A Dictionary of Arts, Manufactures and Mines
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Title: A Dictionary of Arts, Manufactures and Mines
Author: Andrew Ure
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Language: English
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Transcriber’s Notes
Italicised texts in the original work have been transcribed between
_underscores_; small capitals have been transcribed as CAPITALS.
Superscript c is transcribed as ^{c}. ● and ○ represent a solid and an
open circle with a vertical line, respectively. [S] represents a letter
S rotated 90 degrees. In ([26 × 2] + [40 × 2]) the original work has a
horizontal line over the numbers between the square brackets.
More Transcriber’s notes may be found at the end of this text.
A
DICTIONARY
OF
ARTS, MANUFACTURES,
AND
MINES:
CONTAINING
A CLEAR EXPOSITION OF THEIR PRINCIPLES
AND PRACTICE.
BY
ANDREW URE, M.D.
F.R.S. M.G.S. M.A.S. LOND.; M. ACAD. N.S. PHILAD.; S. PH. SOC. N.
GERM. HANOV.; MULII. ETC. ETC.
ILLUSTRATED WITH TWELVE HUNDRED AND FORTY
ENGRAVINGS ON WOOD.
Second Edition.
LONDON:
PRINTED FOR
LONGMAN, ORME, BROWN, GREEN, & LONGMANS,
PATERNOSTER-ROW.
1840.
LONDON:
Printed by A. SPOTTISWOODE,
New-Street-Square.
PREFACE.
It is the business of operative industry to produce, transform, and
distribute all such material objects as are suited to satisfy the wants
of mankind. The primary production of these objects is assigned to the
husbandman, the fisherman, and the miner; their transformation to the
manufacturer and artisan; and their distribution to the engineer,
shipwright, and sailor.[1] The unworked or raw materials are
derived,--1. from the organic processes of vegetables and animals,
conducted either without or with the fostering care of man; 2. from the
boundless stores of mineral and metallic wealth, arranged upon or within
the surface of the earth by the benignant Parent of our being, in the
fittest condition to exercise our physical and intellectual powers in
turning them to the uses of life.
[1] For correct and copious information upon _agricultural_
production, I have great pleasure in referring my readers to Mr.
Loudon’s elaborate _Encyclopedias of Agriculture, Gardening, and
Plants_; and for _mercantile_ production and distribution, to Mr.
M’Culloch’s excellent _Dictionary of Commerce and Commercial
Navigation_.
The task which I have undertaken in the present work, is to describe and
explain the transformations of these primary materials, by mechanical
and chemical agencies, into general objects of exchangeable value;
leaving, on the one hand, to the mechanical engineer, that of
investigating the motive powers of transformation and transport; and, on
the other hand, to the handicraftsman, that of tracing their
modifications into objects of special or local demand. Contemplated in
this view, an art or manufacture may be defined to be that species of
industry which effects a certain change in a substance, to suit it for
the general market, by combining its parts in a new order and form,
through mechanical or chemical means. Iron will serve the purpose of
illustrating the nature of the distinctions here laid down, between
mechanical engineering; arts and manufactures; and handicraft trades.
The engineer perforates the ground with a shaft, or a drift, to the
level of the ore, erects the pumps for drainage, the ventilating, and
hoisting apparatus, along with the requisite steam or water power; he
constructs the roads, the bridges, canals, railways, harbours, docks,
cranes, &c., subservient to the transport of the ore and metal; he
mounts the steam or water power, and bellows for working the
blast-furnaces, the forges, and the cupolas; his principal end and aim
on all occasions being to overcome the forces of inertia, gravity, and
cohesion. The ores extracted and sorted by the miner, and transported by
the engineer to the smelting station, are there skilfully blended by the
iron-master (manufacturer), who treats them in a furnace appropriately
constructed, along with their due proportions of flux and fuel, whereby
he reduces them to cast iron of certain quality, which he runs off at
the right periods into rough pigs or regular moulds; he then transforms
this crude metal, by mechanical and chemical agencies, into bar and
plate iron of various sizes and shapes, fit for the general market; he
finally converts the best of the bars into steel, by the cementation
furnace, the forge, and the tilt-hammer; or the best of the plates into
tin-plate. When farther worked by definite and nearly uniform processes
into objects of very general demand in all civilized countries, these
iron and steel bars still belong to the domain of manufactures; as, for
example, when made into anchors, chain-cables, files, nails, needles,
wire, &c.; but when the iron is fashioned, into ever varying and
capricious forms, they belong either to the general business of the
founder and cutler, or to the particular calling of some handicraft, as
the locksmith, gratesmith, coachsmith, gunsmith, tinman, &c.
Such are the principles which have served to guide me in selecting
articles for the present volume. By them, as a clue, I have endeavoured
to hold a steady course through the vast and otherwise perplexing
labyrinth of arts, manufactures, and mines; avoiding alike engineering
and mechanical arts, which cause no change in the texture or
constitution of matter,--and handicraft operations, which are multiform,
capricious, and hardly susceptible of scientific investigation. In fact,
had such topics been introduced into the volume, it would have presented
a miscellaneous farrago of incongruous articles, too numerous to allow
of their being expounded in a manner either interesting or instructive
to the manufacturer and the metallurgist. I readily acknowledge,
however, that I have not been able to adhere always so rigorously as I
could have wished to the above rule of selection; having been
constrained by intelligent and influential friends to introduce a few
articles which I would gladly have left to the mechanical engineer. Of
these _Printing_ is one, which, having had no provision made for it in
my original plan, was too hastily compiled to admit of my describing,
with suitable figures, the flat-printing automatic machine of Mr.
Spottiswoode, wherewith the pages of this volume were worked off; a
mechanism which I regard as the most elegant, precise, and productive,
hitherto employed to execute the best style of letter press.
I have embodied in this work the results of my long experience as a
Professor of Practical Science. Since the year 1805, when I entered at
an early age upon the arduous task of conducting the schools of
chemistry and manufactures in the Andersonian Institution, up to the
present day, I have been assiduously engaged in the study and
improvement of most of the chemical and many of the mechanical arts.
Consulted professionally by proprietors of factories, workshops, and
mines, of various descriptions, both in this country and abroad,
concerning derangements in their operations, or defects in their
products, I have enjoyed peculiar opportunities of becoming familiar
with their minutest details, and have frequently had the good fortune to
rectify what was amiss, or to supply what was wanting. Of the stores of
information thus acquired, I have availed myself on the present
occasion; careful, meanwhile, to neglect no means of knowledge which my
extensive intercourse with foreign nations affords.
I therefore humbly hope that this work will prove a valuable
contribution to the literature of science, serving--
_In the first place_, to instruct the Manufacturer, Metallurgist, and
Tradesman, in the principles of their respective processes, so as to
render them in reality the masters of their business, and to emancipate
them from a state of bondage to operatives, too commonly the slaves of
blind prejudice and vicious routine.
_Secondly_, to afford to Merchants, Brokers, Drysalters, Druggists, and
Officers of the Revenue, characteristic descriptions of the commodities
which pass through their hands.
_Thirdly_, by exhibiting some of the finest developments of chemistry
and physics, to lay open an excellent practical school to students of
these kindred sciences.
_Fourthly_, to teach Capitalists, who may be desirous of placing their
funds in some productive bank of industry, to select judiciously among
plausible claimants.
_Fifthly_, to enable Gentlemen of the Law to become well acquainted with
the nature of those patent schemes which are so apt to give rise to
litigation.
_Sixthly_, to present to our Legislators such a clear exposition of our
staple manufactures, as may dissuade them from enacting laws which
obstruct industry, or cherish one branch of it to the injury of many
others: and,
_Lastly_, to give the General Reader, intent chiefly on intellectual
cultivation, a view of many of the noblest achievements of science, in
effecting those grand transformations of matter to which Great Britain
owes her paramount wealth, rank, and power among the kingdoms.
The latest statistics of every important object of manufacture is given,
from the best, and, usually, from official authority, at the end of each
article.[2]
[2] The statistics of agriculture, trade, and manufactures is ably and
fully discussed in Mr. M’Culloch’s _Dictionary_ already referred to.
The following summary of our manufactures is extracted from Mr.
Macqueen’s _General Statistics of the British Empire_, published in
1836. It shows the amount of capital embarked in the various
departments of manufacturing industry, and of the returns of that
capital:--
+----------------------------------+-----------+-----------+
| | Capital. | Produce. |
| +-----------+-----------+
| | _£_ | _£_ |
|Cotton manufactures | 40,973,872| 52,513,586|
|Woollen ditto | 36,000,000| 44,250,000|
|Silk ditto | 8,000,000| 10,000,000|
|Linen ditto | 12,000,000| 15,421,186|
|Leather ditto | 13,000,000| 16,000,000|
|Iron ditto, to making pig iron| 10,000,000| 7,098,000|
|Ditto, hardware, cutlery, &c. | 25,000,000| 31,072,600|
|Copper and brass ditto | 3,600,000| 4,673,186|
|China, glass, &c. | 8,600,000| 10,892,794|
|Paper, furniture, books, &c. | 10,000,000| 14,000,000|
|Spirits (British), ales, soap, &c.| 37,600,000| 47,163,847|
|Sundries additional | | 9,000,000|
| +-----------+-----------+
| Totals |204,773,872|262,085,199|
+----------------------------------+-----------+-----------+
In consequence of an arrangement with Mr. William Newton, patent agent,
and proprietor of the _London Journal of Arts, Sciences, and
Manufactures_, I have been permitted to enrich this Dictionary with many
interesting descriptions and illustrative figures of modern patent
inventions and improvements, which I could not otherwise have presented
to my readers. Mr. Newton has lately enhanced the value of his Journal
by annexing to it a _catalogue raisonnée_, entitled “An Analytical Index
to the Subjects contained in the 23 Volumes,” which constitute the first
and second series. The subsequent 13 volumes, of his Conjoined Series,
are of still superior interest; and the whole form a vast storehouse of
Mechanical and Chemical Invention.
Although I am conscious of having used much diligence for many years in
collecting information for this work, from every quarter within my
reach, the utmost pains in preparing it for publication, and incessant
vigilance during its passage through the press, yet I am fully aware
that it must contain several errors and defects. These I shall study to
rectify, should the Public deem this volume worthy of a supplement. In
this hope, I earnestly solicit the suggestions of my readers; trusting
that ere long our Post Office system will cease to be such an obstacle
as it has long been to the collection and diffusion of useful knowledge,
and a tax upon science which the remuneration of its literature cannot
by any means bear.
Since this book is not a Methodical Treatise, but a Dictionary, one
extensive subject may be necessarily dispersed through many articles.
Thus, for example, information upon the manufacture of _Colours_ will be
found under azure; black pigment; bone-black; bronze; brown dye;
calico-printing; carmine; carthamus; chromium; cochineal; crayons;
dyeing; enamels; gold; gilding; gamboge; gray dye; green dye; green
paints; indigo; kermes; lac dye; lakes; madder; massicot; mercury,
periodide of; Naples yellow; orange dye; orpiment; paints, grinding of;
ochres; paper-hangings; pastes; pearl white; Persian berries; pottery
pigments; Prussian blue; purple of Cassius; red lead; rouge; Scheele’s
green; Schweinfurth green; stained glass; terra di Sienna; ultramarine;
umber; verditer; vermilion; vitrifiable colours, weld, white lead; woad;
yellow, king’s.
A casual consulter of the Dictionary, who did not advert to this
distribution, might surmise it to be most deficient, where it is in
reality most copious.
The elaborate and costly Encyclopedias, and Dictionaries of Arts, which
have appeared from time to time in this country, and abroad, have, for
the most part, treated of the mechanical manufactures, more fully and
correctly than of the chemical. The operations of the former are, in
fact, tolerably obvious and accessible to the inspection of the curious;
nor are they difficult to transfer into a book, with the aid of a
draughtsman, even by a person but moderately versed in their principles.
But those of the latter are not unfrequently involved in complicated
manipulations, and depend, for their success, upon a delicate play of
affinities, not to be understood without an operative familiarity with
the processes themselves. Having enjoyed the best opportunities of
studying the chemical arts upon the greatest scale in this kingdom and
on the Continent, I may venture, without the imputation of arrogance, to
claim for my work, in this respect, more precision and copiousness than
its predecessors possess. I have gone as far in describing several
curious processes, hitherto veiled in mystery, as I felt warranted,
without breach of confidence, to go; regarding it as a sacred duty never
to publish any secret whatever, without the consent of its proprietor.
During my numerous tours through the factory districts of Great Britain,
France, &c., many suggestions, however, have been presented to my mind,
which I am quite at liberty to communicate in private, or carry into
execution, in other districts too remote to excite injurious competition
against the original inventors. I am also possessed of many plans of
constructing manufactories, of which the limits of this volume did not
permit me to avail myself, but which I am ready to furnish, upon
moderate terms, to proper applicants. I conclude by pointing attention
to the very insecure tenure by which patents for chemical or
chemico-mechanical inventions are held; of which there is hardly one on
record which may not be readily evaded by a person skilled in the
resources of practical chemistry, or which could stand the ordeal of a
court of law directed by an experienced chemist. The specifications of
such patents stand in need of a thorough reform; being for the most part
not only discreditable and delusive to the patentees, but calculated to
involve them in one of the greatest of evils--a chancery suit.
LONDON:
13. Charlotte Street, Bedford Square,
March 1. 1839.
DR. URE is preparing for publication, in one large volume, 8vo.,
CHEMISTRY IN THEORY AND PRACTICE; embodying a New System of Research, of
such facility and precision, as will enable chemical manufacturers of
every class, medical practitioners, metallurgists, farmers, merchants,
brokers, druggists, drysalters, officers of the revenue, as well as
general students, to analyze their respective objects in much less time
than is usually required at present by professional chemists. A
descriptive Index will be annexed for converting this systematic work
into a Dictionary of Chemical Science.
A
DICTIONARY
OF
ARTS, MANUFACTURES, AND MINES.
ABB-WOOL. Among clothiers, this term signifies the _woof_ or _weft_.
ACETATE. (_Acétate_, Fr.; _Essigsäure_, Germ.) Any saline compound of
which the acetic is the acid constituent; as acetate of soda, of iron,
of copper, &c.
ACETATE OF ALUMINA, see RED LIQUOR and MORDANT; of COPPER, see COPPER;
of IRON, see IRON; of LEAD, see LEAD; of LIME, see PYROLIGNOUS ACID.
ACETIC ACID (_Acide Acétique_, Fr.; _Essigsäure_, Germ.) is the name of
the sour principle which exists in vinegar. It occurs, ready formed, in
several products of the vegetable kingdom, and is generated during the
spontaneous fermentation of many vegetable and animal juices. The
_sambucus nigra_, or black elder, the _phœnix dactilifera_, and the
_rhus typhinus_ are plants which afford a notable quantity of vinegar.
It is found, likewise, in the sweat, urine, milk, and stomach of
animals. All infusions of animal or vegetable matters in water, when
exposed for some time to the air, at a moderate temperature, ferment
into vinegar; and most vegetables, when subjected to decomposition by
fire, give off condensable vapours of acetic acid. All liquids
containing alcohol are susceptible of passing into the state of vinegar;
but the pre-existence of alcohol is not necessary to this change, as we
learn from the acetification of vegetable soups, infusion of cabbage,
starch--paste, &c.
Vinegar may be distinguished into four varieties, according to the mode
of its production, though all of them are capable of being converted, by
chemical means, into one identical acetic acid. 1. Wine vinegar. 2. Malt
vinegar. 3. Sugar vinegar. 4. Wood vinegar, or pyrolignous acid.
Fermentation is the source of the acid in the first three varieties.
Here alcohol is first generated, and is next converted into vinegar by
the influence of the air at a genial temperature; a change which will be
investigated under FERMENTATION. But the conversion of spirit of wine
into acetic acid may be demonstrated by direct experiment. When the
vapour of alcohol is brought into contact in the atmosphere with the
black powder obtained by mixing muriate of platina, potash, and alcohol,
vinegar is rapidly formed at the expense of the alcohol. In Germany,
where crude alcohol bears a low price, the manufacture of vinegar has
been arranged upon that principle, which, as throwing some light on the
process of acetification, I shall briefly describe. See PLATINUM _for
the mode of preparing the above powder_.
Under a large case, which for experimental purposes may be made of
glass, several saucer-shaped dishes of pottery or wood are to be placed
in rows, upon shelves over each other, a few inches apart. A portion of
the black platina powder moistened being suspended over each dish, let
as much vinous spirits be put into them as the oxygen of the included
air shall be adequate to acidify. This quantity may be inferred from the
fact, that 1000 cubic inches of air can oxygenate 110 grains of absolute
alcohol, converting them into 122 grains of absolute acetic acid, and
64-1/2 grains of water.
The above simple apparatus is to be set in a light place (in sunshine,
if convenient), at a temperature of from 68° to 86° Fahr., and the
evaporation of the alcohol is to be promoted by hanging several leaves
of porous paper in the case, with their bottom edges dipped in the
spirit. In the course of a few minutes, a most interesting phenomenon
will be perceived. The mutual action of the platina and the alcohol will
be displayed by an increase of temperature, and a generation of acid
vapours, which, condensing on the sides of the glass-case, trickle in
streams to the bottom. This striking transformation continues till all
the oxygen of the air be consumed. If we wish, then, to renew the
process, we must open the case for a little, and replenish it with air.
With a box of 12 cubic feet in capacity, and with a provision of 7 or 8
ounces of the platina powder we can, in the course of a day, convert
one pound of alcohol into pure acetic acid, fit for every purpose,
culinary or chemical. With from 20 to 30 pounds of the platina powder
(which does not waste), we may transform, daily, nearly 300 pounds of
bad spirits into the finest vinegar. Though our revenue laws preclude
the adoption of this elegant process upon the manufacturing scale in
this country, it may be regarded as one of the greatest triumphs of
chemistry, where art has rivalled nature in one of her most mysterious
operations.
To readers acquainted with chemical symbols, the following numerical
representation of the conversion of alcohol into acetic acid may be
acceptable:--
580·64 parts by weight of alcohol = H¹² C⁴ O² consist of
74·88 of hydrogen = H¹²
305·76 of carbon = C⁴
200·00 of oxygen = O²
If we combine with this mixture, 400 parts of oxygen = O⁴, we have,--
of water = 337·44 = H⁶ O³
acetic acid = 643·20 = H⁶ C⁴ O³
Hence, in this formation of vinegar, 100 parts by weight of alcohol take
68·89 parts of oxygen; and there are produced 58·11 parts of water, and
110·78 of acetic acid.
These beautiful experiments prove, that when in a mere mixture of
alcohol and water, under the influence of the atmospheric air and heat,
some vinegar comes to be formed after a considerable time, the same
formation of vinegar takes place in a similar, but more effective,
manner, when a ferment is present, which acts here in a somewhat
analogous way to the platina powder in the preceding case. Several
azotized substances serve as re-agents towards the acetous
fermentation,--such as vinegar ready-made, vinegar-yeast, or lees,
barley bread, leaven, beer barm, and similar vegetable matters, which
contain gluten. The best and purest ferment is, however, vinegar itself.
With this ferment we must conjoin, as an essential condition of
acetification, the free access of atmospheric air.
It is a well-known fact, that spirituous liquors, as weak brandy, wine,
and beer, &c., may be preserved for years in close vessels, without
undergoing the acetous fermentation, even when they repose upon a layer
of lees. It is equally well known, that these very liquors, if they
stand for some time in open vessels, become readily sour, especially if
exposed, also, to a somewhat high temperature. If we fill a flask with
common brandy, and subject it, without a stopper, to the influence of
air and warmth, the contained liquor may, at the end of many weeks,
discover no sensible acidity: if we add to the same brandy a ferment,
and stop the flask air-tight, everything will still remain unchanged;
but if we leave a portion of air in the flask, or leave it uncorked,
vinegar will soon make its appearance in the brandy.
If we investigate the nature of the air which remains over brandy in the
act of acetification, we shall find that it consists entirely of
carbonic acid and azote, the oxygen being absorbed and combined in the
acetic acid and water formed.
Since this absorption of oxygen from the air can take place only at the
surface of the fermenting liquors, we thus see the necessity and the
practical importance of amplifying that surface, in order to accelerate
and complete the acetification, by multiplying the points of contact
between the alcohol and the oxygen. The essence of the new German method
of rapid acetification depends upon this principle.
Temperature has also a remarkable influence on the formation of vinegar.
The acid fermentation proceeds very feebly in the cold, but takes an
accelerated pace as the heat is raised. It would even appear that
spirituous vapours brought by themselves in contact with atmospheric
air, without the aid of any ferment, are capable of being converted into
acetic acid, since it has happened in the rectification of brandy, in a
still furnished with a large capital and adopter pipe into which air was
allowed to enter, that vinegar made its appearance. Hence, warmth does
not seem to act as a promoter of the combination of alcohol with oxygen
in a merely chemical point of view, but it acts, so to speak,
physically. Over the warm liquor a stratum of spirit vapour appears to
float, which, coming there into conflict with the atmospherical oxygen,
probably causes the generation of some acetic acid, and thus accelerates
the operation, much more than by the mere contact of the oxygen with the
liquid surface.
When we expose any spirituous liquors, as wine, beer, &c., with the
requisite ferment, to the external air, at a temperature of from 64° to
68° Fahr., the fluid, however clear before, becomes soon turbid;
filamentous slimy particles begin to appear moving in the middle and on
the sides of the vessel, and then form a scum on the top of the liquor.
When this scum has acquired a certain thickness and consistence, it
falls in a sediment to the bottom. The Germans call it the vinegar
_mother_, as it serves to excite acetification in fresh liquors.
Meanwhile, the liquor has become warmer than the surrounding air, and
the vinegar process betrays itself by diffusing a peculiar aroma in the
apartment. Whenever all the alcohol present has been converted into
acetic acid, the liquor comes into a state of repose; its temperature
sinks to the pitch of the atmosphere; it becomes bright, and is the
article well known by its taste and smell under the name of vinegar.
Genuine wine or raisin vinegar differs from that formed either from
apples, or sugar, beer, &c., in containing wine-stone or tartar; by
which peculiarity it may be distinguished, except in those cases where
crude tartar has been artificially added to the other vinegars, as a
disguise. Barley-malt vinegar contains some phosphoric acid, in the
state of phosphate of lime or magnesia, derived from the grain.
After these general observations upon acetification, we shall now
proceed to describe the processes for manufacturing vinegar on the
commercial scale.
1. _Wine vinegar._--The first consideration with a vinegar maker is a
good fermenting room, in which the wines may be exposed to a steady
temperature, with an adequate supply of atmospherical air. As this air
is soon deprived of its oxygenous constituent, facilities ought to be
provided for a renewal of it by moderate ventilation. The air holes for
this purpose ought to be so contrived that they may be shut up when the
temperature begins to fall too low, or in windy weather. The best mode
of communicating the proper warmth to a chamber of this kind is by means
of fire-flues or hot water pipes, running along its floor at the sides
and ends, as in a hothouse; the fireplace being on the outside, so that
no dust may be created by it within. The flue is best made of bricks,
and may have a cross section of 10 or 12 inches by 15 deep. The soot
deposited, even when coals are burned, will find ample space in the
bottom of the flue, without interfering essentially with the draught,
for a very long period, if it be made of the above dimensions.
Low-roofed apartments are preferable to high ones; and those built with
thick walls, of imperfectly conducting materials, such as bricks, lined
with lath and plaster work. Should the chamber, however, have a high
ceiling, the fermenting tuns must be raised to a suitable height on
scaffolding, so as to benefit by the warmest air. Sometimes the vinegar
vessels are placed at different levels; in which case the upper ones
acetify their contents much sooner than the under, unless they are
emptied and filled alternately, which is a good plan.
Orleans is the place most famous for vinegars. The building there
destined to their manufacture is called a _vinaigrerie_, and is placed,
indifferently, either on the ground floor or the floor above it; but it
has always a southern exposure, to receive the influence of the
sunbeams. The vessels employed for carrying on the fermentation are
casks, called _mothers_. Formerly they were of a large capacity,
containing about 460 litres (115 gallons, Eng.); but at the present day
they are barrels of half that capacity, or somewhat less than an old
English hogshead. It is now known that the wine passes sooner into
vinegar the smaller the mass operated upon, the more extensive its
contact with the air, and the more genial its warmth. These casks were
formerly arranged in three ranks by means of massive scaffolding; they
are now set in four ranks, but they rest on much smaller rafters,
sustained by uprights, and can be packed closer together. The casks,
which are laid horizontally, are pierced at the upper surface of their
front end with two holes: one, to which the name of _eye_ is given, is
two inches in diameter; it serves for putting in the charge, and drawing
off the vinegar when it is made; the other hole is much smaller, and is
placed immediately alongside; it is merely an air hole, and is necessary
to allow the air to escape, because the funnel completely fills the
other hole in the act of filling the cask.
When new vessels are mounted in a vinegar work, they must be one third
filled with the best vinegar that can be procured, which becomes the
true _mother_ of the vinegar to be made; because it is upon this portion
that the wine to be acidified is successively added. At the ordinary
rate of work, they put at first upon the _mother_, which occupies one
third of the vessel, a _broc_ of 10 litres of red or white wine; eight
days afterwards they add a second _broc_; then a third, and a fourth,
always observing the same interval of time, 8 days. After this last
charge, they draw off about 40 litres of vinegar, and then recommence
the successive additions.
It is necessary that the vessel be always one third empty if we wish the
acetification to go on steadily; but as a portion of the tartar and the
lees forms and accumulates in the lower part of the cask, so as
eventually to counteract the fermentation, the time arrives when it is
requisite to interrupt it, in order to remove this residuum, by clearing
out all the contents. The whole materials must be renovated every 10
years; but the casks, if well made and repaired, will serve for 25
years.
We have mentioned a definite period at which the vinegar may be drawn
off; but that was on the supposition that the process had all the
success we could wish: there are circumstances, difficult to appreciate,
which modify its progress, as we shall presently show. We ought,
therefore, before discharging the vinegar, to test and see if the
fermentation has been complete. We proceed as follows: we plunge into
the liquor a white stick or rod, bent at one end, and then draw it out
in a horizontal direction: if it be covered with a white thick froth, to
which is given the name of _work_ (_travail_), we judge that the
operation is terminated; but if the work, instead of being white and
pearly, be red, the manufacturers regard the fermentation to be
unfinished, and they endeavour to make it advance, by adding fresh wine,
or by increasing the heat of the apartment.
It is not always easy to explain why the fermentation does not go on as
rapidly in one case as in another. There are even certain things which
seem at present to be entirely inexplicable. It happens sometimes, for
example, that although all the vessels have been equally charged, and
with the same wine, yet the fermentation does not form in the same
manner in the whole; it will move rapidly in some, be languid, or
altogether inert, in others. This is a very puzzling anomaly; which has
been ascribed to electrical and other obscure causes, because it is not
owing to want of heat, the casks in the warmest positions being
frequently in fault; nor to the timber of the cask. It, however,
paralyses the process so completely that the most expert vinegar makers
have nothing else for it, when this accident happens, than to empty
entirely what they call the lazy cask, and to fill it with their best
vinegar. The fermentation now begins, and proceeds as well in it as in
the others. See FERMENTATION.
We must here make an important remark, relatively to the temperature
which should prevail in the fermentation room. In many chemical works we
find it stated, that the heat should not exceed 18° R., or 65° Fahr.,
for fear of obtaining bad products. But the vinegar makers constantly
keep up the heat at from 24° to 25° R., 75° to 77° F.; when the
acetification advances much more rapidly, and the vinegar is equally
strong. The best proof of this heat not being too high is, that under
it, the vessels in the upper part of the room, work best and quickest.
In Orleans, cast-iron stoves and wood fuel are used for communicating
the requisite warmth.
Before pouring the wine into the _mothers_, it is clarified in the
following manner. There are tuns which can contain from 12 to 15 pieces
of wine. Their upper end has at its centre an opening of four or five
inches diameter, which may be closed afterwards with a wooden cover;
this opening is for the purpose of receiving a large funnel. The inside
of the tun is filled with chips of beechwood, well pressed down. The
wine is poured upon these chips, allowed to remain for some time, and
then gently drawn off by a pipe in the lower part of the vessel. The
lees are deposited upon the chips, and the wine runs off quite clear.
However, it happens sometimes, notwithstanding this precaution, that the
vinegar, after it is made, requires to be clarified, more particularly
if the wine employed had been weak. The vinegar must be filtered in the
same way; and it derives an advantage from it, as the products of
different casks get thereby mixed and made uniform.
By this Orleans method several weeks elapse before the acetification is
finished; but a plan has been lately devised in Germany to quicken
greatly the acid fermentation by peculiar constructions. This system is
called, the _quick_ vinegar work, because it will complete the process
in the course of 2 or 3 days, or even in a shorter time. It depends,
chiefly, upon the peculiar construction of the fermenting vessels,
whereby the vinous liquor is exposed on a vastly expanded surface to the
action of the atmospheric air.
An oaken tub, somewhat narrower at the bottom than the top, from 6 to 7
feet high and 3 feet in diameter, is furnished with a well-fitted
grooved, but loose, cover. About half a foot from its mouth, the tub has
a strong oak or beech hoop fitted to its inside surface, sufficiently
firm to support a second cover, also well fitted, but moveable. The
space under this second cover is destined to contain the vinous liquor,
and in order to bring it very amply into contact with the atmosphere,
the following contrivances have been resorted to: This cover is
perforated, like a sieve, with small holes, of from 1 to 2 lines in
diameter, and about 1-1/2 inch apart. Through each of these holes a wick
of pack-thread or cotton is drawn, about 6 inches long, which is
prevented from falling through by a knot on its upper end, while its
under part hangs free in the lower space. The wicks must be just so
thick as to allow of the liquor poured above the cover passing through
the holes in drops. The edges of the lid must be packed with tow or hemp
to prevent the liquor running down through the interval.
The whole lower compartment is now to be filled with chips of beechwood
up to nearly the perforated cover. The liquor, as it trickles through
the holes, diffuses itself over the chips, and, sinking slowly, collects
at the bottom of the tub. The chips should be prepared for this purpose
by being repeatedly scalded in boiling water, then dried, and imbued
with hot vinegar. The same measures may also be adopted for the tub. To
provide for the renewal of the air, the tub is perforated at about a
foot from its bottom with eight holes, set equally apart round the
circumference, two thirds of an inch wide, and sloping down, through
which the air may enter into this lower compartment, without the
trickling liquor being allowed to flow out. In order that the foul air
which has become useless may escape, four large holes are pierced in
the sieve cover, at equal distances asunder and from the centre, whose
united areas are rather smaller than the total areas of the holes in the
side of the tub. Into these four holes open glass tubes must be
inserted, so as to stand some inches above the cover, and to prevent any
of the liquor from running through them. The proper circulation of the
air takes place through these draught holes. This air may afterwards
pass off through a hole of 2-1/2 inches diameter in the uppermost cover,
in which a funnel is placed for the supply of liquor as it is wanted to
keep up the percolation.
The temperature of the fermenting compartment is ascertained by means of
a thermometer, whose bulb is inserted in a hole through its side, and
fastened by a perforated cork. The liquor collected in the under vessel
runs off by a syphon inserted near its bottom, the leg of which turns up
to nearly the level of the ventilating air pipes before it is bent
outwards and downwards. Thus the liquor will begin to flow out of the
under compartment only when it stands in it a little below the sieve
cover, and then it will run slowly off at the inclined mouth of the
syphon, at a level of about 3 inches below the lower end of the glass
tubes. There is a vessel placed below, upon the ground, to receive it.
The tub itself is supported upon a wooden frame, or a pier of brickwork,
a foot or 18 inches high.
A tub constructed like the above is called a GRADUATION VESSEL, which
see. It is worked in the following way:--The vinegar room must be, in
the first place, heated to from 100° to 110° F., or till the thermometer
in the graduation vessel indicates at least 77°. The heat may then be
modified. We now pour through the uppermost cover of the tub a mixture,
warmed to 144° F., of 8 parts proof spirits, 25 parts soft water, 15
parts of good vinegar, and as much clear wine or beer. The water should
be first heated, and then the vinegar, spirits, and wine may be added to
it. Of this mixture, so much should be poured in as is necessary to
cover over the second lid, 2 or 3 inches deep, with the liquor; after
which, the rest may be poured slowly in, as it is wanted.
When the liquor has run for the first time through the graduation
vessel, it is not yet sufficiently acidified; but the weak vinegar
collected in the exterior receiving cistern must be a second time, and,
if need be, a third time, passed through the graduation tub, in order to
convert all the alcohol into acetic acid. In general, we may remark,
that the stronger the vinous liquor the more difficult and tedious is
its conversion into vinegar, but it is so much the stronger. To lessen
this difficulty somewhat, it would be well not to put all the spirits at
first into the wash, or mixed liquors, but to add a little more of it at
the second and the third running, especially when we desire to have very
strong vinegar.
After the graduation vessel has been some days at work, it is no longer
necessary to add vinegar to the mixture of spirits and water, since the
sides of the graduation tub, the beech chips, and the packthreads, are
all impregnated with the ferment, and supply its place. The mixture
must, however, be always maintained at the temperature of 100°.
Instead of the above mixture of brandy, water, and wine, we may employ,
according to Dingler, a clear fermented wort of malt, mixed with a
little spirits. The perfect vinegar, which collects in the receiving
cistern, may be immediately racked off into the store casks for sale.
It has been objected to this process, that, in consequence of the
mixture of saccharine and glutinous materials, which are contained in
beer or worts, along with the acetous fermentation, there is also,
partially, a vinous fermentation, and much carbonic acid, thereby
disengaged, so as to obstruct the acetification. This obstruction may be
remedied by a freer circulation of air, or by the exposure of quicklime
in the chamber. It is a more substantial objection, that, from the
addition of beer, &c., more lees, or dregs, are deposited in the
graduation tub, whereby a more frequent cleansing of it, and of the
beech chips, with a loss of time and vinegar, becomes necessary. The
only mode of obviating this difficulty is, to take well-clarified
fermented wash.
Another evil attendant on the quick process is, the evaporation of the
spirituous liquors. Since, in the graduation tub, there is a temperature
of 110°, it is impossible to avoid a loss of spirit from the circulation
and efflux of the air. The air, indeed, that issues from the top hole in
the uppermost cover, might be conducted over an extensive surface of
fresh water, where its spirit would be condensed in a great measure.
But, after all, this fear of great loss is, I believe, groundless;
because the spirit is rapidly acidified by the oxygen of the air, and
thereby rapidly loses its volatility.
The supply of the warm wash should be drawn from a cistern placed near
the ceiling, where the temperature of the apartment is hottest; and it
may be replenished from the partly acetified liquor in the cistern on
the floor. With this view, two cisterns should be placed above, so that
one of them may always contain liquor sufficiently hot, and thus the
process will suffer no interruption.
When malt wash is used for this quick process, the resulting vinegar
must be clarified in a tun with beech chips, as above described. In two
or three days the impurities will be deposited, and the fine vinegar may
be racked off.
The following prescription, for preparing what he calls malt wine, is
given by Dr. Kastner. Eighty pounds of pale barley malt, and 40 pounds
of pale wheat malt, are to be crushed together. These 120 pounds are to
be infused with 150 quarts of water, at the temperature of 122° Fahr.,
afterwards with 300 quarts of boiling water, and the whole body is to be
mashed thoroughly, till all the lumps disappear. It is then to be left
at rest in a large covered tub, for two or three hours, to allow the
grains to settle down, from which the wort is to be drawn off. When it
has fallen to the temperature of 64° Fahr., 15 pounds of good yeast are
to be stirred in, and it must now be left for two or three days to
ferment, in a loosely covered tun. When the vinous fermentation has
taken place, the clear liquor must be drawn off by a tap hole, a little
above the bottom, so as to leave the lees and scum in the tun. This malt
wine, he adds, may be kept for a long time in close vessels, and is
always ready for making quick vinegar.
2. _Malt Vinegar._--The greater part of British vinegar is made from
malt, by the following process:--1 boll of good barley malt, properly
crushed, is to be mashed with water at 160° Fahr. The first water should
have that temperature; the second must be hotter than 160°, and the
third water, for the extraction of all the soluble matter, may be
boiling hot. Upon the whole, not more than 100 gallons of wort should be
extracted. After the liquor has cooled to 75° Fahr., 3 or 4 gallons of
beer yeast are poured in, and well mixed with a proper stirrer. In 36 or
40 hours, according to the temperature of the air, and the fermenting
quality of the wash, it is racked off into casks, which are laid upon
their sides in the fermenting apartment of the vinegar work, which
should be kept at a temperature of 70° at least; in summer partly by the
heat of the sun, but in general by the agency of proper stoves, as above
described. The bung-holes should be left open, and the casks should not
be full, in order that the air may act over an extensive surface of the
liquor. It would be proper to secure a freer circulation to the air, by
boring a hole in each end of the cask, near its upper edge. As the
liquor, by evaporation, would be generally a few degrees colder than the
air of the apartment, a circulation of air would be established in at
the bung-hole, and out by the end holes. By the ordinary methods, three
months are required to make this vinegar marketable, or fit for the
manufacture of sugar of lead.
In making vinegar for domestic purposes, the casks are usually set on
their ends; and they have, sometimes, a false bottom, pierced with
holes, placed about a foot above the true one. On this bottom, a
quantity of _rape_, or the refuse raisins, &c. from the making of
British wines, is laid. The malt liquor has a proper quantity of yeast
added to it. In about 24 hours it becomes warm, and is then racked off
into another similar cask. After some time, this racking process is
discontinued, and the vinegar is allowed to complete its fermentation
quietly. The proper temperature must always be kept up, by placing the
cask in a warm situation. A little wine-stone (_argal_) added to the
malt wash, would make the vinegar liker that made from wine. Sometimes a
little isinglass is employed to clarify vinegar. A portion of sulphuric
acid is often added to it.
3. _Sugar vinegar._--By pursuing the following plan, an excellent sugar
vinegar may be made. In 158 quarts of boiling water dissolve 10 pounds
of sugar, and 6 pounds of wine-stone; put the solution into a fermenting
cask, and when it is cooled to the temperature of from 75° to 80°, add 4
quarts of beer yeast to it. Stir the mixture well, then cover the vessel
loosely, and expose it for 6 or 8 days to the vinous fermentation, at a
temperature of from 70° to 75° Fahr. When it has become clear, draw off
the vinous liquor, and either acetify it in the graduation tub above
described, or by the common vinegar process. Before it is finished, we
should add to it 12 quarts of strong spirits (brandy), and 15 quarts of
good vinegar, to complete the acetous fermentation. With a graduation
tub which has been used, this addition of vinegar is unnecessary.
The following simpler prescription for making sugar vinegar deserves
attention. For every gallon of hot water take 18 ounces of sugar; and
when the syrup has cooled to 75°, add 4 per cent., by measure, of yeast.
When the vinous fermentation is pretty well advanced, in the course of 2
or 3 days, rack off the clear wash from the lees into a proper cask, and
add 1 ounce of wine-stone, and 1 of crushed raisins, for every gallon of
water. Expose it in a proper manner, and for a proper time, to the
acetifying process; and then rack off the vinegar, and fine it upon
beech chips. It should be afterwards put into bottles, which are to be
well corked.
Vinegar obtained by the preceding methods has always a yellowish or
brownish colour. It may be rendered colourless by distillation. For
nicer chemical purposes, this is done in a glass retort; but on a large
scale, it is usually performed in a clean copper still, furnished with a
capital and worm-refrigeratory, either of silver or block tin. It is
volatile at the boiling temperature of water; and if the process be
carried on briskly, it will not sensibly corrode the copper. But we can
never obtain, in this way, a strong article; for, as soon as the vinegar
gets concentrated to a certain degree, we cannot force off the
remainder by heat, for fear of giving it an empyreumatic odour; because
the gluten, colouring matter, &c. begin to adhere to the bottom of the
still. We are, therefore, obliged to suspend the operation at the very
time when the acid is acquiring strength. It has been also proposed to
concentrate vinegar by the process of congelation; but much of it
remains entangled among the frozen water; and common distilled vinegar
is so weak, that it congeals in one mass.
[Illustration: _Fig._ 1.]
Before the process for pyrolignous acid, or wood vinegar, was known,
there was only one method of obtaining strong vinegar practised by
chemists; and it is still followed by some operators, to prepare what is
called radical or aromatic vinegar. This consists in decomposing, by
heat alone, the crystallised binacetate of copper, commonly, but
improperly, called distilled verdigris. With this view, we take a
stoneware retort, (_fig._ 1.) of a size suited to the quantity we wish
to operate upon; and coat it with a mixture of fire clay and horsedung,
to make it stand the heat better. When this coating is dry, we introduce
into the retort the crystallised acetate slightly bruised, but very dry;
we fill it as far as it will hold without spilling when the beak is
considerably inclined. We then set it in a proper furnace. We attach to
its neck an adopter pipe, and two or three globes with opposite
tubulures, and a last globe with a vertical tubulure. The apparatus is
terminated by a Welter’s tube, with a double branch; the shorter issues
from the last globe, and the other dips into a flask filled with
distilled vinegar. Every thing being thus arranged, we lute the joinings
with a putty made of pipeclay and linseed oil, and cover them with glue
paper. Each globe is placed in a separate basin of cold water, or the
whole may be put into an oblong trough, through which a constant stream
of cold water is made to flow. The tubes must be allowed a day to dry.
Next day we proceed to the distillation, tempering the heat very nicely
at the beginning, and increasing it by very slow degrees till we see the
drops follow each other pretty rapidly from the neck of the retort, or
the end of the adopter tube. The vapours which pass over are very hot,
whence a series of globes are necessary to condense them. We should
renew, from time to time, the water of the basins, and keep moist pieces
of cloth upon the globes; but this demands great care, especially if the
fire be a little too brisk, for the vessels become, in that case, so
hot, that they would infallibly be broken, if touched suddenly with cold
water. It is always easy for us to regulate this operation, according to
the emission of gas from the extremity of the apparatus. When the air
bubbles succeed each other with great rapidity, we must damp the fire.
The liquor which passes in the first half hour is weakest; it proceeds,
in some measure, from a little water sometimes left in the crystals,
which when well made, however, ought to be anhydrous. A period arrives
towards the middle of the process when we see the extremity of the beak
of the retort, and of the adopter, covered with crystals of a lamellar
or needle shape, and of a pale green tint. By degrees these crystals are
carried into the condensed liquid by the acid vapours, and give a colour
to the product. These crystals are merely some of the cupreous salt
forced over by the heat. As the process approaches its conclusion, we
find more difficulty in raising the vapours; and we must then augment
the intensity of the heat, in order to continue their disengagement.
Finally, we judge that the process is altogether finished, when the
globes become cold, notwithstanding the furnace is at the hottest, and
when no more vapours are evolved. The fire may then be allowed to go
out, and the retort to cool.
As the acid thus obtained is slightly tinged with copper, it must be
rectified before bringing it into the market. For this purpose we may
make use of the same apparatus, only substituting for the stoneware
retort a glass one, placed in a sand bath. All the globes ought to be
perfectly clean and dry. The distillation is to be conducted in the
usual way. If we divide the product into thirds, the first yields the
feeblest acid, and the third the strongest. We should not push the
process quite to dryness, because there remains in the last portions
certain impurities, which would injure the flavour of the acid.
The total acid thus obtained forms nearly one half of the weight of the
acetate employed, and the residuum forms three tenths; so that about two
tenths of the acid have been decomposed by the heat, and are lost. As
the oxide of copper is readily reduced to the metallic state, its oxygen
goes to the elements of one part of the acid, and forms water, which
mingles with the products of carbonic acid, carburetted hydrogen, and
carbonic oxide gases which are disengaged; and there remains in the
retort some charcoal mixed with metallic copper. These two combustibles
are in such a state of division, that the residuum is pyrophoric. Hence
it often takes fire the moment of its being removed from the cold
retort. The very considerable loss experienced in this operation has
induced chemists to try different methods to obtain all the acid
contained in the acetate. Thus, for example, a certain addition of
sulphuric acid has been prescribed; but, besides that the radical
vinegar obtained in this way always contains sulphurous acid, from which
it is difficult to free it, it is thereby deprived of that spirit called
the _pyro-acetic_, which tempers the sharpness of its smell, and gives
it an agreeable aroma. It is to be presumed, therefore, that the
preceding process will continue to be preferred for making aromatic
vinegar. Its odour is often further modified by essential oils, such as
those of rosemary, lavender, &c.
4. _Pyrolignous Acid, or Wood Vinegar._--The process for making this
acid is founded upon the general property of heat, to separate the
elements of vegetable substances, and to unite them anew in another
order, with the production of compounds which did not exist in the
bodies subjected to its action. The respective proportion of these
products varies, not only in the different substances, but also in the
same substance, according as the degree of heat has been greater or
less, or conducted with more or less skill. When we distil a vegetable
body in a close vessel, we obtain at first the included water, or that
of vegetation; there is next formed another portion of water, at the
expense of the oxygen and hydrogen of the body; a proportional quantity
of charcoal is set free, and, with the successive increase of the heat,
a small portion of charcoal combines with the oxygen and hydrogen to
form acetic acid. This was considered, for some time, as a peculiar
acid, and was accordingly called _pyrolignous_ acid. As the proportion
of carbon becomes preponderant, it combines with the other principles,
and then some empyreumatic oil is volatilised, of little colour, but
which becomes thicker, and of a darker tint, always getting more loaded
with carbon.
Several elastic fluids accompany these different products. Carbonic acid
comes over, but in small quantity, much carburetted hydrogen, and,
towards the end, a considerable proportion of carbonic oxide. The
remainder of the charcoal, which could not be carried off in these
several combinations, is found in the retort, and preserves, usually,
the form of the vegetable body which furnished it. Since mankind have
begun to reason on the different operations of the arts, and to raise
them to a level with scientific researches they have introduced into
several branches of manufacture a multitude of improvements, of which,
formerly, they would hardly have deemed them susceptible. Thus, in
particular, the process for carbonising wood has been singularly
meliorated, and in reference to the preceding observations, advantage
has been derived from several products that formerly were not even
collected.
[Illustration: _Fig._ 2.]
The apparatus employed for obtaining crude vinegar from wood, by the
agency of heat, are large iron cylinders. In this country they are made
of cast iron, and are laid horizontally in the furnace; in France, they
are made of sheet iron riveted together, and they are set upright in the
fire. _Fig._ 2. will give an accurate idea of the British plan, which is
much the same as that adopted for decomposing pit coal in gas works,
only that the cylinders for the pyrolignous acid manufacture are
generally larger, being frequently 4 feet in diameter, and 6 or 8 feet
long, and built horizontally in brickwork, so that the flame of one
furnace may play around two of them. It would, probably, answer better,
if their size were brought nearer the dimensions of the gas-light
retorts, and if the whole system of working them were assimilated to
that of coal gas.
The following arrangement is adopted in an excellent establishment in
Glasgow, where the above large cylinders are 6 feet long, and both ends
of them project a very little beyond the brickwork. One end has a disc
or round plate of cast iron, well fitted, and firmly bolted to it, from
the centre of which disc an iron tube, about 6 inches diameter, proceeds
and enters, at a right angle, the main tube of refrigeration. The
diameter of this tube may be from 9 to 14 inches, according to the
number of cylinders. The other end of the cylinder is called the mouth
of the retort; this is closed by a disc of iron, smeared round its edge
by clay lute, and secured in its place by fir wedges. The charge of wood
for such a cylinder is about 8 cwt. The hard woods--oak, ash, birch, and
beech--are alone used; fir does not answer. The heat is kept up during
the day-time, and the furnace is allowed to cool during the night. Next
morning, the door is opened, the charcoal removed, and a new charge of
wood is introduced. The average product of crude vinegar called
pyrolignous acid, is 35 gallons. It is much contaminated with tar, is of
a deep brown colour, and has a sp. gr. of 1·025. Its total weight is
therefore about 300 lbs., but the residuary charcoal is found to weigh
no more than one fifth of the wood employed; hence nearly one half of
the ponderable matter of the wood is dissipated in incondensable gases.
Count Rumford states, that the charcoal is equal in weight to more than
four tenths of the wood from which it is made. The count’s error seems
to have arisen from the slight heat of an oven to which his wood was
exposed in a glass cylinder. The result now given, is the experience of
an eminent manufacturing chemist.
The crude pyrolignous acid is rectified by a second distillation in a
copper still, in the body of which about 20 gallons of viscid tarry
matter are left from every 100. It has now become a transparent brown
vinegar, having a considerably empyreumatic smell, and a sp. gr. of
1·013. Its acid powers are superior to those of the best household
vinegar, in the proportion of three to two. By redistillation,
saturation with quicklime, evaporation of the liquid acetate to dryness,
and conversion into acetate of soda by sulphate of soda, the
empyreumatic matter is so completely dissipated, that on decomposing the
pure acetate of soda by sulphuric acid, a perfectly colourless and
grateful vinegar rises in distillation. Its strength will be
proportionable to the concentration of the decomposing acid.
The acetic acid of the chemist may be prepared also in the following
modes:--1. Two parts of fused acetate of potash, with one of the
strongest oil of vitriol, yield, by slow distillation from a glass
retort into a refrigerated receiver, concentrated acetic acid. A small
portion of sulphurous acid, which contaminates it, may be removed by
redistillation from a little acetate of lead. 2. Or four parts of good
sugar of lead, with one part of sulphuric acid, treated in the same way,
afford a slightly weaker acetic acid. 3. Gently calcined sulphate of
iron, or green vitriol, mixed with sugar of lead, in the proportion of 1
of the former to 2-1/2 of the latter, or with acetate of copper, and
carefully distilled from a porcelain retort into a cool receiver, may be
also considered an economical process. But that with binacetate of
copper above described, is preferable to any of these.
[Illustration: _Fig._ 3.]
The manufacture of pyrolignous acid is conducted in the following way in
France. Into large cylindrical vessels (_fig._ 3.) made of rivetted
sheet iron, and having at their top and side a small sheet iron
cylinder, the wood intended for making charcoal is introduced. To the
upper part of this vessel a cover of sheet iron, B, is adapted, which is
fixed with bolts. This vessel, thus closed, represents, as we see, a
vast retort. When it is prepared, as we have said, it is lifted by means
of a swing crane, C, and placed in a furnace, D, (_fig._ 4.) of a form
relative to that of the vessel, and the opening of the furnace is
covered with a dome, E, made of masonry or brickwork. The whole being
thus arranged, heat is applied in the furnace at the bottom. The
moisture of the wood is first dissipated, but by degrees the liquor
ceases to be transparent, and becomes sooty. An adopter tube, A, is then
fitted to the lateral cylinder. This adopter enters into another tube at
the same degree of inclination which commences the condensing apparatus.
The means of condensation vary according to the localities. In certain
works they cool by means of air, by making the vapour pass through a
long series of cylinders, or sometimes, even, through a series of casks
connected together; but most usually water is used for condensing, when
it can be easily procured in abundance. The most simple apparatus
employed for this purpose consists of two cylinders, F, F, (_fig._ 4.)
the one within the other, and which leave between them a sufficient
space to allow a considerable body of water to circulate along and cool
the vapours. This double cylinder is adapted to the distilling vessel,
and placed at a certain inclination. To the first double tube, F, F, a
second, and sometimes a third, entirely similar, are connected, which,
to save space, return upon themselves in a zigzag fashion. The water is
set in circulation by an ingenious means now adopted in many different
manufactories. From the lower extremity, G, of the system of condensers,
a perpendicular tube rises, whose length should be a little more than
the most elevated point of the system. The water, furnished by a
reservoir, L, enters by means of the perpendicular tube through the
lower part of the system, and fills the whole space between the double
cylinders. When the apparatus is in action, the vapours, as they
condense, raise the temperature of the water, which, by the column in L
G, is pressed to the upper part of the cylinders, and runs over by the
spout K. To this point a very short tube is attached, which is bent
towards the ground, and serves as an overflow.
[Illustration: _Fig._ 4.]
The condensing apparatus is terminated by a conduit in bricks covered
and sunk in the ground. At the extremity of this species of gutter is a
bent tube, E, which discharges the liquid product into the first
cistern. When it is full, it empties itself, by means of an overflow
pipe, into a great reservoir; the tube which terminates the gutter
plunges into the liquid, and thus intercepts communication with the
inside of the apparatus. The disengaged gas is brought back by means of
pipes M L, from one of the sides of the conduit to the under part of the
ash pit of the furnace. These pipes are furnished with stopcocks M, at
some distance in front of the furnace, for the purpose of regulating the
jet of the gas, and interrupting, at pleasure, communication with the
inside of the apparatus. The part of the pipes which terminates in the
furnace rises perpendicularly several inches above the ground, and is
expanded like the rose of a watering can, N. The gas, by means of this
disposition, can distribute itself uniformly under the vessel, without
suffering the pipe which conducts it to be obstructed by the fuel or the
ashes.
The temperature necessary to effect the carbonisation is not
considerable: however, at the last it is raised so high as to make the
vessels red hot; and the duration of the process is necessarily
proportional to the quantity of wood carbonised. For a vessel which
shall contain about 5 meters cube (nearly 6 cubic yds.), 8 hours of fire
is sufficient. It is known that the carbonisation is complete by the
colour of the flame of the gas: it is first of a yellowish red; it
becomes afterwards blue, when more carbonic oxide than carbonic hydrogen
is evolved; and towards the end it becomes entirely white,--a
circumstance owing, probably, to the furnace being more heated at this
period, and the combustion being more complete. There is still another
means of knowing the state of the process, to which recourse is more
frequently had; that is the cooling of the first tubes, which are not
surrounded with water: a few drops of this fluid are thrown upon their
surface, and if they evaporate quietly, it is judged that the
calcination is sufficient. The adopter tube is then unluted, and is slid
into its junction pipe; the orifices are immediately stopped with plates
of iron and plaster loam. The brick cover, E, of the furnace is first
removed by means of the swing crane, then the cylinder itself is lifted
out and replaced immediately by another one previously charged. When the
cylinder which has been taken out of the furnace is entirely cooled, its
cover is removed, and the charcoal is emptied. Five cubic meters of wood
furnish about 7 chaldrons (voies) and a half of charcoal. (For
modifications of the wood-vinegar apparatus, see CHARCOAL and
PYROLIGNOUS ACID.)
The different qualities of wood employed in this operation give nearly
similar product in reference to the acid; but this is not the case with
the charcoal, for it is better the harder the wood; and it has been
remarked, that wood long exposed to the air furnishes a charcoal of a
worse quality than wood carbonised soon after it is cut.
Having described the kind of apparatus employed to obtain pyrolignous
acid, I shall now detail the best mode of purifying it. This acid has a
reddish brown colour; it holds in solution a portion of empyreumatic oil
and of the tar which were formed at the same time; another portion of
these products is in the state of a simple mixture; the latter may be
separated by repose alone. It is stated, above, that the distilling
apparatus terminates in a subterranean reservoir, where the products of
all the vessels are mixed. A common pump communicates with the
reservoir, and sinks to its very bottom, in order that it may draw off
only the stratum of tar, which, according to its greater density,
occupies the lower part. From time to time the pump is worked to remove
the tar as it is deposited. The reservoir has at its top an overflow
pipe, which discharges the clearest acid into a cistern, from which it
is taken by means of a second pump.
The pyrolignous acid thus separated from the undissolved tar is
transferred from this cistern into large sheet iron boilers, where its
saturation is effected either by quicklime or by chalk; the latter of
which is preferable, as the lime is apt to take some of the tar into
combination. The acid parts by saturation with a new portion of the tar,
which is removed by skimmers. The neutral solution is then allowed to
rest for a sufficient time to let its clear parts be drawn off by
decantation.
The acetate of lime thus obtained indicates by the hydrometer, before
being mixed with the waters of edulcoration, a degree corresponding to
the acidimetric degree of the acid employed. This solution must be
evaporated till it reaches a specific gravity of 1·114 (15° Baumé),
after which there is added to it a saturated solution of sulphate of
soda. The acids exchange bases; sulphate of lime precipitates, and
acetate of soda remains in solution. In some manufactures, instead of
pursuing the above plan, the sulphate of soda is dissolved in the hot
pyrolignous acid, which is afterwards saturated with chalk or lime. By
this means no water need be employed to dissolve the sulphate, and
accordingly the liquor is obtained in a concentrated form without
evaporation. In both modes the sulphate of lime is allowed to settle,
and the solution of acetate of soda is decanted. The residuum is set
aside to be edulcorated, and the last waters are employed for washing
fresh portions.
The acetate of soda which results from this double decomposition is
afterwards evaporated till it attains to the density of 1·225 or 1·23,
according to the season. This solution is poured into large
crystallising vessels, from which, at the end of 3 or 4 days, according
to their capacity, the mother waters are decanted, and a first
crystallisation is obtained of rhomboidal prisms, which are highly
coloured and very bulky. Their facettes are finely polished, and their
edges very sharp. The mother waters are submitted to successive
evaporations and crystallisations till they refuse to crystallise, and
they are then burnt to convert them into carbonate of soda.
To avoid guesswork proportions, which are always injurious, by the loss
of time which they occasion, and by the bad results to which they often
lead, we should determine experimentally, beforehand, the quantities
absolutely necessary for the reciprocal decomposition, especially when
we change the acid or the sulphate. But it may be remarked that,
notwithstanding all the precautions we can take, there is always a
notable quantity of sulphate of soda and acetic acid, which disappear
totally in this decomposition. This arises from the circumstance that
sulphate of soda and acetate of lime do not completely decompose each
other, as I have ascertained by experiments on a very considerable
scale; and thus a portion of each of them is always lost with the mother
waters. It might be supposed that by calcining the acetate of lime we
could completely destroy its empyreumatic oil; but, though I have made
many experiments, with this view I never could obtain an acetate capable
of affording a tolerable acid. Some manufacturers prefer to make the
acetate of soda by direct saturation of the acid with the alkali, and
think that the higher price of this substance is compensated by the
economy of time and fuel which it produces.
The acetate of soda is easily purified by crystallisations and
torrefaction; the latter process, when well conducted, freeing it
completely from every particle of tar. This torrefaction, to which the
name of fusion may be given, requires great care and dexterity. It is
usually done in shallow cast iron boilers of a hemispherical shape.
During all the time that the heat of about 500° Fahr. is applied, the
fused mass must be diligently worked with rakes; an operation which
continues about 24 hours for half a ton of materials. We must carefully
avoid raising the temperature so high as to decompose the acetate, and
be sure that the heat is equally distributed; for if any point of the
mass enters into decomposition, it is propagated with such rapidity, as
to be excessively difficult to stop its progress in destroying the
whole. The heat should never be so great as to disengage any smoke, even
when the whole acetate is liquefied. When there is no more frothing up,
and the mass flows like oil, the operation is finished. It is now
allowed to cool in a body, or it may be ladled out into moulds, which is
preferable.
When the acetate is dissolved in water, the charcoaly matter proceeding
from the decomposition of the tar must be separated by filtration, or by
boiling up the liquor to the specific gravity 1·114, when the
carbonaceous matter falls to the bottom. On evaporating the clear
liquor, we obtain an acetate perfectly fine, which yields beautiful
crystals on cooling. In this state of purity it is decomposed by
sulphuric acid, in order to separate its acetic acid.
This last operation, however simple it appears, requires no little care
and skill. The acetate of soda crystallised and ground is put into a
copper, and the necessary quantity of sulphuric acid of 1·842 (about 35
per cent. of the salt) to decompose almost, but not all, the acetate, is
poured on. The materials are left to act on each other; by degrees the
acetic acid quits its combination, and swims upon the surface; the
greater part of the resulting sulphate of soda falls in a pulverulent
form, or in small granular crystals, to the bottom. Another portion
remains dissolved in the liquid, which has a specific gravity of 1·08.
By distillation we separate this remainder of the sulphate, and finally
obtain acetic acid, having a specific gravity of 1·05, an agreeable
taste and smell, though towards the end it becomes a little
empyreumatic, and coloured; for which reason, the last portions must be
kept apart. The acid destined for table use ought to be distilled in an
alembic whose capital and condensing worm are of silver; and to make it
very fine, it may be afterwards infused over a little washed bone-black.
It is usually obtained in a pretty concentrated state; but when we wish
to give it the highest degree of concentration, we mix with it a
quantity of dry muriate of lime, and distil anew. This acid may be
afterwards exposed to congelation, when the strongest will crystallise.
It is decanted, and the crystals are melted by exposing them to a
temperature of from 60° to 70° Fahr.; this process is repeated till the
acid congeals without remainder, at the temperature of 55° Fahr. It has
then attained its maximum strength, and has a specific gravity of 1·063.
We shall add an observation on the above mode of decomposing the acetate
of soda by sulphuric acid. Many difficulties are experienced in this
process, if the sulphuric acid be poured on in small quantities at a
time; for then such acrid fumes of acetic acid are disengaged, that the
workmen are obliged to retire. This inconvenience may be saved by adding
all the sulphuric acid at once; it occupies the lower part of the
vessel, and decomposes only the portion of the acetate in contact with
it; the heat evolved in consequence of this reaction is diffused through
a great mass, and produces no sensible effect. When the sulphuric acid
forms an opening, or a species of little crater, the workman, by means
of a rake, depresses the acetate into it by degrees, and then the
decomposition proceeds as slowly as he desires.
The acetic acid, like the nitric, chloric, and some others, has not
hitherto been obtained free from water, and the greatest degree of
concentration which we have been able to give it is that in which it
contains only the quantity of water equivalent to the atomic weight of
another oxidized body; a quantity which amounts to 14·89 per cent. The
processes prescribed for preparing concentrated acetic acid sometimes
tend to deprive it of that water without which it could not exist:
hence, in all such cases, there is a part of the acid itself decomposed
to furnish the water necessary to the constitution of the remainder. The
constituent principles of the decomposed portion then form a peculiar,
intoxicating, highly inflammatory liquid, called the PYRO-ACETIC SPIRIT.
The most highly concentrated acid of 1·063 becomes denser by the
addition of a certain quantity of water up to a certain point. According
to Berzelius, the prime equivalent of this acid is 643·189, oxygen being
reckoned 100. Now, the above strongest acid consists of one prime of
acid, and one of water = 1124·79. When it contains three atoms of water,
that is, 337·437 parts to 643·189, or 34·41 to 65·59 in 100, it then has
taken its maximum density of 1·075; after which the further addition of
water diminishes its specific gravity, as the following table of
Mollerat shows. His supposed anhydrous or dry acid contains, at 1·0630,
0·114 parts of water.
_Table of Acetic Acid._
+----------+--------+
| Water in |Specific|
|100 parts.|gravity.|
+----------+--------+
| 0·00 | 1·0630 |
| 8·37 | 1·0742 |
| 17·00 | 1·0770 |
| 23·00 | 1·0791 |
| 28·10 | 1·0763 |
| 33·83 | 1·0742 |
| 37·60 | 1·0728 |
| 47·00 | 1·0658 |
| 50·00 | 1·0637 |
| 51·80 | 1·063 |
+----------+--------+
Acetic acid readily takes fire when it is heated in open vessels to the
boiling point, and it burns with a blue flame, nearly like alcohol. It
must be kept in close vessels, otherwise it loses its strength, by
attracting humidity from the air. When concentrated, it is used only as
a scent, or pungent exciter of the olfactory organs, in sickness and
fainting fits. Its anti-epidemic qualities are apocryphal. What is met
with in the shops under the name of salts of vinegar is nothing but
sulphate of potash, put up in small phials, and impregnated with acetic
acid, sometimes rendered aromatic with oil of rosemary or lavender.
Acetic acid, in its dry state, as it exists in fused acetate of potash
or soda, is composed of
47·536 carbon
5·822 hydrogen
46·642 oxygen
-------
100·000
And its symbol by Berzelius is H⁶ C⁴ O³ = A. We must bear in mind that
his atomic weight for hydrogen is only one half of the number usually
assigned to it by British chemists, in consequence of his making water a
compound of two atoms of hydrogen and one of oxygen.
When the vapour of acetic acid is made to traverse a red-hot tube of
iron, it is converted into water, carbonic acid, carburetted hydrogen,
but chiefly pyro-acetic spirit. Acetic acid is a solvent of several
organic products; such as camphor, gluten, gum-resins, resins, the
fibrine of blood, the white of egg, &c.
It is an important problem to ascertain the purity and strength of
vinegar. Spurious acidity is too often given to it by cheaper acids,
such as the sulphuric and the nitric. The former, may most surely be
detected by the nitrate of baryta, or even by acetate of lead, which
occasion a white precipitate in such adulterated vinegar. For the case
of nitric, which is more insidious, the proper test is, a bit of gold
leaf, wetted with a few drops of muriatic acid. If the leaf dissolves,
on heating the mixture in a watch glass, we may be sure that nitric acid
is present.
Specific gravity, if determined by a sensible hydrometer, is a good test
of the strength of the genuine vinegar; and the following table of
Messrs. Taylor is nearly correct, or sufficiently so for commercial
transactions.
Revenue proof vinegar, called by the English manufacturer No. 24., has a
specific gravity of
1·0085 and contains of real acid in 100-- 5
1·0170 10
1·0257 15
1·0320 20
1·0470 30
1·0580 40
An excise duty of 2_d._ is levied on every gallon of the above proof
vinegar. Its strength is not, however, estimated directly by its
specific gravity, but by the specific gravity which it assumes when
saturated with quicklime. The decimal fraction of the specific gravity
of the calcareous acetate is very nearly the double of that of the pure
vinegar; or, 1·009 in vinegar becomes 1·018 in acetate of lime. The
vinegar of malt contains so much mucilage or gluten, that when it has
only the same acid strength as the above, it has a density of 1·0014,
but it becomes only 1·023 when converted into acetate of lime: indeed,
0·005 of its density is due to mucilaginous matter. This fact shows the
fallacy of trusting to the hydrometer for determining the strength of
vinegars, which may be more or less loaded with vegetable gluten. The
proper test of this, as of all other acids, is, the quantity of alkaline
matter which a given weight or measure of it will saturate. For this
purpose the bicarbonate of potash, commonly called, in the London shops,
carbonate, may be employed very conveniently. As it is a very uniform
substance, and its atomic weight, by the hydrogen radix, is 100·584,
while the atomic weight of acetic acid, by the same radix, is 51·563, if
we estimate 2 grains of the bicarbonate as equivalent to 1 of the real
acid, we shall commit no appreciable error. Hence, a solution of the
carbonate containing 200 grains in 100 measures, will form an acetimeter
of the most perfect and convenient kind; for the measures of test liquid
expended in saturating any measure,--for instance, an ounce or 1000
grains of acid,--will indicate the number of grains of real acetic acid
in that quantity. Thus, 1000 grains of the above proof, would require 50
measures of the acetimetrical alkaline solution, showing that it
contains 50 grains of real acetic acid in 1000, or 5 per cent.
It is common to add to purified wood vinegar, a little acetic ether, or
caramelised (burnt) sugar to colour it, also, in France, even wine, to
flavour it. Its blanching effect upon red cabbage, which it has been
employed to pickle, is owing to a little sulphurous acid. This may be
removed by redistillation with peroxide of manganese. Indeed, Stoltze
professes to purify the pyrolignous acid solely by distilling it with
peroxide of manganese, and then digesting it with bruised wood charcoal;
or by distilling it with a mixture of sulphuric acid and manganese. But
much acid is lost in this case by the formation of acetate of that
metal.
Birch and beech afford most Pyrolignous acid, and pine the least. It is
exclusively employed in the arts, for most purposes of which it need not
be very highly purified. It is much used in calico printing, for
preparing acetate of iron called IRON LIQUOR, and acetate of alumina,
called RED LIQUOR; which see. It serves also to make sugar of lead; yet
when it contains its usual quantity, after rectification, of tarry
matter, the acetate of lead will hardly crystallise, but forms
cauliflower concretions. This evil may be remedied, I believe, by
boiling the saline solution with a very little nitric acid, which causes
the precipitation of a brown granular substance, and gives the liquor a
reddish tinge. The solution being afterwards treated with bruised
charcoal, becomes colourless, and furnishes regular crystals of acetate
or sugar of lead.
Pyrolignous acid possesses, in a very eminent degree, anti-putrescent
properties. Flesh steeped in it for a few hours may be afterwards dried
in the air without corrupting; but it becomes hard, and somewhat
leather-like: so that this mode of preservation does not answer well for
butcher’s meat. Fish are sometimes cured with it. See PYRO-ACETIC
SPIRIT; PYROXILIC ETHER; PYROXOLIC SPIRIT; PYROLIGNOUS ACID and
VINEGAR.
ACETIMETER. An apparatus for determining the strength of vinegar. See
the conclusion of the preceding article for a description of my simple
method of acetimetry.
ACETONE. The new chemical name of pyro-acetic spirit.
ACID OF ARSENIC. (_Acide Arsenique_, Fr.; _Arseniksäure_, Germ.)
ACIDS. A class of chemical substances characterised by the property of
combining with and neutralising the alkaline and other bases, and of
thereby forming a peculiar class of bodies called salts. The acids which
constitute objects of special manufacture for commercial purposes are
the following:--acetic, arsenious, carbonic, chromic, citric, malic,
muriatic, nitric, oxalic, phosphoric, sulphuric, tartaric, which see.
ACROSPIRE. (_Plumule_, Fr.; _Blattkeim_, Germ.) That part of a
germinating seed which botanists call the plumula, or plumes. See BEER
and MALT.
ADDITIONS. Such articles as are added to the fermenting wash of the
distiller are distinguished by this trivial name.
ADIPOCIRE. Fr. (_Fettwachs_, Germ.) The fatty matter generated in dead
bodies buried under peculiar circumstances. In 1786 and 1787, when the
churchyard of the _Innocents_, at Paris, was cleaned out, and the bones
transported to the catacombs, it was discovered that not a few of the
_cadavres_ were converted into a saponaceous white substance, more
especially many of those which had been interred for fifteen years in
one pit, to the amount of 1500, in coffins closely packed together.
These bodies were flattened, in consequence of their mutual pressure;
and, though they generally retained their shape, there was deposited
round the bones of several a grayish white, somewhat soft, flexible
substance. Fourcroy presented to the Academy of Sciences, in 1789, a
comprehensive memoir upon this phenomenon, which appeared to prove that
the fatty body was an ammoniacal soap, containing phosphate of lime;
that the fat was similar to spermaceti, as it assumed on slow cooling a
foliated crystalline structure; as also to wax, as, when rapidly cooled,
it became granular: hence he called it _Adipocire_. Its melting point
was 52·5° C. (126·5° Fahr.). He likewise compared this soap to the fat
of gall-stones, and supposed it to be a natural product of the slow
decomposition of all animal matter, except bones, nails, and hairs.
This substance was again examined by Chevreul in 1812, and was found by
him to contain margaric acid, oleic acid, combined with a yellow
colouring, odorous matter, besides ammonia, a little lime, potash, oxide
of iron, salts of lactic acid, an azotized substance; and was therefore
considered as a combination of margaric and oleic acids, in variable
proportions (whence arose its variable fusibility), but that it was not
analogous with either spermaceti or cholesterine (gallstones). These fat
acids are obviously generated by the reaction of the ammonia upon the
margarine and oleine, though they eventually lose the greater part of
that volatile alkali.
According to the views of both Gay Lussac and Chevreul, this _adipocire_
proceeds solely from the pre-existing fat of the dead body, and not from
the flesh, tendons, or cartilages, as had been previously imagined;
which had led to some expensive and abortive attempts, upon the great
scale of manufacture, to convert the dead bodies of cattle into
adipocire, for the purposes of the candle-maker or soap-boiler, by
exposing them for some time to the action of moisture.
Von Hartkol made experiments during 25 years upon this subject, from
which he inferred, that there is no formation of adipocire in bodies
buried in dry ground; that in moist earth the fat of the dead body does
not increase, but changes into a fetid saponaceous substance, incapable
of being worked into either soap or candles; that the dead bodies of
_mammalia_ immersed in running water, leave behind after 3 years a pure
fat, which is more abundant from young than from old animals; that the
intestines afford more fat than the muscles; that from this fat, without
any purification, candles may be made, as void of smell, as hard, and as
white, as from bleached wax; that from cadavers immersed for 3 years in
stagnant water, more fat is procured than from those in running water,
but that it needs to be purified before it can be made into soap or
candles.
The cause of the difference between Hartkol’s and Chevreul’s results
cannot be assigned, as the latter has not published his promised remarks
upon the subject. At any rate, dead animal matter can be worked up more
profitably than in making artificial _adipocire_.
ADIT. The horizontal entrance of a mine. It is sometimes called the
drift. See MINING and METALLURGY.
ADULTERATION. The debasing any product of manufacture, especially
chemical, by the introduction of cheap materials. The art of
ascertaining the genuineness of the several products will be taught
under the specific objects of manufacture.
ÆTHER. See ETHER.
AFFINITY. The chemical term denoting the peculiar attractive force which
produces the combination of dissimilar substances; such as of an alkali
with an acid, or of sulphur with a metal.
AGARIC. A species of boletus or fungus, which grows in dunghills; with
the salts of iron it affords a black dye. It is said to be convertible
into a kind of china ink.
AGATE. A siliceous mineral which is cut into seals and other forms for
the coarser kinds of jewellery. See GEM.
AIR. See VENTILATION.
ALABASTER, is a stone usually white, and soft enough to be scratched by
iron. There are two kinds of it: the gypseous, which is merely a natural
semi-crystalline sulphate of lime; and the calcareous alabaster, which
is a carbonate of lime. The oriental alabaster is always of the latter
kind, and is most esteemed, because it is agreeably variegated with
lively colours, and especially with zones of honey-yellow, yellow-brown,
red, &c.; it is, moreover, susceptible of taking a marble polish.
The fineness of the grain of alabaster, the uniformity of its texture,
the beauty of its polished surface, and its semi-transparency, are the
qualities which render it valuable to the sculptor and to the
manufacturer of ornamental toys.
The limestone alabaster is frequently found as a yellowish-white deposit
in certain fountains. The most celebrated spring of this kind is that of
the baths of San Filippo, in Tuscany. The water, almost boiling hot,
runs over an enormous mass of stalactites, which it has formed, and
holds the carbonate of lime in solution by means of sulphuretted
hydrogen (according to M. Alexandre Brongniart), which escapes by
contact of the atmosphere. Advantage has been taken of this property to
make _basso relievos_ of considerable hardness, by placing moulds of
sulphur very obliquely, or almost upright, in wooden tubs open at the
bottom. These tubs are surmounted at the top with a large wooden cross.
The water of the spring, after having deposited in an external conduit
or cistern the coarser sediment, is made to flow upon this wooden cross,
where it is scattered into little streamlets, and thence lets fall, upon
the sulphur casts, a precipitate so much the finer the more nearly
vertical the mould. From one to four months are required for this
operation, according to the thickness of the deposited crust. By
analogous processes, the artists have succeeded in moulding vases,
figures of animals, and other objects, in relief, of every different
form, which require only to be trimmed a little, and afterwards
polished.
The common alabaster is composed of sulphuric acid and lime, though some
kinds of it effervesce with acids, and therefore contain some carbonate
of lime. This alabaster occurs in many different colours, and of very
different degrees of hardness, but it is always softer than marble. It
forms, usually, the lowest beds of the gypsum quarries. The sculptors
prefer the hardest, the whitest, and those of a granular texture, like
Carrara marble, and so like that they can only be distinguished by the
hardness.
The alabaster is worked with the same tools as marble; and as it is many
degrees softer, it is so much the more easily cut; but it is more
difficult to polish, from its little solidity. After it has been
fashioned into the desired form, and smoothed down with pumice stone, it
is polished with a pap-like mixture of chalk, soap, and milk; and, last
of all, finished by friction with flannel. It is apt to acquire a
yellowish tinge.
Besides the harder kinds, employed for the sculpture of large figures,
there is a softer alabaster, pure white and semi-transparent, from which
small ornamental objects are made, such as boxes, vases, lamps, stands
of time-pieces, &c. This branch of business is much prosecuted in
Florence, Leghorn, Milan, &c., and employs a great many turning lathes.
Of all the alabasters the Florentine merits the preference, on account
of its beauty and uniformity, so that it may be fashioned into figures
of considerable size; for which purpose there are large work-shops where
it is cut with steel saws into blocks and masses of various shapes.
Other sorts of gypsum, such as that of Salzburg and Austria, contain
sand veins, and hard nodules, and require to be quarried by cleaving and
blasting operations, which are apt to crack it, and unfit it for all
delicate objects of sculpture. It is, besides, of a gray shade, and
often stained with darker colours.
The alabaster best adapted for the fine arts is pretty white when newly
broken, and becomes whiter on the surface by drying. It may be easily
cut with the knife or chisel, and formed into many pleasing shapes by
suitable steel tools. It is worked either by the hand alone, or with the
aid of a turning lathe. The turning tools should not be too thin or
sharp-edged; but such as are employed for ivory and brass are most
suitable for alabaster, and are chiefly used to shave and to scratch the
surface. The objects which cannot be turned may be fashioned by the
rasping tools, or with minute files, such as variegated foliage. Fine
chisels and graving tools are also used for the better pieces of
statuary.
For polishing such works, a peculiar process is required: pumice stone,
in fine powder, serves to smooth down the surfaces very well, but it
soils the whiteness of the alabaster. To take away the unevennesses and
roughnesses dried shave-grass (_equisetum_) answers best. Frictions with
this plant and water polish down the asperities left by the chisel: the
fine streaks left by the grass may be removed by rubbing the pieces with
slaked lime, finely pulverised and sifted, made into a paste, or putty,
with water. The polish and satin-lustre of the surface are communicated
by friction, first with soap-water and lime, and finally with powdered
and elutriated talc or French chalk.
Such articles as consist of several pieces are joined by a cement
composed of quicklime and white of egg, or of well-calcined and
well-sifted Paris plaster, mixed with the least possible quantity of
water.
Alabaster objects are liable to become yellow by keeping, and are
especially injured by smoke, dust, &c. They may be in some measure
restored by washing with soap and water, then with clear water, and
again polished with shave-grass. Grease spots may be removed either by
rubbing with talc powder, or with oil of turpentine.
The surface of alabaster may be etched by covering over the parts that
are not to be touched with a solution of wax in oil of turpentine,
thickened with white lead, and immersing the articles in pure water
after the varnish has set. The action of the water is continued from 20
to 50 hours, more or less, according to the depth to which the etching
is to be cut. After removing the varnish with oil of turpentine, the
etched places, which are necessarily deprived of their polish, should be
rubbed with a brush dipped in finely-powdered gypsum, which gives a kind
of opacity, contrasting well with the rest of the surface.
Alabaster may be stained either with metallic solutions, with spirituous
tinctures of dyeing plants, or with coloured oils, in the same way as
marbles.
This substance has been hardened, it is said, by exposing it to the heat
of a baker’s oven for 10 or 20 hours, after taking it out of the quarry,
and giving it the figure, roughly, which it is intended to have. After
this exposure, it must be dipped for two minutes in running water; when
it is cold, it must be dipped a second time for the same period. On
being exposed to the air for a few days, alabaster so treated acquires a
marble-like hardness. I doubt the truth of this statement.
ALBUM GRÆCUM. The white dung of dogs, sometimes used to soften leather
in the process of dressing it after the depilatory action of lime.
ALCARAZZAS. A species of porous earthenware, made in Spain, for cooling
liquors. See POTTERY.
ALCOHOL. The well-known intoxicating liquor procured by distillation
from various vegetable juices, and infusions of a saccharine nature,
which have undergone the vinous fermentation. Common alcohol, or proof
spirit, as it is called, contains about one half its weight of water. It
may be concentrated till its specific gravity becomes so low as 0·825,
by simple redistillation at a steam or water-bath heat; but to make it
stronger, we must mix with it, in the still or retort, dry carbonate of
potash, muriate of lime, or some other substances strongly attractive of
water, and then it may be obtained of a specific gravity so low as 0·791
at 16° Reaumur (68° Fahr.), water being 1·000. At 0·825, it contains,
still, 11 per cent. of water; and in this state it is as volatile as
absolute alcohol, on account of the inferior density of the aqueous
vapour, compared to the alcoholic. Indeed, according to Yelin and Fuchs,
the boiling point of anhydrous alcohol is higher than of that which
contains 2 or 3 per cent. of water; hence, in the distillation of
alcohol of 94 per cent., the first portions that come over are more
aqueous than the following. Absolute alcohol has its boiling point at
168-1/2° Fahr.: but when it holds more than 6 per cent. of water, the
first portions that come over are richest in alcohol, and the
temperature of the boiling point, or of the spirituous vapour, is always
higher the longer the distillation continues. According to Gröning’s
researches, the following temperatures of the alcoholic vapours
correspond to the accompanying contents of alcohol in per centage of
volume, which are disengaged in the boiling of the spirituous liquid.
+------------+-----------+-----------+
| |Alcoholic |Alcoholic |
|Temperature.|content of |content of |
| |the vapour.|the boiling|
| | |liquid. |
+------------+-----------+-----------+
|Fahr. 170·0 | 93 | 92 |
| 171·8 | 92 | 90 |
| 172 | 91 | 85 |
| 172·8 | 90-1/2 | 80 |
| 174 | 90 | 70 |
| 174·6 | 89 | 70 |
| 176 | 87 | 65 |
| 178·3 | 85 | 50 |
| 180·8 | 82 | 40 |
| 183 | 80 | 35 |
| 185 | 78 | 30 |
| 187·4 | 76 | 25 |
| 189·8 | 71 | 20 |
| 192·0 | 68 | 18 |
| 164 | 66 | 15 |
| 196·4 | 61 | 12 |
| 198·6 | 55 | 10 |
| 201 | 50 | 7 |
| 203 | 42 | 5 |
| 205·4 | 36 | 3 |
| 207·7 | 28 | 2 |
| 210 | 13 | 1 |
| 212 | 0 | 0 |
+------------+-----------+-----------+
Gröning undertook this investigation in order to employ the thermometer
as an alcoholmeter in the distillation of spirits; for which purpose he
thrust the bulb of the thermometer through a cork, inserted into a tube
fixed in the capital of the still. The state of the barometer ought also
to be considered in making comparative experiments of this kind. Since,
by this method, the alcoholic content may be compared with the
temperature of the vapour that passes over at any time, so, also, the
contents of the whole distillation may be found approximately; and the
method serves as a convenient means of making continual observations on
the progress of the distillation.
The temperature, corresponding to a certain per centage of alcohol in
vapour, suggests the employment of a convenient method for obtaining, at
one process, a spirit as free from water as it can be made by mere
distillation. We place over the top of the capital a water-bath, and
lead up through it a spiral pipe from the still, which there passes
obliquely downwards, and proceeds to the refrigeratory. If this bath be
maintained, by a constant influx of cold water, at a certain
temperature, only the alcoholic vapour corresponding to that temperature
will pass over, and the rest will be recondensed and returned into the
still. If we keep the temperature of the water at 174°, for example, the
spirituous vapour which passes over will contain 90 per cent. of
absolute alcohol, according to the preceding table. The skilful use of
this principle constitutes the main improvement in modern distilleries.
See DISTILLATION and STILL.
Another method for concentrating alcohol is that discovered by
Sömmering, founded upon the property of ox bladders to allow water to
pass through and evaporate out of them, but not to permit alcohol to
transpire, or only in a slight degree. Hence, if an ox’s bladder is
filled with spirit of wine, well tied at the mouth, and suspended in a
warm place, the water will continually exhale, and the alcohol will
become nearly anhydrous; for in this way alcohol of 97 or 98 per cent.
may be obtained.
According to Sömmering, we should take for this purpose the bladder of
an ox or a calf, soak it for some time in water, then inflate it and
free it from the fat and the attached vessels; which is to be also done
to the other surface, by turning it inside out. After it is again
inflated and dried, we must smear over the outer side twice, and the
inner side four times, with a solution of isinglass, by which its
texture is made closer, and the concentration of the alcohol goes on
better. A bladder so prepared may serve more than a hundred times. It
must be charged with the spirits to be concentrated, leaving a small
space vacant, it is then to be tightly bound at the mouth, and suspended
in a warm situation, at a temperature of 122° Fahr., over a sand-bath,
or in the neighbourhood of an oven. The surface of the bladder remains
moist with the water, as long as the sp. gr. of the contained spirit is
greater than 0·952. Weak spirit loses its water quicker than strong; but
in from 6 to 12 hours the alcohol may be concentrated, when a suitable
heat is employed. This economical method is particularly applicable in
obtaining alcohol for the preparation of varnishes. When the alcohol is
to serve for other purposes, it must be freed, by distillation, from
certain matters dissolved out of the bladder. Alcohol may likewise be
strengthened, as Sömmering has ascertained when the vessel that contains
the spirit is bound over with a bladder which does not come into contact
with the liquid. Thus, too, all other liquors containing alcohol and
water, as wine, cider, &c., may be made more spirituous.
To procure absolute alcohol, we must take chloride of calcium recently
fused, reduce it to coarse powder, and mix it with its own weight of
spirit of wine, of sp. gr. 0·833, in a bottle, which is to be well
stoppered, and to be agitated till the salt is dissolved. The clear
solution is to be poured into a retort, and half of the volume of the
alcohol employed, or so much as has the sp. gr. 0·791 at 68° Fahr., is
to be distilled off at a gentle heat. Quicklime has also been employed
for the same purpose, but it is less powerful and convenient. Alcohol,
nearly free from water, may be obtained without distillation, by adding
dry carbonate of potash to a spirit of wine, of sp. gr. 0·825. The water
combines with the potash, and falls to the bottom in a dense liquid,
while the pure spirit floats on the surface. This contains however a
little alkali, which can only be separated by distillation.
Anhydrous alcohol is composed by weight of 52·66 carbon, 12·90 hydrogen,
and 34·44 of oxygen. It has a very powerful attraction for water, and
absorbs it from the atmosphere; therefore it must be kept in well-closed
vessels. It also robs vegetable and animal bodies of their moisture; and
hence common alcohol is employed for preserving anatomical preparations.
Alcohol is a solvent for many substances: resins, essential oils,
camphor, are abundantly dissolved by it, forming varnishes, perfumed
spirits, &c. The solution of a resin or essential oil in alcohol becomes
milky on the addition of water, which, by its attraction for alcohol,
separates these substances. Several salts, especially the deliquescent,
are dissolved by it, and some of them give a colour to its flame; thus,
the solutions of the salts of strontia in alcohol burn with a crimson
flame, those of copper and borax green, lime reddish, and baryta yellow.
When water is mixed with alcohol, heat and a condensation of volume are
the result; these effects being greatest with 54 per cent. of alcohol
and 46 of water, and thence decreasing with a greater proportion of
water. For alcohol which contains 90 per cent. of water, this
condensation amounts to 1·94 per cent. of the volume; for 80 per cent.,
2·87; for 70 per cent., 3·44; for 60 per cent., 3·73; for 40 per cent.,
3·44; for 30 per cent., 2·72; for 20 per cent., 1·72; for 10 per cent.,
0·72. Hence, to estimate the quantity of alcohol in any spirit it is
necessary that the specific gravity be ascertained for each determinate
proportion of alcohol and water that are mixed together. When this is
done, we may, by means of an areometer constructed for liquids lighter
than water, determine the strength of the spirit, either by a scale of
specific gravities or by an arbitrary graduation corresponding to
certain commercial objects, and thus we may determine the per centage of
alcohol in whisky or brandy of any strength or purity. An areometer
intended for this use has been called an alcoholmeter, in particular
when the scale of it is so graduated that, instead of the specific
gravity, it indicates immediately the per centage of anhydrous alcohol
in a given weight or volume of the liquid. The scale graduated according
to the per centage of pure alcohol by weight, constitutes the
alcoholmeter of Richter; and that by the per centage in volume, the
alcoholmeter of Tralles and Gay Lussac.
As liquors are sold in general by the measure, not by the weight, it is
convenient, therefore, to know the alcoholic content of the mixtures in
the per centage by volume. Tralles has constructed new tables upon the
principles of those of Gilpin, in which the proportion is given by
volume, and anhydrous alcohol is assumed for the basis; which, at 60°
Fahr., has a specific gravity of 0·7939 compared with water at its
maximum density, or a specific gravity 0·7946 compared with water of the
temperature of 60° Fahr. Gilpin’s alcohol of 0·825 contains 92·6 per
cent. by volume of anhydrous alcohol.
The following table exhibits the per centage of anhydrous alcohol by
volume, at a temperature of 60° Fahr., in correspondence with the
specific gravities of the spirits, water being considered at 60° Fahr.
to have a specific gravity of 0·9991.
Alcoholmetrical Table of Tralles.
+------------+------------+----------+
|Alcohol in | Specific |Difference|
|100 measures| gravity | of the |
| of spirit. |at 60° Fahr.| sp. gr. |
+------------+------------+----------+
| 0 | 9991 | |
| 1 | 9976 | 15 |
| 2 | 9961 | 15 |
| 3 | 9947 | 14 |
| 4 | 9933 | 14 |
| 5 | 9919 | 14 |
| 6 | 9906 | 13 |
| 7 | 9893 | 13 |
| 8 | 9881 | 12 |
| 9 | 9869 | 12 |
| 10 | 9857 | 12 |
| 11 | 9845 | 12 |
| 12 | 9834 | 11 |
| 13 | 9823 | 11 |
| 14 | 9812 | 11 |
| 15 | 9802 | 10 |
| 16 | 9791 | 11 |
| 17 | 9781 | 10 |
| 18 | 9771 | 10 |
| 19 | 9761 | 10 |
| 20 | 9751 | 10 |
| 21 | 9741 | 10 |
| 22 | 9731 | 10 |
| 23 | 9720 | 11 |
| 24 | 9710 | 10 |
| 25 | 9700 | 10 |
| 26 | 9689 | 11 |
| 27 | 9679 | 10 |
| 28 | 9668 | 11 |
| 29 | 9657 | 11 |
| 30 | 9646 | 11 |
| 31 | 9634 | 12 |
| 32 | 9622 | 12 |
| 33 | 9609 | 13 |
| 34 | 9596 | 13 |
| 35 | 9583 | 13 |
| 36 | 9570 | 13 |
| 37 | 9556 | 14 |
| 38 | 9541 | 15 |
| 39 | 9526 | 15 |
| 40 | 9510 | 16 |
| 41 | 9494 | 16 |
| 42 | 9478 | 16 |
| 43 | 9461 | 17 |
| 44 | 9444 | 17 |
| 45 | 9427 | 17 |
| 46 | 9409 | 18 |
| 47 | 9391 | 18 |
| 48 | 9373 | 18 |
| 49 | 9354 | 19 |
| 50 | 9335 | 19 |
| 51 | 9315 | 20 |
| 52 | 9295 | 20 |
| 53 | 9275 | 20 |
| 54 | 9254 | 21 |
| 55 | 9234 | 20 |
| 56 | 9213 | 21 |
| 57 | 9192 | 21 |
| 58 | 9170 | 22 |
| 59 | 9148 | 22 |
| 60 | 9126 | 22 |
| 61 | 9104 | 22 |
| 62 | 9082 | 22 |
| 63 | 9059 | 23 |
| 64 | 9036 | 23 |
| 65 | 9013 | 23 |
| 66 | 8989 | 24 |
| 67 | 8965 | 24 |
| 68 | 8941 | 24 |
| 69 | 8917 | 24 |
| 70 | 8892 | 25 |
| 71 | 8867 | 25 |
| 72 | 8842 | 25 |
| 73 | 8817 | 25 |
| 74 | 8791 | 26 |
| 75 | 8765 | 26 |
| 76 | 8739 | 26 |
| 77 | 8712 | 27 |
| 78 | 8685 | 27 |
| 79 | 8658 | 27 |
| 80 | 8631 | 27 |
| 81 | 8603 | 28 |
| 82 | 8575 | 28 |
| 83 | 8547 | 28 |
| 84 | 8518 | 29 |
| 85 | 8488 | 30 |
| 86 | 8458 | 30 |
| 87 | 8428 | 30 |
| 88 | 8397 | 31 |
| 89 | 8365 | 32 |
| 90 | 8332 | 33 |
| 91 | 8299 | 33 |
| 92 | 8265 | 34 |
| 93 | 8230 | 35 |
| 94 | 8194 | 36 |
| 95 | 8157 | 37 |
| 96 | 8118 | 39 |
| 97 | 8077 | 41 |
| 98 | 8034 | 43 |
| 99 | 7988 | 46 |
| 100 | 7939 | 49 |
+------------+------------+----------+
_Remarks on the preceding Table of Alcohol._
The third column of this table exhibits the differences of the specific
gravities, which give the denominator of the fraction for such densities
as are not found sufficiently near in the table; and the difference of
their numerators is the next greatest to the density found in the table.
For example: if the specific gravity of the liquor found for 60° Fahr. =
9605 (the per centage will be between 33 and 34), the difference from
9609 (which is the next greatest number in the table) = 4, and the
fraction is 4/13; therefore the true per centage is 33-4/13. From the
construction of this table the per centage of alcohol by weight may also
be found. For instance: we multiply the number representing the
_volumes_ of alcohol (given in the table for any determinate specific
gravity of the mixture) by the specific gravity of the pure alcohol,
that is, by 7939, and the product is the number of pounds of alcohol in
so many pounds as the specific gravity multiplied by 100 gives. Thus, in
the mixture of 9510 specific gravity, there are 40 measures of alcohol;
hence there are also in 95,100 pounds of this spirit 7939 + 40 = 31·756
pounds of alcohol; and in 100 pounds of the spirits of 0·9510 specific
gravity, 33·39 pounds of alcohol are contained.
As the preceding table gives the true alcoholic content when the portion
of spirit under trial has the normal temperature of 60° Fahr., the
following table gives the per centage of alcohol for the specific
gravities corresponding to the accompanying temperatures.
For example: if we have a spirituous liquor at 80° Fahr., whose specific
gravity is 0·9342, the alcohol present is 45 per cent. of the volume, or
that specific gravity at that temperature is equal to the specific
gravity 0·9427 at the normal temperature of 60° Fahr. This table may
also be employed for every degree of the thermometer and every per
centage, so as to save computation for the intervals. It is evident from
inspection that a difference of 5° Fahr. in the temperature changes the
specific gravity of the liquor by a difference nearly equal to 1 volume
per cent. of alcohol; thus at 35° and 85° Fahr. the very same specific
gravity of the liquor shows nearly 10 volumes per cent. of alcohol more
or less; the same, for example, at 60 and 40 per cent.
+-------+-----------------------------------------------------------+
|Alcohol| Temperature. |
| per +----+----+----+----+----+----+----+----+----+----+----+----+
| cent. | 30°| 35°| 40°| 45°| 50°| 55°| 60°| 65°| 70°| 75°| 80°| 85°|
| | F.| F.| F.| F.| F.| F.| F.| F.| F.| F.| F.| F.|
+-------+----+----+----+----+----+----+----+----+----+----+----+----+
| 0 |9994|9997|9997|9998|9997|9994|9991|9987|9991|9976|9970|9962|
| 5 |9924|9926|9926|9926|9925|9922|9919|9915|9909|9903|9897|9889|
| 10 |9868|9869|9868|9867|9865|9861|9857|9852|9845|9839|9831|9823|
| 15 |9823|9822|9820|9817|9813|9807|9802|9796|9788|9779|9771|9761|
| 20 |9786|9782|9777|9772|9766|9759|9751|9743|9733|9722|9711|9700|
| 25 |9753|9746|9738|9729|9720|9709|9700|9690|9678|9665|9652|9638|
| 30 |9717|9707|9695|9684|9672|9659|9646|9632|9618|9603|9588|9572|
| 35 |9671|9658|9644|9629|9614|9599|9583|9566|9549|9532|9514|9495|
| 40 |9615|9598|9581|9563|9546|9528|9510|9491|9472|9452|9433|9412|
| 45 |9544|9525|9506|9486|9467|9447|9427|9406|9385|9364|9342|9320|
| 50 |9460|9440|9420|9399|9378|9356|9335|9313|9290|9267|9244|9221|
| 55 |9368|9347|9325|9302|9279|9256|9234|9211|9187|9163|9139|9114|
| 60 |9267|9245|9222|9198|9174|9150|9126|9102|9076|9051|9026|9000|
| 65 |9162|9138|9113|9088|9063|9038|9013|8988|8962|8936|8909|8882|
| 70 |9046|9021|8996|8970|8944|8917|8892|8866|8839|8812|8784|8756|
| 75 |8925|8899|8873|8847|8820|8792|8765|8738|8710|8681|8652|8622|
| 80 |8798|8771|8744|8716|8688|8659|8631|8602|8573|8544|8514|8483|
| 85 |8663|8635|8606|8577|8547|8517|8488|8458|8427|8396|8365|8333|
| 90 |8517|8486|8455|8425|8395|8363|8322|8300|8268|8236|8204|8171|
+-------+----+----+----+----+----+----+----+----+----+----+----+----+
The importance of extreme accuracy in determining the density of
alcoholic mixtures in the United Kingdom, on account of the great
revenue derived from them to the State, and their consequent high price
in commerce, induced the Lords of the Treasury a few years ago to
request the Royal Society to examine the construction and mode of
applying the instrument now in use for ascertaining and charging the
duty on spirits. This instrument, which is known and described in the
law as Sikes’s hydrometer, possesses, in many respects, decided
advantages over those formerly in use. The committee of the Royal
Society state, that a definite mixture of alcohol and water is as
invariable in its value as absolute alcohol can be; and can be more
readily, and with equal accuracy, identified by that only quality or
condition to which recourse can be had in practice, namely, specific
gravity. The committee further proposed, that the standard spirit be
that which, consisting of alcohol and water alone, shall have a specific
gravity of 0·92 at the temperature of 62° Fahr., water being unity at
the same temperature; or, in other words, that it shall at 62° weigh
92/100 or 23/25 of an equal bulk of water at the same temperature.
This standard is rather weaker than the old proof, which was 12/13, or
0·923; or in the proportion of nearly 1·1 gallon of the present proof
spirit per cent. The proposed standard will contain nearly one half by
weight of absolute alcohol. The hydrometer ought to be so graduated as
to give the indication of strength; not upon an arbitrary scale, but in
terms of specific gravity at the temperature of 62°.
The committee recommend the construction of an equation table, which
shall indicate the same strength of spirit at every temperature. Thus in
standard spirit at 62° the hydrometer would indicate 920, which in this
table would give proof spirit. If that same spirit were cooled to 40°,
the hydrometer would indicate some higher number; but which, being
combined in the table with the temperature as indicated by the
thermometer, should still give proof or standard spirit as the result.
It is considered advisable, in this and the other tables, not to express
the quality of the spirit by any number over or under proof, but to
indicate at once the number of gallons of standard spirit contained in,
or equivalent to, 100 gallons of the spirit under examination. Thus,
instead of saying 23 over proof, it is proposed to insert 123; and in
place of 35·4 under proof, to insert its difference to 100, or 64·6.
It has been considered expedient to recommend a second table to be
constructed, so as to show the bulk of spirit of any strength at any
temperature, relative to a standard bulk of 100 gallons at 62°. In this
table a spirit which had diminished in volume, at any given temperature,
0·7 per cent., for example, would be expressed by 99·3; and a spirit
which had increased at any given temperature 0·7 per cent., by 100·7.
When a sample of spirit, therefore, has been examined by the hydrometer
and thermometer, these tables will give first the proportion of standard
spirit at the observed temperature, and next the change of bulk of such
spirit from what it would be at the standard temperature. Thus, at the
temperature of 51°, and with an indication (sp. gr.) of 8240, 100
gallons of the spirit under examination would be shown by the first
table to be equal to 164·8 gallons of standard spirit of that
temperature; and by the second table it would appear that 99·3 gallons
of the same spirit would become 100 at 62°, or in reality contain the
164·8 gallons of spirit in that state only in which it is to be taxed.
But as it is considered that neither of these tables can alone be used
for charging the duty (for neither can express the actual quantity of
spirit of a specific gravity of 0·92 at 62° in 100 gallons of stronger
or weaker spirit at temperatures above or below 62°), it is considered
essential to have a third table, combining the two former, and
expressing this relation directly, so that upon mere inspection it shall
indicate the proportion of standard spirit in 100 gallons of that under
examination in its then present state. In this table the quantities
should be set down in the actual number of gallons of standard spirit at
62°, equivalent to 100 of the spirit under examination; and the column
of quantities may be expressed by the term _value_, as it in reality
expresses the proportion of the only valuable substance present. As this
will be the only table absolutely necessary to be used with the
instrument for the purposes of the excise, it may, perhaps, be thought
unnecessary to print the former two.
The following specimen table has been given by the committee:--
+-------------------------------++----------------------------+
| Temperature 45°. || Temperature 75°. |
+--------------+---------+------++-----------+---------+------+
|Indication.[3]|Strength.|Value.||Indication.|Strength.|Value.|
+--------------+---------+------++-----------+---------+------+
| 9074 | 114·5 | || 8941 | 114·5 | |
| 7 | 114·3 | || 4 | 114·3 | |
| 9 | 114·2 | || 5 | 114·2 | |
| 81 | 114·0 | || 8 | 114·0 | |
| 3 | 113·9 | || 9 | 113·9 | |
| 5 | 113·7 | || 52 | 113·7 | |
| 6 | 113·6 | || 3 | 113·6 | |
| 9 | 113·4 | || 6 | 113·4 | |
| 90 | 113·3 | || 7 | 113·3 | |
| 3 | 113·1 | || 9 | 113·1 | |
+--------------+---------+------++-----------+---------+------+
[3] By specific gravity.
The mixture of alcohol and water, taken as spirit in Mr. Gilpin’s
tables, is that of which the specific gravity is 0·825 at 60° Fahr.,
water being unity at the same temperature. The specific gravity of water
at 60° being 1000, at 62° it is 99,981. Hence, in order to compare the
specific gravities given by Mr. Gilpin with those which would result
when the specific gravity of water at 62° is taken at unity, all the
former numbers must be divided by 99,981.
Table of the Specific Gravities of different Mixtures, by Weight, of
Alcohol and Water, at different Temperatures; constructed by Mr. Gilpin,
for the use of the British Revenue on Spirits.
+------+-------+-------+-------+-------+-------+-------+-------+
|Tem- | Pure | 100 | 100 | 100 | 100 | 100 | 100 |
|pera- | Alco- |Alcohol|Alcohol|Alcohol|Alcohol|Alcohol|Alcohol|
|ture, | hol. | 5 | 10 | 15 | 20 | 25 | 30 |
|Fahr. | | Water.| Water.| Water.| Water.| Water.| Water.|
+------+-------+-------+-------+-------+-------+-------+-------+
|_Deg._| | | | | | | |
| 30 |0·83896|0·84995|0·85957|0·86825|0·87585|0·88282|0·88921|
| 35 | ·83672| ·84769| ·85729| ·86587| ·87357| ·88059| ·88701|
| 40 | ·83445| ·84539| ·85507| ·86361| ·87184| ·87838| ·88481|
| 45 | ·83214| ·84310| ·85277| ·86131| ·86905| ·87613| ·88255|
| 50 | ·82977| ·84076| ·85042| ·85902| ·86676| ·87384| ·88030|
| 55 | ·82736| ·83834| ·84802| ·85664| ·86441| ·87150| ·87796|
| 60 | ·82500| ·83599| ·84568| ·85430| ·86208| ·86918| ·87569|
| 65 | ·82262| ·83362| ·84334| ·85193| ·85976| ·86686| ·87337|
| 70 | ·82023| ·83124| ·84092| ·84951| ·85736| ·86451| ·87105|
| 75 | ·81780| ·82878| ·83851| ·84710| ·85496| ·86212| ·86864|
| 80 | ·81530| ·82631| ·83603| ·84467| ·85248| ·85966| ·86622|
| 85 | ·81291| ·82396| ·83371| ·84243| ·85036| ·85757| ·86411|
| 90 | ·81044| ·82150| ·83126| ·84001| ·84797| ·85518| ·86172|
| 95 | ·80794| ·81900| ·82877| ·83753| ·84550| ·85272| ·85928|
| 100 | ·80548| ·81657| ·82630| ·83513| ·84038| ·85031| ·85688|
+------+-------+-------+-------+-------+-------+-------+-------+
+------+-------+-------+-------+-------+--------+-------+-------+
|Tem- | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
|pera- |Alcohol|Alcohol|Alcohol|Alcohol|Alcohol |Alcohol|Alcohol|
|ture, | 35 | 40 | 45 | 50 | 55 | 60 | 65 |
|Fahr. | Water.| Water.| Water.| Water.| Water. | Water.| Water.|
+------+-------+-------+-------+-------+--------+-------+-------+
|_Deg._| | | | | | | |
| 30 |0·89511|0·90054|0·90558|0·91023|0·91449 |0·91847|0·92217|
| 35 | ·89294| ·89839| ·90345| ·90811| ·91241 | ·91640| ·92009|
| 40 | ·89073| ·89617| ·90127| ·90596| ·91026 | ·91428| ·91799|
| 45 | ·88849| ·89396| ·89909| ·90380| ·90812 | ·91211| ·91584|
| 50 | ·88626| ·89174| ·89684| ·90160| ·90596 | ·90997| ·91370|
| 55 | ·88393| ·88945| ·89458| ·89933| ·90367 | ·90768| ·91144|
| 60 | ·88169| ·88720| ·89232| ·89707| ·90144 | ·90549| ·90927|
| 65 | ·87938| ·88490| ·89006| ·89479| ·89920 | ·90328| ·90707|
| 70 | ·87705| ·88254| ·88773| ·89252| ·89695 | ·90104| ·90484|
| 75 | ·87466| ·88018| ·88538| ·89018| ·89464 | ·89872| ·90252|
| 80 | ·87228| ·87776| ·88301| ·88781| ·89225 | ·89639| ·90021|
| 85 | ·87021| ·87590| ·88120| ·88609| ·89043 | ·89460| ·89843|
| 90 | ·86787| ·87360| ·87889| ·88376| ·88817 | ·89230| ·89617|
| 95 | ·86542| ·87114| ·87654| ·88146| ·88588 | ·89003| ·89390|
| 100 | ·86302| ·86879| ·87421| ·87915| ·883671| ·88769| ·89158|
+------+-------+-------+-------+-------+--------+-------+-------+
+------+-------+-------+-------+-------+-------+-------+-------+
|Tem- | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
|pera- |Alcohol|Alcohol|Alcohol|Alcohol|Alcohol|Alcohol|Alcohol|
|ture, | 70 | 75 | 80 | 85 | 90 | 95 | 100 |
|Fahr. | Water.| Water.| Water.| Water.| Water.| Water.| Water.|
+------+-------+-------+-------+-------+-------+-------+-------+
|_Deg._| | | | | | | |
| 30 |0·92563|0·92889|0·93191|0·93474|0·93741|0·93991|0·94222|
| 35 | ·92355| ·92680| ·92986| ·93274| ·93541| ·93790| ·94025|
| 40 | ·92151| ·92476| ·92783| ·93072| ·93341| ·93592| ·93827|
| 45 | ·91937| ·92264| ·92570| ·92859| ·93131| ·93382| ·93621|
| 50 | ·91723| ·92051| ·92358| ·92647| ·92919| ·93177| ·93419|
| 55 | ·91502| ·91837| ·92145| ·92436| ·92707| ·92963| ·93208|
| 60 | ·91287| ·91622| ·91933| ·92225| ·92499| ·92758| ·93002|
| 65 | ·91066| ·91400| ·91715| ·92010| ·92283| ·92546| ·92794|
| 70 | ·90847| ·91181| ·91493| ·91793| ·92069| ·92333| ·92580|
| 75 | ·90617| ·90952| ·91270| ·91569| ·91849| ·92111| ·92364|
| 80 | ·90385| ·90723| ·91046| ·91340| ·91622| ·91891| ·92142|
| 85 | ·90209| ·90558| ·90882| ·91186| ·91465| ·91729| ·91969|
| 90 | ·89988| ·90342| ·90688| ·90967| ·91248| ·91511| ·91751|
| 95 | ·89763| ·90119| ·90443| ·90747| ·91029| ·91290| ·91531|
| 100 | ·89536| ·89889| ·90215| ·90522| ·90805| ·91066| ·91310|
+------+-------+-------+-------+-------+-------+-------+-------+
+------+-------+-------+-------+-------+-------+-------+-------+
|Tem- | 95 | 90 | 85 | 80 | 75 | 70 | 65 |
|pera- |Alcohol|Alcohol|Alcohol|Alcohol|Alcohol|Alcohol|Alcohol|
|ture, | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
|Fahr. | Water.| Water.| Water.| Water.| Water.| Water.| Water.|
+------+-------+-------+-------+-------+-------+-------+-------+
|_Deg._| | | | | | | |
| 30 |0·94447|0·94675|0·94920|0·95173|0·95429|0·95681|0·95944|
| 35 | ·94249| ·94484| ·94734| ·94988| ·95246| ·95502| ·95772|
| 40 | ·94058| ·94295| ·94547| ·94802| ·95060| ·95328| ·95602|
| 45 | ·93860| ·94096| ·94348| ·94605| ·94871| ·95143| ·95423|
| 50 | ·93658| ·93897| ·94149| ·94414| ·94683| ·94958| ·95243|
| 55 | ·93452| ·93696| ·93948| ·94213| ·94486| ·94767| ·95057|
| 60 | ·93247| ·93493| ·93749| ·94018| ·94296| ·94579| ·94876|
| 65 | ·93040| ·93285| ·93546| ·93822| ·94099| ·94388| ·94689|
| 70 | ·92828| ·93076| ·93337| ·93616| ·93898| ·94193| ·94500|
| 75 | ·92613| ·92865| ·93132| ·93413| ·93695| ·93989| ·94301|
| 80 | ·92393| ·92646| ·92917| ·93201| ·93488| ·93785| ·94102|
+------+-------+-------+-------+-------+-------+-------+-------+
+------+-------+-------+-------+-------+-------+-------+-------+
|Tem- | 60 | 55 | 50 | 45 | 40 | 35 | 30 |
|pera- |Alcohol|Alcohol|Alcohol|Alcohol|Alcohol|Alcohol|Alcohol|
|ture, | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
|Fahr. | Water.| Water.| Water.| Water.| Water.| Water.| Water.|
+------+-------+-------+-------+-------+-------+-------+-------+
|_Deg._| | | | | | | |
| 30 |0·96209|0·96470|0·96719|0·96967|0·97200|0·97418|0·97635|
| 35 | ·96048| ·96315| ·96579| ·96840| ·97086| ·97319| ·97556|
| 40 | ·95879| ·96159| ·96434| ·96706| ·96967| ·97220| ·97472|
| 45 | ·95703| ·95993| ·96280| ·96563| ·96840| ·97110| ·97384|
| 50 | ·95534| ·95831| ·96126| ·96420| ·96708| ·96995| ·97284|
| 55 | ·95357| ·95662| ·95966| ·96272| ·96575| ·96877| ·97181|
| 60 | ·95181| ·95493| ·95804| ·96122| ·96437| ·96752| ·97074|
| 65 | ·95000| ·95318| ·95635| ·95962| ·96288| ·96620| ·96959|
| 70 | ·94813| ·95139| ·95469| ·95802| ·96143| ·96484| ·96836|
| 75 | ·94623| ·94957| ·95292| ·95638| ·95987| ·96344| ·96708|
| 80 | ·94431| ·94768| ·95111| ·95467| ·95826| ·96192| ·96568|
+------+-------+-------+-------+-------+-------+-------+-------+
+------+-------+-------+-------+-------+-------+
|Tem- | 25 | 20 | 15 | 10 | 5 |
|pera- |Alcohol|Alcohol|Alcohol|Alcohol|Alcohol|
|ture, | 100 | 100 | 100 | 100 | 100 |
|Fahr. | Water.| Water.| Water.| Water.| Water.|
+------+-------+-------+-------+-------+-------+
|_Deg._| | | | | |
| 30 |0·97860|0·98108|0·98412|0·98804|0·99334|
| 35 | ·97801| ·98076| ·98397| ·98804| ·99344|
| 40 | ·97737| ·98033| ·98373| ·98795| ·99345|
| 45 | ·97666| ·97980| ·98338| ·98774| ·99338|
| 50 | ·97589| ·97920| ·98293| ·98745| ·99316|
| 55 | ·97500| ·97847| ·98239| ·98702| ·99284|
| 60 | ·97410| ·97771| ·98176| ·98654| ·99244|
| 65 | ·97309| ·97688| ·98106| ·98594| ·99194|
| 70 | ·97203| ·97596| ·98028| ·98527| ·99134|
| 75 | ·97086| ·97495| ·97943| ·98454| ·99066|
| 80 | ·96963| ·97385| ·97845| ·98367| ·98991|
+------+-------+-------+-------+-------+-------+
Experiments were made, by direction of the committee, to verify Gilpin’s
tables, which showed that the error introduced in ascertaining the
strength of spirits by tables founded on Gilpin’s numbers must be quite
insensible in the practice of the revenue. The discrepancies thus
detected, on a mixture of a given strength, did not amount in any one
instance to unity in the fourth place of decimals. From a careful
inspection of such documents the committee are of opinion, that Gilpin’s
tables possess a degree of accuracy far surpassing what could be
expected, and sufficiently perfect for all practical or scientific
purposes.
The following table is given by Mr. Lubbock, for converting the
_apparent_ specific gravity, or _indication_, into true specific
gravity:--
+-----+-----------------------------------------+-----+
|Indi-| - Temperature + |Indi-|
| ca- +------+------+------+------+------+------+ ca- |
|tion.| 30° | 32° | 37° | 42° | 47° | 52° |tion.|
+-----+------+------+------+------+------+------+-----+
| ·82 |·00083|·00078|·00065|·00052|·00039|·00025| ·82 |
| ·83 |·00084|·00079|·00066|·00052|·00039|·00026| ·83 |
| ·84 |·00085|·00080|·00066|·00053|·00039|·00026| ·84 |
| ·85 |·00086|·00081|·00067|·00054|·00040|·00026| ·85 |
| ·86 |·00087|·00082|·00068|·00054|·00040|·00027| ·86 |
| ·87 |·00088|·00083|·00069|·00055|·00041|·00027| ·87 |
| ·88 |·00089|·00084|·00070|·00055|·00041|·00027| ·88 |
| ·89 |·00090|·00085|·00070|·00055|·00042|·00028| ·89 |
| ·90 |·00091|·00085|·00071|·00056|·00042|·00028| ·90 |
| ·91 |·00092|·00086|·00072|·00057|·00043|·00028| ·91 |
| ·92 |·00093|·00087|·00073|·00058|·00043|·00029| ·92 |
| ·93 |·00094|·00088|·00073|·00059|·00044|·00029| ·93 |
| ·94 |·00095|·00089|·00074|·00059|·00044|·00029| ·94 |
| ·95 |·00096|·00090|·00075|·00060|·00045|·00029| ·95 |
| ·96 |·00097|·00091|·00076|·00060|·00045|·00030| ·96 |
| ·97 |·00098|·00092|·00077|·00061|·00046|·00030| ·97 |
| ·98 |·00099|·00093|·00077|·00062|·00046|·00030| ·98 |
| ·99 |·00100|·00094|·00078|·00062|·00047|·00031| ·99 |
|1·00 |·00101|·00095|·00079|·00063|·00047|·00031|1·00 |
+-----+------+------+------+------+------+------+-----+
+-----+-----------------------------------------+-----+
|Indi-| - Temperature + |Indi-|
| ca- +------+------+------+------+------+------+ ca- |
|tion.| 57° | 62° | 67° | 72° | 77° | 80° |tion.|
+-----+------+------+------+------+------+------+-----+
| ·82 |·00012| |·00011|·00024|·00035|·00042| ·82 |
| ·83 |·00012| |·00012|·00024|·00036|·00042| ·83 |
| ·84 |·00013| |·00012|·00024|·00036|·00043| ·84 |
| ·85 |·00013| |·00012|·00025|·00037|·00043| ·85 |
| ·86 |·00013| |·00012|·00025|·00037|·00044| ·86 |
| ·87 |·00013| |·00012|·00025|·00037|·00044| ·87 |
| ·88 |·00013| |·00012|·00026|·00038|·00045| ·88 |
| ·89 |·00013| |·00012|·00026|·00038|·00045| ·89 |
| ·90 |·00014| |·00013|·00026|·00039|·00046| ·90 |
| ·91 |·00014| |·00013|·00026|·00039|·00046| ·91 |
| ·92 |·00014| |·00013|·00027|·00040|·00047| ·92 |
| ·93 |·00014| |·00013|·00027|·00040|·00047| ·93 |
| ·94 |·00014| |·00013|·00027|·00040|·00048| ·94 |
| ·95 |·00014| |·00013|·00028|·00041|·00048| ·95 |
| ·96 |·00014| |·00013|·00028|·00041|·00049| ·96 |
| ·97 |·00015| |·00014|·00028|·00042|·00049| ·97 |
| ·98 |·00015| |·00014|·00028|·00042|·00050| ·98 |
| ·99 |·00015| |·00014|·00029|·00043|·00050| ·99 |
|1·00 |·00015| | | | | |1·00 |
+-----+------+------+------+------+------+------+-----+
[Illustration: _Fig._ 5.]
The hydrometer constructed, under the directions of the Commissioners of
Excise, by Mr. Bate, has a scale of 4 inches in length divided into 100
parts, and 9 weights. It has thus a range of 900 divisions, and
expresses specific gravities at the temperature of 62° Fahr. In order to
render this instrument so accurate a measurer of the specific gravity,
at the standard temperature, as to involve no error of an appreciable
amount, Mr. Bate has constructed the weights (which in this instrument
are immersed in the fluid of different specific gravities) so that each
successive weight should have an increase of bulk over the preceding
weight equal to that part of the stem occupied by the scale, and an
increase of weight sufficient to take the whole of the scale, and no
more, down to the liquid. This arrangement requires great accuracy of
workmanship, and enhances the price of the instrument. But it allows of
increased strength in the ball, where it is very much required, and it
gives, upon inspection only, the indication (apparent specific gravity)
by which the general table is to be examined and the result ascertained.
_Fig._ 5. represents this instrument and two of its nine ballast
weights. It comprehends all specific gravities between 820 and 1000. It
indicates true specific gravity with almost perfect accuracy at the
temperature of 62° Fahr.; but it does not exclude other instruments from
being used in conjunction with tables. The latter are, in fact,
independent of the instrument, and may be used with gravimeters, or any
instrument affording indications by specific gravity at a given
temperature.
The commercial value of spirituous liquors being much lower in France
than in England, a less sensible instrument becomes sufficient for the
wants of that country. Baumé’s and Cartier’s hydrometers, with short
arbitrary scales, are very much employed, but they have been lately
superseded by an ingenious and ready instrument contrived by M. Gay
Lussac, and called by him an _alcoomètre_. He takes for the term of
comparison pure alcohol by volume, at the temperature of 15° Cent., and
represents the strength of it by 100 _centimes_, or by unity.
Consequently, the strength of a spirituous liquid is the number of
centimes in volume of pure alcohol which that liquid contains at the
temperature of 15° Cent. The instrument is formed like a common
hydrometer, and is graduated for the temperature of 15° Cent. Its scale
is divided into 100 parts or degrees, each of which denotes a centime of
alcohol; the division 0 at the bottom of the stem corresponds to pure
water, and the division 100 at its top, to pure alcohol. When immersed
in a spirituous liquor at 15° Cent. (59° Fahr.) it announces its
strength directly. For example: if in spirits supposed at the
temperature of 15° Cent. it sinks to the division 50, it indicates that
the strength of this liquor is 50 per cent., or that it contains 50
centimes of pure alcohol. In our new British proof spirit, it would sink
to nearly 57, indicating 57 by volume of pure alcohol, allowing for
condensation, or 50 by weight. A table of correction is given for
temperature, which he calls “Table of real strength of spirituous
liquors.” The first vertical column of this table contains the
temperatures, from 0° to 30° Cent., and the first horizontal line the
indications of the alcoomètre. In the same table we have most
ingeniously inserted a correction for the volume of the spirits when the
temperature differs from 15° Cent. If we take 1000 litres or gallons,
measured at the temperature of 2°, of a spirituous liquor whose apparent
strength is 44^{c}; its real strength at 15° will from the preceding
mode of correction be 49^{c}. On heating this liquid to 15°, in order to
find its real specific gravity or strength, its bulk will become
greater; and, instead of 1000 litres or gallons, which it measured at
2°, we shall have 1009 at 15° C. This number is inscribed in smaller
characters in the same square cell with the real force, precisely under
49^{c}. All the numbers in small characters, printed under each _real
strength_, indicate the volume which 1000 litres of a spirituous liquor
would have, when measured at the temperature at which its apparent
strength is taken. In the above example, the quantity in litres or
gallons of pure alcohol contained in 1000 litres or gallons of the
spirits, measured at the temperature of 2°, will be, therefore,--1009
lit. × 0·49 = 494 lit. 41.
This quantity of pure alcohol, thus estimated, is called _richness of
spirit in alcohol_, or simply _richness_.
Let us take an example similar to the preceding, but at a higher
temperature than 15° Cent. Suppose we have 1000 litres measured, at the
temperature of 25°, of spirits whose apparent strength is 53^{c}, what
is the real quantity of pure alcohol which this spirit contains at the
temperature of 15°? We shall find in the table, first of all, that the
real strength of the spirits is 49^{c}·3. As to its bulk or volume, it
is very clear that the 1000 litres in cooling from 25° to 15°, will
occupy a smaller space. This volume will be 993 litres; it is inscribed
directly below 49^{c}·3, the real strength. We shall therefore have of
pure alcohol, contained in the 1000 litres of spirits, measured at the
temperature of 25°, or their _richness_, 993 lit. × 0·493 = 489 lit. 55.
Alcometrical Table of real Strength, by M. Gay Lussac.
+-------+------+------+------+------+------+------+------+------+
|Temper-|31^{c}|32^{c}|33^{c}|34^{c}|35^{c}|36^{c}|37^{c}|38^{c}|
| ature | | | | | | | | |
| C. | | | | | | | | |
+-------+------+------+------+------+------+------+------+------+
| _Deg._| | | | | | | | |
| 10 | 33·0 | 34 | 35 | 36 | 37 | 38 | 39 | 40 |
| | 1002 | 1002 | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 |
| +------+------+------+------+------+------+------+------+
| 11 | 32·6 | 33·6 | 34·6 | 35·6 | 36·6 | 37·6 | 38·6 | 39·6 |
| | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 |
| +------+------+------+------+------+------+------+------+
| 12 | 32·2 | 33·2 | 34·2 | 35·2 | 36·2 | 37·2 | 38·2 | 39·2 |
| | 1001 | 1001 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 |
| +------+------+------+------+------+------+------+------+
| 13 | 31·8 | 32·8 | 33·8 | 34·8 | 35·8 | 36·8 | 37·8 | 38·8 |
| | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 |
| +------+------+------+------+------+------+------+------+
| 14 | 31·4 | 32·4 | 33·4 | 34·4 | 35·4 | 36·4 | 37·4 | 38·4 |
| | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 |
| +------+------+------+------+------+------+------+------+
| 15 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 |
| | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 |
| +------+------+------+------+------+------+------+------+
| 16 | 30·6 | 31·6 | 32·5 | 33·5 | 34·5 | 35·5 | 36·5 | 37·5 |
| | 1000 | 1000 | 999 | 999 | 999 | 999 | 999 | 999 |
| +------+------+------+------+------+------+------+------+
| 17 | 30·2 | 31·2 | 32·1 | 33·1 | 34·1 | 35·1 | 36·1 | 37·1 |
| | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 |
| +------+------+------+------+------+------+------+------+
| 18 | 29·8 | 30·8 | 31·7 | 32·7 | 33·7 | 34·7 | 35·7 | 36·7 |
| | 999 | 999 | 998 | 998 | 998 | 998 | 998 | 998 |
| +------+------+------+------+------+------+------+------+
| 19 | 29·4 | 30·4 | 31·3 | 32·3 | 33·3 | 34·3 | 35·3 | 36·3 |
| | 998 | 998 | 998 | 998 | 998 | 998 | 998 | 998 |
| +------+------+------+------+------+------+------+------+
| 20 | 29 | 30 | 30·9 | 31·9 | 32·9 | 33·9 | 34·9 | 35·9 |
| | 998 | 998 | 997 | 997 | 997 | 997 | 997 | 997 |
| +------+------+------+------+------+------+------+------+
| 21 | 28·6 | 29·6 | 30·5 | 31·5 | 32·5 | 33·5 | 34·5 | 35·5 |
| | 997 | 997 | 997 | 997 | 997 | 997 | 997 | 996 |
| +------+------+------+------+------+------+------+------+
| 22 | 28·2 | 29·2 | 30·1 | 31·1 | 32·1 | 33·1 | 34·1 | 35·1 |
| | 997 | 997 | 996 | 996 | 996 | 996 | 996 | 996 |
| +------+------+------+------+------+------+------+------+
| 23 | 27·8 | 28·8 | 29·7 | 30·7 | 31·7 | 32·7 | 33·7 | 34·7 |
| | 996 | 996 | 996 | 996 | 996 | 996 | 996 | 995 |
| +------+------+------+------+------+------+------+------+
| 24 | 27·4 | 28·4 | 29·3 | 30·3 | 31·3 | 32·3 | 33·3 | 34·3 |
| | 996 | 996 | 995 | 995 | 995 | 995 | 995 | 995 |
| +------+------+------+------+------+------+------+------+
| 25 | 27 | 28 | 28·9 | 29·9 | 30·9 | 31·9 | 32·9 | 33·9 |
| | 995 | 995 | 995 | 995 | 995 | 994 | 994 | 994 |
+-------+------+------+------+------+------+------+------+------+
+-------+------+------+------+------+------+------+------+------+
|Temper-|39^{c}|40^{c}|41^{c}|42^{c}|43^{c}|44^{c}|45^{c}|46^{c}|
| ature | | | | | | | | |
| C. | | | | | | | | |
+-------+------+------+------+------+------+------+------+------+
| _Deg._| | | | | | | | |
| 10 | 41 | 42 | 43 | 44 | 45 | 46 | 46·9 | 47·9 |
| | 1003 | 1003 | 1003 | 1004 | 1004 | 1004 | 1004 | 1004 |
| +------+------+------+------+------+------+------+------+
| 11 | 40·6 | 41·6 | 42·6 | 43·6 | 44·6 | 45·6 | 46·6 | 47·6 |
| | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 |
| +------+------+------+------+------+------+------+------+
| 12 | 40·2 | 41·2 | 42·2 | 43·2 | 44·2 | 45·2 | 46·2 | 47·2 |
| | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 |
| +------+------+------+------+------+------+------+------+
| 13 | 39·8 | 40·8 | 41·8 | 42·8 | 43·8 | 44·8 | 45·8 | 46·8 |
| | 1001 | 1001 | 1001 | 1001 | 1001 | 1002 | 1002 | 1002 |
| +------+------+------+------+------+------+------+------+
| 14 | 39·4 | 40·4 | 41·4 | 42·4 | 43·4 | 44·4 | 45·4 | 46·4 |
| | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 |
| +------+------+------+------+------+------+------+------+
| 15 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 |
| | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 |
| +------+------+------+------+------+------+------+------+
| 16 | 38·5 | 39·5 | 40·6 | 41·6 | 42·6 | 43·6 | 44·6 | 45·6 |
| | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 |
| +------+------+------+------+------+------+------+------+
| 17 | 38·1 | 39·1 | 40·2 | 41·2 | 42·2 | 43·2 | 44·9 | 45·2 |
| | 999 | 999 | 999 | 999 | 999 | 998 | 998 | 998 |
| +------+------+------+------+------+------+------+------+
| 18 | 37·7 | 38·7 | 39·8 | 40·8 | 41·8 | 42·8 | 43·8 | 44·9 |
| | 998 | 998 | 998 | 998 | 998 | 998 | 998 | 998 |
| +------+------+------+------+------+------+------+------+
| 19 | 37·3 | 38·3 | 39·4 | 40·4 | 41·4 | 42·5 | 43·5 | 44·5 |
| | 997 | 997 | 997 | 997 | 997 | 997 | 997 | 997 |
| +------+------+------+------+------+------+------+------+
| 20 | 36·9 | 37·9 | 39 | 40 | 41 | 42·1 | 43·1 | 44·1 |
| | 997 | 997 | 997 | 997 | 997 | 997 | 996 | 996 |
| +------+------+------+------+------+------+------+------+
| 21 | 36·5 | 37·5 | 38·6 | 39·6 | 40·6 | 41·7 | 42·7 | 43·7 |
| | 996 | 996 | 996 | 996 | 996 | 996 | 996 | 996 |
| +------+------+------+------+------+------+------+------+
| 22 | 36·1 | 37·1 | 38·2 | 39·2 | 40·2 | 41·3 | 42·3 | 43·3 |
| | 996 | 996 | 996 | 995 | 995 | 995 | 995 | 995 |
| +------+------+------+------+------+------+------+------+
| 23 | 35·7 | 36·7 | 37·8 | 38·8 | 39·8 | 40·9 | 41·9 | 42·9 |
| | 995 | 995 | 995 | 995 | 995 | 994 | 994 | 994 |
| +------+------+------+------+------+------+------+------+
| 24 | 35·3 | 36·3 | 37·4 | 38·4 | 39·4 | 40·5 | 41·5 | 42·5 |
| | 995 | 994 | 994 | 994 | 994 | 994 | 994 | 994 |
| +------+------+------+------+------+------+------+------+
| 25 | 34·9 | 35·9 | 37 | 38 | 39 | 40·1 | 42·1 | 42·2 |
| | 994 | 994 | 994 | 994 | 993 | 993 | 993 | 993 |
+-------+------+------+------+------+------+------+------+------+
+-------+------+------+------+------+------+------+------+------+
|Temper-|47^{c}|48^{c}|49^{c}|50^{c}|51^{c}|52^{c}|53^{c}|54^{c}|
| ature | | | | | | | | |
| C. | | | | | | | | |
+-------+------+------+------+------+------+------+------+------+
| _Deg._| | | | | | | | |
| 10 | 48·9 | 49·9 | 50·9 | 51·8 | 52·8 | 53·8 | 54·8 | 55·8 |
| | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 |
| +------+------+------+------+------+------+------+------+
| 11 | 48·6 | 49·5 | 50·5 | 51·5 | 52·5 | 53·5 | 54·4 | 55·4 |
| | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 |
| +------+------+------+------+------+------+------+------+
| 12 | 48·2 | 49·2 | 50·2 | 51·1 | 52·1 | 53·1 | 54·1 | 55 |
| | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 |
| +------+------+------+------+------+------+------+------+
| 13 | 47·8 | 48·8 | 49·8 | 50·8 | 51·8 | 52·7 | 53·7 | 54·7 |
| | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 |
| +------+------+------+------+------+------+------+------+
| 14 | 47·4 | 48·4 | 49·4 | 50·4 | 51·4 | 52·3 | 53·3 | 54·3 |
| | 1001 | 1001 | 1001 | 1000 | 1001 | 1001 | 1001 | 1001 |
| +------+------+------+------+------+------+------+------+
| 15 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 |
| | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 |
| +------+------+------+------+------+------+------+------+
| 16 | 46·6 | 47·6 | 48·6 | 49·6 | 50·6 | 51·6 | 52·6 | 53·6 |
| | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 |
| +------+------+------+------+------+------+------+------+
| 17 | 46·2 | 47·2 | 48·2 | 49·2 | 50·3 | 51·3 | 52·3 | 53·3 |
| | 998 | 998 | 998 | 998 | 998 | 998 | 998 | 998 |
| +------+------+------+------+------+------+------+------+
| 18 | 45·9 | 46·9 | 47·9 | 48·9 | 49·9 | 50·9 | 51·9 | 52·9 |
| | 998 | 998 | 998 | 998 | 998 | 998 | 998 | 998 |
| +------+------+------+------+------+------+------+------+
| 19 | 45·5 | 46·5 | 47·5 | 48·5 | 49·5 | 50·6 | 51·6 | 52·6 |
| | 997 | 997 | 997 | 997 | 997 | 997 | 997 | 997 |
| +------+------+------+------+------+------+------+------+
| 20 | 45·1 | 46·1 | 47·2 | 48·2 | 49·2 | 50·2 | 51·2 | 52·2 |
| | 996 | 996 | 996 | 996 | 996 | 996 | 996 | 996 |
| +------+------+------+------+------+------+------+------+
| 21 | 44·8 | 45·8 | 46·8 | 47·8 | 48·8 | 49·8 | 50·8 | 51·8 |
| | 996 | 996 | 995 | 995 | 995 | 995 | 995 | 995 |
| +------+------+------+------+------+------+------+------+
| 22 | 44·3 | 45·3 | 46·4 | 47·4 | 48·4 | 49·4 | 50·4 | 51·4 |
| | 995 | 995 | 995 | 995 | 995 | 995 | 995 | 994 |
| +------+------+------+------+------+------+------+------+
| 23 | 43·9 | 44·9 | 46 | 47 | 48 | 49·1 | 50·1 | 51·1 |
| | 994 | 994 | 994 | 994 | 994 | 994 | 994 | 994 |
| +------+------+------+------+------+------+------+------+
| 24 | 43·6 | 44·6 | 45·6 | 46·6 | 47·6 | 48·7 | 49·7 | 50·7 |
| | 994 | 994 | 993 | 993 | 993 | 993 | 993 | 693 |
| +------+------+------+------+------+------+------+------+
| 25 | 43·2 | 44·2 | 45·2 | 46·3 | 47·3 | 48·3 | 49·3 | 50·3 |
| | 993 | 993 | 993 | 993 | 993 | 993 | 993 | 992 |
+-------+------+------+------+------+------+------+------+------+
+-------+------+------+------+------+------+------+------+------+
|Temper-|55^{c}|56^{c}|57^{c}|58^{c}|59^{c}|60^{c}|61^{c}|62^{c}|
| ature | | | | | | | | |
| C. | | | | | | | | |
+-------+------+------+------+------+------+------+------+------+
| _Deg._| | | | | | | | |
| 10 | 56·8 | 57·8 | 58·8 | 59·7 | 60·7 | 61·7 | 62·7 | 63·7 |
| | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 |
| +------+------+------+------+------+------+------+------+
| 11 | 56·4 | 57·4 | 58·4 | 59·4 | 60·4 | 61·4 | 62·4 | 63·4 |
| | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 |
| +------+------+------+------+------+------+------+------+
| 12 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 |
| | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 |
| +------+------+------+------+------+------+------+------+
| 13 | 55·7 | 56·7 | 57·7 | 58·7 | 59·7 | 60·7 | 61·7 | 62·7 |
| | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 |
| +------+------+------+------+------+------+------+------+
| 14 | 55·3 | 56·3 | 57·3 | 58·3 | 59·3 | 60·3 | 61·3 | 62·3 |
| | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 |
| +------+------+------+------+------+------+------+------+
| 15 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 |
| | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 |
| +------+------+------+------+------+------+------+------+
| 16 | 54·6 | 55·6 | 56·6 | 57·6 | 58·6 | 59·6 | 60·6 | 61·7 |
| | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 |
| +------+------+------+------+------+------+------+------+
| 17 | 54·3 | 55·3 | 56·3 | 57·3 | 58·3 | 59·3 | 60·3 | 61·3 |
| | 998 | 998 | 998 | 998 | 998 | 998 | 998 | 998 |
| +------+------+------+------+------+------+------+------+
| 18 | 53·9 | 54·9 | 55·9 | 56·9 | 57·9 | 58·9 | 59·9 | 61 |
| | 998 | 998 | 998 | 997 | 997 | 997 | 997 | 997 |
| +------+------+------+------+------+------+------+------+
| 19 | 53·6 | 54·6 | 55·6 | 56·6 | 57·6 | 58·6 | 59·6 | 60·6 |
| | 997 | 997 | 997 | 997 | 997 | 997 | 997 | 997 |
| +------+------+------+------+------+------+------+------+
| 20 | 53·2 | 54·2 | 55·2 | 56·2 | 57·2 | 58·2 | 59·2 | 60·3 |
| | 996 | 996 | 996 | 996 | 996 | 996 | 996 | 996 |
| +------+------+------+------+------+------+------+------+
| 21 | 52·9 | 53·9 | 54·9 | 55·9 | 56·9 | 57·9 | 58·9 | 59·9 |
| | 995 | 995 | 995 | 995 | 995 | 995 | 995 | 995 |
| +------+------+------+------+------+------+------+------+
| 22 | 52·5 | 53·5 | 54·5 | 55·5 | 56·5 | 57·5 | 58·5 | 59·5 |
| | 994 | 994 | 994 | 994 | 994 | 994 | 994 | 994 |
| +------+------+------+------+------+------+------+------+
| 23 | 52·1 | 53·1 | 54·1 | 55·1 | 56·1 | 57·1 | 58·1 | 59·2 |
| | 994 | 994 | 994 | 993 | 993 | 993 | 993 | 993 |
| +------+------+------+------+------+------+------+------+
| 24 | 51·8 | 52·8 | 53·8 | 54·8 | 55·8 | 56·8 | 57·8 | 58·9 |
| | 993 | 993 | 993 | 993 | 993 | 992 | 992 | 992 |
| +------+------+------+------+------+------+------+------+
| 25 | 51·4 | 52·4 | 53·4 | 54·4 | 55·5 | 56·5 | 57·5 | 58·5 |
| | 992 | 992 | 992 | 992 | 992 | 992 | 992 | 992 |
+-------+------+------+------+------+------+------+------+------+
+-------+------+------+------+------+------+------+------+------+
|Temper-|63^{c}|64^{c}|65^{c}|66^{c}|67^{c}|68^{c}|69^{c}|70^{c}|
| ature | | | | | | | | |
| C. | | | | | | | | |
+-------+------+------+------+------+------+------+------+------+
| _Deg._| | | | | | | | |
| 10 | 64·7 | 65·7 | 66·7 | 67·6 | 68·6 | 69·6 | 70·6 | 71·6 |
| | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 |
| +------+------+------+------+------+------+------+------+
| 11 | 64·4 | 65·4 | 66·4 | 67·3 | 68·3 | 69·3 | 70·3 | 71·3 |
| | 1003 | 1003 | 1003 | 1003 | 1003 | 1004 | 1004 | 1004 |
| +------+------+------+------+------+------+------+------+
| 12 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 |
| | 1002 | 1002 | 1002 | 1002 | 1003 | 1003 | 1003 | 1003 |
| +------+------+------+------+------+------+------+------+
| 13 | 63·7 | 64·7 | 65·7 | 66·7 | 67·7 | 68·7 | 69·6 | 70·6 |
| | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 |
| +------+------+------+------+------+------+------+------+
| 14 | 63·3 | 64·3 | 65·3 | 66·3 | 67·3 | 68·3 | 69·3 | 70·3 |
| | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 |
| +------+------+------+------+------+------+------+------+
| 15 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 |
| | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 |
| +------+------+------+------+------+------+------+------+
| 16 | 62·7 | 63·7 | 64·7 | 65·7 | 66·7 | 67·7 | 68·7 | 69·7 |
| | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 |
| +------+------+------+------+------+------+------+------+
| 17 | 62·3 | 63·3 | 64·3 | 65·3 | 66·3 | 67·3 | 68·3 | 69·3 |
| | 998 | 998 | 998 | 998 | 998 | 998 | 998 | 998 |
| +------+------+------+------+------+------+------+------+
| 18 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 |
| | 997 | 997 | 997 | 997 | 997 | 997 | 997 | 997 |
| +------+------+------+------+------+------+------+------+
| 19 | 61·6 | 62·7 | 63·7 | 64·7 | 65·7 | 66·7 | 67·7 | 68·7 |
| | 997 | 997 | 997 | 997 | 997 | 997 | 996 | 996 |
| +------+------+------+------+------+------+------+------+
| 20 | 61·3 | 62·3 | 63·3 | 64·3 | 65·4 | 66·4 | 67·4 | 68·4 |
| | 996 | 996 | 996 | 996 | 996 | 996 | 996 | 996 |
| +------+------+------+------+------+------+------+------+
| 21 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68·1 |
| | 995 | 995 | 995 | 995 | 995 | 995 | 995 | 995 |
| +------+------+------+------+------+------+------+------+
| 22 | 60·6 | 61·6 | 62·7 | 63·7 | 64·7 | 65·7 | 66·7 | 67·7 |
| | 994 | 994 | 994 | 994 | 994 | 994 | 994 | 994 |
| +------+------+------+------+------+------+------+------+
| 23 | 60·2 | 61·3 | 62·3 | 63·3 | 64·3 | 65·4 | 66·4 | 67·4 |
| | 993 | 993 | 993 | 993 | 993 | 993 | 993 | 993 |
| +------+------+------+------+------+------+------+------+
| 24 | 59·9 | 61 | 62 | 63 | 64 | 65 | 66 | 67·1 |
| | 992 | 992 | 992 | 992 | 992 | 992 | 992 | 992 |
| +------+------+------+------+------+------+------+------+
| 25 | 59·5 | 60·6 | 61·6 | 62·6 | 63·7 | 64·7 | 65·7 | 66·7 |
| | 992 | 991 | 991 | 991 | 991 | 991 | 991 | 991 |
+-------+------+------+------+------+------+------+------+------+
+-------+------+------+------+------+------+------+------+------+
|Temper-|71^{c}|72^{c}|73^{c}|74^{c}|75^{c}|76^{c}|77^{c}|78^{c}|
| ature | | | | | | | | |
| C. | | | | | | | | |
+-------+------+------+------+------+------+------+------+------+
| _Deg._| | | | | | | | |
| 10 | 72·6 | 73·5 | 74·5 | 75·5 | 76·5 | 77·5 | 78·5 | 79·5 |
| | 1004 | 1004 | 1005 | 1005 | 1005 | 1005 | 1005 | 1005 |
| +------+------+------+------+------+------+------+------+
| 11 | 72·3 | 73·2 | 74·2 | 75·2 | 76·2 | 77·2 | 78·2 | 79·2 |
| | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 |
| +------+------+------+------+------+------+------+------+
| 12 | 72 | 72·9 | 73·9 | 74·9 | 75·9 | 76·9 | 77·9 | 78·9 |
| | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 |
| +------+------+------+------+------+------+------+------+
| 13 | 71·6 | 72·6 | 73·6 | 74·6 | 75·6 | 76·6 | 77·6 | 78·6 |
| | 1002 | 1002 | 1002 | 1002 | 1092 | 1002 | 1002 | 1002 |
| +------+------+------+------+------+------+------+------+
| 14 | 71·3 | 72·3 | 73·3 | 74·3 | 75·3 | 76·3 | 77·3 | 78·3 |
| | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 |
| +------+------+------+------+------+------+------+------+
| 15 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 |
| | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 |
| +------+------+------+------+------+------+------+------+
| 16 | 70·7 | 71·7 | 72·7 | 73·7 | 74·7 | 75·7 | 76·7 | 77·7 |
| | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 |
| +------+------+------+------+------+------+------+------+
| 17 | 70·3 | 71·3 | 72·3 | 73·3 | 74·3 | 75·4 | 76·4 | 77·4 |
| | 998 | 998 | 998 | 998 | 998 | 998 | 998 | 998 |
| +------+------+------+------+------+------+------+------+
| 18 | 70 | 71 | 72 | 73 | 74 | 75·1 | 76·1 | 77·1 |
| | 997 | 997 | 997 | 997 | 997 | 997 | 997 | 997 |
| +------+------+------+------+------+------+------+------+
| 19 | 69·7 | 70·7 | 71·7 | 72·7 | 73·7 | 74·7 | 75·8 | 76·8 |
| | 996 | 996 | 996 | 996 | 996 | 996 | 996 | 996 |
| +------+------+------+------+------+------+------+------+
| 20 | 69·4 | 70·4 | 71·4 | 72·4 | 73·4 | 74·4 | 75·5 | 76·5 |
| | 996 | 996 | 995 | 995 | 995 | 995 | 995 | 995 |
| +------+------+------+------+------+------+------+------+
| 21 | 69·1 | 70·1 | 71·1 | 72·1 | 73·1 | 74·1 | 75·2 | 76·2 |
| | 995 | 995 | 995 | 994 | 994 | 994 | 994 | 994 |
| +------+------+------+------+------+------+------+------+
| 22 | 68·8 | 69·8 | 70·8 | 71·8 | 72·8 | 73·8 | 74·8 | 75·9 |
| | 994 | 994 | 994 | 994 | 993 | 993 | 993 | 993 |
| +------+------+------+------+------+------+------+------+
| 23 | 68·4 | 69·4 | 70·5 | 71·5 | 72·5 | 73·5 | 74·5 | 75·5 |
| | 993 | 993 | 993 | 993 | 992 | 992 | 992 | 992 |
| +------+------+------+------+------+------+------+------+
| 24 | 68·1 | 69·1 | 70·1 | 71·2 | 72·2 | 73·2 | 74·2 | 75·2 |
| | 992 | 992 | 992 | 992 | 992 | 992 | 992 | 991 |
| +------+------+------+------+------+------+------+------+
| 25 | 67·8 | 68·8 | 69·8 | 70·8 | 71·8 | 72·8 | 73·9 | 74·9 |
| | 991 | 991 | 991 | 991 | 991 | 991 | 991 | 991 |
+-------+------+------+------+------+------+------+------+------+
+-------+------+------+------+------+------+------+------+------+
|Temper-|79^{c}|80^{c}|81^{c}|82^{c}|83^{c}|84^{c}|85^{c}|86^{c}|
| ature | | | | | | | | |
| C. | | | | | | | | |
+-------+------+------+------+------+------+------+------+------+
| _Deg._| | | | | | | | |
| 10 | 80·5 | 81·5 | 82·4 | 83·4 | 84·4 | 85·4 | 86·4 | 87·4 |
| | 1005 | 1005 | 1005 | 1005 | 1005 | 1005 | 1005 | 1005 |
| +------+------+------+------+------+------+------+------+
| 11 | 80·2 | 81·2 | 82·2 | 83·1 | 84·1 | 85·1 | 86·1 | 87·1 |
| | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 | 1004 |
| +------+------+------+------+------+------+------+------+
| 12 | 79·9 | 80·9 | 81·9 | 82·9 | 83·9 | 84·8 | 85·8 | 86·8 |
| | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 | 1003 |
| +------+------+------+------+------+------+------+------+
| 13 | 79·6 | 80·6 | 81·6 | 82·6 | 83·6 | 84·6 | 85·5 | 86·5 |
| | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 | 1002 |
| +------+------+------+------+------+------+------+------+
| 14 | 79·3 | 80·3 | 81·3 | 82·3 | 83·3 | 84·3 | 85·3 | 86·3 |
| | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 | 1001 |
| +------+------+------+------+------+------+------+------+
| 15 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 |
| | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 |
| +------+------+------+------+------+------+------+------+
| 16 | 78·7 | 79·7 | 80·7 | 81·7 | 82·7 | 83·7 | 84·7 | 85·7 |
| | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 |
| +------+------+------+------+------+------+------+------+
| 17 | 78·4 | 79·4 | 80·4 | 81·4 | 82·4 | 83·4 | 84·4 | 85·4 |
| | 998 | 998 | 998 | 998 | 998 | 998 | 998 | 998 |
| +------+------+------+------+------+------+------+------+
| 18 | 78·1 | 79·1 | 80·1 | 81·1 | 82·1 | 83·1 | 84·1 | 85·2 |
| | 997 | 997 | 997 | 997 | 997 | 997 | 997 | 997 |
| +------+------+------+------+------+------+------+------+
| 19 | 77·8 | 78·8 | 79·8 | 80·8 | 81·9 | 82·9 | 83·9 | 84·9 |
| | 996 | 996 | 996 | 996 | 996 | 996 | 996 | 996 |
| +------+------+------+------+------+------+------+------+
| 20 | 77·5 | 78·5 | 79·5 | 80·5 | 81·6 | 82·6 | 83·6 | 84·6 |
| | 995 | 995 | 995 | 995 | 995 | 995 | 995 | 995 |
| +------+------+------+------+------+------+------+------+
| 21 | 77·2 | 78·2 | 79·2 | 80·2 | 81·3 | 82·3 | 83·3 | 84·3 |
| | 994 | 994 | 994 | 994 | 994 | 994 | 994 | 994 |
| +------+------+------+------+------+------+------+------+
| 22 | 76·9 | 77·9 | 78·9 | 79·9 | 81 | 82 | 83 | 84 |
| | 993 | 993 | 993 | 993 | 993 | 993 | 993 | 993 |
| +------+------+------+------+------+------+------+------+
| 23 | 76·6 | 77·6 | 78·6 | 79·6 | 80·7 | 81·7 | 82·7 | 83·8 |
| | 992 | 992 | 992 | 992 | 992 | 992 | 992 | 992 |
| +------+------+------+------+------+------+------+------+
| 24 | 76·3 | 77·3 | 78·3 | 79·3 | 80·4 | 81·4 | 82·4 | 83·5 |
| | 991 | 991 | 991 | 991 | 991 | 991 | 991 | 991 |
| +------+------+------+------+------+------+------+------+
| 25 | 76 | 77 | 78 | 79 | 80·1 | 81·1 | 82·1 | 83·2 |
| | 991 | 991 | 991 | 991 | 990 | 990 | 990 | 990 |
+-------+------+------+------+------+------+------+------+------+
+-------+------+------+------+------+
|Temper-|87^{c}|88^{c}|89^{c}|90^{c}|
| ature | | | | |
| C. | | | | |
+-------+------+------+------+------+
| _Deg._| | | | |
| 10 | 88·3 | 89·3 | 90·2 | 91·2 |
| | 1005 | 1005 | 1005 | 1005 |
| +------+------+------+------+
| 11 | 88 | 89 | 90 | 91 |
| | 1004 | 1004 | 1004 | 1004 |
| +------+------+------+------+
| 12 | 87·8 | 88·7 | 89·7 | 90·7 |
| | 1003 | 1003 | 1003 | 1003 |
| +------+------+------+------+
| 13 | 87·5 | 88·5 | 89·5 | 90·5 |
| | 1002 | 1002 | 1002 | 1002 |
| +------+------+------+------+
| 14 | 87·3 | 88·2 | 89·2 | 90·2 |
| | 1001 | 1001 | 1001 | 1001 |
| +------+------+------+------+
| 15 | 87 | 88 | 89 | 90 |
| | 1000 | 1000 | 1000 | 1000 |
| +------+------+------+------+
| 16 | 86·7 | 87·7 | 88·7 | 89·7 |
| | 999 | 999 | 999 | 999 |
| +------+------+------+------+
| 17 | 86·4 | 87·4 | 88·4 | 89·5 |
| | 998 | 998 | 998 | 998 |
| +------+------+------+------+
| 18 | 86·2 | 87·2 | 88·2 | 89·2 |
| | 997 | 997 | 997 | 997 |
| +------+------+------+------+
| 19 | 85·9 | 86·9 | 87·9 | 88·9 |
| | 996 | 996 | 996 | 996 |
| +------+------+------+------+
| 20 | 85·6 | 86·6 | 87·7 | 88·7 |
| | 995 | 995 | 995 | 995 |
| +------+------+------+------+
| 21 | 85·3 | 86·4 | 87·4 | 88·4 |
| | 994 | 994 | 994 | 994 |
| +------+------+------+------+
| 22 | 85 | 86·1 | 87·1 | 88·2 |
| | 993 | 993 | 993 | 993 |
| +------+------+------+------+
| 23 | 84·8 | 85·8 | 86·8 | 87·9 |
| | 992 | 992 | 992 | 992 |
| +------+------+------+------+
| 24 | 84·5 | 85·5 | 86·5 | 87·6 |
| | 991 | 991 | 991 | 991 |
| +------+------+------+------+
| 25 | 84·2 | 85·2 | 86·3 | 87·4 |
| | 990 | 990 | 990 | 990 |
+-------+------+------+------+------+
I consider the preceding table, which I have extracted from the longer
tables of M. Gay Lussac, as an important addition to the resources of
British dealers and manufacturing chemists. With the aid of his little
instrument, which may be got for a trifle from its ingenious maker, M.
Collardeau, Rue Faubourg St. Martin, at Paris, or constructed by one of
the London hydrometer artists, the per centage of real alcohol, and the
real value of any spirituous liquor, may be determined to sufficient
nicety for most purposes, in a far easier manner than by any instruments
now used in this country. It has been adopted by the Swedish government,
with M. Gay Lussac’s tables.
M. Gay Lussac’s table gives, by inspection, the true bulk of the spirits
as corrected for temperature; that is, their volume, if of the normal
temperature of 15° Cent. (59° Fahr.). Now this is important information;
for, if a person buys 1000 gallons of spirits in hot weather, and pays
for them exactly according to their strength corrected for temperature,
he will not have 1000 gallons when the weather is in its mean state. He
may lose, in this way, several gallons without being aware of it from
his hydrometer.
Sometimes, after moist autumns, when damaged grain abounds, the alcohol
distilled from its fermented wash contains a peculiar volatile body.
When we apply our nose to this species of spirits in its hot state, the
volatile substance dissolved in it irritates the eyes and nostrils: it
has very nearly the same smell as an alcoholic solution of cyanogen, as
any chemist may discover by standing near the discharge pipe of the
refrigeratory worm of a raw-grain whisky still. Such spirits intoxicate
more strongly than pure spirits of the same strength, and excite, in
many persons, even temporary frenzy. It is a volatile fatty matter, of a
very fetid odour, when obtained by itself, as I have procured it in cold
weather at some of the great distilleries in Scotland. It does not
combine with bases. At the end of a few months, it spontaneously
decomposes in the spirits, and leaves them in a less nauseous and
noxious state. By largely diluting the spirits with water, and
distilling at a moderate temperature, the greater part of this oil may
be separated. Part of it comes over with the strongest alcohol, and part
with the latter runnings, which are called by the distillers strong and
weak feints. The intermediate portion is purer spirit. The feints are
always more or less opalescent, or become so on dilution with water, and
then throw up an oily pellicle upon their surface. The charcoals of
light wood, such as pine or willow, well calcined, and infused in
sufficient quantity with the spirits prior to rectification, will
deprive them of the greater part of that oily contamination. Animal
charcoal, well calcined, has also been found useful; but it must be
macerated for some time with the empyreumatic spirits, before
distillation. Another mode of separating that offensive oil is, to
agitate the impure spirits with a quantity of a fat oil, such as olive
oil, or oil of almonds, to decant off the oil, and re-distil the spirits
with a little water.
Some foreign chemists direct empyreumatic or rank spirits, to be
rectified with the addition of chloride of lime. I have tried this
method in every way, and on a considerable scale, but never found the
spirits to be improved by it. They were rather deteriorated. See
_Brandy_, _Distillation_, _Fermentation_, _Gin_, _Rum_, _Whisky_.
Anhydrous or absolute alcohol, when swallowed, acts as a mortal poison,
not only by its peculiar stimulus on the nervous system, but by its
abstracting the aqueous particles from the soft tissue of the stomach,
with which it comes in contact, so as to destroy its organisation.
Alcohol of 0·812 consists, by experiments, of 3 atoms of carbon, 6 of
hydrogen, and 2 of oxygen; absolute alcohol consists, probably, of 2 of
carbon, 3 of hydrogen, and 1 of oxygen.
ALE. The fermented infusion of pale malted barley, usually combined with
infusion of hops. See BEER.
ALEMBIC, a STILL; which see.
ALEMBROTH, salt of. The salt of wisdom, of the alchemists; a compound of
bichloride of mercury and sal ammoniac, from which the old white
precipitate of mercury is made.
ALGAROTH, powder of. A compound of oxide and chloride of antimony, being
a precipitate obtained by pouring water into the acidulous chloride of
that metal.
ALIZARINE. See MADDER.
ALKALI. A class of chemical bodies, distinguished chiefly by their
solubility in water, and their power of neutralising acids, so as to
form saline compounds. The alkalis of manufacturing importance are,
ammonia, potash, soda, and quinia. These alkalis change the purple
colour of red cabbage and radishes to a green, the reddened tincture of
litmus to a purple, and the colour of turmeric and many other yellow
dyes to a brown. Even when combined with carbonic acid, the first three
alkalis exercise this discolouring power, which the alkaline earths,
lime and barytes, do not. The same three alkalis have an acrid, and
somewhat urinous taste; the first two are energetic solvents of animal
matter; and the three combine with oils, so as to form soaps. They unite
with water in every proportion, and also with alcohol; and the first
three combine with water after being carbonated.
ALKALIMETER. An instrument for measuring the alkaline force or purity of
any of the alkalis of commerce. It is founded on the principle, that the
quantity of real alkali present in any sample, is proportional to the
quantity of acid which a given weight of it can neutralize. See the
individual alkalis, POTASH, and SODA.
ALKANA, is the name of the root and leaves of _Lausania inermis_, which
have been long employed in the East, to dye the nails, teeth, hair,
garments, &c. The leaves, ground and mixed with a little limewater,
serve for dyeing the tails of horses in Persia and Turkey.
ALKANET, the root of. (_Anchusa tinctoria._) A species of bugloss,
cultivated chiefly in the neighbourhood of Montpellier. It affords a
fine red colour to alcohol and oils; but a dirty red to water. Its
principal use is for colouring ointments, cheeses, and _pommades_. The
spirituous tincture gives to white marble a beautiful deep stain.
ALLIGATION. An arithmetical formula, useful, on many occasions, for
ascertaining the proportion of constituents in a mixture, when they have
undergone no change of volume by chemical action. When alcoholic liquors
are mixed with water, there is a condensation of bulk, which renders
that arithmetical rule inapplicable. The same thing holds, in some
measure, in the union of metals by fusion. See ALLOY.
ALLOY. (_Alliage_, Fr.; _Legirung_, Germ.) This term formerly signified
a compound of gold and silver, with some metal of inferior value, but it
now means any compound of any two or more metals whatever. Thus, bronze
is an alloy of copper and tin; brass, an alloy of copper and zinc; and
type metal, an alloy of lead and antimony. All the alloys possess
metallic lustre, even when cut or broken to pieces; they are opaque; are
excellent conductors of heat and electricity; are frequently susceptible
of crystallising; are more or less ductile, malleable, elastic, and
sonorous. An alloy which consists of metals differently fusible is
usually malleable in the cold, and brittle when hot, as is exemplified
with brass and gong metal.
Many alloys consist of definite or equivalent proportions of the simple
component metals, though some alloys seem to form in any proportion,
like combinations of salt or sugar with water. It is probable that
peculiar properties belong to the equivalent or atomic ratio, as is
exemplified in the superior quality of brass made in that proportion.
One metal does not alloy indifferently with every other metal, but it is
governed in this respect by peculiar affinities; thus, silver will
hardly unite with iron, but it combines readily with gold, copper, and
lead. In comparing the alloys with their constituent metals, the
following differences may be noted; in general, the ductility of the
alloy is less than that of the separate metals, and sometimes in a very
remarkable degree; on the contrary, the alloy is usually harder than the
mean hardness of its constituents. The mercurial alloys or amalgams are,
perhaps, exceptions to this rule.
The specific gravity is rarely the mean between that of each of its
constituents, but is sometimes greater and sometimes less, indicating,
in the former case, an approximation, and in the latter, a recedure, of
the particles from each other in the act of their union. The following
tables of binary alloys exhibit this circumstance in experimental
detail:--
Alloys having a density Alloys having a density
greater than the mean of less than the mean of
their constituents. their constituents.
Gold and zinc Gold and silver
Gold and tin Gold and iron
Gold and bismuth Gold and lead
Gold and antimony Gold and copper
Gold and cobalt Gold and iridium
Silver and zinc Gold and nickel
Silver and lead Silver and copper
Silver and tin Silver and lead
Silver and bismuth Iron and bismuth
Silver and antimony Iron and antimony
Copper and zinc Iron and lead
Copper and tin Tin and lead
Copper and palladium Tin and palladium
Copper and bismuth Tin and antimony
Lead and antimony Nickel and arsenic
Platinum and molybdenum Zinc and antimony.
Palladium and bismuth.
It would be hardly possible to infer the melting point of an alloy from
that of each of its constituent metals; but, in general, the fusibility
is increased by mutual affinity in their state of combination. Of this,
a remarkable instance is afforded in the fusible metal consisting of 8
parts of bismuth, 5 of lead, and 3 of tin, which melts at the heat of
boiling water or 212° Fahr., though the melting point deduced from the
mean of its components should be 514°. This alloy may be rendered still
more fusible by adding a very little mercury to it, when it forms an
excellent material for certain anatomical injections, and for filling
the hollows of carious teeth. Nor do the colours of alloys depend, in
any considerable degree, upon those of the separate metals; thus, the
colour of copper, instead of being rendered paler by a large addition of
zinc, is thereby converted into the rich-looking pinchbeck metal.
By means of alloys, we multiply, as it were, the numbers of useful
metals, and sometimes give usefulness to such as are separately of
little value. Since these compounds can be formed only by fusion, and
since many metals are apt to oxidise readily at their melting
temperature, proper precautions must be taken in making alloys to
prevent this occurrence, which is incompatible with their formation.
Thus, in combining tin and lead, rosin or grease is usually put on the
surface of the melting metals, the carbon produced by the decomposition
of which protects them, in most cases, sufficiently from oxidisement.
When we wish to combine tin with iron, as in the tinning of cast-iron
tea kettles, we rub sal ammoniac upon the surfaces of the hot metals in
contact with each other, and thus exclude the atmospheric oxygen by
means of its fumes. When there is a notable difference in the specific
gravities of the metals which we wish to combine, we often find great
difficulties in obtaining homogeneous alloys; for each metal may tend to
assume the level due to its density, as is remarkably exemplified in
alloys of gold and silver made without adequate stirring of the melting
metals. If the mass be large, and slow of cooling after it is cast in an
upright cylindrical form, the metals sometimes separate, to a certain
degree, in the order of their densities. Thus, in casting large bells
and cannons with copper alloys, the bottom of the casting is apt to
contain too much copper and the top too much tin, unless very dexterous
manipulation in mixing the fused materials have been employed
immediately before the instant of pouring out the melted mass. When such
inequalities are observed, the objects are broken and re-melted, after
which they form a much more homogeneous alloy. This artifice of a double
melting is often had recourse to, and especially in casting the alloys
for the specula of telescopes.
When we wish to alloy three or more metals, we often experience
difficulties, either because one of the metals is more oxidable, or
denser, or more fusible, than the others, or because there is no direct
affinity between two of the metals. In the latter predicament, we shall
succeed better by combining the three metals, first in pairs, for
example, and then melting the two pairs together. Thus, it is difficult
to unite iron with bronze directly; but if, instead of iron, we use tin
plate, we shall immediately succeed, and the bronze, in this manner,
acquires valuable qualities from the iron. Thus, also, to render brass
better adapted for certain purposes, a small quantity of lead ought to
be added to it, but this cannot be done directly with advantage: it is
better to melt the lead first along with the zinc, and then to add this
alloy to the melting copper, or the copper to that alloy, and fuse them
together.
We have said that the difference of fusibility was often an obstacle to
metallic combination; but this circumstance may also be turned to
advantage in decomposing certain alloys by the process called
_eliquation_. By this means silver may be separated from copper, if a
considerable quantity of lead be first alloyed with the said copper;
this alloy is next exposed to a heat just sufficient to melt the lead,
which then sweats out, so to speak, from the pores of the copper, and
carries along with it the greater part of the silver, for which it has a
strong affinity. The lead and the silver are afterwards separated from
each other, in virtue of their very different oxidability, by the action
of heat and air.
One of the alloys most useful to the arts is brass; it is more ductile
and less easily oxidised than even its copper constituent,
notwithstanding the opposite nature of the zinc. This alloy may exist in
many different proportions, under which it has different names, as
tombac, similor, pinchbeck, &c. Copper and tin form, also, a compound of
remarkable utility, known under the names of hard brass, for the bushes,
steps, and bearings of the axles, arbours, and spindles in machinery;
and of bronze, bell-metal, &c. Gold and silver, in their pure state, are
too soft and flexible to form either vessels or coins of sufficient
strength and durability; but when alloyed with a little copper, they
acquire the requisite hardness and stiffness for these and other
purposes.
When we have occasion to unite several pieces of the same or of
different metals, we employ the process called _soldering_, which
consists in fixing together the surfaces by means of an interposed
alloy, which must be necessarily more fusible than the metal or metals
to be joined. That alloy must also consist of metals which possess a
strong affinity for the substances to be soldered together. Hence each
metal would seem to require a particular kind of solder, which is, to a
certain extent, true. Thus, the solder for gold trinkets and plate is an
alloy of gold and silver, or gold and copper; that of silver trinkets,
is an alloy of silver and copper; that of copper is either fine tin, for
pieces that must not be exposed to the fire, or a brassy alloy called
hard solder, of which the zinc forms a considerable proportion. The
solder of lead and tinplate is an alloy of lead and tin, and that of tin
is the same alloy with a little bismuth. Tinning, gilding, and silvering
may also be reckoned a species of alloys, since the tin, gold, and
silver are superficially united in these cases to other metals.
Metallic alloys possess usually more tenacity than could be inferred
from their constituents; thus, an alloy of twelve parts of lead with one
of zinc has a tenacity double that of zinc. Metallic alloys are much
more easily oxidised than the separate metals, a phenomenon which may be
ascribed to the increase of affinity for oxygen which results from the
tendency of the one of the oxides to combine with the other. An alloy of
tin and lead heated to redness takes fire, and continues to burn for
some time like a piece of bad turf.
Every alloy is, in reference to the arts and manufactures, a new metal,
on account of its chemical and physical properties. A vast field here
remains to be explored. Not above sixty alloys have been studied by the
chemists out of many hundred which may be made; and of these very few
have yet been practically employed. Very slight modifications often
constitute very valuable improvements upon metallic bodies. Thus, the
brass most esteemed by turners at the lathe contains from two to three
per cent. of lead; but such brass does not work well under the hammer;
and, reciprocally, the brass which is best under the hammer is too tough
for turning.
That metallic alloys tend to be formed in definite proportions of their
constituents is clear from the circumstance that the native gold of the
auriferous sands is an alloy with silver, in the ratios of 1 atom of
silver united to 4, 5, 6, 12 atoms of gold, but never with a fractional
part of an atom. Also, in making an amalgam of 1 part of silver with 12
or 15 of mercury, and afterwards squeezing the mixture through chamois
leather, the amalgam separates into 2 parts: one, containing a small
proportion of silver and much mercury, passes through the skin; and the
other, formed of 1 of silver and 8 of mercury, is a compound in definite
proportions, which crystallises readily, and remains in the knot of the
bag. An analogous separation takes place in the tinning of mirrors; for
on loading them with the weights, a liquid amalgam of tin is squeezed
out, while another amalgam remains in a solid form composed of tin and
mercury in uniform atomic proportions. But, as alloys are generally
soluble, so to speak, in each other, this definiteness of combination is
masked and disappears in most cases.
M. Chaudet has made some experiments on the means of detecting the
metals of alloys by the cupelling furnace, and they promise useful
applications. The testing depends upon the appearances exhibited by the
metals and their alloys when heated on a cupel. Pure tin, when heated
this way, fuses, becomes of a greyish black colour, fumes a little,
exhibits incandescent points on its surface, and leaves an oxide, which,
when withdrawn from the fire, is at first lemon-yellow, but when cold,
white. Antimony melts, preserves its brilliancy, fumes, and leaves the
vessel coloured lemon-yellow when hot, but colourless when cold, except
a few spots of a rose tint. Zinc burns brilliantly, forming a cone of
oxide; and the oxide, much increased in volume, is, when hot, greenish,
but when cold, perfectly white. Bismuth fumes, becomes covered with a
coat of melted oxide, part of which sublimes, and the rest enters the
pores of the cupel; when cold, the cupel is of a fine yellow colour,
with spots of a greenish hue. Lead resembles bismuth very much; the cold
cupel is of a lemon-yellow colour. Copper melts, and becomes covered
with a coat of black oxide; sometimes spots of a rose tint remain on the
cupel.
Alloys.--Tin 75, antimony 25, melt, become covered with a coat of black
oxide, have very few incandescent points; when cold, the oxide is nearly
black, in consequence of the action of the antimony: a 1/400 part of
antimony may be ascertained in this way in the alloy. An alloy of
antimony, containing tin, leaves oxide of tin in the cupel: a 1/100 part
of tin may be detected in this way. An alloy of tin and zinc gives an
oxide which, whilst hot, is of a green tint, and resembles philosophic
wool in appearance. An alloy containing 99 tin, 1 zinc, did not present
the incandescent points of pure tin, and gave an oxide of greenish tint
when cold. Tin 95, bismuth 5 parts, gave an oxide of a grey colour. Tin
and lead give an oxide of a rusty brown colour. An alloy of lead and
tin, containing only 1 per cent. of the latter metal, when heated, does
not expose a clean surface, like lead, but is covered at times with
oxide of tin. Tin 75, and copper 25, did not melt, gave a black oxide:
if the heat be much elevated, the under part of the oxide is white, and
is oxide of tin; the upper is black, and comes from the copper. The
cupel becomes of a rose colour. If the tin be impure from iron, the
oxide produced by it is marked with spots of a rust colour.
The degree of affinity between metals may be in some measure estimated
by the greater or less facility with which, when of different degrees of
fusibility or volatility, they unite, or with which they can, after
union, be separated by heat. The greater or less tendency to separate
into differently proportioned alloys, by long-continued fusion, may also
give some information upon this subject. Mr. Hatchett remarked, in his
elaborate researches on metallic alloys, that gold made standard with
the usual precautions, by silver, copper, lead, antimony, &c., and then
cast, after long fusion, into vertical bars, was by no means an uniform
compound; but that the top of the bar, corresponding to the metal at the
bottom of the crucible, contained the larger proportion of gold. Hence,
for a more thorough combination, two red-hot crucibles should be
employed, and the liquefied metals should be alternately poured from the
one into the other. To prevent unnecessary oxidisement from the air, the
crucibles should contain, besides the metal, a mixture of common salt
and pounded charcoal. The metallic alloy should also be occasionally
stirred up with a rod of pottery ware.
The most direct evidence of a chemical change having been effected in
alloys is, when the compound melts at a lower temperature than the mean
of its ingredients. Iron, which is nearly infusible, acquires almost the
fusibility of gold when alloyed with this precious metal. The analogy is
here strong with the increase of solubility which salts acquire by
mixture, as is exemplified in the difficulty of crystallising residuums
of saline solutions, or mother waters, as they are called.
In common cases the specific gravity affords a good criterion whereby to
judge of the proportion of two metals in an alloy. But a very fallacious
rule has been given in some respectable works for computing the specific
gravity that should result from the alloying of given quantities of two
metals of known densities, supposing no chemical condensation or
expansion of volume to take place. Thus, it has been taught, that if
gold and copper be united in equal weights, the computed specific
gravity is merely the arithmetical mean between the numbers denoting the
two specific gravities. Whereas, the specific gravity of any alloy must
be computed by dividing the sum of the two weights by the sum of the two
volumes, compared, for conveniency sake, to water reckoned unity. Or, in
another form, the rule may be stated thus:--Multiply the sum of the
weights into the products of the two specific-gravity numbers for a
numerator; and multiply each specific gravity-number into the weight of
the other body, and add the two products together for a denominator. The
quotient obtained by dividing the said numerator by the denominator, is
the truly computed mean specific gravity of the alloy. On comparing with
that density, the density found by experiment, we shall see whether
expansion or condensation of volume has attended the metallic
combination. Gold having a specific gravity of 19·36, and copper of
8·87, when they are alloyed in equal weights, give, by the fallacious
rule of the arithmetical mean of the densities (19·36 + 8·87)/2 = 14·11;
whereas the rightly computed mean density is only 12·16. It is evident
that, on comparing the first result with experiment, we should be led to
infer that there had been a prodigious condensation of volume, though
expansion has actually taken place. Let W, w be the two weights; P, p
the two specific gravities, then M, the mean specific gravity, is given
by the formula--
(W + w) P p (P - p)²
M = ----------- ∴ 2Δ = - -------- =
P w + p W P + p
twice the error of the arithmetical mean; which is therefore always in
excess.
ALMOND. (_Amande_, Fr.; _Mandel_, Germ.) There are two kinds of almond
which do not differ in chemical composition, only that the bitter, by
some mysterious reaction of its constituents, generates in the act of
distillation a quantity of a volatile oil, which contains hydrocyanic
acid. Vogel obtained from bitter almonds 8·5 per cent. of husks. After
pounding the kernels, and heating them to coagulate the albumen, he
procured, by expression, 28 parts of an unctuous oil, which did not
contain the smallest particle of hydrocyanic acid. The whole of the oil
could not be extracted in this way. The expressed mass, treated with
boiling water, afforded sugar and gum, and, in consequence of the heat,
some of that acid. The sugar constitutes 6·5 per cent. and the gum 3.
The vegetable albumen extracted, by means of caustic potash, amounted to
30 parts: the vegetable fibre to only 5. The poisonous aromatic oil,
according to Robiquet and Boutron-Charlard, does not exist ready-formed
in the bitter almond, but seems to be produced under the influence of
ebullition with water. These chemists have shown that bitter almonds
deprived of their unctuous oil by the press, when treated first by
alcohol, and then by water, afford to neither of these liquids any
volatile oil. But alcohol dissolves out a peculiar white crystalline
body, without smell, of a sweetish taste at first, and afterwards
bitter, to which they gave the name of _amygdaline_. This substance does
not seem convertible into volatile oil.
Sweet almonds by the analysis of Boullay, consist of 54 parts of the
bland almond oil, 6 of uncrystallisable sugar, 3 of gum, 24 of vegetable
albumen, 24 of woody fibre, 5 of husks, 3·5 of water, 0·5 of acetic
acid, including loss. We thus see that sweet almonds contain nearly
twice as much oil as bitter almonds do.
ALMOND OIL. A bland fixed oil, obtained usually from bitter almonds by
the action of a hydraulic press, either in the cold, or aided by hot
iron plates. See OIL.
ALOE. A series of trials has been made within a few years at Paris to
ascertain the comparative strength of cables made of hemp and of the
aloe from Algiers; and they are said to have all turned to the advantage
of the aloe. Of cables of equal size, that made of aloe raised a weight
of 2,000 kilogrammes (2 tons nearly); that made of hemp, a weight of
only 400 kilogrammes. At the exposition of objects of national industry,
two years ago, in Brussels, I saw aloe cordage placarded, as being far
preferable to hempen. See ROPE.
ALUDEL. A pear-shaped vessel open at either end, of which a series are
joined for distilling mercury in Spain. See MERCURY.
ALUM. (_Alun_, Fr.; _Alaum_, Germ.) A saline body, consisting of the
earth of clay, called alumina by the chemists, combined with sulphuric
acid and potash, or sulphuric acid and ammonia, into a triple compound.
It occurs in the crystallised form of octahedrons, has an acerb subacid
taste, and reddens the blue colour of litmus or red cabbage.
Alum works existed many centuries ago at Roccha, formerly called Edessa,
in Syria, whence the ancient name of Roch alum given to this salt. It
was afterwards made at Foya Nova, near Smyrna, and in the neighbourhood
of Constantinople. The Genoese, and other trading people of Italy,
imported alum from these places into western Europe, for the use of the
dyers of red cloth. About the middle of the fifteenth century, alum
began to be manufactured at La Tolfa, Viterbo, and Volaterra, in Italy;
after which time the importation of oriental alum was prohibited by the
pope, as detrimental to the interests of his dominions. The manufacture
of this salt was extended to Germany at the beginning of the sixteenth
century, and to England at a somewhat later period, by Sir Thomas
Chaloner, in the reign of Elizabeth. In its pure state, it does not seem
to have been known to the ancients; for Pliny, in speaking of something
like plumose alum, says, that it struck a black colour with pomegranate
juice, which shows that the green vitriol was not separated from it. The
_stypteria_ of Dioscorides, and the _alumen_ of Pliny, comprehended,
apparently, a variety of saline substances, of which sulphate of iron,
as well as alumina, was probably a constituent part. Pliny, indeed,
says, that a substance called in Greek Ὑγρα, or watery, probably from
its very soluble nature, which was milk-white, was used for dyeing wool
of bright colours. This may have been the mountain butter of the German
mineralogists, which is a native sulphate of alumina, of a soft texture,
waxy lustre, and unctuous to the touch.
The only alum manufactories now worked in Great Britain, are those of
Whitby, in England, and of Hurlett and Campsie, near Glasgow, in
Scotland; and these derive the acid and earthy constituents of the salt
from a mineral called alum slate. This mineral has a bluish or
greenish-black colour, emits sulphurous fumes when heated, and acquires
thereby an aluminous taste. The alum manufactured in Great Britain
contains potash as its alkaline constituent; that made in France
contains, commonly, ammonia, either alone, or with variable quantities
of potash. Alum may in general be examined by water of ammonia, which
separates from its watery solutions its earthy basis, in the form of a
light flocculent precipitate. If the solution be dilute, this
precipitate will float long as an opalescent cloud.
If we dissolve alum in 20 parts of water, and drop this solution slowly
into water or caustic ammonia till this be nearly, but not entirely,
saturated, a bulky white precipitate will fall down, which, when
properly washed with water, is pure aluminous earth or clay, and dried
forms 10·82 per cent. of the weight of the alum. If this earth, while
still moist, be dissolved in dilute sulphuric acid, it will constitute,
when as neutral as possible, the sulphate of alumina, which requires
only two parts of cold water for its solution. If we now decompose this
solution, by pouring into it water of ammonia, there appears an
insoluble white powder, which is subsulphate of alumina, or basic alum;
and contains three times as much earth as exists in the neutral
sulphate. If, however, we pour into the solution of the neutral sulphate
of alumina a solution of sulphate of potash, a white powder will fall if
the solutions be concentrated, which is true _alum_; but if the
solutions be dilute, by evaporating their mixture, and cooling it,
crystals of alum will be obtained.
When newly precipitated alumina is boiled in a solution of alum, a
portion of the earth enters into combination with the salt, constituting
an insoluble compound, which falls in the form of a white powder. The
same combination takes place, if we decompose a boiling hot solution of
alum with a solution of potash, till the mixture appears nearly neutral
by litmus paper. This insoluble or basic alum exists native in the
alum-stone of Tolfa, near Civita Vecchia, and it consists in 100 parts
of 19·72 parts of sulphate of potash, 61·99 basic sulphate of alumina,
and 18·29 water. When this mineral is treated with a due quantity of
sulphuric acid, it dissolves, and is converted into the crystallisable
alum of commerce.
These experimental facts develope the principles of the manufacture of
alum, which is prosecuted under various modifications, for its important
uses in the arts. Alum seldom occurs ready-formed in nature;
occasionally, as an efflorescence on stones, and in certain mineral
waters in the East Indies. The alum of European commerce is fabricated
artificially, either from the alum schists or stones, or from clay. The
mode of manufacture differs according to the nature of these earthy
compounds. Some of them, such as the alum stone, contain all the
elements of the salt, but mixed with other matters, from which it must
be freed. The schists contain only the elements of two of the
constituents, namely, clay and sulphur, which are convertible into
sulphate of alumina, and this may be then made into alum by adding the
alkaline ingredient. To this class belong the alum slates, and other
analogous schists, containing brown coal.
1. _Manufacture of Alum from the Alum Stone._--The alum-stone is a rare
mineral, being found in moderate quantity at Tolfa, and in larger in
Hungary, at Bereghszasz, and Muszag, where it forms entire beds in a
hard substance, partly characterised by numerous cavities, containing
drusy crystallisations of alum-stone or basic alum. The larger lumps
contain more or fewe
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