of zinc by means of sodium
sulphide (Schaffner's method). But as a remnant of sulphur, as sulphuric
acid, in roasted blende causes a material loss during distillation, and
otherwise being induced to produce a zinc free of lead, the estimation of
sulphur, sulphuric acid, and lead became necessary. These impurities are
determined by well-known methods; sulphur is oxidized and precipitated
with barium chloride, lead by sulphuric acid and alcohol. The examination
of zinc dust, when used for the regeneration of metal, determines the
quantity of zinc resident therein, and employed as reducing agent, the
quantity of metal which causes the generation of hydrogen. Cadmium,
showing the same deportment, must also be considered as well as lead and
arsenic.
A most complete and rapidly working method for the examination of
zinciferous products has originated with the application of neutral
ammonium carbonate as solvent. A solution of this preparation is made,
according to H. Rose, by dissolving 230 grm. commercial ammon carbonate in
180 c.c. ammoniacal liquor of 0.92 s.g., and, by addition of water,
augmenting it to one liter.
This solution dissolves the metallic components, their oxides, and basic
zinc sulphate, and transfers cadmium and lead oxide, also lead, magnesium,
and lime sulphate, into insoluble carbonates. Iron and manganese, when
present as protoxide, are dissolved; of iron sesquioxide but traces, and
of cadmium oxide _in statu nascendi_ a small portion enter into solution.
The solution of ammonium carbonate contains in each 10 c.c. 1 grm.
ammonia, which dissolves 1.5 grm. zinc.
The sample for examination is moistened with water and mixed with an
adequate volume of the solvent, is digested at 50-60° C. until complete
decomposition is effected. The heating of the liquid prevents the solution
of iron, manganese, and cadmium. The content, sediment and liquid, is
thrown on a filter and washed with hot water to which a small quantity of
the solvent has been added. When the solution contains iron and manganese,
it is separated by decantation from the sediment and oxidized with bromine
(according to the method of Nic-Wolff) until a flocculent precipitate of
iron sesquioxide and manganese dioxide becomes visible; it is united with
the original residue and filtered.
The filtrate is diluted till it appears cloudy, boiled to expel ammonia,
tested with sodium sulphide upon the presence of zinc, and, when freed of
all zinc, decanted. The precipitate of zinc carbonate is filtered,
exhausted with water, transferred into zinc oxide by ignition, and
weighed. The gravimetric method can be substituted by the volumetric by
introducing a solution of sodium sulphide of known strength into the
ammoniacal filtrate. On dividing the filtered liquid into various equal
portions other substances, arsenic and sulphuric acid, can be determined
from the same sample. For this purpose the filtrate is concentrated;
divided into two equal portions, one of which is acidified and treated
with hydrogen sulphide for the determination of arsenic, the other is
acidified and used for the estimation of sulphuric acid by means of barium
chloride. The original residue is dissolved in muriatic or acetic acid and
filtered. The lead of the filtered liquid is thrown down by sulphuric
acid, and alcohol, and cadmium, after dissipation of alcohol into gas,
precipitated by hydrogen sulphide. Iron, manganese, alumina, and other
substances present in the solution are determined by known methods.
It is manifest that the determination of substances--zinc, lead, and
sulphuric acid--which are of importance in technical analysis of zinc ash,
can be executed by this method within a comparatively short time. The
application of ammonium carbonate as solvent has the advantage, over the
application of ammonia, that it is a far better solvent, that it
decomposes insoluble basic sulphates, and that the remaining carbonates
are readily dissolved by acids.
The decomposition of zinc dust is accompanied by a lively evolution of
gas; it is therefore necessary to continue the digestion of the sample
till no more hydrogen is given off. Zinc dust contains both metals and
their oxides, and methods which, from the volume of hydrogen generated,
determine indirectly the percentage of metallic zinc do not give the real
composition of the zinc dust. For the determination of the metallic
components the material is digested with a solution of copper sulphate,
which dissolves zinc and cadmium; the liquid is filtered, acidified, and
decomposed with hydrogen sulphide, or treated with a solution of ammonium
carbonate. The use of cupric chloride is not advisable, as it corrodes
lead, and gives rise to the formation of soluble chloride of lead, which
complicates the separation of zinc from cadmium. The best mode of
operation is the following: Both copper sulphate and zinc dust are weighed
separately, the former is dissolved in water and the latter introduced
into the solution of copper sulphate in small portions until it appears
colorless. During the operation the vessel is freely shaken, lumps are
comminuted with a glass rod, and a few drops of the liquid are ultimately
tested with hydrogen sulphide or ammonia. The remainder of zinc dust is
then weighed, and its value deducted from the original weight. Zinc and
cadmium of the filtrate are determined as above. On repeating this method
several times most satisfactory results are obtained.
Another mode of operating is to employ an excess of copper sulphate and to
determine the copper dissolved in the filtrate. The separation of copper
from cadmium being difficult and laborious, and the volumetric estimation
with potassium cyanide not practicable, it is not prudent to apply this
method.
When calcined zinciferous pyrites have to be examined, the estimation of
zinc is similar to that employed in the analysis of zinc ore. The sample
is exhausted with water, filtered, and, to eliminate calcium sulphate and
basic iron sulphate, evaporated to dryness. It is then dissolved in a
small quantity of alcohol and water, refiltered, and the filtrate
decomposed with ammonium carbonate. The original residue is treated with a
solution of ammonium carbonate, which dissolves arsenious acid and basic
zinc sulphate, filtered, and united with the first filtrate. When iron and
manganese are present, the filtrates are treated with bromine. The united
filtrates are boiled or examined volumetrically with sodium sulphide.
* * * * *
PETROLEUM AS FUEL IN LOCOMOTIVE ENGINES.[2]
[Footnote 2: Abstract of paper read before the Institution of Mechanical
Engineers.]
By Mr. THOMAS URQUHART.
Comparing naphtha refuse and anthracite, the former has a theoretical
evaporative power of 16.2 lb. of water per lb. of fuel, and the latter of
12.2 lb., at a pressure of 8 atm. or 120 lb. per square inch; hence
petroleum has, weight for weight, 33 per cent. higher evaporative value
than anthracite. Now in locomotive practice a mean evaporation of from 7
lb. to 7½ lb. of water per lb. of anthracite is about what is generally
obtained, thus giving about 60 per cent. efficiency, while 40 per cent. of
the heating power is unavoidably lost. But with petroleum an evaporation
of 12.25 lb. is practically obtained, giving 12.25/16.2 = 75 per cent.
efficiency. Thus in the first place petroleum is theoretically 33 per
cent. superior to anthracite in evaporative power; and secondly, its
useful effect is 25 per cent. greater, being 75 percent. instead of 60
percent.; while, thirdly, weight for weight, the practical evaporative
value of petroleum must be reckoned as at least from (12.25 - 7.50)/7.50 =
63 per cent. to (12.25 - 7.00)/7.00 = 75 per cent. higher than that of
anthracite.
_Spray injector._--Steam not superheated, being the most convenient for
injecting the spray of liquid fuel into the furnace, it remains to be
proved how far superheated steam or compressed air is really superior to
ordinary saturated steam, taken from the highest point inside the boiler
by a special internal pipe. In using several systems of spray injectors
for locomotives, the author invariably noticed the impossibility of
preventing leakage of tubes, accumulation of soot, and inequality of
heating of the fire box. The work of a locomotive boiler is very different
from that of a marine or stationary boiler, owing to the frequent changes
of gradient on the line, and the frequent stoppages at stations. These
conditions render firing with petroleum very difficult; and were it not
for the part played by properly arranged brickwork inside the fire box,
the spray jet alone would be quite inadequate. Hitherto the efforts of
engineers have been mainly directed toward arriving at the best kind of
"spray injector," for so minutely subdividing a jet of petroleum into a
fine spray, by the aid of steam or compressed air, as to render it
inflammable and of easy ignition. For this object nearly all the known
spray injectors have very long and narrow orifices for petroleum as well
as for steam; the width of the orifices does not exceed from ½ mm. to 2
mm. or 0.02 in. to 0.08 in., and in many instances is capable of
adjustment. With such narrow orifices it is clear that any small solid
particles which may find their way into the spray injector along with the
petroleum will foul the nozzle and check the fire. Hence in many of the
steamboats on the Caspian Sea, although a single spray injector suffices
for one furnace, two are used, in order that when one gets fouled the
other may still work; but, of course, the fouled orifices require
incessant cleaning out.
_Locomotives._--In arranging a locomotive for burning petroleum, several
details are required to be added in order to render the application
convenient. In the first place, for getting up steam to begin with, a gas
pipe of 1 inch internal diameter is fixed along the outside of the boiler,
and at about the middle of its length it is fitted with a three-way cock
having a screw nipple and cap. The front end of the longitudinal pipe is
connected to the blower in the chimney, and the back end is attached to
the spray injector. Then by connecting to the nipple a pipe from a
shunting locomotive under steam, the spray jet is immediately started by
the borrowed steam, by which at the same time a draught is also maintained
in the chimney. In a fully equipped engine shed the borrowed steam would
be obtained from a fixed boiler conveniently placed and specially arranged
for the purpose of raising steam. In practice steam can be raised from
cold water to 3 atm. pressure--45 lb. per square inch--in twenty minutes.
The use of auxiliary steam is then dispensed with, and the spray jet is
worked by steam from its own boiler; a pressure of 8 atm.--120 lb.--is
thus obtained in fifty to fifty-five minutes from the time the spray jet
was first started. In daily practice, when it is only necessary to raise
steam in boilers already full of hot water, the full pressure of 7 to 8
atm. is obtained in from twenty to twenty-five minutes. While
experimenting with liquid fuel for locomotives, a separate tank was placed
on the tender for carrying the petroleum, having a capacity of about 3
tons. But to have a separate tank on the tender, even though fixed in
place, would be a source of danger from the possibility of its moving
forward in case of collision. It was therefore decided, as soon as
petroleum firing was permanently introduced, to place the tank for fuel in
the tender between the two side compartments of the water tank, utilizing
the original coal space. For a six-wheeled locomotive the capacity of the
tank is 3-1/2 tons of oil--a quantity sufficient for 250 miles, with a
train of 480 tons gross exclusive of engine and tender. In charging the
tender tank with petroleum, it is of great importance to have strainers of
wire cloth in the manhole of two different meshes, the outer one having
openings, say, of 1/4 in., the inner, say 1/8 in.; these strainers are
occasionally taken out and cleaned. If care be taken to prevent any solid
particles from entering with the petroleum, no fouling of the spray
injector is likely to occur; and even if an obstruction should arise, the
obstacle being of small size can easily be blown through by screwing back
the steam cone in the spray injector far enough to let the solid particles
pass and be blown out into the fire-box by the steam. This expedient is
easily resorted to even when running; and no more inconvenience arises
than an extra puff of dense smoke for a moment, in consequence of the
sudden admission of too much fuel. Besides the two strainers in the
manhole of the petroleum tank on the tender, there should be another
strainer at the outlet valve inside the tank, having a mesh of 1/3 in.
holes.
_Driving locomotives._--In lighting up, certain precise rules have to be
followed, in order to prevent explosion of any gas that may have
accumulated in the fire box. Such explosions do often take place through
negligence; but they amount simply to a puff of gas, driving smoke out
through the ash-pan dampers, without any disagreeably loud report. This is
all prevented by adhering to the following simple rules: First clear the
spray nozzle of water by letting a small quantity of steam blow through,
with the ash-pan doors open; at the same time start the blower in the
chimney for a few seconds, and the gas, if any, will be immediately drawn
up the chimney. Next place on the bottom of the combustion chamber a piece
of cotton waste, or a handful of shavings saturated with petroleum and
burning with a flame. Then by opening first the steam valve of the spray
injector, and next the petroleum valve gently, the very first spray of oil
coming on the flaming waste immediately ignites without any explosion
whatever; after which the quantity of fuel can be increased at pleasure.
By looking at the top of the chimney, the supply of petroleum can be
regulated by observing the smoke. The general rule is to allow a
transparent light smoke to escape, thus showing that neither too much air
is being admitted nor too little. The combustion is quite under the
control of the driver, and the regulation can be so effected as to prevent
smoke altogether. While running, it is indispensable that the driver and
fireman should act together, the latter having at his side of the engine
the four handles for regulating the fire, namely, the steam wheel and the
petroleum wheel for the spray injector, and the two ash-pan door handles
in which there are notches for regulating the air admission. Each
alteration in the position of the reversing lever or screw, as well as in
the degree of opening of the steam regulator or the blast pipe, requires a
corresponding alteration of the fire. Generally the driver generally
passes the word when he intends shutting off steam, so that the alteration
in the firing can be effected before the steam is actually shut off; and
in this way the regulation of the fire and that of the steam are virtually
done together. All this care is necessary to prevent smoke, which is
nothing less than a waste of fuel. When, for instance, the train arrives
at the top of a bank, which it has to go down with the brakes on, exactly
at the moment of the driver shutting off the steam and shifting the
reversing lever into full forward gear, the petroleum and steam are shut
off from the spray injector, the ash-pan doors are closed, and if the
incline be a long one, the revolving iron damper over the chimney top is
moved into position, closing the chimney, though not hermetically. The
accumulated heat is thereby retained in the fire-box; and the steam even
rises in pressure, from the action of the accumulated heat alone. As soon
as the train reaches the bottom of the incline and steam is again
required, the first thing done is to uncover the chimney top; then the
steam is turned on to the spray injector, and next a small quantity of
petroleum is admitted, but without opening the ash-pan doors, a small fire
being rendered possible by the entrance of air around the spray injector,
as well as by possible leakage past the ash-pan doors. The spray
immediately coming in contact with the hot chamber ignites without any
audible explosion; and the ash-pan doors are finally opened, when
considerable power is required, or when the air otherwise admitted is not
sufficient to support complete combustion. By looking at the fire through
the sight hole it can always be seen at night whether the fire is white or
dusky; in fact, with altogether inexperienced men it was found that after
a few trips they could become quite expert in firing with petroleum. The
better men contrive to burn less fuel than others, simply by greater care
in attending to all the points essential to success. At present
seventy-two locomotives are running with petroleum firing; ten of them are
passenger engines, seventeen are eight-wheel coupled goods engines, and
forty-five are six-wheel coupled. As might be expected, several points
have arisen which must be dealt with in order to insure success. For
instance, the distance ring between the plates around the firing door is
apt to leak, in consequence of the intense heat driven against it, and the
absence of water circulation; it is therefore either protected by having
the brick arch built up against it, or, better still, it is taken out
altogether when the engines are in for repairs, and a flange joint is
substituted, similar to what is now used in the engines of the London and
Northwestern Railway. This arrangement gives better results, and occasions
no trouble whatever.
_Storage of petroleum._--The length of line now worked with petroleum is
from Tsaritsin to Burnack, 291 miles. There is a main iron reservoir for
petroleum at each of the four engine sheds, namely at Tsaritsin, Archeda,
Filonoff, and Borisoglebsk. Each reservoir is 66 ft. internal diameter and
24 ft. high, and when full holds about 2,050 tons. The method of charging
the reservoir, which stands a good way from the line, and is situated at a
convenient distance from all dwelling houses and buildings, is as follows:
On a siding specially prepared for the purpose are placed ten cistern cars
full of oil, the capacity of each being about ten tons. From each of these
cars a connection is made by a flexible India rubber pipe to one of ten
stand pipes which project 1 ft. above the ground line. Parallel with the
rails is laid a main pipe, with which the ten stand pipes are all
connected, thus forming one general suction main. About the middle of the
length of the main, which is laid underground and covered with sawdust or
other non-conducting material, is fixed a Blake steam pump. As soon as all
the ten connections are made with the cistern cars, the pump is set to
work, and in about one hour the whole of the cars are discharged into the
main reservoir, the time depending of course upon the capacity of the
pump. All the pipes used are of malleable iron, lap-welded, and of 5 in.
internal diameter, having screwed coupling muffs for making the
connections. At each engine shed, in addition to the main storage
reservoir, there is a smaller distributing tank, which is erected at a
sufficient height to supply the tenders, and very much resembles the
ordinary water tanks. These distributing tanks are circular, about 8½ ft.
diameter and 6 ft. high, and of ¼ in. plates; their inside mean area is
calculated exactly, and a scale graduated in inches stands in the middle
of the tank; a glass with scale is used outside in summer time. Each inch
in height on the scale is converted into cubic feet, and then by means of
a table is converted into Russian poods, according to the specific gravity
at various temperatures. As it would be superfluous to graduate the table
for each separate degree of temperature, the columns in the table show the
weights for every 8 degrees Reaumur, which is quite sufficient: namely,
from 24 deg. to 17 deg., from 16 deg. to 9 deg., and so on, down to -24
deg.; the equivalent Fahrenheit range being from 86 deg. down to -22 deg.
Suppose the filling of a tender tank draws off a height of 27 in. from the
distributing tank, at a temperature of say -20 deg. R., these figures are
shown by the table to correspond with 200.61 poods = 7,245 lb., or 3.23
tons, of petroleum. This arrangement does very well in practice; both the
quantity and the temperature are entered on the driver's fuel bill at the
time of his taking in his supply.
_Engines._--The engines used in the trials were built by Borsig, of
Berlin, Schneider, of Creusot, and the Russian Mechanical and Mining
Company, of St. Petersburg. Their main dimensions and weights were about
the same, as follows, all of them having six wheels coupled, and 36 tons
adhesive weight; as originally constructed they had ordinary fire boxes
for burning anthracite or wood; cylinders 18-1/8 in. diameter and 24 in.
stroke; slide valves, outside lap 1-1/16 in., inside lap 3/32 in., maximum
travel, 4-9/16 in.; Stephenson link motion; boiler pressure, 120 lb. per
square inch; six wheels, all coupled, 4 ft. 3 in. in diameter; distance
between centers of leading and middle wheels, 6 ft. 2-3/4 in.; between
middle and trailing, 4 ft. 9-1/4 in.; total length of wheel base, 11 ft.;
weight empty, on leading wheels, 12.041 tons; middle, 10.782 tons;
trailing, 10.685 tons; total weight, 33.508 tons empty; weight in running
order, on leading wheels, 12.563 tons; middle, 11.885 tons; trailing
12.790 tons; total weight, 37.238 tons in running order. Tubes number 151;
outside diameter, 2-1/8 in.; length between tube plates, 13 ft. 10-1/8
in.; outside heating surface, 1,166 square feet; fire box heating surface,
82 square feet; total heating surface, 1,248 square feet; fire grate area,
17 square feet; tractive power =
65 per cent. of boiler pressure × (cyl. diam.)² × stroke / diameter of wheels
= 0.65 × 120 × (18.125)² × 24 / 51 = 5.383 tons. Ratio of tractive power
to adhesion weight = 5.383 / 37.238 = 1 / 6.9.
_Tender._--Contents: water, 310 cubic feet, or 1,933 gallons, or 8½
tons; anthracite, 600 poods, or 10 tons; or wood, 1½ cubic sajene, or
514 cubic feet; weight empty, 13.477 tons; weight in running order, 28.665
tons; six wheels.
* * * * *
_Petroleum Refuse--Comparative Trials with Petroleum, Anthracite,
Bituminous Coal, and Wood, between Archeda and Tsaritsin on Grazi and
Tsaritsin Railway, in Winter Time._
-----+---+-----+------+---+-----+------+-----------+-------------+------+------------
| L | | | | | | | |
| o | | Train | | | | Consumption | |
| c | | alone. | | | | Including | |
Date.| o | | | | | | Lighting up.| |
1883.| m | |----+-----| | | | | Cost |
| o |Train|Num-| | Dis-| Car | | | of |Atmospheric
| t | |ber |Gross|tance|miles.| Fuel. |-------+-----| fuel |temperature
| i | | of |load.| run.| | | | Per | per | and
| v | |Loa-| | | | | Total |train| train| weather.
| e | |ded | | | | | |mile.| mile.|
| . | |cars| | | | | | | |
-----+---+-----+----+-----+-----+------+-----------+-------+-----+------+------------
| | | No.| Tons|Miles| | | | |Pence.|
-----+---+-----+----+-----+-----+------+-----------+-------+-----+------+------------
| 8|32-23| 25 | 400 | 388 | 9,700|Anthracite.| 31799 |81.90|11.957|-17° to -18°
| |32-23| | | | | | lb. | lb. | | Reau.,
Feb.| | | | | | | | | | | equiv. to
8 | |24-21| | | | | | | | |-6° to -8½°
| 14|24-21| 25 | 400 | 388 | 9,700|Bituminous |37557.5|96.53|14.093| Fah.
| | | | | | | Coal. | lb. | lb. | |
| 7|26-29| 25 | 400 | 194 | 4,830|Petroleum | 9462 |48.77| 5.487| Strong
| | | | | | refuse. | lb. | lb. | | side wind.
-----+---+-----+----+-----+-----+------+-----------+-------+-----+------+------------
| 24|32-23| 25 | 400 | 194 | 4,850|Anthracite.|12639.5|65.15| 9.512|-5° to -9°
March| | | | | | | | lb. | lb. | | Reau.,
6 | 21|24-21| 25 | 400 | 194 | 4,850|Wood, in | 1071.8| 5.52| 8.5 | equiv. to
| | | | | | | billets. | c. ft.|c. ft| | 21° to 12°
| | | | | | | | | Fah.
| 23|26-27| 25 | 400 | 194 | 4,850|Petroleum | 7228 |37.28| 4.188| Light
| | | | | | refuse. | lb. | lb. | | side wind.
-----+---+-----+----+-----+-----+------+-----------+-------+-----+------+------------
Prices of fuel:
Petroleum refuse, 21s. per ton; Anthracite and bituminous coal, 27s. 3d. per ton;
Wood, in billets, 42s. per cubic sajene = 343 cubic feet;
equivalent to 1.47d. per cubic foot.
Dimensions of locomotives:
Cylinders, 18 1/8 in. diam. and 24 in. stroke; Wheels, 4 feet 3 in. diam.;
Total heating surface, 1,248 sq. feet: Total adhesion weight, 36 tons;
Boiler pressure, 8 to 9 atm.
The preceding table shows the results of comparative trials made in winter
with different sorts of fuel, under exactly similar conditions as to type
of engine, profile of line, and load of train. Two sets of comparative
trials were made, both of them in winter. The three engines used were some
of those built by Schneider. In comparison with anthracite, the economy in
favor of petroleum refuse was 41 per cent. in weight, and 55 per cent. in
cost. With bituminous coal there was a difference of 49 per cent. in favor
of petroleum as to weight and 61 per cent. as to cost. As compared with
wood petroleum was 50 per cent. cheaper. At a speed of fourteen miles an
hour up an incline of 1 in 125 the steam pressure was easily kept up at 9
to 9½ atm. with a No. 9 injector feeding the boiler all the time.
Up to the present time the author has altered seventy-two locomotives to
burn petroleum; and from his own personal observations made on the foot
plate with considerable frost he is satisfied that no other fuel can
compare with petroleum either for locomotives or for other purposes. In
illustration of its safety in case of accident, a photograph was exhibited
of an accident that occurred on the author's line on 30th December, 1883,
when a locomotive fired with petroleum ran down the side of an embankment,
taking the train after it; no explosion or conflagration of any kind took
place under such trying circumstances, thus affording some proof of the
safety of the petroleum refuse in this mode of firing. Although it is
scarcely possible that petroleum firing will ever be of use for
locomotives on the ordinary railways of coal-bearing England, yet the
author is convinced chat, even in such a country, its employment would be
an enormous boon on underground lines.
* * * * *
CHARCOAL KILNS.
[Illustration: KILN FOR BURNING CHARCOAL.]
In answer to the inquiry of a correspondent about charcoal making, we
offer two illustrations that show a method of manufacture differing from
that usually adopted, which is that of burning on the bare ground, and
covering with soil or sods to exclude the air. These kilns are made of
brick, one course being sufficient, bands of iron or timber framework
being added to strengthen the brickwork with greater economy. The usual
style is conical, and the size is 24 feet in diameter, with an equal
height, holding about 40 cords of wood. The difference in price is 1-1/8
d. per bushel in favor of these kilns as compared with the usual mounds,
the burner being furnished with the use of the kilns, and the timber
standing, the kiln burning costing 2-1/8 d., and the other 3-1/4 d. The
kilns must be lined to about halfway up with fire-brick, the cost of which
will vary with the locality, but will be about £200, and as 40 to 50
bushels of coal have been made per cord the extra yield on good charcoal
and the lessening of the cost of making soon covers any extra outlay on
the cost of the kilns. The wall of the kiln is carried up nearly straight
for 6 feet, when it is drawn in, so as to become bluntly conical. Upon the
top a plate of iron is fastened in the manner of the keystone of an arch,
and bands of iron are passed round the kiln and drawn tight with screw
bolts and nuts to strengthen it. Double doors of sheet-iron are made at
the bottom and near the tops, by which it is either filled or emptied, and
a few air-holes (B), which may be stopped with loose bricks, left in the
bottom. The second figure shows a kiln of another shape made to burn 3,000
bushels of charcoal, or about 80 cords of wood. The shape is a
parallelogram, having an arched roof, and it is strengthened by a
framework of timber 10 inches square. As the pressure of the gas is
sometimes very great, the walls must be built a brick and a half thick to
prevent their bursting. The usual size is 16 feet wide and high, and 40
feet in length, outside measure. The time occupied in filling, burning,
and emptying a small cone is about three weeks, and four weeks is required
for the larger ones.--_The Gardeners' Chronicle._
[Illustration: KILN FOR BURNING CHARCOAL.]
* * * * *
ENTRANCE, TIDDINGTON HOUSE, OXON.
Our illustration is a view of the entrance facade to Tiddington House,
Oxfordshire, the residence of the Rev. Joshua Bennett. The house is an old
building of the Georgian period, and though originally plain and
unpretentious, its bold coved cornices under the eaves, its rubbed and
shaped arches, moulded strings, and thick sash bars, made it of
considerable interest to the admirers of the "Queen Anne" school of
architecture, and led to the adoption of that style in the alterations and
additions made last year, of which the work shown in our illustration
formed a small part. Between the "entrance facade" and the wall of the
house there is a space of some twenty feet in length, which is inclosed by
a substantially built conservatory-like erection of Queen Anne design,
forming an outer hall.
[Illustration: ENTRANCE TIDDINGTON HOUSE OXON.--Morris &
Stallwood--Architects.]
The works were executed by Messrs. Holly & Butler, of Nettlebed. The brick
carving was beautifully done by the late Mr. Finlay; and the architects
were Messrs. Morris & Stallwood, of Reading.--_The Architect._
* * * * *
NEW ARRANGEMENT OF THE BICHROMATE OF POTASH PILE.
Since Poggendorff in 1842 thought of substituting in the Bunsen battery a
solution of bichromate of potash and sulphuric acid for nitric acid, and
of thus making a single liquid pile of it, in suppressing the porous
vessel, his idea has been taken up a considerable number of times. Some
rediscovered it simply, while others, who were better posted in regard to
the work of their predecessors, took Poggendorff's pile as he conceived
it, and, considering the future that was in store for it, thought only of
modifying it in order to render it better. Among these, Mr. Grenet was one
of the first to present the bichromate of potash pile under a truly
practical form. As long ago as 1856, in fact, he gave it the form that is
still in use, and that is known as the bottle pile. Thus constructed, this
pile, as is well known, presents a feeble internal resistance, and a
greater electro-motive power than the Bunsen element. Unfortunately, its
energy rapidly decreases, and the alteration of the liquid, as well as the
large deposit of oxide of chromium that occurs on the positive electrode,
prevents its being employed in experiments of quite long duration. Mr.
Grenet, it is true, obviated these two defects by first renewing the
liquid slowly and continuously, and causing a current of air to bubble up
in the pile so as to detach the oxide of chromium in measure as the
deposit formed. Thus improved, the bichromate pile was employed on a large
scale in the lighting of the Comptoir d'Escompte. In an extensive
application like this latter, the use of compressed air for renewing the
liquid can be easily adapted to the bichromate pile, as the number of
elements is great enough to allow of the putting in of all the piping
necessary; but when it is only desired to use this pile for laboratory
purposes, and when there is need of but a small number of elements, it is
impossible to adopt Mr. Grenet's elements in the form required by an
electric lighting installation. It becomes absolutely necessary, then, to
come back to a simpler form, and attempt at the same time to obviate the
defects which are inherent to its very principle. In accordance with this
idea, it will be well to point out the arrangement adopted by Mr. Courtot
for his bichromate of potash piles--an arrangement that is very simple,
but, sufficiently well worked out to render the use of it convenient in a
laboratory.
[Illustration: Fig. 1.--COURTOT'S ARRANGEMENT OF THE BICHROMATE PILE.]
Fig. 1 gives the most elementary form. It consists of an earthen vessel
into which dip four carbon plates connected with each other by a copper
ring which carries one of the terminals. In the center there is a
cylindrical porous vessel that contains a very dilute and feebly
acidulated solution of bichromate of potash into which dips a prism of
zinc, which may be lifted by means of a rod when the pile ceases to
operate. It is true that the presence of the porous vessel in the
bichromate of potash element increases the internal resistance, but, as an
offset, although it decreases the discharge, it secures constancy and
quite a long duration for it.
[Illustration: Fig. 2.--COURTOT'S ARRANGEMENT OF THE BICHROMATE PILE.]
The elements thus constituted may be grouped, to the number of six, in a
frame analogous to that shown in the engraving, and, sum total, form a
small sized battery adapted to the current experiments of the laboratory,
and capable of supplying two small four volt lamps for ten or twelve
hours. We have had occasion to make use of these elements for the
graduation of galvanometers, and, after ascertaining the constancy of the
discharge, have found that the internal resistance of each couple is
nearly 0.175 ohm, with an electro-motive force of two volts. As may be
seen, these elements should, in general, all be mounted for tension, as
they are in the figure, inasmuch as the mobility of the zincs permits,
according to circumstances, of employing a variable number of them without
changing anything. Moreover, with zincs amalgamated in a special manner,
the attack is imperceptible, and the work in open circuit need scarcely to
be taken into consideration.
Yet, despite the qualities inherent to the arrangement that we have just
described, that defect common to all bichromate of potash piles--the
deposit of oxide of chromium upon the carbon--is not here avoided. It
occurs quite slowly, to be sure, but it does occur, and, from this point
of view, the arrangement shown in Fig. 2 is preferable. The elements here
are composed of prismatic porcelain vessels containing, as before, the
solution and porous vessel.
[Illustration: Fig. 3.--COURTOT'S ARRANGEMENT OF THE BICHROMATE PILE.]
The whole is covered with a sheet of ebonite connected with the zinc and
the two carbon plates in such a way that when the pile is not in operation
the whole can be lifted from the liquid. Under such circumstances the
deposit of oxide is notably diminished, and the duration of the discharge
is consequently greatly increased.
Fig. 3 shows the details of a windlass that permits of lifting, according
to circumstances, all the elements of the same trough or only a part of
them. To effect this, the drum around which the chain winds that carries
the carbons is mounted upon a sleeve fixed upon the axle. This latter is
actuated by a winch; and a ratchet wheel, R, joined to a click which is
actuated by a spiral spring, prevents the ebonite plates from falling back
when it is desired to place the bolt under the button, B, of the spring.
When it is desired to put an element out of the circuit, it is only
necessary to act with the finger upon the extremity of the lever, D. Under
the action of the latter, the piece, _s_, which carries a groove for the
passage of the screws that fix it to the upper cross-piece, takes on a
longitudinal motion and consequently gears with the drum through the
toothed sleeve, E. When an experiment is finished the zinc may thus be
lifted from the liquid, and the deposit of oxide be prevented from forming
upon the carbon. As may be seen, the arrangements which we have just
described exhibit nothing that is particularly original. The windlasses
used for removing the elements from a pile when the circuit is open have
been employed for a long time; the bichromate pile is itself old, and, as
we said in the beginning, it has been modified in its details a number of
times. In spite of this, we have thought it well to point out the mode of
construction adopted by Mr. Courtot, since, owing to the simplicity of the
arrangements, it renders convenient and easily manageable a pile of very
great constancy that may be utilized for supplying incandescent lamps, as
well as for the most varied experiments of the laboratory.--_La Lumiere
Electrique._
* * * * *
THE DISTRIBUTION OF ELECTRICITY BY INDUCTION.
There has been much said in recent times about the distribution of
electricity by means of induction coils, and the use of this process has
given rise to several systems that differ but little from one another in
principle.
The following are a few details in regard to a system due to a Dutch
engineer:
In the month of December, 1881, a patent relating to the distribution of
electricity was taken out in Germany and other countries by Mr. B.
Haitzema Enuma, whose system is based upon a series of successive
inductions. The primary current developed by a dynamo-electric machine
gives rise to secondary, tertiary, etc., currents. The principal line runs
through the streets parallel with their axes, and, when the arrangement of
the places is adapted thereto, it is closed upon the generator itself. In
those frequent cases where it is necessary to cause the line to return
over a path that it has already traversed, it is more advantageous to
effect the return through the earth or to utilize the street water mains
or gas pipes as conductors. This return arrangement may likewise be
applied to the lines of secondary, tertiary, etc., order, as may easily be
seen.
The induction is effected by the aid of bobbins whose interior consists of
a bundle of soft iron. The wire of the inducting current is wound directly
around this core. The wire of the induced current is superposed upon the
first and presents a large number of spirals. It is useless to say that
these wires must be perfectly insulated from each other, as well as from
the soft iron core. We shall call primary bobbins those which are
interposed in the principal line, and secondary bobbins those in which the
inducting current is a secondary one, and so on.
It will be at once seen that this arrangement permits of continuing the
distribution of electricity to the interior of buildings by the simple
adjunction of one or several bobbins. Each electric apparatus, whether it
be a lamp or other mechanism, is furnished with a special current. If the
number of these apparatus be increased, it is only necessary to increase
the number of bobbins in the same ratio, on condition, be it understood,
that the intensity of the currents remain sufficient to secure a proper
working of the apparatus in question. When such intensity diminishes to
too great a degree, the bobbin must be replaced by a stronger one.
[Illustration: DISTRIBUTION OF ELECTRICITY BY INDUCTION.]
It results from what precedes that each apparatus must be put in in such a
way as to permit, of the opening and closing of the corresponding circuit.
This arrangement, moreover, has no need of being dependent upon the
apparatus, and may just as well be transferred to any part of this same
circuit. As regards lighting, it is preferable to employ alternating
current dynamo machines; yet there is nothing to prevent the use of
continuous current ones, provided that there is an arrangement that
permits of constantly opening and closing this same circuit. That portion
of the line which is placed under ground is insulated in the ordinary way
at the places where it is necessary. As for the underground circuit and
the induction coils connected therewith, these are protected against all
external influence, and are at the same time insulated very economically
by covering them with a coat of very fine silicious sand mixed with
asphalt.
It is only necessary to inspect the annexed figure to get an accurate idea
of this system of distribution. C represents the building in which the
generator of electricity, D, is placed; B, the public street, and Q the
house of a subscriber. The principal line, E, starts from the terminals,
_a, b_, of the machine, passes through the primary bobbins, G, and is
closed through the earth at F. It will be seen that the primary current
communicates through _d_ and _c_ with the internal winding of the bobbins,
G, while the secondary currents, H, are connected through _e_ and _f_ with
the external winding. The same arrangement is repeated for the tertiary
currents, M, and the quaternary ones, _o, p_. In the annexed example all
the lines that run parallel with the axis of the streets are closed
through the earth, while those that have a direction perpendicular thereto
enter the houses of subscribers and form a closed circuit. In the interior
of these houses the wires, as well as the induction coils, are insulated
and applied to the walls. At Q is represented the arrangement that would
have to be adopted in the case of a structure consisting of a vestibule,
_r_, and two rooms, _s_, lighted by two electric lamps, R. In the portion
of the figure situated to the left it is easy to see the process employed
for insulating the line. A commencement is made by digging a ditch in the
street and paving the bottom of it with bricks. Upon these latter there is
laid a mixture of sand and asphalt, and then the wires and bobbins are put
in, and the whole is finally covered with a new insulating layer.
It is a simple statement that we make here, and it is therefore not for us
to discuss the advantages and disadvantages of the system. If we are to
believe Mr. Enuma, the advantages are very numerous, to wit: (1) The
cables have no need of being of large size; (2) the intensity is the same
through the entire extent of the primary circuit, secondary one, etc.; (3)
the resistance is invariable in all portions of the line; (4) the
apparatus are independent of each other, and consequently there may be a
disturbance in one or several of them without the others suffering
therefrom; (5) either a strong or weak luminous intensity may be produced,
since, that depends only upon the size of the coil employed; (6) there is
no style of lamp that may not be used, since each lamp is mounted upon a
special circuit; (7) any number of lamps may be lighted or extinguished
without the others being influenced thereby; (8) when a fire or other
accident happens in a house, it in no wise interferes with the service in
the rest of the line; (9) the system could, were it required, be connected
with any other kind of existing line; and (10) the cost of installation is
infinitely less than that of a system of gas pipes embracing the same
extent of ground.--_La Lumiere Electrique._
* * * * *
ELECTRICITY APPLIED TO THE STUDY OF SEISMIC MOVEMENTS.
Italy, with her volcanic nature, has very naturally made a specialty of
movements of the ground, or seismic perturbations. So the larger part of
the apparatus designed for such study are due to Italians. Several of
these instruments have already been, described in this journal, and on the
present occasion we shall make known a few others that will serve to give
an idea of the methods employed.
For the observation of the vertical and horizontal motions of the ground,
different apparatus are required. The following is a description of those
constructed for each of such purposes by the Brassart Brothers.
[Illustration: FIG. 1.--APPARATUS FOR THE STUDY OF HORIZONTAL SEISMIC
MOVEMENTS.]
_Apparatus for Studying Horizontal Movements._--A lever, (Fig. 1), movable
about a horizontal axis, carries a corrugated funnel, _i_, at one of its
extremities. At the other extremity it is provided with a counterpoise
which permits of its being exactly balanced, while not interfering with
its sensitiveness.
[Illustration: FIGS. 2 AND 3.--DETAILS OF THE APPARATUS.]
The opening of the funnel passes freely around a column, _v_ (Fig. 2),
upon which is placed in equilibrium a rod that terminates in a weight, P.
The corrugations of the funnel carry letters indicating the four cardinal
points, and the funnel itself is capable of revolving in such a way that
the marked indications shall always correspond to the real position of the
cardinal points. When a horizontal shock occurs, the weight, P, falls in a
direction opposite thereto, and into one of the corrugations, where it
rests, so that the direction of the shock is indicated. But, in falling,
it causes the lever, F, to tilt, and this brings about an electric contact
between the screw, _h_, and the column, _n_, which sends a current into
the electro, E, so that the armature of the latter is attracted. In its
position of rest this armature holds a series of parts, S, A, L, which
have the effect of stopping the pendulum of a clock placed upon the same
apparatus. At the moment, then, that the armature is attracted the
pendulum is set free and the clockwork is started. As the current, at the
same time, sets a bell ringing, the observer comes and arranges the
apparatus again to await a new shock. Knowing the hour at which the hand
of the clock was stopped, he sees how long it has been in motion again and
deduces therefrom the precise moment of the shock.
The small rod, _f_, which is seen at the extremity of F, is for the
purpose of allowing electricity to be dispensed with, if need be. In this
case the screw, _h_, is so regulated that F descends farther, and that _f_
may depress the armature of the magnet just as the current would have
done.
[Illustration: FIG. 4.--APPARATUS FOR THE STUDY OF VERTICAL MOVEMENTS.]
_Apparatus for the Study of Vertical Movements._--In this apparatus (Fig.
4), the contact is formed between a mercury cup, T, and a weight, D. The
cup is capable of being raised and lowered by means of a screw, so that
the two parts approach each other very closely without touching. At the
moment of a vertical shock a contact occurs between the mercury and
weight, and there results a current which, acting upon the electro, E,
frees the pendulum of the clock as in the preceding apparatus. In this
case, in order that the contact may be continuous and that the bell may be
rung, the piece, A, upon falling, sets up a permanent contact with the
part, _a_ (Fig. 3).
[Illustration: FIG. 5.--BRASSART'S SEISMIC CLOCK.]
_Brassart's Seismic Clock._--This apparatus is designed for being put in
connection at a distance with an indicator like the ones just described.
It is a simple clock to which a few special devices have been added.
Seismic clocks may be classed in two categories, according as they are
stopped by the effect of a shock or are set running at the very instant
one occurs. The Messrs. Brassart have always given preference to those of
the second category, because there is no need of watching them during a
seismic calm, and because they are much more easily constructed. It is to
this class, then, that their seismic clock belongs. It is capable of being
used for domestic purposes in place of any other clock, and of becoming a
seismoscopic clock as soon as it is put in electric communication with the
seismic telltales.
To the cross-piece that holds the axle of the drums the inventors have
added (Fig. 5) a support formed of a strip of brass, S, with whose
extremity is jointed (at the lower part) a double lever, A. This latter is
held in a horizontal position by a small counterpoise, _i_, so that the
finger at the opposite extremity shall prevent the pendulum, P, from
swinging. To keep the latter in a position of rest a bent lever, _n n'_,
is jointed to the upper part of the support, S. The longer arm, _n'_, of
this lever is bent forward at right angles, so that it may come into
contact with and repel the small rod of the pendulum as soon as the lever
has been lifted by means of a small cord which is connected with the
larger arm, _n_, and runs up to a small hook, from whence it descends and
makes its exit under the clock-case.
In order to stop the clock, then, it is only necessary to pull on this
cord slightly, when, by moving the pendulum to the left, it will thrust
it against the inclined plane of the finger of the lever arm, A. It is
clear that the extremity of the pendulum, upon striking against the
finger, will depress it slightly and go beyond the projection against
which it remains fixed owing to the counterpoise, _i_. The fever, _n n'_,
is brought back to its position of rest by means of a small counterpoise
at the extremity of the arm, _n_. When the lever, A, is depressed, the
pendulum escapes and sets the clock running. This depression is effected
by means of an electro-magnet, E, whose armature, which is connected with
the rod, _t, t_, lifts the arm, _i_, of the lever, and depresses A. The
wires of the two bobbins of the electro-magnet end in two clamps, 1 and 2.
The second of these latter is insulated from the clock-case. Both
communicate with the extremities of the circuit in which is interposed the
seismic telltale that brings about a closing of the current. Having noted
the position of the hands on the dial when the clock was running, one can
deduce therefrom the moment at which the shock occurred that set the clock
in motion.
In addition to the parts that we have described, there are other accessory
ones, R R_r_, and a third clamp, 3, which constitute a sort of rheotome
that is designed to keep the circuit closed after the momentary closing
that is produced by the telltale has occurred. This little mechanism is
indispensable when the disturbed telltale has also to act upon an electric
bell. This rheotome, which is very simple, is constructed as follows: A
small brass rod, R, which is screwed to the support, S, carries at its
left extremity a brass axis, X, which is insulated from the rod, R, by
means of an ivory piece. Toward the center of this small rod, the bent
lever, _r_, carries a small arm that is bent forward, and against which
abuts the axis of the pendulum, thus causing it to be thrust toward the
left when the pendulum is arrested by the projection of the finger, A. As
soon as the pendulum is set free, the lever, _r_, redescends and places
itself against the axis, X. This latter communicates with clamp 3, which
is insulated, while the rod, R, communicates with clamp 1. The external
communications are so arranged that the circuit in which the bell is
interposed remains definitely closed when the lever, _r_, is in contact
with the rod, X.
[Illustration: FIG. 6.--ROSSI'S TREMITOSCOPE.]
_Rossi's Tremitoscope._--This instrument (Fig. 6) unites, upon the same
stone base, three different arrangements for showing evidences of
trepidations of the earth. On one side we find (protected by a glass tube)
a weight suspended over a mercury cup by a spring, and designed to show
vertical motions. The two other parts of the apparatus are designed for
registering horizontal motions. The first is a pendulum which causes a
contact with four distinct springs, and whose movements are watched with a
spy-glass. The second is a steel spring which carries at its upper part a
heavy ball that vibrates at the least shock. This ball is provided with a
point which is movable within a second ball, so that its motion produces
a contact. All these different contacts are signaled or registered
electrically.
[Illustration: FIG. 7.--SCATENI'S SEISMOGRAPH.]
_Scateni's Registering Seismograph._--This apparatus, which is shown in
Figs. 7 and 8, consists of two parts--of a transmitter and of a
registering device.
[Illustration: FIG. 8.--REGISTERING APPARATUS.]
The transmitter consists of a glass vessel supported upon a steel point
and provided beneath with a platinum circle connected with a pile. All
around this circle are four strips of platinum, against one of which abuts
the circle at every movement of the glass. Each strip of platinum
communicates, through a special wire, with one of the electro-magnets of
the registering device (Fig. 8). This latter consists of an ordinary clock
that carries three concentric dials--one for minutes, one for hours, and
one for seconds. In a direction with the radii of these dials there are
four superposed levers, each of which is actuated by one of the electros.
On another hand, each dial is divided into four zones that correspond to
the four cardinal points. When a shock coming from the north, for example,
produces a contact, the corresponding electro is affected, and its lever
falls and marks upon each of the dials a point in its north zone. We thus
obtain the exact hour of the shock, as well as its direction. As may be
seen, the apparatus, as regards principle, is one of the simplest of its
kind.--_La Lumiere Electrique._
* * * * *
NEW ACCUMULATORS.
[Illustration: FIG. 1.--ARNOULD & TAMINE'S ACCUMULATOR.]
In Messrs. Arnould and Tamine's accumulators, shown in Fig. 1, the
formation is effected directly by the current, as in the Planté pile, but
the plates are formed of wires connected horizontally at their extremities
by soldering. These plates are held apart either by setting them into
paraffined wooden grooves at the ends of the trough or by interposing
between them pieces of paraffined wood.
[Illustration: FIG. 2.--BARRIER & TOURVIELLE'S ELECTRODOCK.]
In Messrs. Barrier and Tourville's _Electrodock_ (Fig. 2) the plates are
formed of concentric leaden tubes fixed into a wooden cover. These tubes
are threaded internally and externally, and the grooves thus produced are
filled with a peculiar cement composed of litharge, powdered charcoal, and
permanganate of potash, triturated together, sifted, and then mixed with
glucose or sugar sirup so as to make a paste of them. This mixture forms a
cement that is very adhesive after, as well as before, the electrolytic
action.
[Illustration: FIG. 3.--KORNBLUH'S ACCUMULATOR.]
In Kornbluh's accumulators the plates consist of ribbed leaden gratings
between which is compressed red lead prepared in a peculiar manner, and
constituting, 48 hours after formation, a compact mass with the lead. The
tangs of the plates are widened so as to touch one another while leaving a
proper distance between the plates themselves, and are hollowed out for
the reception of a rod provided at its extremities with a winged nut and
jam nut for passing them up close to one another. The plates, properly so
called, are held apart by rubber bauds. The glass vessels are placed in
osier baskets.--_La Lumiere Electrique._
* * * * *
INDUSTRIAL MODEL OF THE REYNIER ZINC ACCUMULATOR.
The three models of a secondary battery that I recently made known to the
readers of this journal have been the object of continuous experiment.
Conformably to the provisions of theory, the zinc accumulator has shown
itself practically superior to the two others, and I have therefore chosen
this type for getting up an industrial model, which is shown in the
annexed cut. The accumulator contains four Planté positives, having a wide
surface, and three negatives constructed of smooth sheets of lead covered
with zinc by the electrolysis of the acidulated solution of zinc sulphate
in which the couple is immersed. Accidental contact with the interior of
the pile is prevented by glass tubes fixed to the negatives by means of
leaden bands. The seven electrodes are carried by as many distinct
crosspieces of paraffined wood, which rest upon the edges of the trough
and hold the plates at a certain distance from the bottom. These various
crosspieces, which touch one another, take the place of a cover. Each
plate is provided with a terminal. The four positive terminals are all on
the same side, and the three negatives are on the opposite side. Two brass
rods ending in a wire-clamp connect the respective terminals of the same
name. The trough consists of two oblong wooden receptacles, one within the
other, and having a play of several millimeters. This space is lined with
a tight, elastic, insulating cement having tar for a base.
[Illustration: REYNIER'S ZINC ACCUMULATOR. (One-fifth actual size.)]
The careful insulation of the trough and all parts of the apparatus, and
the purity of the metal and its amalgamation, reduce the local attack of
the zinc to almost nothing. So the coefficient of restitution is now
comparable with that of accumulators of the Planté type.
The following are the principal numerical data of the new zinc
accumulator.
PHYSICAL DATA.
E. Electromotive force. 2.36 volts.
R. Mean resistance. 0.02 ohm.
I. Normal intensity of the discharge current. 25 amperes.
i. Intensity of the charge current. 5 to 10 amperes.
Q. Capacity of accumulation after 200 hours' formation. 550,000 couples.
DATA CONCERNING CONSTRUCTION.
Efficient surface of the 4 positive electrodes. 200 square dec.
Efficient surface of the 3 negative electrodes. 15 square dec.
Weight of the positive electrodes. 8.2 kilogrammes.
Weight of the negative electrodes. 1.4 kilogrammes.
Weight of the trough. 2.7 kilogrammes.
Weight of the liquid. 4.4 kilogrammes.
Weight of the attachments. 0.46 kilogrammes.
Weight, total. 17.16 kilogrammes.
The total electric work stored up is 130,000 kilogrammeters, or 7,600
kilogrammeters per kilogramme of accumulator. Theory indicates that a zinc
accumulator might store up as much as 15,600 kilogrammeters per
kilogramme. If the present model gives half less, it is because I have
purposely exaggerated the solidity of the trough and the mass of the
electrodes.
It should be remarked that this capacity of 7,600 kilogrammeters per
kilogramme is much greater than that of any other accumulator constructed
in France. The new model possesses, then, despite the size of the
positives and the box, a relative lightness that will permit it to take a
place upon electric locomotives as well as in fixed installations.
Independently of their use as accumulators, secondary zinc batteries may
be utilized as regulating voltameters in lighting by incandescence, for
deadening piston strokes, attenuating the irregularities in speed, and
covering accidental stoppages.--_E. Reynier, in La Nature._
* * * * *
THE HISTORY OF A LIGHTNING FLASH.
By W. SLINGO.
Lately we have all felt, I doubt not, a considerable amount of interest in
the various phenomena attending this summer's unusually heavy
thunderstorms, accompanied, as they have been, by vivid lightning
discharges of a more or less hurtful nature. The list of disasters
published in _Knowledge_, No. 143, might be very materially augmented were
we to record such damage as has been wrought since that list was compiled.
There is not, I suppose, in the mind of any intelligent man at the present
day a doubt as to the electrical origin of a lightning flash. The
questions to be considered are rather whence comes the electricity, and in
what way is the thunderstorm brought about. In attempting to answer these
questions, sight must not be lost of the fact that the very nature of
electricity is in itself almost sufficient to baffle any effort put forth
to ascertain from lightning, as such, its whence and its whither.
It is possible, however, with the aid of our knowledge of static
electricity, to arrive at hypotheses of a more than chimerical nature. In
the first place, that our sphere is a more or less electrified body is
generally admitted. More than this, it is demonstrated that the different
parts of the earth's surface and its enveloping atmosphere are variously
charged. As a consequence of these varying charges, there is a constant
series of currents flowing through the various parts of the earth, which
show themselves in such telegraph wires as may lie in the direction
followed by the currents. Such currents are known as earth currents, and
present phenomena of a highly interesting nature. But, apart from these
electrical manifestations, there is generally a difference of electrical
condition between the various parts of the earth's surface and those
portions of the atmosphere adjacent to or above them. Inasmuch as air is
one of the very best insulators, this difference of condition (or
potential) in any particular region is in most cases incapable of being
neutralized or equilibrated by an electric flow. Consequently the air
remains more or less continually charged. With these points admitted as
facts, the question arises, Whence this electricity? There have been very
many and various opinions expressed as to the cause of terrestrial
electricity, but far the greater portion of such theories lack fundamental
probability, and indicate causes which cannot be regarded as sufficiently
extensive or operative to produce such tremendous effects as are
occasionally witnessed. I take it that we may safely regard the evolution
of electricity as one of the ways in which force exhibits itself, that, in
other words, when work is performed electricity may result. When two
bodies are rubbed together, electricity is produced, so also is it when
two connected metals are immersed in water and one of them is dissolved,
or when one of the junctions of two metals is raised to a higher
temperature than the other junction. I will go further than this, so far,
in fact, as to maintain that there is a reasonable ground for supposing
that every movement, whether it be of the mass or among the constituent
particles, is attended by a change of electrical distribution; and if this
is true, it may easily be conceived that inasmuch as motion is the rule of
the universe, there must be a constant series of electrical changes. Now,
these changes do not all operate in one direction, nor are they all of
similar character, whence it is that not only are there earth currents of
feeble electro-motive force, but that this E.M.F. is constantly varying,
and that, furthermore, electricity of high E.M.F. is to be met with in
various parts of the atmosphere.
With earth currents we have here very little to do. The rotation of the
earth is in itself sufficient to generate small currents, and the fact
that they vary in strength at regular periods of the day and of the year
enforces the suggestion that the sun exerts considerable electrical
influence on the earth. Letting it be granted, however, that the earth is
variously charged, how comes it that the air is also charged, and with
electricity of greater tension than that of the earth itself? It was
pointed out by Sir W. Grove that if the extremities of a piece of platinum
wire be placed in a candle flame, one at the bottom and the other near the
top, an electric current will flow through the wire, indicating the
presence of electricity. If an electrified body be heated, the electricity
escapes more rapidly as the temperature rises. If a vessel of water be
electrified, and the water then converted into steam, the electric charge
will be rapidly dissipated. If a vessel containing water be electrified,
and the water allowed to escape drop by drop, electricity will escape with
each drop, and the vessel will soon be discharged.
We regard it as an established fact that the earth has always a greater or
less charge; whence it is safe to assume that in the process of
evaporation which is going on all over the surface of the globe, more
particularly in equatorial regions, every particle of water, as it rises
into the air, carries with it its portion, however minute that portion may
be, of the earth's electric charge. This small charge distributes itself
over the surface of the aqueous particle, and the vapor rises higher and
higher until it reaches that point above which the air is too rare to
support it. It then flows away laterally, and as it approaches colder
regions gets denser, sinking lower and nearer to the earth's surface. The
aqueous particles becoming reduced in size, the extent of their surfaces
is proportionately reduced. It follows that as the particles and their
surfaces are reduced, the charge is confined to a smaller surface, and
attains, therefore, a greater "surface density," or in simpler language, a
greater amount of electricity per unit of surface.
Electricity, as above set forth, is in what is known as the "static"
condition (to distinguish it from electricity which is being transferred
in the form of a current), when it has the property of "repelling itself"
to the utmost limits of any conductor upon which it may be confined. This
will account for the charge finding its way to the surface of the water
particles, and will furthermore account for the greater density of the
charge as the particle gets smaller and has the extent of its surface
rapidly diminished. It may be mentioned that the surface of a sphere
varies as the cube of its radius.
Returning to the discussion of the state of affairs existing when the
particles have reached their highest position in the atmosphere, we may
imagine that they set themselves off on journeys toward either the north
or the south pole. As they pass from the hotter to the colder regions, a
number of particles coalesce; these again combine with others on the road
until the vapor becomes visible as cloud. The increased density implies
increased weight, and the cloud particles, as they sail poleward, descend
toward the surface of the earth. Assuming that a spherical form is
maintained throughout, the condensation of a number of particles implies a
considerable reduction of surface. Thus, the contents of two spheres vary
as the cubes of their radii, or eight (the cube of 2) drops on combining
will form a drop twice the radius of one of the original drops. We may
safely conceive hundreds and thousands of such combinations to take place
until a cloud mass is formed, in which the constituent parts are more or
less in contact, and, therefore, behave electrically as a single conductor
of irregular surface, upon which is accumulated all the electricity that
was previously distributed over the surfaces of the millions of particles
that now compose it.
The tendency of an electric charge upon the surface of a conductor is to
take upon itself a position in which it may approach nearest to an equal
and opposite charge; or, if possible, to attain neutrality. If, then, a
cloud has a charge, and there is no other cloud above or near it, the
charge _induces_ on the adjacent earth surface electricity of the opposite
kind. Thus, assuming the cloud to be charged with positive electricity,
the subjacent earth will be in the negative state. The two
electricities[3] exert a strong tendency to combine or to produce
neutrality, whence there is a species of stress applied to the intervening
air. Possibly the cloud will be drawn bodily toward the earth more or less
rapidly, according as the charge is great or small. Or, on the other hand,
the cloud may roll on for leagues, carrying its influence with it, so that
the various portions of the earth underneath become successively charged
and discharged as the cloud progresses on its journey.
[Footnote 3: We may speak of two electricities or two electric states
without necessarily implying adherence either to the single or the double
"fluid" theory. Whether electricity be of two kinds or no, the fact
remains that there are two conditions, and all the features of this paper
may be explained with equal facility by the supporters of either
hypothesis.]
Should the cloud be near the earth, or should it be very highly charged,
the tension of the two electricities may be so great as to overcome the
resistance of the intervening air; and if this resistance should prove too
weak, what happens? How does the discharge show itself? It takes place in
the form of a lightning flash, and passing from the one surface to the
other--or, maybe, simultaneously from both--produces neutrality more or
less complete.
There has recently been a little discussion in these pages on the subject
of lightning, some having stated that they discerned the discharge to take
place upward--that is, from the earth toward the cloud. I will not venture
so far as to say whether or not the direction of the discharge is
discernible; possibly the flash may sometimes be long enough to enable one
to tell; but I have never so seen it, and have always looked upon the eye
as a deceitful member--very. "The lightning flash itself never lasts more
than 1/100000 of a second." It is, however, just as likely that a
discharge may travel upward as downward. What controls the discharge? Does
the quality of the charge?--that is to say, is the positive or the
negative more prone to break disruptively through the insulating medium?
Investigations with Geissler's and other tubes containing highly rarefied
gases have made it tolerably clear that there is a greater "tearing away"
influence at the negative than at the positive pole, and if two equal
balls, containing one a positive and the other a negative charge, be
equally heated, the negative is more readily dissipated than the positive.
But, so far as we at present know, this question enters into the
discussion scarcely, if at all. Our knowledge seems rather to point to the
substances upon which the charges are collected. The self-repellent nature
of electricity compels it to manifest itself at the more prominent parts
of the surface, the level being forsaken for the point. The tension of the
charge, or its tendency to fly off, is proportionately increased. And if
at a given moment the tension attains a certain intensity, the discharge
follows, emanating from the surface which offers the greatest facilities
for escape. The earth is generally flatter than the cloud, whence, in all
probability, the discharge more frequently originates with the cloud.
Should a lightning flash strike the earth and produce direct neutrality,
it is possible that no damage will result, although this again is not
always certain, because when the cloud charge acts inductively on the
earth it produces the opposite (say negative) charge on the nearer parts,
the similar (or positive) state is also produced at some place more or
less distant. Sometimes this "freed" positive (which, by the way,
accumulates gradually and physiologically imperceptibly) is collected at
some portion of the earth's surface. When the negative is neutralized by
the discharge, the freed positive is no longer confined to a particular
region, but tends to dissipate itself, and a shock may be felt more or
less severely by any person within the region. Or, again, a similar shock
may be experienced by a person standing within the negative zone on the
neutralization of the charge.
I may take the opportunity here to mention a highly interesting and
instructive incident observed on local telegraph circuits during a
thunderstorm. The storm may be taking place at some distance from the
point of observation. The electrified cloud induces the opposite charge
beneath it, the similar charge being repelled. It is noticeable that the
needle of a galvanometer, starting from the middle position, goes
gradually over to one side, eventually indicating a considerable
deflection. Suddenly, owing apparently to a lightning discharge some
distance away, the force which caused the deflection is withdrawn, and the
needle rebounds with great violence to the opposite side. In a short time,
the cloud becoming again charged on its under surface, and recommencing
its inductive effect upon the adjacent earth, the needle starts again, and
goes through the same series of movements, a violent counterthrow
following every flash of lightning.
If we can so far control our imagination, we may conceive the earth to be
one large insulated conductor, susceptible to every influence around it.
If then the earth, as a mass of matter, behaves as above indicated, there
is no plausible reason for declining to regard any other large conducting
mass in a similar light, and as a body capable of being subjected more or
less completely to the various impulses affecting the earth. In other
words, a large mass of conducting material, partially or perfectly
insulated, is, during a thunderstorm, in considerable danger. With this
portion of the subject I shall, however, deal more fully when discussing
the merits of lightning protectors.
Lightning discharges do not take place between cloud and earth only, but
also, and perhaps more frequently, between too oppositely charged clouds.
We then get atmospheric lightning, the flash often extending for miles.
This form of lightning is harmless, and in all probability what we see is
only a reflection of the discharge. The oft-told tale of the lightning
flying in at the window, across the room, and out of the door, or up the
chimney, is all moonshine, and before dealing with lightning protectors I
intend to expose some of the fallacies concerning lightning. Were the
discharge to pass through a house, it would infallibly leave more decided
traces and do more damage than simply scaring a superstitious old lady now
and again. Many people are often and unnecessarily frightened during a
thunderstorm, but it may be safely predicted that a person under a roof is
infinitely safer than one who is standing alone on level ground, and
making himself a prominence inviting a discharge. Rain almost invariably
accompanies the discharge, and the roof and sides of the house being wet,
they form a more or less perfect channel of escape should a flash strike
the building.--_Knowledge._
* * * * *
RESEARCHES ON MAGNETISM.
By M. DUTER.
If we place a thin plate of steel in a uniform magnetic field, so that the
lines of force of the field may be normal to the surface of the plate, we
have a very flat magnet, the two faces of which are the two polar
surfaces. The magnetic distribution thus obtained seems to disappear when
the plate is no longer in the field. The following experiments show that
this disappearance is not complete. I made use of plates of tempered steel
of 1 millimeter in thickness, and varying in diameter from 0.040 to 0.005
meter. With these plates I formed cylindrical batteries. In some of these
batteries the plates are directly in contact, and in others they were
separated by leaves of pasteboard, the thickness of which varied from that
of the thinnest paper to 0.001 meter. The batteries were placed in the
central portion of a very powerful magnetic field, and after they have
been taken out they formed perfectly regular permanent magnets. The
supporting power of these magnets was the greater the nearer its
constituent plates were to each other. In a battery of 100 plates,
touching each other directly, and strongly pressed into a brass cylinder,
the portative force at each extremity rose to 30 grammes. This first
result having been obtained, I dismounted the batteries, plate by plate,
taking care to mark the upper and under side of each. I found then that
each plate retained only an excessively slight magnetism. Yet each of them
still constituted a flat magnet, of which the two faces are the polar
surfaces; for on rebuilding the battery it gave again a perfectly regular
magnet, though weaker than it was at first. The separation of the magnet
into its constituent plates, and its reconstruction, maybe repeated
indefinitely.--_Comptes Rendus._
* * * * *
Dr. T. Tommasi (_Cosmos les Mondes_) notes that the thermic constant of
thallium is exactly the mean of the thermic constants of potassium and
lead, the two metals which it most resembles in its chemical character.
* * * * *
IMPROVED GAS LIGHT BUOY.
[Illustration: GAS LIGHT BUOY.]
The accompanying engravings represent a light buoy made by the Pintsch's
Patent Lighting Company for the river Humber. The chief dimensions of the
buoy are given in the engraving, which also shows that the gas holder is
placed within the boat in such a way as to be protected from blows likely
to cause any leakage. The buoy has a special form to meet its requirements
as a lightship, and the conditions of its employment is the fast tidal
current of the river. It was designed by Mr. C. Berthon, of Westminster,
and is intended to carry a six months' supply of gas, the burner,
regulator, and lamp being on the well known Pintsch system. The hull is
formed of 3/8 inch plate, 24 feet 3 inches total length, and 9 feet beam
at the line of flotation. The laps of the plates are 4 inches wide, and
riveted with 3/4 inch rivets, spaced 2-1/4 inch apart center to center.
The keel and stem are both in one piece, as shown, and to this the
garboard strake is to be fastened. The bilge pieces are riveted on to the
bilge, and made of 9 inches by 4-1/2 inches by 9/16 inch T-iron. A wooden
fender, 4 inches by 4 inches wood, is fitted on both sides of hull,
running from stern to stern, by 3 inches by 3-1/2 inches by 7/16 inch
L-iron top and bottom with the sheer as shown. The hull from water line
falls in as shown, so as to describe at midships an arc of 4 feet 6
inches, and a circular deck of 1/8 inch plate is riveted on the hull.
There are two man-holes, each 16 inches diameter in the clear, placed in
end plates of the circular deck as shown, and provided with covers 3/8
inch thick, secured by twenty screws 3/4 inch diameter. The edge of each
manhole is stiffened by a welded iron ring. The surface of the mooring
link that comes in contact with the shackle and mooring chain is steeled.
The gas holder rests upon a plate bent up on each side, and riveted to the
keelson, and is prevented from rolling by four gusset plates, with two
short pieces of angle iron riveted thereto at the ends and coming in
contact with the holder, and at the ends by angular plates, and angle iron
riveted on each side and riveted to the keelson. The superstructure
consists of four legs of angle iron 2-1/2 inches by 2-1/2 inches by 5/16
inch, the upper ends of the legs being attached to a square flanged plate
for supporting the lighting apparatus. Four wooden battens of pitch pine,
4 inches by 1-1/2 inches, and bolted on to each cant of the angle iron
superstructure, with 7/8 inch galvanized iron bolts and nuts.
[Illustration: GAS LIGHT BUOY.]
* * * * *
PROJECT FOR A ROADSTEAD AT HAVRE.
The present port of Havre is absolutely insufficient to answer the ever
increasing requirements of commerce. Its entrance, which is too narrow and
not deep enough, does not permit steamers to go in, come out, and perform
their evolutions with the rapidity required by our epoch. So they are
gradually abandoning our port, and going to load and unload at Anvers and
elsewhere. A large number of wise heads, who are anxious about the future
of this port and our national interests, have devoted themselves to
finding a means of enlarging it, not by dredging _new_ basins, which would
prove ruinous to the budget and useless in twenty years, but by installing
a true roadstead at the entrance to the present basins.
[Illustration: FIG 1.--PLAN OF THE PROJECTED ROADSTEAD AT HAVRE.]
Upon the maps of the hydrographic service may be seen, under the name of
the Little Roadstead, a vast extent of sea nearly two kilometers wide by
three to four in length, bounded upon one side by the heights of Heve and
St. Adresse, and upon the other by the rocky line of Eclat and of the
heights of the roadstead (Fig. 1). This Little Roadstead, so called, in
order to become a genuine one, would have to be protected against the
great waves of the open sea. To thus protect it, to close it as quickly
and as cheaply as possible--that is the problem.
In 1838, Charles de Massas presented a project (the first in order of
date), which consisted in constructing upon the Eclat reef a semi-lunate
dike, and a breakwater at Cape Heve. Moreover, upon the emergent parts of
the Eclat reef and heights of the roadstead he proposed to erect two
forts.
[Illustration: FIG. 2.--LEWIS' FLOATING BREAKWATER.]
The defense of the port of Havre is a very important question, and one
that appears to be completely abandoned. Since Engineer Degaulle in 1808
advised the erection of a fort upon the Eclat, and requests have
periodically been made and projects drawn. The requests are forgotten, but
the drawings are in the Ministers' portfolios, and if France should
to-morrow have a war with a maritime power our great northern port might
be destroyed and burned by the smallest squadron.
Some years after Massas' project, two officers, Deloffre and Bleve, and an
engineer named Renaud, received a commission to search for a means of
closing a portion of Seine Bay. These gentlemen advised the erection of
two dikes, one on the Eclat shoal in the very axis of this reef, and the
other at Heve. Between these two masonry dikes was to be placed a floating
breakwater. This project, which was submitted to Admiral de Hell in 1845,
had a favorable reception, and the Admiral especially applauded the trial
of breakwaters, "which were much talked of in England, although the
effects that they might produce were not well known." Deloffre, Bleve, and
Renauds' project comprised two forts--one to the north and the other to
the south of the roadstead. For a long time nothing more was said about
it, and it is only during recent years, when the peril has become imminent
for Havre (threatened as it is of being abandoned even by the French
transatlantics), that the question has again became the order of the day.
[Illustration: FIG. 3.--FROIDEVILLE'S FLOATING BREAKWATER.--END VIEW.]
Mr. Bert, a merchant, would protect the Little Roadstead by means of two
jetties, 1,000 and 1,600 meters in length, built, one of them upon the
Eclat and the other upon the eminences of the roadstead. These would be
constructed by forming a foundation of loose rocks, and using earth and
brick above the level of the water. Mr. Vial has likewise proposed a
rockwork of 2,000 meters in length, to form a dike 10 meters in height and
width, whose platform would be on a level with the highest tides.
Next comes the more recent project of Mr. Coulon. Seeing that it is the
deposits of the ocean and not those of the Seine that accumulate upon the
estuary, Mr. Coulon advises the construction of a dike about 2,000 meters
in length, starting from the Havre jetty, and ending at the southwest
extremity of the shoals at the roadstead heights, and a second one
returning toward the northwest, of from 500 to 1,000 meters. A third and
very long one of not less than 8 kilometers would be built from Honfleur
to the Ratier shoals.
This latter one, in contracting the bay, would contribute to increase the
force of the current, which, throwing back at the ocean its mud and
pebbles, would give us the depths of 15 and 20 meters indicated on the map
of Beautemps-Beaupre.
This year, again, two projects have arisen; one of them due to Mr.
Thuillard-Froideville, and the other to Mr. Hersent.
According to Mr. Hersent, it would be necessary to surround the Little
Roadstead with an insubmersible dike built upon the rocky shoals, which
would begin at Cape Heve (which it would consolidate) and end opposite the
entrance to the port at 1,600 meters from the jetties. Through it there
would be five passages. Afterward another dike would be constructed,
starting from the shore and running to meet the jetty designed to inclose
the Little Roadstead. On turning the angle at which it met the jetty it
would be continued as far as to Berville. Finally, a third dike, running
from Honfleur to Berville, would complete the system.
Mr. Hersent's project, which is one of the most remarkable of those that
have been proposed, has one fault, and that is that it would require
twelve years of work, and cost 158 million francs.
Mr. Thuillard-Froideville, completely renouncing masonry dikes as being
too costly and taking too long to construct, proposes to inclose the Havre
roadstead by means of floating breakwaters. As we have already seen, the
use of these between Cape Heve and the Eclat shoals had already been
proposed in 1845. As the project was abandoned, the models of these
breakwaters are rare.
In Bouniceau's "Marine Constructions" we find a curious figure, a sort of
open framework of clumsy form anchored in a singular manner, and
surmounted by rooms for watchmen, semaphores, posts for the shipwrecked,
etc. It is, indeed, the most complicated and most impracticable type that
could be imagined.
Mr. Lewis' model, which was exhibited last year at the International
Fisheries Exhibition, was, on the contrary, one of the simplest. It
consisted of a strong piece of wood of nearly triangular section, the
sharpest angle of which, being turned oceanward, was designed to cut the
waves and cause them to break over it (Fig. 2). If, by favor of divine
Providence, this breakwater, which presents absolutely plane surfaces to
the shock and pressure of the waves, is not broken to fragments in the
first tempest, it will certainly acquit itself of the _role_ for which the
inventor destined it. When we have a system of resistance to the sea,
anchored and facing a certain direction, and consequently not being able
to revolve around its axis as vessels do, care must be taken not to give
it entire surfaces.
[Illustration: FIG. 4.--FROIDEVILLE'S BREAKWATER.--MODE OF JOINING THE
PARTS.]
Mr. Froideville's breakwater consists of a framework 25 meters in length,
and 9 in height and width, and having the form of an irregular 5-sided
prism (Fig. 3). The smallest side of the prism is designed to serve as a
flat keel. The axis is formed of a metallic float, from whence start radii
that form the skeleton of the framework, and that are designed for
connecting the center with five long spruce beams that form the angles of
the prism. To these beams are affixed the cross pieces that form the
openwork sides. Five long pieces of wood parallel with the beams, but not
so strong as they, protect the cross pieces and secure them against
breakage in the middle. All the angles of the breakwater and all points of
juncture of the pieces are protected with iron, and it is in order to
counterbalance the weight of all this iron that the central float is
used. Parallel with this first breakwater, there are two other and smaller
ones, which are designed for reducing the effect of rolling as much as
possible. Reduced to a single float, the breakwater might remain under the
waves too long, but, owing to the two others, it rights itself, warps
around, and always presents the spur of its sharp roof to the wave.
In order to prevent the breakwaters from clashing against each other, they
are united end to end in a very simple and ingenious manner. From each of
them there starts a deeply inserted iron bar which terminates in a journal
that permits the breakwater to oscillate. Between these two bars there is
a sort of swivel, whose pieces, in playing upon one another, give the
breakwaters elasticity, while always holding them apart (Fig. 4). From
each side of the swivel start the branches of a stirrup iron to which the
anchorage chain is attached. This latter is of steel, without solderings,
and it is so perfectly constructed that no breakage need be feared. To the
other extremity of the chain is attached an anchor having two flukes,
which both engage with the bottom.
Mr. Froideville proposes to set up two lines of these breakwaters, for a
length of about 7½ kilometers, starting at the north from Cape Heve,
taking in depths of 15 meters (the best that are found in the Little
Roadstead), passing in front of the Eclat shoal and the heights, and
ending opposite the entrance of the present port.
The first row is designed for breaking the force of the waves, and the
second for lending its aid in times of high tempests, and stopping the
surge that has escaped from the first.
The extreme simplicity of this project has permitted its promoter to
affirm that in a few months, and with nine millions, he can inclose the
Havre roadstead.
The Little Roadstead, being thenceforward protected, will become an
excellent port of refuge in bad weather. In addition, a system of
lighters, or, better, a few floats connected with the shore and forming a
rock, will permit vessels to take on their cargoes with great rapidity.
Mr. Froideville's project presents the further advantage of rendering it
easier to put the port of Havre quickly in defense. A certain number of
floating batteries, anchored behind the breakwaters and protecting the
advances of torpedo boats by means of their firing, would make a
formidable defense. Not having to perform any evolutions, they might
without danger be invested with armor plate thicker than that of ordinary
ironclads. In order to complete the system, there might be erected upon
the Eclat shoal an ironclad fort like that which defends the entrance of
Portsmouth.
An English chronicler of the fourteenth century, in speaking of his
country, places it above all others, and declares that men are handsomer,
whiter, and purer blooded there than elsewhere, and he says that this is
so "because it is so." We would not like to imitate his naive reasoning,
and yet, for defending the very original system proposed by Mr.
Froideville, we have only our conviction, which we share, moreover, with a
large number of sea-faring men and engineers. Mathematics are powerless to
predict to us with accuracy the manner in which the floating breakwaters
will behave, but experiment remains. Let the promoter of the project,
then, be given authority to inclose a few hundred meters, and if, as we
suppose, the breakwaters shall remain immovable in a northwester, a
maritime revolution will have been brought about.--_La Nature._
* * * * *
IMPROVED CATCH BASIN.
In 1882, M. Bacle published in _Le Génie Civil_ a study of the sewer
systems in some of the large foreign cities. There may be found there a
description of the Liernur system at Amsterdam, Leyden, and Dordrecht, in
Holland, and in certain cities of Germany and the United States.
[Illustration: IMPROVED CATCH BASIN.]
This system consists in the employment of two distinct systems of ducts,
one for the discharges from water-closets and the other for household
wastes, rain water, and the discharges from factories when sufficiently
purified. This arrangement allows the employment of sewers of small
section, provided that it shall be unnecessary to enter them for the
purpose of cleansing them. It has been necessary, therefore, to provide
inlets with a separating apparatus called "gully" or "catch basin," which
retains as completely as possible all solid matter, mud, excrement, and
_debris_ of every kind which maybe floated in by street washing or by
rain-water, and which may be capable of causing stoppages in the sewers,
the choking up being followed by fermentation and the emanation of noxious
vapors.
M.C. Pieper of Berlin suggests a device for a catch basin, which appears
to meet the requirements. It is in the form of a cylindrical metal box,
enlarged in its upper section to receive a filtering cylinder of
perforated sheet iron, which occupies almost the upper half of the device
and rests upon the smaller lower part. The entire apparatus is covered by
a movable funnel, through which enter water and any rubbish which it may
carry with it. From one side a tube allows the liquid to be discharged,
while a siphon placed on the opposite side serves the same purpose under
certain circumstances, as will be explained.
Figure 1 represents the apparatus discharging under normal conditions. The
heavy matter, sand, stones, etc., falls to the bottom into a receptacle
which can be lifted out from time to time and emptied. The lighter buoyant
matters, straw, vegetable _debris_, paper, etc., remain at the surface,
and are retained by the filter; the water passing through the holes in the
sheet iron rushes in a filtered condition through the annular space which
exists in the upper part between the two cylinders, and escapes by the
waste-pipe when the water reaches a proper level. If at a given moment the
quantity of water flowing in is too much to be discharged through this
waste-pipe, the level of the water mounts in the cylinder until it reaches
the top of the siphon. Immediately the siphon comes into play and empties
the upper part of the apparatus, and the filtered water contained in the
annular space already mentioned quickly re-enters the cylinder through the
perforated sheet iron, and in so doing cleans out the perforations with
considerable energy. This second period is represented in the second
figure.
The mouth of the siphon being placed above the movable basket, the heavy
matters contained in the latter are not in the least disturbed, and the
metallic screen placed over the mouth prevents the entrance of any
floating matters. When siphonic action ceases, the water in the short arm
of the siphon empties itself into the main receptacle, and by so doing
cleanses the screen. During a rain or the washing of the streets, the
siphon can work in concurrence with the ordinary discharge-pipe. It is
evident of course that these two--pipes can be placed on the same side of
the apparatus, if this prove the most convenient arrangement.
We will add that this apparatus can be applied not only to the Liernur
system, but also can be used for preventing the entrance of obstructions
into sewers of the ordinary type, where the grade is small or where the
quantity of water is insufficient; and if we adopt the system of
"everything to the sewer," can we not find in the employment of this
apparatus an element for the realization of the famous formula, "Always in
circulation, and never in stagnation?"--_Le Génie Civil._
* * * * *
[Concluded from SUPPLEMENT No. 454, page 7249.]
WATER-POWER WITH HIGH PRESSURES AND WROUGHT-IRON WATER-PIPE.
By HAMILTON SMITH, JR., M. Am. Soc. C.E.
METHODS OF CONDUCTING WATER AND TRANSMITTING POWER.
A description of the mode of using water-power for driving the North
Bloomfield tunnel in California, some years since, will give a good
illustration of some of the advantages of the hurdy-gurdy. This tunnel was
originally about 8,000 feet long, through a slate highly metamorphosed,
with its general line passing under a good-sized stream, at a depth of
about 190 feet. There were eight working-shafts, each about 200 feet deep,
which, with the lower entrance or portal, gave sixteen working faces.
Diamond drills were used at the lower heading requiring power; the other
fifteen headings were driven by hand-work. It was uncertain how much water
would be encountered; but from the location, it was evident that a large
quantity might be struck in any shaft, and hence it became necessary to
have ample power at hand at each opening, in readiness for such an
emergency. A pipe main was laid along the general line of the tunnel, with
its pen-stock 285 feet vertical above the surface at the upper shaft, and
549 feet above the lowest shaft. It was made of single riveted sheet-iron,
of No. 14 (Birmingham) gauge, in lengths of 20 feet, put together
stove-pipe fashion, with the joints made tight by cloth tarred strips and
pine wedges. This pipe had a diameter of 15 inches at the pen-stock,
diminishing from this to 13, 11, and 7 inches at its lower end. From it,
short branches, 7 inches in diameter, were extended to the several shafts.
It was in one place carried across the stream by a light suspension
bridge, some 150 feet long, the trunk of a tree on each side forming a
convenient tower. The aggregate length of the main and branches was 9,960
feet, with some 2,500 feet additional, for the branch to the diamond
drills. The pipe was laid on the surface of the ground, its only
protection being in places a couple of 1½-inch planks tacked together, and
placed over it; the range of temperature was from 10 degrees to 107
degrees Fahr. (in the shade). It was inspected by the foreman of the
tunnel-work as he daily walked over the line; besides the occasional
driving of a few wedges and putting on a band or two, it gave no trouble
from leakage, which probably for its entire length did not amount to more
than an average of 3 or 4 cubic feet a minute; from time to time, a little
sawdust was put into the pen-stock. Three stop-gates were placed on the
main, and a separate stop-gate at each shaft, operated by a fine-threaded
screw, so that the water could be cut off when desired.
[Illustration: FIG. 13.]
Fig. 13 shows the arrangement of the machinery for hoisting and pumping,
which was identical at the several shafts, except that the hurdy-gurdies
varied from 16½ feet in diameter at the upper shaft to 21 feet at the
lowest shaft. The water-wheel moved only in one direction; the pinion on
the wheel-shaft drove the spur-wheel, to which the pitman of the pump-bob
was attached. On the spur-wheel shaft was a friction-gear, driving the
hoisting-reel; this reel was mounted on sliding blocks, so that hoisting
was done by putting it in gear, the empty load being dropped by a
friction-band. Changing the size of the water-wheel as the pressure
increased permitted the use of the same pattern of machinery at the
different shafts. The water was brought to the wheel by a discharge-pipe,
some nine feet long, having a vertical movement by ball-and-socket joint,
so that at pleasure, by dropping the pipe, the machinery could be run at
various speeds, or entirely stopped. At the end of this discharge-pipe
was a cast tapered nozzle, about 3½ inches in diameter, in which was
inserted a ring of saw-plate steel having the desired diameter, and which
was held in place by an annular screw-cap. By changing the ring, which
only required a few moments' time, any desired amount of water, up to 3 or
4 cubic feet a second, could be discharged against the wheel. The
stop-gate was left wide open while the machinery was running. The pumping
was done by eighteen pumps, of Cornish pattern; the largest amount of
water pumped from any one shaft was something over 30 cubic feet a minute;
the power at hand, however, was ample to pump more than twice that
quantity. It was rather curious at, this shaft to see more water coming
from the pumps than was used on the wheel. The two diamond drills were
driven by a small hurdy-gurdy set on the rear of the drill carriage. This,
but at another tunnel, was afterward modified by placing a separate
hurdy-gurdy on a sleeve on each drill-rod; the advance movement of the
drill being given by hydrostatic pressure on an annular piston, thus doing
away with all gearing. These eight sets of machinery were run for nearly
2½ years' time; the only break being that of a spur-wheel, doubtless
caused by the careless dropping of a steel bar between it and its pinion.
Aside from this accident, practically not a dollar was spent for repairs,
and the machinery, including the pipe, was in about as good order when the
tunnel was finished as when it was first erected. One man, on a twelve
hour shift, operated the machinery at each shaft, besides dumping the
cars; two men kept the 18 pumps on the line in order, the principal work
being in keeping the suction-pipes for the down-grade headings tight; thus
a force of 18 men was only required for the eight shafts. The cost of the
pipe, gates, etc., when put in place, was $14,631, and of the machinery
about $60,000.
[Illustration: FIG. 14.]
At the Idaho gold quartz mine, situated near Grass Valley, California,
water-power has been introduced during the past year (1883), taking the
place of steam. The supply main is of wrought-iron, 22 inches in diameter,
8,764 feet long, buried in the ground below frost-line. The joints, as a
rule, are riveted together, with occasional lead joints to admit of slight
movements in the pipe.[4] The pipe was coated by placing each joint in a
bath of boiling tar and asphaltum; to insure the most thorough coating, it
is necessary to keep the pipe for ten or fifteen minutes in the boiling
mixture. A cast-iron stop-gate is placed at the lower end of the main, and
also one at each of the branches. Cast-iron man-holes are attached to the
main, which, although they have given no trouble in this particular case,
are very objectionable for high pressures, as it is difficult to avoid
ruptures with cast and wrought-iron combined, owing to the great
difference in the elasticity of the two metals. The long seams of this
pipe are double-riveted, and the round seams single riveted; at the lower
end, iron of No. 6 gauge is used. From the end of the main, the water is
led to the several wheels by branches of smaller diameter.
[Footnote 4: With buried wrought-iron pipe this precaution is unnecessary,
as the elasticity of the iron will admit of the movement due to changes of
temperature, without injury to the rivets.]
The water is delivered at the hoisting-wheel with a total head of 542.6
feet. For power and for mill uses, etc., the required supply is about 8
cubic feet a second; this draught reduces the effective head to say 523
feet.
The work done consists in driving the following described machinery:
A large air-compressor--2 cylinders, double acting, air compressed to 75
pounds--requiring about 140 horse-power.
A line of Cornish pumps, forcing the water from a depth of 1,450 feet
vertical; 12-inch plungers for upper 800 feet, 6-inch plungers for lower
650 feet, with 6-foot stroke, requiring from 55 to 70 horse-power.
Hoisting from a double-compartment shaft--two connected winding reels,
moving separate cages--requiring 35 horse-power, or more.
A few small machine-tools and smithy forges, requiring 3 or 4 horse-power.
A 35-stamp mill, with concentrating apparatus, etc., requiring about 70
horse-power.
The total amount of power required being say 320 horse-power, for which
seven Pelton hurdy-gurdy wheels are employed.
The power in all cases is transmitted by systems of Manila rope belting;
the rope is 2 inches in diameter; the grooves in the sheaves or pulleys
are slightly oval, so that the rope does not go quite to the bottom; the
ropes are horizontal, and run very slack (no tighteners), with no
appreciable slip; the splices are made very long, to obtain uniformity in
diameter.
[Illustration: FIG. 15.]
This method of transmitting power appears to work most perfectly and has
given excellent satisfaction. It is thought, at the Idaho, to be greatly
preferable to the gearing formerly in use when the works were driven by
steam (for such work as pumping or hoisting, leather or rubber belting is
never used), besides being much cheaper in first cost.
The wheel driving the air-compressor is 6 feet in diameter, running 300
turns[5] per minute, with 1-15/18-inch nozzle; three ropes are used from
the wheel shaft to the counter-shaft, and six ropes from the latter to the
fly-wheel shaft.
[Footnote 5: The revolutions per minute, of these wheels, as here given,
are only approximate, as the design was to have the bucket speed=½
2(gh)^{½}.]
For driving the pumps, there are two water-wheels, set on the same shaft,
one 5 feet and the other 7 feet in diameter, either of which can be used
at will, thus permitting different rates of speed; two nozzles are placed
on each wheel, so that if necessary the power can at any time be doubled.
The smaller wheel has a 1-1/4 inch nozzle, and runs 360 turns a minute;
the larger has 1-1/8-inch nozzle, and makes 270 turns a minute. There are
two ropes from the wheel-shaft to a counter-shaft, and four ropes to the
fly-wheel shaft, on which is the pinion driving the spur-wheel attached to
the pitman of the pump-bob. Hoisting is done by two wheels placed side by
side on the same shaft, the buckets and nozzle of each wheel being placed
in opposite directions. Both wheels are 8 feet in diameter, with
15/16-inch nozzles, and make at full speed about 225 turns a minute.
Reversing the movement of the shaft is done by shutting off water from one
wheel, and turning water on the other wheel; the two water-gates for these
nozzles are quickly opened or closed by hydrostatic pressure, afforded
from the water main. In addition to the usual brakes on the winding-reels,
a brake is placed on the wheel-shaft, so that it can be stopped in a very
short period of time.
The shock to the pipe by the almost instantaneous cutting off the water at
these hoisting-wheels (nearly one cubic foot per second) has not
apparently had any injurious, effect. To lessen this shock, a compensating
balance was designed, but which is not now in use. A wheel, of small
diameter, is used for the smithy, etc., running at a very high velocity.
The wheel driving the stamp-mill is 6 feet in diameter, makes 300
revolutions a minute, and is supplied through a 1-3/16 inch nozzle. The
head of water at this point is a few feet greater than at the other
wheels. Power is transmitted from the hoisting and mill-wheel shafts by
two and four ropes, the same as with the pumping rig. The amount of work
done, or of water used, has not been carefully determined; judging from
the indicator cards taken from the old steam-engines, the managers of the
Idaho believe that an efficiency of fully 80 per cent. of the theoretic
power of the water is obtained on the main driving-shafts of the
machinery. The substitution of water for steam-power has resulted in a
large saving of expense. Although the hills near by are covered with fine
forests, thus making wood cheap, and although a round price is charged for
water by the company furnishing it, the cost of the water is considerably
less than that of the wood formerly used as fuel. The cost of attendance
is altogether in favor of the water-wheels, which hardly require any
attention. The cost of the change from steam to water-power was
$46,496.32.
* * * * *
TEXAS CREEK PIPE AND AQUEDUCT.
A description of this work will be of interest in showing the general
practice followed in California for carrying water across deep mountain
gorges. In order to augment its water supply, the North Bloomfield Gravel
Mining Company desired to conduct water from a stream known as Texas
Creek, in Nevada County, California, across the Big Cañon branch of the
South Yuba River into the main Bloomfield flume or aqueduct, which was
located on the side of Big Cañon Creek, at a vertical elevation of 620
feet above the bed of the latter stream. The quantity of water to be
carried was about 32 cubic feet a second (1,250 miner's inches), which
could be diverted from Texas Creek at a point 480 feet vertical above the
Bloomfield flume. An aqueduct about 4,000 feet long, partly of ditch and
partly of flume, was needed to bring the water from the catchment dam on
the creek to the brow of the gorge. The vertical head for the pipe could
therefore be from a maximum of 460 feet down to any lesser head; with a
head of 460 feet, the pipe would be 4,790 feet long; and with a head of
220 feet, the length would be 4,290 feet. Assuming a maximum tensile
strain upon the iron of 16,500 pounds per square inch, with the formula
for the greatest head of about
d = (.359 l/h)^{1/5}, [or, v = 68 (dh/l)^{1/2}, and Q = 32],
and a lower value of the coefficient in the last equation for the lesser
heads, it was found, by calculation, that the least cost could be obtained
with a head from 300 to 350 feet. The head fixed upon was 303.6 feet, with
a length of 4,438.7 feet. A profile of the pipe, with nearly the same
horizontal and vertical scales (horizontal scale, showing slope lengths),
is given in Fig. 14; details are given in Figs. 15 and 16. The pipe was of
double riveted sheet iron, made in lengths of about 20 feet, and of the
following thicknesses:
1,349 linear feet, 0.083 inch thick.
220 " 0.095 "
240 " 0.109 "
250 " 0.120 "
320 " 0.134 "
610 " 0.148 "
1,450 " 0.165 "
Some of the iron was of the very poorest quality; the pipe was made by
contract in San Francisco, without the supervision of an inspector, as the
contractors were a firm of good reputation; the bad quality of the iron
was not detected until too late to have it corrected. Since then, the
writer has always had such pipes--the mines of which he has been the
manager using large quantities--made directly on the ground where they are
to be used; the pipe makers, in the latter case, always reject such sheets
as are too much below in thickness the standard gauge, and those which
show in passing through the rolls the bad quality of iron; tests of each
joint by hydrostatic pressure would add too much to the cost.
[Illustration: FIG. 16.]
The maximum tensile strain upon each of the seven thicknesses of iron used
was intended to be 16,500 pounds per square inch. Some of the sheets were
below the standard gauge, so that, in reality, the tensile strain is
sometimes as high as 18,000 pounds. The mean diameter of the pipe was
1.416 feet. The entrance into the pen-stock was tapered, so that the
coefficient of contraction was about 0.92. For pressures not exceeding say
380 feet, the joints were put together stove-pipe fashion. For greater
pressures, the joints were made by an inner sleeve riveted on one end of
the joint, with an outer lap-welded band, as shown by Fig. 15; lead was
run into the space between the outer band and the pipe, and then tightly
driven up by calking-irons. The pipe was laid under the bed of the Big
Cañon Creek, a large stream when in freshet, where the head below the
hydraulic grade line was 760 feet. Some of the lead joints leaked slightly
at first, but this was soon remedied by more careful calking. No man-holes
or escape-gates were used. The pipe for the larger part of the year is not
filled at its upper end; when such is the case, the water at the inlet
carries down the pipe a great quantity of air, for which escapes must be
provided to prevent a jarring or throbbing, which would soon destroy the
pipe. The escape air-valves used are shown by Fig. 16. They consist simply
of a heavy flap valve of cast-iron, with recess for lead filling to give
greater weight set on top the pipe, seating on a vulcanized rubber
cushion, and swinging on a loose hinge. When the pipe is only partly
filled with water, the valves drop down by their own weight, allowing the
air to freely escape; when the water rises above the level of a valve, it
is tightly closed by the resulting pressure. There are fourteen of these
valves, those on the lower end being designed to allow air to freely enter
the pipe in case it should burst in the deeper portion, and thus prevent
any collapse from atmospheric pressure. The valves have answered the
desired purposes most effectually. The pipe was hauled over a road built
to the inlet end, and shot down the mountain side by means of a V-shaped
trough of wood. For the lower end, the joints were hauled up the cliff
side into place by a crab worked by horse-power. On steep inclinations,
the pipe was held firmly in place by wire ropes fastened to iron pins in
the solid rock, as shown by the sketch. The covering of earth and stone
was 1 foot to 2 feet in depth; with steep slopes, the earth was kept from
sliding by rough dry walls, or by cedar plank placed crosswise. The pipe
was laid in 1878; the first year it broke twice, owing to the wretched
quality of the iron; since then, it has given no trouble, and has required
practically no attention. The cost of this work--ditch and flume 4,000
feet, and pipe 4,440 feet--was $23,779.53.
A comparison of the relative values of n, in the formula v = n (r s)^{½},
for the foregoing ditch, flume, and pipe will be instructive. The ditch
has a width on the bottom of 3 feet, on the top of 6 feet, with a depth of
3 feet, and an inclination of 20 feet per mile; its sides are rough, being
cut in part through the rock and with sharp curves, although fairly
regular; with a flow of about 1,300 miner's inches (32.8 cubic feet per
second) the ditch runs about full.
Therefore:
6 + 3
a = ----- × 3 = 13.5 ;
2
[TEX: a = \frac{6+3}{2} \times 3 = 13.5;]
a
r = ------------- = 1.41 ;
3.3 + 3 + 3.3
[TEX: r = \frac{a}{3.3 + 3 + 3.3} = 1.41;]
20 1
s = ------ = ----- ;
5280 264
[TEX: s = \frac{20}{5280} = \frac{1}{264};]
Q = 32.8, hence
Q
v = --- = 2.43;
a
[TEX: v = \frac{Q}{a} = 2.43;]
and
/ {½} \
n ( in v = n (r s)^ ) = 33.
\ /
[TEX: n\ (\text{in}\ v = n (r s)^\frac{1}{2}) = 33.]
The flume is of unplaned boards, rectangular, 2.67 wide × 2.83 deep, with
an inclination of 32 feet per mile. There are sharp curves, although these
were made as regular as practicable; the boiling action of the water
passing around these curves brought the flow line (Q = 32.8) nearly up to
the top of the sides; with a straight flume of the same size, the water
would have doubtless stood several inches lower.
Therefore:
a = 2.67 × 2.83 = 7.56 ;
a
r = -------------------- = 0.908 ;
2.83 + 2.67 + 2.83
[TEX: r = \frac{a}{2.83 + 2.67 + 2.83} = 0.908;]
32 1
s = ------ = ----- ;
5280 165
[TEX: s = \frac{32}{5280} = \frac{1}{165};]
Q = 32.8, hence
Q
v = --- = 4.34;
a
[TEX: v = \frac{Q}{a} = 4.34;]
and n = 59.
With the pipe,[6] 1.416 diameter,
d
r = --- = 0.354; Q = 31.69; v = 20.13.
4
[TEX: r = \frac{d}{4} = 0.354;\ Q = 31.69;\ v = 20.13.]
[Footnote 6: _Vide_ pages 120-122, Transactions American Society of Civil
Engineers for 1883.]
Allowing for loss of head due to imparting velocity to water, and for
contraction,
296.1
s= --------; and n = 131.
4438.7
[TEX: s = \frac{296.1}{4438.7};\ \text{and}\ n = 131.]
We hence have the following values of n, in v = n (r s)^{½}, Q being
constant:
Rough ditch, with sharp curves. 33
Rectangular flume, with sharp curves. 59
Wrought-iron pipe, with easy curves, coated with
asphalt, but with rivet-heads forming noteworthy
obstructions (m = 65.5, and 2m = n) 131
* * * * *
PARACHUTE HYDRAULIC MOTOR.
The very singular and simple hydraulic motor which we illustrate herewith
is the invention of a Russian engineer, Mr. Jagn. It is scarcely as yet
known in Western Europe, where, however, something will probably be heard
of it ere long. Its true field would seem to be Egypt, India, or any
country where canals or rivers are used for irrigation, and where it is
desired to draw water from them at particular spots in the simplest and
cheapest manner. At present in nearly all such cases water is raised by
hand or steam power; nevertheless it must be obvious that the current of
the canal itself, slow though it may be, is quite sufficient to raise a
small portion of the discharge to the very moderate height generally
needed to lift it over the banks into the adjoining fields. Why then is it
not employed for the purpose? The answer is obvious, when we consider the
various hydraulic motors at present in use. Of course, motors worked by
water pressure must here be excluded; and we are left with scarcely
anything but the undershot wheel, the turbine, and the screw pump. All
these require expensive buildings and erections to set them to work,
present but a very small fraction of their surface to the water at any one
time, and must be very large and costly if they are to draw even a very
moderate amount of power from such a source. There is no possibility of
adjusting them readily to suit variations in the speed of the current or
in the quantity of water required, nor of moving them from place to place
should this be convenient.
[Illustration: PARACHUTE HYDRAULIC MOTOR.]
The motor of Mr. Jagn is on a totally different principle. Its essential
features consist, as shown, of an endless rope made of hemp or aloe fiber,
which takes a turn or two round a pair of drums mounted on a barge or
pontoon, and then passes down the channel to return over a pulley hung
from a floating punt, at such a depth that the whole of the rope is
immersed in the water. Along this rope are suspended at equal intervals a
number of parachutes made of sail cloth. The rope passes through the
center of each of these, and to it are attached a series of strings, the
other ends of which are connected to the outside edge of the parachute.
Thus they act like the spokes of an umbrella to prevent the parachute from
opening too far under the pressure of the current. The parachutes must be
placed so far apart that the current may act fairly on each, and the sum
of the pressures forms the force which draws the rope through the water.
The moment, however, that any parachute has passed round the return
pulley, the current acts upon it in the opposite direction. It then shuts
up like an umbrella, and assumes a volume so small that its resistance on
the return journey is insignificant. After passing round the drum at the
upper end, it at once opens afresh of its own accord, and once more
becomes part of the moving power of the whole system. The parachutes are
formed by first cutting out a complete circle of cloth, and then taking
from this a sector equal to one-fifth or one-sixth of the total area. Such
parachutes are found to keep their form when stretched by the water better
than a surface originally spherical, although the latter would be
theoretically more correct. The motion of the drum is transmitted by spur,
gear, or otherwise as may be required, to give the requisite speed.
It will be seen that the advantages of the system are as follows: First,
the facility it offers for obtaining a large working area, which may be
increased or diminished at will, according to the requirements of the
moment, by lengthening or shortening the rope. Secondly, the ease with
which it is erected and set to work. Thirdly, the small part of the river
section which it occupies, so as to present no obstacle to navigation.
Fourthly, the ease with which it can be mounted on a barge of any kind,
and carried wherever it may be needed. Fifthly, it is not stopped, like
all other hydraulic motors, by the appearance of ice--it has, in fact,
already been worked under ice in the Neva. At the same time, winds and
waves have no influence upon it.
The principle of the apparatus is not altogether new. In 1872 there was
tried on the Ohio River an arrangement termed the Brooks motor. It was
composed of two drums, placed horizontally and parallel to each other.
Round these there passed endless chains at equal spaces apart on the
length of the drums, and to these chains were fixed wooden blades or arms
of a curved form, and so jointed to the frames that they opened when
moving in one direction, and closed down on the chain when moving in the
other. In this machine the weight of the chains was a serious obstacle to
obtaining any large amount of power. The whole apparatus was mounted on a
heavy wooden scaffold, which proved an impediment to the flow of the
river. Again, the resistance due to the surface of the returning blades
and to their stiffness was found to be far from insignificant.
In the present system Mr. Jagn has found, after many experiments, that the
best effect was obtained when the parachutes were spaced apart at twice
their diameter, and when the rope made an angle of 8 degrees to 10 degrees
with the current. It is found that when open and in motion the parachutes
never touch the bottom. This was the case with a rope containing 180
parachutes of 4 feet diameter, and working in a depth of only 6 feet. This
is easily explained by the fact that the velocity of a current always
diminishes as it approaches the bottom. Hence the pressure on the lower
part of the parachute will be less than that on the upper part; but the
former pressure tends to draw the parachute downward, while the latter
tends to raise it to the top of the water. Thus, the latter being the
larger, the parachute will always have a tendency to rise. In fact, it is
necessary to sink the return pulley sufficiently deep to make sure that
the parachutes will not emerge from the surface. For the same reason no
intermediate supports are needed over the driving span; if any are needed
it is for the return span, on which the parachutes are closed. Of course,
if metal were used instead of hemp, the case would be entirely different,
and intermediate supports would have to be used for anything but very
moderate lengths.
In practice, Mr. Jagn has employed two ropes wound upon the same pair of
drums, which are mounted upon a pontoon. The ropes are spread out from
each other, as in Fig. 1, making an angle of about 10 degrees. The low
specific gravity of the system enables ropes to be employed of as great a
length as 450 yards, each of them carrying 350 parachutes of 17.2 square
feet area. As half of these are in action at the same time, the total
working area for the two cables is 5,860 square feet. This immense area
furnishes a considerable amount of power even in a river of feeble
current. Comparing this with a floating water wheel of the type sometimes
employed, and supposing this to have only 172 square feet of working area,
such a wheel must have a length of 46 feet, a diameter of 23 feet, and
seventy-two floats, each 2½ feet wide. The enormous dimensions thus
required for a comparatively small working area point sufficiently clearly
to the advantage which remains on the side of the parachute motor.
The general arrangement of the system is shown in the engraving. Behind
the return pulleys, D D, are attached cords, A A, with some parachutes
strung upon them. These present their openings to the current and preserve
the tension of the connecting ropes. At the further end of each cord is a
board, B, which is kept in a vertical plane, but lying at a slight angle
to the direction of the current; and this acts to keep the two moving
ropes apart from each other. The two return pulleys are, however,
connected by a line, E, which can be shortened or lengthened from the
pontoon, and in this way the angle of inclination between the two ropes
can be varied if required. A grooved pulley presses upon the trailing span
at the moment before it reaches the circumference of the drum. It is
mounted on a screwed spindle, which is depressed by a nut, and thus makes
the wet rope grip the outside of the drum in a thoroughly efficacious
manner.
The author has made a theoretical investigation of the power which may be
developed by the system, and has worked out tables by which, when the
velocity of the current and the other elements of the problem are known,
the power developed by any given number of parachutes can be at once
determined. We do not reproduce this investigation, which takes account of
the resistance of the returning parachutes and other circumstances, but
will content ourselves with quoting the final equation, which is as
follows: T = 0.328 S V³. Here T is the work done in H.P., S is the total
working area in sq. m., and V is the velocity of the current in m. per
sec. Taking V = 1, and S = 1 sq. m., which is by no means an impracticable
quantity, we have T = 0.328 H.P. per sq. m. We may check this result by
the equation given, in English measures, by Rankine--"Applied Mechanics,"
p. 398--for the pressure of a current upon a solid body immersed in it.
This equation, F = 1.8 m A v² / 2g, where m is the weight of a unit of
volume of the fluid--say 62 lb.--A is the area exposed, and v the relative
velocity of the current. Mr. Jagn finds that the maximum of efficiency is
obtained when the rope moves at one-third the velocity of the stream. If
this velocity be 3 feet per second, we shall have v = 2. and we then get F
= 7 lb. per sq. ft. very nearly. Now 1 sq. meter = 10.76 sq. ft., and a
speed of 1 ft. per second (which is that of the rope) is 60 ft. per
minute. Hence the H.P. realized in the same case as that taken above will
be 7 × 10.76 × 60 / 33,000 = 0.137 H.P. The difference between the two
values is very large, but Rankine, of course, depends entirely on the
value of the constant 1.8, which is quite empirical, and is for a flat
band instead of a hollow parachute. Taking, however, his smaller figure,
and an area of 544 square inches, which Mr. Jagn has actually employed, we
get a gross power of = 0.137 × 544 = 7.43 H.P. Hence it will be seen that
the amount of power which can be realized by the system is far from being
inconsiderable.
Lastly, we may point out that the durability of the apparatus will be
considerable. There is no wear except at the moment when the rope is
passing round the drum, and even then there need be no slipping or
grinding. The apparatus worked in the Neva was in very good condition
after running for four months day and night. After five months about
one-fifth of the parachutes had to be replaced, but after seven months the
hemp rope still showed no signs of wear. We think we have said enough to
show that for certain purposes, and especially, as we have, already
mentioned, for irrigation purposes, the new motor is well worthy of a
careful and extended trial. It may be questioned even whether we have not
here the germ of an idea which may hereafter enable us to solve one of the
most interesting and important of engineering problems, viz., the
utilization of the great store of power provided for us twice daily in the
ebb and flow of the tide.--_The Engineer._
* * * * *
IMPROVED SHAFTING LATHE.
Our engraving represents a new departure in shaft turning lathes, and is
the result of thirty years' experience in the manufacture of shafting,
with many years' study, to perfect a machine of the greatest practical
capacity and efficiency.
[Illustration: IMPROVED SHAFTING LATHE.]
The principal points of difference from a common engine lathe are readily
distinguished, among which may be mentioned the absence of centers and
tail stock, a traveling head with hollow driving spindle, and a stationary
tool rest and water tank. By dispensing with a tail stock a much shorter
bed may be used, and the hollow driving spindle enables any length shaft
to be turned, with one setting of the tools. The tool rest is so arranged
as to allow of perfect lubrication of the tools, keeping the shaft cool,
and at the same time holding it perfectly rigid and strong; the operator
is not required to travel the length of the bed, but remains near the
driving belt, feed gearing, etc. Power is communicated to the driving
spindle by means of a sliding pinion on a splined rod inside the bed, the
driving belt and gears being at the end.
The driving head, after having traveled the length of the bed and turned a
shaft, is returned by a quick feed, and stops automatically, allowing
nearly time enough for the operator to grind tools and be ready with
another shaft, thus economizing the time completely.
Wood, Jennison & Co., Worcester, Mass., are the makers, and they say that
with a good quality of iron they have turned three hundred feet of two
inch iron in ten hours.
* * * * *
POWER STRAIGHTENING MACHINE.
The machine is provided with a pair of rolls at each end of the bed, which
are adjustable for different lengths of shaft, and are made to revolve by
power applied through suitable gearing and a splined rod inside the bed;
the bar of iron being placed on the periphery of the rolls receives a
rotary motion by friction, and shows the crooked places in the same way
and with the same ease as though rotating on centers in the usual manner;
vertically adjustable blocks are arranged in the base of the press to
support the iron; power is applied by means of gearing to a splined rod at
the back of the machine, on which is a sliding clutch connecting, at the
will of the operator, with an eccentric; the eccentric conveys motion and
power through a link to the elbow joint at the front of the press, which
forces a plunger down against the iron.
[Illustration: POWER STRAIGHTENING MACHINE.]
Sufficient adjustment is provided for different sizes of iron by turning a
nut at the top of the press.
Any point in the length of the bar can be reached by moving the press on
the bed. Any length of iron can be straightened, and the most laborious
and disagreeable work in the process of making shafting is rendered easy
and rapid. Made by Wood, Jennison & Co., Worcester, Mass.
* * * * *
HYDRAULIC MINING IN CALIFORNIA.
By GEORGE O'BRIEN.
Our knowledge of the primitive operations of the aboriginal inhabitants of
the globe in pursuit of gold is barely traditional, as we are only aware
that from very early times the precious metal was collected and highly
prized by them, and that they chiefly extracted the visible gold, which
existed in prodigious quantities on or closely beneath the surface of the
earth, and of its being particularly abundant in Asia and Africa. But we
can draw more positive conclusions as we survey remains of the rude but
effective contrivances used by them in later, but still remote, periods,
with full evidence as to the extent of their operations, in the numerous
perpendicular shafts located at short distances from each other, over
large areas of auriferous gravel in India, as well as from precisely
similar memorials of ancient workings which remain also further
demonstrations, in the abandoned "hill diggings," and shifted beds, and
beds of rivers, in Peru South America, flowing between the sea and coast
ranges of the Andes, descending in a northeasterly direction to the river
Amazon, and that their much coveted and enormous productions were the
accumulated riches of the Incas, transferred as spoils of war to their
Spanish conquerors in the sixteenth century. And for similar explorations
in the same class of depositions we have the experiences of our own times,
and which explain by comparison all the previous operations alluded to.
Thus in the year 1849, after the cession of the northern portion of Mexico
to the United States of North America, the rich mineral district of
California was at once invaded by hardy and intelligent bands of mining
adventurers from all parts of the world, who, with little other means at
their disposal but pick, shovel, and pan, soon fell on the productive bars
of rivers and rich ravines where the gold was trapped, derived from its
original birthplaces, where it had been sparsely disseminated, to be
dispersed by the subsequent disintegrations and denudations of the
mountains themselves, and deposited in a disengaged form for the first
comer; and so perfect were sometimes these concentrations, in certain
localities where water once streamed, that, divested of its earthy matrix,
the cleansed pure metal was found deposited, detained by its superior
specific gravity, on the bare rock, and only hidden from vision by a
slight covering of vegetable mould. In this manner, as an example of such
concentration, a "pot" or "find" (in mining parlance) to the value of
£10,000 was collected in a space of 15 square yards, or within the limits
of a particular "mining claim," at the foot of Mokulumne Hill, in a
southern county of California, soon after the territorial transfer from
Mexico. And in search of such locations we must account for the numberless
shafts which still exist both in India and Peru, and sometimes sunk within
a few feet of each other, passing through the alluvium to a depth of 40
feet to the bed rock.
These mining adventurers soon extended their explorations over the other
recently acquired territories, and built Virginia City, the capital of
Montana, with the gold derived from the alluvium of a river channel which
they excavated; and its inhabitants were the founders of an institution
called the Vigilance Committee, with "Lynch law," and by it ruled
supremely for many years. But their surface diggings, by the manual
operations alone of multitudes, were soon exhausted in every direction,
and then their energies and powers of invention were dedicated to discover
and explore deeper and more permanent depositions, along the western
slopes of the Sierra Nevada, the Andes of the Western Territories, and
which originally were without doubt several miles higher than they are at
the present time--probably 20,000 feet above the sea-level--and of which,
or whatever superior elevation they formerly had, the greater portion of
it has already been removed, by the continuous natural action of
centuries, to form there, as elsewhere, the plains and prairies of the
earth, burying and diverting by the mutation the ancient river system,
whose sources of supply were consequently extinguished by the removal of
these altitudes. These denudations and subsequent depositions have been
caused by alternations of temperature and combined action of air, water,
and time since the creation of the world; and powerful demonstrations of
these transformations instruct us in all directions, if we care to observe
them. Thus in "Little Cottonwood" ravine, in the Wahsatch range of
mountains in Utah Territory, lie isolated in the center of the valley huge
masses of metamorphic granite, some blocks of which weigh individually
thousands of tons, and were dislodged from the hills--which on either side
are of limestone formation--with no visible granite in them, having been
undermined by the removal of their pulverized basis by denudation, and
which is the material now forming the tablelands, the foundation, of Salt
Lake City. The blocks of granite, having alone resisted the atmospheric
changes, were precipitated into the valley beneath, and the Mormons are
now constructing their cathedral church from these granitic remains.
The melting of the snow which formerly capped all these ranges of
mountains furnished the water that once flowed in the extinguished
channels of ancient rivers, and whose now diverted waters were also the
powerful agent to assist in causing these marvelous alternations; and by
the means of hydraulic mining we can advance our feeble knowledge on the
subject.
These mighty changes have gradually been accomplished, and the accumulated
denudations of the mineral zones have defended themselves by strata of
crystallized silicates of quartz of various thicknesses, and thus in
places beneath such system of defense, or by their own concretion, have
preserved in many localities a thickness of from 500 to 600 feet of
conglomerate, but without this necessary cementation its further removal
is very certain when again attacked by water. An example of this
continuous process is very observable in "Death Valley," Lower California,
where a width of about 100 miles has been filled up from the hills to the
gulf of same name, invading and occupying its former bed; and this
activity is still proceeding, and a temporary formation of tableland
above it is in course of removal, although already overgrown with forest
trees, which are toppling over the side which is being attacked. But
eternal snow now only covers a small portion of these Sierras, and a
period of comparative repose may be expected, as the distribution has
already been far advanced by the excessive reduction of the mountains.
The deep and extensive depositions which I now attempt to describe
attracted the early attention of the mining adventurers, and were called
"hill diggings," but not being properly understood were therefore not
immediately operated upon, and remained in abeyance, while the lower,
richer, and more manifest alluvials endured. They were designated "blue
gravel," the color being due to the action of sulphuret of iron and other
salts, the cementing auxiliaries requisite to form the hard conglomerate,
and on exposure to the atmosphere changes color to yellow and violet,
losing also its firmness by oxidation.
The "great blue lead" is another important mining term and designates the
alluvium found reposing in a well-defined channel on the bed rock, being
the well-worn path of an ancient river; and it is obvious that the
material in these channels should be richer than the general mass beyond
their limits.
"Rim rock" is the boundary line of the banks of the old channel, and, like
the bottom, is well worn and corrugated by the running water into cavities
and "pot holes," where the force of the stream eddied. The width of these
channels varies from 60 to 400 feet, and the cement near the rim and
bottom is always richer than elsewhere. The wider and deeper channels
generally course from N. to N.W. The richest and most explored belt of
gold-bearing alluvium in California lies between the South and Middle Yuba
Rivers, commencing near Eureka, in Nevada county, and extends downwards to
Smartsville and Timbuctoo, in Yuba county, a distance of 40 miles; and
from among snowy mountains the country falls gradually from where the
ravines or canons are cut by the actual rivers, which are 2,000 feet
beneath the auriferous gravel and region near Smartsville, and 2,000 feet
above the Yuba River, where snow is unknown, and near its terminus the
ancient river bed courses more westerly than it does above it, and crosses
Yuba below Timbuctoo, where the auriferous depositions disappear. The
whole distance of 40 miles has been ransacked by the earlier adventurers,
and around the village of Timbuctoo was a center famed for its wonderful
yield of gold, obtained chiefly in the ravines, in holes, and depressions
in the bed rock. These hollows detained the concentrations of the
denudated alluvium from the altitudes, and were generally closely beneath
the surface, and by such guidance and means of discovery the miners traced
the gold up the ravines to their sources in the lofty mounds and deposits,
or hills of cemented conglomerate, near Eureka in Nevada county; and by
constructing canals from a higher level began the new system of "hydraulic
mining" and washing, and gradually extended their operations over the area
of the metallic zone mentioned, of 40 miles long by 20 wide, using the
Yuba River below Timbuctoo to receive and discharge the tailings, or
refuse from their operations. The result in gold was considerable, but the
system is from its violent nature difficult to control, by presuming to
handle and remove such huge depositions in order to collect the richest
material. The idea was bold, being an anticipation of Nature's operations;
but the equitable disposal of the "tailings" in a cultivated country is
impossible, as the silt runs down the rivers, creating banks and bars in
their channels, obstructing navigation and agricultural arrangements.
_General Description of Hydraulic Mining._
The first work to be accomplished, after calculating that the amount or
value of the material to be operated upon is sufficient to guarantee the
cost of the undertaking in general, is the construction of a canal or
canals, to convey the requisite volume of water from the fountain-head,
and of sufficient elevation to command the ground to be worked upon,
having also in view the levels of the necessary tunnels and shafts as
outlets for the discharge of the gravel through them, these being
engineering operations requiring much skill and labor to avoid useless
after-cost.
Aqueducts of considerable elevation have to be constructed across deep
valleys, and the speculation is at all times problematical, as the ground
cannot be properly tested until the water arrives upon it, and disputes
may arise between the shareholders of the canal and the mining company,
ending frequently in the one devouring the other, unless the two interests
be quickly amalgamated.
The starting point should be the lowest level, or "bed rock," on the white
cement in the ancient channel, which is probably the original silt
collected in it, and is harder than the conglomerate above it, which is
more easily removed. The courses of these beds can be easily traced by
landmarks and undulations, and occasional exposures of the bed rock at low
levels; also trial shafts are sunk in various places in search of it, to a
depth of 100 feet, passing through blue gravel. The grades of these beds
are not steep, being from 10 to 40 feet per mile as of an ordinary river,
and the calculated thickness of the alluvial conglomerate is about 600
feet in many places across the ridge between the South and Middle Yuba
River across the Columbia.
The power of the water for the operation is dependent on a given volume
deposited in a reservoir, and at sufficient elevation above the points of
discharge, as on this depends effectivity to tear down the gravel. It is
delivered to the miner by huge pipes made of wrought iron, and laid down
to follow the curvatures of the surface of the ground; and the pipe I now
treat of, belonging to the Excelsior Water Company, has a diameter of 40
inches on a length of 6,000 feet, and 20 inches on the rest of its length
of 8,000 feet, being 9,000 feet in all; and this large pipe forms an
inverted siphon across a valley, following on the gravel, to the top of
the hill into the reservoir.
These pipes offer advantages over wooden aqueducts for spanning chasms,
and also to avoid coursing the sides of valleys; being also cheaper to
construct in general, and less liable to accidents from fire and storms,
and have the convenience for conveying the water from point to point, as
the work of excavation advances, necessitating the removal of portions of
the aqueduct forward. The watershed, or reservoir, of the Excelsior
Company embraces the valley of the South Yuba and its affluents, and the
entire cost of its eight amalgamated canals was 750,000 dollars.
The rainfall during three years in the mountains averaged 49 inches
annually, while the medium in the same period did not exceed 20 inches in
the plains beneath. The height of the reservoir above the tailing, or Yuba
River, is 393 feet: and the height of the head above the floor, or outlet
sluice-tunnel, of the Blue Gravel Mining Company was 197 feet.
The exact quantity of water required to wash every class of gravel is
difficult to estimate, but no quantity or pressure would be excessive if
properly arranged. The measurement of water is effected by miner's
inches, by allowing it to flow from the reservoir of the seller to the
purchaser through a box 10 or 12 feet square, with divisions to obtain a
quiet head, with a slide or opening capable of adjustment to any required
measure; thus an opening of 25 inches by 2 inches, with a quiet head of 6
inches above the middle of the orifice, would give 50 inches, or about
89,259 cubic feet of water, flowing during ten hours per day, being an
amount necessary for a first-class operation. The capability of the
Excelsior Canal in rainy seasons reached to a delivery in twenty-four
hours, to the various mining companies, of 21,120,000 cubic feet of water,
or 8,000 miner's inches, and the value of the water paid for by the Blue
Gravel Company in forty-three months ending November 9, 1867, was 157,261
dollars, being at the rate of 15 cents of a dollar per miner's inch; and
the proportion of water used to wash down 989,165 cubic yards of gravel
was 17,074,758 cubic yards, or 17¼ cubic yards of water to 1 cubic yard of
gravel; and when at work the quantity of gravel daily moved was 1,298
cubic yards, and the estimated cost to move one cubic yard of gravel was 5
and 7/10 cents of a dollar. But in the face of contingencies the Blue
Gravel Company moved 1,000,000 cubic yards of gravel in four years, or at
the rate of 250,000 cubic yards per annum, and the cost of washing each
cubic yard stands thus:
Cents.
Cost of water, at 15 cents per miner's inch 5.77
Cost of labor, gunpowder, sluices, and
superintendence 16.10
-----
21.87
Or 21¾ cents of a dollar per cubic yard.
Thus the gravel should contain gold to the value of 22 cents of a dollar
per cubic yard to cover cost, and the value of the gravel referred to
ranged from 20 to 45 cents per cubic yard; and the cost of work done in
shafts and tunnels, in the said Blue Gravel Company's Mining claim,
reached 100,000 dollars. But with the cost of the necessary canals paid
for by the Excelsior Water Company apart, the total cost amounted to about
1,000,000 dollars, and we must note that the latter company sold water to
other mining companies.
The gross yield in gold of the Blue Gravel Company in four years was
837,399 dollars, and in the year 1866 the returns from the Blue Gravel
Company paid all the costs of the developments; but in 1867 assessments
were paid by the owners to meet the deficiency arising from the cost of
sinking two new shafts, and driving fresh tunnels on the lowest levels,
which evidently contain on the bed rock the richest concentrations.
In smaller mining adventures of this description, involving less capital,
large profits have been made in the gold-bearing zone treated of, by also
not having invested in costly canals, which would not have repaid the
latter investment; and thus it is evident that the water companies are
dependent blindly on the prosperity of the miners.
I will now more minutely describe the actual mining operations. The mining
ground being selected, a tunnel is projected from the nearest and most
convenient ravine, so that the starting-point on the bed rock toward the
face of the ravine shall approach the center of the material to be removed
at a gradient of 1 in 10 to 1 in 30. The dimensions of such tunnels are
usually 6 feet in width by 7 in height, and continuing in contact with the
hard river-bed, for the greater ease of excavation, collection of gold,
and conservation of quicksilver amalgam.
These tunnels vary in length from a few hundred feet to a mile, and some
of the longer ones occupying from one to seven years in execution, at a
cost of from 10 to 60 dollars per foot of frontage. The tunnel of the Blue
Gravel Company, with length of 1,358 feet, cost in labor alone 70,000
dollars, but it could now be driven for 35,000 dollars, as skilled labor
is cheaper now than then. The grade in this tunnel is about 12 per cent.,
and the end of the tunnel is designed to be 170 feet of elevation, and
reaching to a point beneath the surface of the gravel which is being
operated upon, and where a shaft or incline is sunk to or through the bed
rock or gravel, until it intersects the tunnel.
The object of this laborious operation is obvious, as the long tunnel
becomes a sluiceway, and through the whole length of which sluice boxes
are laid, for the double motive of carrying off the material and saving
the gold, and for this purpose a trough of strong planks is placed in the
tunnel, 2½ feet wide, and with sides high enough to contain the stream.
The pavement of the trough is generally laid of blocks of wood 6 inches in
thickness, cut across the grain, and placed on their ends, to the width of
the sluiceway. The wooden blocks are usually alternated with sections of
stone pavement, the stones being set endwise, and in the interstices
between the stones and wooden blocks quicksilver is distributed, and as
much as 2 tons of this metal is required to charge a long sluice. The
water in the canal is brought by aqueducts, or other means, to the head of
the mining ground, having an elevation of 100 to 200 ft. above the lowest
level of the mining ground, and is finally conveyed to it by iron pipes,
sometimes sustained on a strong incline of timber.
These pipes are of sheet iron, of adequate strength, riveted at the
joints, and measure from 12 to 20 inches in diameter, and communicate at
the bottom with a strong prismatic box of cast-iron, on the top and sides
of which are openings for the adaptation of flexible tubes, made of very
strong fabric of canvas, strengthened by cording, and terminating in
nozzles of metal of 2½ to 3 inches in diameter. From these nozzles the
streams of water are directed against the face of the gravel to be washed,
exercising incredible effectivity.
The volume of water employed varies of course with the work to be done;
but it is not uncommon to see four such streams acting simultaneously on
the same bank, each conveying from 100 to 600 inches of water per
hour--1,000 miner's inches being equal to 106,600 cubic feet of water per
hour, constantly exerting its force under a pressure of 90 to 200 pounds
to the square inch, varying with the height of the column.
Under the continuous action of this enormous force, aided by the softening
power of the water, large sections of the gravelly mass are dislodged, and
fall with great violence, the _debris_ speedily disintegrating and
disappearing under the resistless force of the water, and is hurried
forward in the sluices to the mouth of the shaft, down which it is
precipitated with the whole volume of turbid water. Bowlders of 100 to 200
lb. in weight are dislodged and shot forward by the impetuous stream,
accompanied by masses of the harder cement which meet in the fall, and by
the concussion from the great bowlders the crushing and pulverizing agency
required is found to disintegrate it. The heavy banks, of 80 feet and
upward, are usually worked in two benches, the upper never being so rich
as the lower, and also less firm, and therefore worked away with greater
rapidity.
The lower section is much the more compact, as this stratum on the bed
rock being strongly cemented resists great pressure, and even sometimes
the full force of the streams of water, until it has been loosened by
gunpowder or other explosives. For this purpose adits are driven in on its
foundation-point of from 40 to 70 feet and more from the face of the bank,
and drifts are extended at right angles therefrom to a short distance on
each side of the adit, and in these drifts a large quantity of gunpowder
is placed (from 1 to 3 tons), and fired at one blast, having been
previously built in with masonry. And in this manner the compact
conglomerate is broken up, and then the water easily completes its work.
Sometimes in the soft, upper strata the systems of tunnel is extended, as
in a coal-mine, by cross alleys, leaving blocks which are afterward washed
away, and then the whole mass settles, and is disintegrated under the
influence of water. The wooden sluices in the tunnels already described
are often made double for the convenience of "cleaning up" one of them,
while the other remains in action. The process of cleaning up is performed
according to the quantity and richness of the material worked upon, at
intervals of twenty to forty days, and consists in removing the pavement
and blocks from the bed of the sluice, and then gathering all the amalgam
of gold and rich dirt collected, and replacing the locks in the same way
as at first. Advantage is taken on this occasion to reverse the position
of the blocks and stones when they are worn irregularly, or substitute new
ones for those which are worn through. The mechanical action of the
washing process on the blocks is of course very rapid and severe,
requiring complete renewal of them once in eight to ten weeks. Some miners
prefer a pavement of egg-shaped stones set like a cobble-stone flooring,
the gold being deposited in the interstices. Most of the sluiceways are,
however, paved with rectangular wooden blocks, with or without stones as
described. Standing at the mouth of one of the long tunnels in full
action, any person unaccustomed to the process is struck with
astonishment, amounting almost to terror, as the muddy mass sweeps onward,
bearing in its course the great rolling bowlders, which add their din to
the roar of the water, the whole being precipitated down a series of
falls, at each of which it is caught up again by new sluices of timber,
lined like the first, and so onward and downward many hundreds of feet
until the level of the river is reached, at a distance of about a half
mile or more from the mouth of the first tunnel.
At each of these new falls of 25 to 50 feet the process of comminution
begun in the first shaft is carried on, and a fresh portion of gold
obtained. Rude as this plan of saving gold appears to be, more gold is
procured by it than by any other method of washing yet devised for this
process of work, and the economical advantages obtained by it cannot be
surpassed, as it would be impossible to handle such vast quantities of
material in any other way, and we can compare the cost of washing and
handling a cubic yard of auriferous gravel by it as follows:
Dollars.
By manual labor with the pan 15.00
" " with rocker 3.75
" " with the long tom .75
By the hydraulic process .15
But this process, even if effective or profitable as a mining operation,
may be prejudicial to the interests of the general public, if conducted on
a large scale, as the vast quantity of material which it so suddenly
removes is merely shifted into the shallows beneath, to be redistributed
by every freshet to points lower and lower down until it reaches the
sea-coast, creating bars at the mouths of rivers in its course, and
changing the hydrography of harbors--as it has done with the Bay of San
Francisco by its silt.
The hills behind, torn up and washed by the gold miner, are abandoned as
desolate and irredeemable; and the costly canals, constructed with
peculiar conveniences for mining purposes, eventually fall into disuse
from being too expensive to maintain or alter for general agricultural
uses.--_Journal of Science._
* * * * *
THE TREATMENT OF CHOLERA.
From the host of remedies and suggestions that are now deluging the
European medical press, we select the following from Dr. Henry A. Rawlins,
in the _London Med. Times_, July 12. 1884:
The man suffering from cholera has been suddenly deprived by diarrhoea of
an enormous quantity of the fluid part of his blood. This loss is one of
simple transudation, increasing as the powers of life decrease. This
_sudden_ loss produces intense prostration, and renders the heart
powerless to perfect the circulation. The body, thus deprived of oxygen,
speedily runs into decomposition, even before life is extinct. Have we any
agent by which we can collect and press forward these scattered and
lethargic drops of blood to the heart, and enable it to renew the
circulation, and with it the blessings of oxygen to the body? My reply is
emphatically--Yes! Flannel bandages from the toes to the trunk, around the
abdomen, and from the fingers to the body, will effect this object
perfectly. Remark that the effect is gradual, increasing with every turn
of the roller, but would be in full force in about twenty minutes. By thus
exposing the blood in the lungs to the action of oxygen in its diluted
form, as it is in the air, instead of pure oxygen, the reaction would
neither be too rapid nor too dangerous. In confirmation of my views, I
have this day learned that it is the custom in India to wear a double roll
of flannel around the abdomen, as a preventive to cholera. The other
advantages resulting from the use of the flannel bandages are:
1. That they prevent the escape of heat from the body of the poor creature
who is already in a state of refrigeration.
2. By their firmly and equally grasping both flexor and extensor muscles
alike, they are steadied, and rendered much less likely to be affected
with spasmodic action or cramp.
3. By their steady _elastic_ pressure and support of about 160 pounds,
they persistently keep up and sustain the circulation of the blood, which
they had previously restored.
4. That the oxygen thus well secured to the blood will, I believe, prove
quite sufficient to neutralize the original poison, and also destroy its
effects.
5. That this much can at least be claimed for their use--that they remove
from nature a stumbling-block, which prevented her from exercising her
marvelous recuperative powers. Diluted sulphuric acid is the best medicine
to arrest the flux from the bowels, acting also as a tonic. It should be
given in five-minim doses about every half hour, with rice gruel. By
adopting this plan, the natural process is brought about, that of the
starch being converted into grape sugar. Plenty of white of egg, well
whipped up, so as to nourish the body and convey oxygen into the stomach,
which it will appropriate, should be given. Opium, in small quantities,
and other stimulants, should be given according to the necessities of the
case. May it not be well, through the medium of wet sponge over the
thorax, to apply a continuous but gentle current of galvanism, so as to
stimulate the heart's action, keep alive the respiratory movements, and
thereby assist in the maintenance of the functions of the body?
* * * * *
TEMPERATURE, MOISTURE, AND PRESSURE IN THEIR RELATIONS TO HEALTH.
At the recent meteorological conference held at the Health Exhibition, Dr.
J.W. Tripe read a paper of much interest on some relations of
meteorological phenomena to health.
In ages long past these relations excited much attention, but the
knowledge concerning them was of the vaguest kind; and indeed, even now,
no very great advance has been made, because it is only quite recently
that we have been able to compare a fairly accurate record of deaths with
observations taken at a number of reliable meteorological stations. The
more useful and searching comparison between cases of sickness, instead of
deaths, and meteorological phenomena has yet to be accomplished on a large
scale in this country, and especially as regards zymotic diseases. In
Belgium there is a Society of Medical Practitioners, embracing nearly the
whole country, that publishes a monthly record of cases of sickness, of
deaths, and of meteorological observations; but the only attempt on a
large scale in this country, which was started by the Society of Medical
Officers of Health for the whole of London, failed partly from want of
funds, and partly from irregularity in the returns. My remarks, which must
necessarily be very brief, will refer to the relations between (1)
meteorological phenomena and the bodily functions of man, and (2) between
varying meteorological conditions and death-rates from certain diseases.
As regards the first, I will commence with a few brief remarks on the
effects of varying barometric pressures. A great deal too much attention
is paid to the barometer if we regard it as indicating only, as it really
does, variations in the weight of the column of air pressing upon our
bodies, because, except at considerable elevations, where the barometer is
always much lower than at sea level, these variations produce but little
effect on health. At considerable elevations the diminished pressure
frequently causes a great feeling of malaise, giddiness, loss of strength,
palpitation, and even nausea; and at greater heights, as was noticed by
Mr. Glaisher in a very lofty balloon ascent, loss of sight, feeling, and
consciousness. These were caused by a want of a sufficient supply of
oxygen to remove effete matters from the system, and to carry on the
organic functions necessary for the maintenance of life. On elevated
mountain plateaus, or even in high residences among the Alps, an increased
rapidity in the number of respirations and of the pulse, as well as
increased evaporation from the lungs and skin, occur.
For some years past, many persons suffering from consumption, gout,
rheumatism, and anæmic affections have gone to mountain stations, chiefly
in Switzerland, for relief, and many have derived much benefit from the
change. It must not, however, be supposed that diminished atmospheric
pressure was the chief cause of the improvement in health, as its
concomitants, viz., a diminution in the quantity of oxygen and moisture
contained in each cubic foot of air, probably the low temperature, with a
total change in the daily habits of life, have assisted in the beneficial
results. The diminution in the quantity of air, and consequently of
oxygen, taken in at each breath is to a certain extent counterbalanced by
an increased frequency and depth of the respirations, and a greater
capacity of the chest. In this country, alterations in the barometric
pressure are chiefly valuable as indicating an approaching change in the
wind, and as well as of the amount of moisture in the air; hence the
instrument is often called "the weather glass." A sudden diminution in the
atmospheric pressure is likely to be attended with an escape of ground air
from the soil, and therefore to cause injury to health, especially among
the occupants of basement rooms, unless the whole interior of the building
be covered with concrete.
_Temperature._--Experience has shown that man can bear greater variations
of temperature than any other animal, as in the Arctic regions a
temperature of -70 degrees Fahrenheit, or more than 100 degrees below
freezing point, can be safely borne; that he can not only live but work,
and remain in good health, in these regions provided that he be supplied
with suitable clothing and plenty of proper food. On the other hand, man
has existed and taken exercise in the interior of Australia when the
thermometer showed a temperature of 120 degrees Fahrenheit, or nearly 90
degrees above freezing point, so that he can live and be in fairly good
health within a range of nearly 200 degrees Fahrenheit.
The effects of a high temperature vary very much according to the amount
of moisture in the air, as when the air is nearly saturated in hot
climates, or even in summer in our own, more or less languor and malaise
are felt, with great indisposition to bodily labor. With a dry air these
are not so noticeable. The cause is evident; in the former case but little
evaporation occurs from the skin, and the normal amount of moisture is not
given off from the lungs, so that the body is not cooled down to such an
extent as by dry air. Sunstroke is probably the result, not only of the
direct action of the sun's rays, but partly from diminished cooling of the
blood by want of evaporation from the lungs and skin.
The effects of temperature on man do not depend so much on the mean for
the day, month, or year, as on the extremes, as, when the days are hot and
the nights comparatively cool, the energy of the system becomes partially
restored, so that a residence near the sea, or in the vicinity of high
mountains, in hot climates is, other things being equal, less enervating
than in the plains, as the night air is generally cooler. It is commonly
believed that hot climates are _necessarily_ injurious to Europeans, by
causing frequent liver derangements and diseases, dysentery, cholera, and
fevers. This, however, is, to a certain extent, a mistake, as the recent
medical statistical returns of our army in India show that in the new
barracks, with more careful supervision as regards diet and clothing, the
sickness and death-rates are much reduced. Planters and others, who ride
about a good deal, as a rule keep in fairly good health; but the children
of Europeans certainly degenerate, and after two or three generations die
out, unless they intermarry with natives, and make frequent visits to
colder climates. This fact shows that hot climates, probably by
interfering with the due performance of the various processes concerned in
the formation and destruction of the bodily tissues, eventually sap the
foundations of life among Europeans; but how far this result has been
caused by bad habits as regards food, exercise, and self-indulgence, I
cannot say. Rapid changes of temperature in this country are often very
injurious to the young and old, causing diarrhoea and derangements of the
liver when great heat occurs, and inflammatory diseases of the lungs,
colds, etc., when the air becomes suddenly colder, even in summer.
The _direct_ influence of rain on man is not very marked in this country,
except by giving moisture to the air by evaporation from the ground and
from vegetable life, and by altering the level of ground water. This is a
subject almost overlooked by the public, and it is therefore as well that
it should be known that when ground water has a level persistently less
than five feet from the surface of the soil, the locality is usually
unhealthy, and should not, if possible, be selected for a residence.
Fluctuations in the level of ground water, especially if great and sudden,
generally cause ill-health among the residents. Thus, Dr. Buchanan in his
reports to the Privy Council in 1866-1867, showed that consumption (using
the word in its most extended sense) is more prevalent in damp than on dry
soils, and numerous reports of medical officers of health, and others,
which have been published since then, show that an effective drainage of
the land, and consequent carrying away of the ground water, has been
followed by a diminution of these diseases.
Varying amounts of moisture in the air materially affect the health and
comfort of man. In this country, however, it is not only the absolute but
the relative proportions of aerial moisture which materially influence
mankind. The quantity of aqueous vapor that a cubic foot of air can hold
in suspension, when it is saturated, varies very much with the
temperature. Thus at 40 degrees Fahr. it will hold 2.86 grains of water;
at 50 degrees, 4.10 grains; at 60 degrees, 5.77 grains; at 70 degrees,
8.01 grains; and at 90 degrees as much as 14.85 grains. If saturation be
represented by 100, more rapid evaporation from the skin will take place
at 70 degrees, and 75 per cent. of saturation, than at 60 degrees when
saturated, although the absolute quantity of moisture in the air is
greater at the first named temperature than at the latter. As regards the
lungs, however, the case is different, as the air breathed out is, if the
respirations be regular and fairly deep, completely saturated with
moisture at the temperature of the body. In cold climates the amount of
moisture and of the effete matters given off from the lungs in the expired
air is much greater than in hot climates, and the body is also cooled by
the evaporation of water in the form of aqueous vapor. Moist air is a
better conductor of heat than dry air, which accounts for much of the
discomfort felt in winter when a thaw takes place as compared with the
feeling of elasticity when the air is dry. In cold weather, therefore,
moist air cools down the skin and lungs more rapidly than dry air, and
colds consequently result. London fogs are injurious, not only on account
of the various vapors given off by the combustion of coal, but in
consequence of the air being in winter generally saturated with moisture
at a low temperature. The injuriousness of fogs and low temperatures will
be presently dwelt upon at greater length.
Variations in the pressure and temperature of the atmosphere exert a
considerable influence on the circulation of air contained in the soil,
which is called ground air. As all the interstices of the ground are
filled with air or water, the more porous the soil, the greater is the
bulk of air. The quantity of a
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