Skip to main content

Full text of "Ures̓ dictionary of arts, manufactures, and mines, containing a clear exposition of their principles and practice"

See other formats


This is a digital copy of a book that was preserved for generations on library shelves before it was carefully scanned by Google as part of a project 

to make the world's books discoverable online. 

It has survived long enough for the copyright to expire and the book to enter the public domain. A public domain book is one that was never subject 

to copyright or whose legal copyright term has expired. Whether a book is in the public domain may vary country to country. Public domain books 

are our gateways to the past, representing a wealth of history, culture and knowledge that's often difficult to discover. 

Marks, notations and other maiginalia present in the original volume will appear in this file - a reminder of this book's long journey from the 

publisher to a library and finally to you. 

Usage guidelines 

Google is proud to partner with libraries to digitize public domain materials and make them widely accessible. Public domain books belong to the 
public and we are merely their custodians. Nevertheless, this work is expensive, so in order to keep providing tliis resource, we liave taken steps to 
prevent abuse by commercial parties, including placing technical restrictions on automated querying. 
We also ask that you: 

+ Make non-commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for 
personal, non-commercial purposes. 

+ Refrain fivm automated querying Do not send automated queries of any sort to Google's system: If you are conducting research on machine 
translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. We encourage the 
use of public domain materials for these purposes and may be able to help. 

+ Maintain attributionTht GoogXt "watermark" you see on each file is essential for in forming people about this project and helping them find 
additional materials through Google Book Search. Please do not remove it. 

+ Keep it legal Whatever your use, remember that you are responsible for ensuring that what you are doing is legal. Do not assume that just 
because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other 
countries. Whether a book is still in copyright varies from country to country, and we can't offer guidance on whether any specific use of 
any specific book is allowed. Please do not assume that a book's appearance in Google Book Search means it can be used in any manner 
anywhere in the world. Copyright infringement liabili^ can be quite severe. 

About Google Book Search 

Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers 
discover the world's books while helping authors and publishers reach new audiences. You can search through the full text of this book on the web 

at |http: //books .google .com/I 






raxKTiB BT sromswooss xin> co. 










Keep«r of Miidiig Beoords 
Fonnerlj PxofiMaor of FbyiioB, GorenmiflDt School of lUiiflt, fte. fte. 

AMiBTSD HT avMMwi M oonMXBVtoaB XHxvun nr aoxBVGi m> vaxiuib wna UAMuwAxmvna 

Olvftzated with nMurly Two Thouaiid BagraTiagi oa Wood 

Fifth Editiov, chietlt Rswbitten akd obsatlt Enlarobd 




ne riffhi qf Uraiul4MHoH w rmeroeA 


VOL. I. 


Page S. ACBTATB. flnt line, for '* by " read " In.' 

ACETIC ACID, fUteenth Hdo, for ** Vanqoelln," rMd ** VaaqueUn." 
„ IS. », fourth line bom bottom, for '* of soda aod acetone," read " of lime,** Ac 

„ la. „ thirteenth line, for " one half of the sulphate of lime,** read " one half of tho 

„ 64. ALCOHOLOMBTRY, the last paragraph of the article Is Incorrect. ** The duties on Scotch 

and Irish sphriU are equalised." 
., 99. There Is an error in the sutement as It stands respecting Dentists' Alloy. The best authority 
on this subject writes : ** In reply to your Inquiry, I have much pleasure in informing you 
that I6-carat gold, which is | fine gold and | ^loy, the alloy being nearly always equal 
portions of i iWer and copper, is not In the slightest degree injurious for dentists' purposes." 
„ 146. AlfVONIUM, Chloride of, in the formula, for " NHs,*' read " NH*." 
„ IS6. ARSENIOUS ACID, last lines, occurs this passage: ** Considerable discussion has arisen 
from a statement made by "Ur. A. S. Taylor, that the arsenic employed in paper-hangings 
was volatilised, Ac." It should read, ** from a statement made by Dr. A, S. Taylor, that 
the arsenic employed in paper-hangings was remoTed, Ac.** Dr. Taylor assures the 
editor that he never sanctioned the idea of Tolatilisation of the arsenical green. 
,. MS. AZOBBNZOIDB. Dele " See Hydrobenxamlde." 
„ S8S. BEER, fourth line from bottom, for ** Banerstock," read " Baverstock." 


„ 286. FORMIC ACID, for " its formuU Is CSHG^, Ac," read '« C'HO." 

„ 82S. GAULTHBRIA OIL. Dele " which see." 

,. 423. GUANO, paragraph 20, for « 3. Soda lime fi)r platinum,** read ** Bichloride of platinum." 

„ 489. ICE-HOUSE, ninth line, for •* Fig. 964," read **F\(g. 985." 

„ 519. Insert the initials E. S. at the end of Indigo. 

,, 70a LEUCOLINE, for " a compound, ftc," read " a synonym of LEUKOL." 





DAG0ERREOTTPE. A photographic process discoyered by M. Dagaerre, a 
celebrated French dioramic painter, and published in July, 1839 ; the French 
Government having secured a pension for life of 6000 francs on M. Dagaerre, and of 
4000 francs on M. Isidore Niepoe, the son of M. Nicephore Niepce, who had for 
some time been associated with Daguerre in carrying forward the experiments which 
led to M. Dagaerre*s discoyery. 

It is rendered clear fh>m some of Niepoe's letters, that he had abandoned all hope 
of succeeding with iodine, upon which the sensibility of the Daguerreotype plate 
entirely depends. In a letter to Dagnerre, Niepce says, ** I repeat it, sir, I do not see 
that we can hope to derive any advantage fh>m this process — the use of iodine — more 
than from any other method which depends on the use of metallic oxides i " and in 
another he writes, ** A decoction of thiaspi (shepherd's purse), fumes of phosphorus, 
and particularly of sulphur, as acting on silver in the same way as iodine, and caloric, 
produce the same effect by oxidising the metal, for from this cause proceeded in 
all these instances their extreme nMibility to light," Niepce died in July, 1833. 
Dagnerre proceeded with his experiments for nearly six years, before he succeeded 
in producing the desired results. The Daguerreotype process depends on the pro- 
duction of a very delicate chemical compound of iodine and silver, on the surface of 
a carefully preptured silver-plate. This compound is chemically changed by the ra- 
diations proceeding from any external object illuminated by the sun. The image is 
developed by the action of mercurial vapour, and lasUy rendered permanent, as fiir 
as the action of light is concerned, by dissolving off the iodide of silver, by hyposul- 
phite of soda. According to the first published description by l^guerre, the process 
is divided into five-operations. The first consists in polishing and cleaning the silver 
snrfiice^ by friction, with cotton fleece imbued with olive oil, upon the plate previously 
dusted over with very finely-ground dry piunicestone out of a muslin bag. The hand 
of the operator should be moved round in circles of various dimensions. The plates 
should be laid upon a sheet of paper solidly supported. The pumice must be ground 
to an impalpable powder upon a porphyry slab with water, and then dried. The surface 
is next to be rubbed with a dossil of cotton, slightly moistened with nitric acid, diluted 
with sixteen parts of water, by applying the tuft to the mouth of the phial of acid, 
and inverting it for a moment. Two or three such dossils should be used in suc- 
cession. The plate is lastly to be sprinkled with pumice powder or Venetian tripoli, 
and rubbed clean with cotton. 

The plate is then placed in a wire fWime, with the silver sur&ce uppermost, over a 
spirit lamp, meanwhile moving it so as to act equally on every part of the plate. In 
about five minutes a whitish coating will indicate that this operation is completed. 
The plate must now be laid upon a flat metal or marble slab to cool it quickly. The 
white surface is to be brightened by rubbing it with cotton and pumice powder. It 
must be once more nibbed with the cotton imbued with acid, and afterwards dried by 
friction with cotton and pumice ; avoiding to touch the plate with the fingers, or with the 
part of the cotton held in them, or to breathe upon the plate, since spots would thereby 

Vol. IL B 


be produced. After cleaning with cotton alone, the plate is ready for the next 

The second stage is that of iodising the plate ; a box is prepared, having iodine 
strewed over its bottom, and the silver plate, face downwards, is placed a few inches 
above the iodine, and the lid of the box being closed, all is left at rest for a short 
time. The plate most be left in this position till the surface of the silver acquires a 
fine golden hue, caused by the vapours of the iodine rising and condensing upon it ; 
but it should not be allowed to assume a violet tint The room should be darkened, 
and no heat should be employed. When the box is in constant use it gets impreg- 
nated with iodine, and acts more uniformly and rapidly ; but in general states of the 
atmospheric temperature this operation will be effected in about twenty minutes. If 
the purple colour be produced, the plate must be repolished, and the whole process 

The plate with its golden hue is to be introduced with its ftvne to the camera 
obscura. During this transfer the light must not be suffered to strike upon the 
surface of the plate ; on which account, the camera obscura may be lighted briefly 
with a small wax taper. 

The plate is now submitted to the third operation, that of the camera obscura, and 
with the least possible delay. The action of this machine is obviously quicker the 
brighter the light which acts upon it ; and more correct, according as the focus is 
previously accurately adjusted to the place of the plate, by moving backwards and 
forwards a roughened pane of glass, till the focal point be found ; and the plate is to 
be inserted precisely there. This apparatus exactly replaces the ground glass. While 
the prepared plate is being fastened, the camera must be closed. The plate is now in 
a proper position to receive and retain the impression of the image of the objects 
presented the moment that the camera is opened. Experience alone can teach the 
proper length of time for submitting the plate to the concentrated rays of light ; be- 
cause that time varies with the climate, the seasons, and the time of day. More time 
should not be allowed to pass than what is necessary for fixing a distinct impression, 
because the parts meant to be clear would be apt to become clouded. The impression 
of the image of nature is now actually made upon the plate ; but it is as yet invisible; 
and it is only after a lapse of several minutes, during which it is exposed to mereorial 
vapour, that faint tracings of the objects begin to be seen. 

The fourth is the operation with quicksilver, which must follow as soon as possible 
the completion of the third. Here a phial of quicksilver, a spirit lamp, and a glass 
funnel with a long neck, are required. The funnel is used for pouring the mercury 
into a cup, placed in the bottom of an apparatus which will allow of uie application 
of heat. No daylight must be admitted to the mercury box, a small taper only being 
used to examine, from time to time, the effects. The plate with the dormant image 
is placed some distance above the mercury, which vaporising, evokes in a truly 
magical manner, the delicate lines which the solar pencil has traced. 

After each operation, the interior of the apparatus, and the black board or fVame 
should be carefully wiped, in order to remove every particle of mercury. The 
picture may now be inspected in a feeble light, to see how far the process has suc- 
ceeded. The plate, freed ftx>m the metallic bands, is to be placed in a box, provided 
with a cover and grooves, to exclude the light, till it is made to undergo the last 
operation. For the fifth and last operation the following articles are now required : — 
strong brine, or a weak solution of hyposulphite of soda ; two troughs of tin plate, and 
a jug of distilled water. The object of this process is to fix the photographic picture. 
One of the troughs is to bo filled with brine to the depth of an inch, and the other 
with pure water, both liquids being heated somewhat under the boiling point The 
solution of hyposulphite of soda is preferable, and does not need to be warm. The 
plate is to be first immersed in the pure water for a moment and transferred imme- 
diately to the saline solution, and moved to and fro in it to equalise the action of the 
liquor. Whenever the yellow tint of the iodine is removed, the plate is to be lifted 
out by the edges, and dipped straightway in the water-trough. The plate, when 
lifted out of the water-trough, is to be placed immediately on an inclined plane : and 
without allowing it time to dry, is to be fioated over with the hot distilled water fW>m 
the top, so as to carry off all the saline matter. As the quicksilver which traces the 
images will not bear touching, the silvered plate should be secured by a cover of glass, 
made tight at the edges by pasting paper round them. 

The Daguerreotype process as thus published, although even then an exceedingly 
beautiful process, was not sufficiently sensitive to enable the operator to obtain 
portraits from the life. A period of twenty minutes was required even with the 
most favourable light to produce the desired effect Numerous modifications were 
speedily introduced, and many of them were patented. 

The progressive advance of this branch of the photographic art, though of great 


intemt, oaoot be direlt on id Ihii place. Thove irfao we intnoted in tlie inquiry, 
■rill find the information folly detailed in Hunt'i Manual of Photography, 31b Edition, 
1857. It will be anSeieat in this work to detail cbe more important improvemenu 
which bare become generally adopted. The SrtI Advance of real importance wu 
made bj Hr. Towaon, of Devonport, «ho hai aince that time diltiDguuhed himaelf 
by the inlrodnction of bia ijium of Great Circle Sailinff. Hr. Towaon anggeited the 
lue of enlarged leniea, and by acting with luch. Dr. Draper, of New York, wai the 
fint to procare a portrait from the life. Still thii was a tedioui proceai, but in IS40, 
Mr. Goddard propowd the nae of bromide of iodine, by which infiuilelj iocreased 
s:;iiaibilily waa obtained. ?rom that time the Daguerreotype waa generally employed 
fbr portraitnre, nntil the Ikcilitiea of the collodion procea droTe it from Che field. 

The imprOTed manipnlalion'now reaoliei ilcelf into 

Carefnllj poliibing the ailrer plate after tome of the methods previotuly deicribed, 
and the application finally of the hi^eat polish by the nie of a buffer, the beat form 
being that employed hj H. Claadet. 

In a box od a roller, to which (here it a haiidle,j!^ eSS, is placed a long piece of 

drab-colonred Telvet, which can be drawn ont and extended by meant of a tecotkd 
roller upon a perfectly flat table. The first foot or two, for example, it drawn oat i 
the plate which hai already receivtd its preliminary polishing ii placed face down- 
wards, and being pressed close with the Bngen, a npid circular molion it given to it, 
and in a few minnles it receives its highest lustre. As Ihr Telvet becomes blackened 
by use, it is rolled tsS, the portion remaining in the box being always perfectly clean 
nnd ready for use. 

The iodtnng process follows : and for this parpote a box dmllar K 
will be (bond to be very aon*enient, (Jig. 639). g^ 

This iodisiDg apparatus consitit of a square box 
with a closely fltling coTer o, &lse sides are 
placed at an angle with Ibis box. a enp u at the 
bottom conluDs the iodine, which it eOTered 

thin game scteeo 

wbich confines the iodine when it is not required 
for the plate; this diriding the box into two 
parta, n B, and k k. the former being always full 
of iodine Taponr. When it is desired (o iodise 
a plate, the cover c is removed, the silver plate 
it placed at E, and the cover a closed. 

The plate ia thus placed in the iodine box 
ontjl it acquires a fine straw yellow colour. In 
another box it placed either bromine or some 
one of the many accelerating fluids. If bro- 
mine, or any bromide ia employed, tho plate 
sbDold remain until il becomes of a rote colour. 
As a general rule, if tbe yellow colour produced 
by iodine be pole, the red should be pale also ; if deep, the red mntt incline to violet- 
The proper lime for exposing a plate to any of those chemical lubalauGet which are 
destined to practice the sensitive film, must vary with the temperature, and it can 
ouly be determined by experience. The sensitive plate is now removed to the 
camera obacnra, for a description of which see Photoobapbt. It is scarcely neeet- 
sary to tay, thai the plate must be preserved in perfect darkness oulil exposed to 
the image in the camera. A few seconds when the plate is properly prepared will 
be found amply tnfficient to produce the best effect. 

The impression must be developed in the mercury box (,fig. MO) in the manner 
described by Dagnerre. This mercurial box consists of a box mounted on legi, 
having a close fitting cover a, and an iron bottom in which i« placed the mercnry c. 


and a small thennometer f tx> indicate the proper temperature, g is a piece of glass 

g^Q let into Uie side of the box through which the 

Daguerreotype plate h fixed in the frame b can 
be seen, d is a spirit-lamp, and i the platform 
on which it stands. The subject is eventually 
fixed by the ose of hyposulphite of soda, which 
removes the bromo-iodidc of silver and leaves 
a picture produced by the contrast between 
a combination of the silver and mercury, and 
the surface of the unchanged polished silver. 

The application of chloride of gold to the 
finished pictare was introduced by M. Fixeao. 
Chloride of gold applied to the picture has 
the e£Pect of fixing and enlivening the tints. A 
small grate being fibced by a clamp to the edge 
of a table, the plate is laid upon it with the image 
uppermost, and overspread evenly with solution 
of chloride of gold, by means of a fine broad 
camel hair brush, without letting any drop over 
the edge. A spirit lamp is now brought under 
the plate, and moved to and fro till a number 
of small steam bubbles appear upon the image. 
The spirit lamp must be immediately withdrawn. 
The remainder of the chloride solution must be 
poured back into the phial , to be used on another 
occasion. It is lastly to be washed and exa* 
mined. This operation has been repeated three 
or four times with the happiest effect of giving 
fixity and force to the picture. It may then 
be wiped with cotton without injury. The process of colourmg these pictures is a 
purely artificial one, which, while it destroys the beauty of the photograph, does not 
m any way improve it as a picture. 

Daauerreotype Engraving. — Several processes for etching the Daguerreotjrpe plate 
were introduced with more or less success. Professor Grove produced a few good 
engravings by the action of voltaic electricity. Berard and Becquerel were also 
enabled to produce some promising results by a similar process. The following 
process by M. Claudet was carried out to some extent with every prospect of success. 
The new art, patented by M. A. F. J. Claudet on the 21st November, 1843, was 
established on the following facts. A mixed acid, consisting of water, nitric acid* 
nitrate of potash, and common salt in certain proportions, being poured upon a Da- 
guerreotype pictare, attacks the pure silver, forming a chloride of that metal, but does 
not affect the white parts, which are produced by the mercury of the picture. This 
action does not last long. Water of ammonia, containing a little chloride of silver 
in solution, dissolves the rest of that chloride, which is then washed away, leaving 
the naked metal to be again attacked, especially with the aid of heat The metallic 
surface should have been perfectly purified by means of alcohol and caustic potass. 
For the rest of the ingenious but complex details, see Newton's Journal^ C. S. vol. xxy. 
p. 112. — Sec Actinism, Collodion, Photography. 

DAHLINE, the same as Inuline. The fecula obtained firom elecampane, ana- 
logons in many respects to starch. It has not been employed in the arts. 

IdAMAR gum, or DAMMARA RESIN. A pale yellow resin, somewhat resem- 
bling cupal, and used like it in the manufacture of varnishes. Dammara resin is 
said to be derived from the Pinus dammara alba of India. A Dammara resin is also 
imported fi*om New Zealand, which is the product of the Dammara Australu. Under 
the name of Cowdie resin it is said to be used extensively as a varnish in America. 
** Damar is easily dissolved in oil of turpentine, and when careAilly selected is almost 
colourless ; it makes a softer varnish than mastic ; the two combined, however, form 
an almost colourless varnish, moderately hard and flexible, and well suited for maps 
and similar purposes." — Holtzapffd, ^ 

DAMASCUS BLADES, are swords or scymitars, presenting upon their surface a 
variegated appearance of watering^ as white, silvery, or black veins, in fine lines, or 
fillets ; fibroQS, crossed, interlaced, or parallel, &c. They are brought fh)m the East, 
being fabricated chiefly at Damascus, whence their name. Their excellent quality- 
has become proverbial ; for which reason these blades are much sought after by mi- 
litary men, and are high priced. The oriental processes have never been satisfactorily 
described ; but of late years methods have been devised in Europe to imitate the fabric 
very well. 


Clonet and Hachette pointed oat the three following processes for producing Da- 
mascus blades : 1, that of paraUel JUleta; 2, that by torMion; 3, the motaic. The 
£ret, which is stiil pursued by some French cutlers, consists in scooping out with a 
graving tool the finoes of a piece of stuff composed of Uiin plates of different kinds of 
steeL These hollows are by a subsequent operation filled up, and brought to a level 
with the external fiuses, upon which they subsequently form tress* like figures. 2. The 
method of torsion, which is more generally employed at present, consists in forming 
a bundle of rods or slips of steel, which are welded together into a well- wrought bar, 
twisted sereral times round its axis. It is repeatedly forged, and twisted alternately ; 
after which it is slit in the line of its axis, and the two halves are welded with thdr 
outsides in contact ; by which means their faces will exhibit rery various configura- 
tions. S. The mosaic method consists in preparing a bar, as by the torsion plan, and 
cutting this bar into short pieces of nearly equal length, with which a &ggot is formed 
and welded together ; taking care to preserve the sections of each piece at the surfiice 
<jf the blade. In this way, all the variety of the design is displayed, corresponding to 
each finagmeut of the cut bar. 

The blades of Clouet, independently of their excellent quality, their flexibility, and 
extreme elasticity, have this advantage over the oriental blades, that they exhibit in 
the Tery substance of the metal, designs, letters, inscriptions, and, generally spetJiing, 
all kinds of figures which had been delineated beforehand. 

Notwithstanding these successful results of Clouet, it was pretty clear that the 
watered designs of the true Damascus scymitar were essentially different M. Bryant 
has attempt^ a solution of this problem. He supposes that the substance of the 
oriental blades is a cast steel more highly charged with carbon than our European 
steel, and in which, by means of a cooling suitably conducted, a crystallisation takes 
place of tsfb distinct combinations of carbon and iron. This separation is, he thinks, 
the essential condition ; for if the melted steel be suddenly cooled in a^mall crucible 
or ingot, there is no damascene appearance. 

If an excess of carbon be mixed with iron, the whole of the metal will be converted 
into steel ; and the residuary carbon will combine in anew proportion with a portion 
of the steel so formed. There will be two distinct compounds ; namely, pure steel, 
and carbnretted steel or cast'iron. These at first being imperfectly mixed, will tend 
to separate if while still fluid they be left in a state of repose ; and form a crystalli- 
sation in which the particles of the two compounds will place themselves in the cru- 
etble in an order determined by their affinity and density conjoined. If a blade 
forged out of steel so prepared be immersed in acidulous water, it will display a very 
distinct Damascus appearance ; the portions of pure steel becoming black, and those of 
carburetted steel remaining white, because the acids with difficulty disengage its carbon. 
The slower such a compound is cooled* the larger the Damascus veins will be. Ta- 
Temier relates that the steel crucible ingots, like those of wootz, for making the true 
oriental Damascus, come from GolcondiE^ that they are the size of a halfpenny roll, and 
. when cut in two, fbrm two swords. 

Steel combined with manganese displays the Damascus appearance very strongly. 

A mixture of 100 parts of soft iron, and 2 of lamp black, melts as readily as ordinary 
SteeL Several of the best blades which M. Bryant presented to the Society d'Encour- 
agement are the product of this combination. This is an easy way of making cast- 
steel without previous cementation of the iron. 100 parts of filings of very grey cast- 
iron, and 100 parts of like filings previously oxidised, produced, by their fusion to- 
l^ether, a beautiful damascene steel, fit for forging into white arms, sabres, swords, &c. 
This compound is remarkable for its elasticity, an essential quality, not possessed by 
the old Indian steeL The greater the proportion of the oxidised cast-iron the 
tougher is the steel. Care should be taken to stir the materials during their fusion, 
before it is allowed to cr.ol ; otherwise they will not afford a homogeneous damasc. 
If the steel contains much carbon it is difficult to forge, and cannot be drawn out ex- 
cept within a narrow range of temperature. When heated to a red- white it crumbles 
itnder the hammer; at a cherry-red it becomes hard and brittle; and as it progres- 
sively cools it becomes still more unmalleable. It resembles completely Indian steel, 
which European blacksmiths cannot forge, because they are ignorant of the suitable 
temperature for working it M. Breant, by studying this point, succeeded in forging 
fine blades. 

Experience has proved that the orbicular veins, called by the workmen knots or 
ikonu (r<mce$\ which are seen upon the finest Eastern scymitars, are the result of the 
jnanner of forging them, as well as the method of twisting the Damascus bars. If 
these be drawn in length, the veins will be longitudinal ; if they be spread equally in 
all directions, the stuff will have a crystalline aspect ; if they be made wavy in the 
two directions, undulated veins will be produced like those in the oriental Da- 



The cliaTacteristics ascribed to the real Damascus blades are extraordinary keenness 
of edge, great flexibility of substance, a singular grain of fleckiness always observable 
on tbe surface, and a peculiar musky odour given out by any friction of the blade» 
either by bending or otherwise. The author of ** Manufactures in Metals,*' remarks: 

^ A gentleman who purchased one of these blades in the East Indies for a thousand 
piastres, remarked to the writer of this volume that, although the instrument was 
very flexible, and bore a very keen edge, it could not with safety be bent to more 
than 45^ from the straight shape, and it was not nearly so sharp as a razor, yet, 
wielded by a skilful hand it would cut through a thick roll of saiUcloth without any- 
apparent difficulty ; a feat which could not be performed with an ordinary sword, nor, 
it should be observed, by the sabre itself in an ordinary hand, though the swordsman 
who tried it could, it appears, do nearly the same thing with a good European 

Emerson, in his letters from the ^gean, says : ^ I have seen some blades (scy- 
mitars) which were valued at 200 or 300 dollars ; many are said to be worth triple that 
sum, and all retain the name of Damascus^ though it is by no means likely that they 
have been manufactured there. The twisting and interwisting of the fibres of the 
metal are considered as the tests of excellence, but I have never seen any possessed 
of the perfume said to be incorporated with the steel in the real Damascus blade." 

The production and use of damask steel has received much attention from the 
late General Anossoff, of the Corps of Engineers of the Imperial Russian army, and 
Master of the Fabric of Arms at Zlataonst, in Siberia. His researches and suec^sful 
practice have become matters of history. 

Steel helmets and cuirasses were formed of cast and damascened steel, intermixed 
with pure iron, a mixture supposed to combine toughness and hardness in greatest 
possible degree. 

At different periods these works have been visited, separately, by two English 
travellers. Major Abbott of the Bengal Artillery, and Mr. Atkinson, who have 
recorded the results of observation^ experiment, and conversational intercourse, and 
they state severally their conviction that the damask steel produced by Anossoff 
rivalled in beauty and excellence any works they had ever seen in other landa They 
accord to Ano6so£P the honour of being the reviver of the art of making damask steel 
in Europe, while they declare the Russian natural damask steel is not approached by 
the fabrics of any Eastern nation now existing. 

The Siberian swords and daggers were compared and tried with the choicest spe- 
cimens, and found equal to the blades of Damascus, and the sabres of Khorassan; 
and while these valued articles might have been selected from numbers manufactured 
by chances of skill and material, Anossoff united chemical analyses of ores and steel, 
and records of observations on progressive stages, to give a true history of the means 
to explain and insure success. See Sword MANUFAcruaiL 


DAMASK is a variegated textile fabric, richly ornamented with figures of flowera^ 
fruits, landscapes, animals, &C., woven in the loom, and is by far the most rich, elegant, 
and expensive species of ornamental weaving, tapestry alone excepted. The name is 
said to be derived from Damascus, where it was anciently made. 

Damask belongs to that species of texture which is distinguished by practical men 
Jby the name of tweeling, of which it is the richest pattern. The tweel of damask is 
usually half that of full satin, and consequently consists of eight leaves moved either 
in regular succession or by regular intervals, ei^ht leaves being the smallest number 
which will admit of alternate tweeling at equal mtervals. 

The generic difference of tweeling, when compared with common cloth, consists in 
the intersections, although uniform and equidistant, being at determinate intervals, and 
not between the alternate threads. Hence we have specimens of tweeled cloth, where 
the intersections take place at the third, fourth, fifth, sixth, seventh, eighth, or six- 
teenth interval only. The threads thus deflecting only from a straight line at inter- 
vals, preserve more of their original direction, and a much greater quantity of ma* 
terials can be combined in an equal space, than in the alternate intersection, where 
tbe tortuous deflection, at every interval, keeps them more asunder. On this principle 
tweeled cloths of three and four leaves are woven for facility of combination alone. 
The coarser species of ornamented cloths, known by the names of domock and diaper, 
usually intersect at the fifth, or half satin interval. The sixth and seventh are rarely 
used, and the intersection at the eighth is distinguished by the name of satin in 
common, and of damask in ornamental tweeling. It will further be very obvious^ 
that where the warp and woof cross only at every eighth interval, the two sides of the 
cloth will present a diversity of appearance ; for on one side the longitudinal or warp 
threads will run parallel from one end of a web to the other, and, on the other, the 
threads of woof will run also parallel, but in a transverse direction across the doth. 


or at rigbt angles to the former. The points of intersection being onlj at erery 
eighth interval, appear only like points ; and in regular tweeling these form the ap- 
pearance of diagonal lines, inclined at an angle of 45^ (or nearly so) to each of the 

The appearance, therefore, of a piece of common tweeled cloth is very similar to that 
of two thin boards glued together, with the grain of the upper piece at right angles 
to that of the under one. That of an ornamental piece of damask may, in the same 
manner, be rery properly assimilated to a piece of veneering, where all the wood is of 
the same substance and colour, and where the figures assume a diversity of appearance 
from the ground, merely by the grain of the one being disposed perpendicularly to that 
of the other. 

From this statement of the principle, it results that the most unlimited variety of 
figures will be produced, by constructing a loom by which every individual thread of 
warp may be placed either above or below the woof at every intersection ; and to effect 
this, in boundless variety, is the olject of the Jaequard mounting. See Loon, Jao- 

The chief seat of this manufacture is the town and neighbourhood of Dunferm- 
line, in Fifeshire, — and Lisbum and Ardoyne, near Belfast, where it is considered 
as the staple, having proved a very profitable branch of tridfic to the manufacturer, 
and giren employment to many industrious people. 

The material used there is chiefly linen ; but many haye been recently woven of 
cotton, since the introduction of that article into the manufacture of cloth has become 
so prevalenL The cotton damasks are considerably cheaper than those of linen, but 
are not considered either so elegant or durable. The cotton, also, unless frequently 
bleached, does not preserve the purity of the white colour nearly so well as the linen. 

DAMASKEENING.; the art of ornamenting iron, steel, &c., by making incisions 
npon its surftce, and filling them up with gold or silver wire ; it is chiefly used in en- 
chasing sword blades, gnsjrds, and gripes, locks of pistols, &c 

Its name shows the place oif its origin, or, at least, the place where it has been prac- 
tised in the greatest perfection, vis. Uie city of Damascus, in Syria ; though M. Fell* 
bien attributes the perfection of the art to his countryman, Cursinet, who wrought 
under the reign of Henry IV. 

Damaskeening is partly mosaic work, partly engraving, and partly carving. As 
mosaic work, it consists of pieces inlaid ; as engravmg, the metal is indented, or cut 
in intaglio; and as carving, gold and silver are wrought into it in relievo. 

There are two ways of damaskeening ; in the first, which is the most beautiful, the 
artists cut into the metal with a graver, and other tools proper for engraving upon 
ateel, and afterwards fill up the iocisions, or notches, with a pretty thick silver or 
gold wire. In the other, which is only superficial, tbey content themselves to make 
hatches, or strokes across the iron, &c., with a cutting knife, such as is used in making 
small files. Atf to the first, it is necessary for the gravings or incisions to be made in 
dove-tail form, that the gold or silver wire, which is thrust forcibly into them, may 
Adhere the m<M« strongly. As to the second, which is the more usual, the method is 
this : having heated the steel till it changes to a violet, or blue colour, they hatch it 
over and across with a knife, then draw &e ensign or ornament intended upon this 
liafAhing with a fine brass point or bodkin. This done, they take fine gold wire, and 
eoodncting or chasing it according to the figures already designed, they sink it care- 
fully into the hatches of the metal with a copper tooL 

An inferior description of damaskeen work has been introduced since the discovery 
Off the electrotype processes. The pattern has been etched on the steel, and then 
gold or silver deposited into the etched lines. 

DAHASSIN. A kind of damask, with gold and silver flowers woven in the warp 
and woot, or occasionally with silk organsine. 

DAMP, til mining are dangerous exhalations, or rather gases, — so called from the 
German dampf, vapour ^escaping from the mineral formations, or accumulating in 
the workings. 

Ftre-Vanq), which occurs in coal mines, is carburetied hydrogen gae* 

Ckoke-Dangf}, After- Damp^ and Black Damp, may be regarded as Carbonic acid. 
See M1NE8, ventilation of , 

DAPHNINE. The bitter principle of the Daphne alpina. 

DASH WHEELS. These were revolving wheels having dash-boards, which are 
inoeh used in the washing processes necessary in calico printing. See Bi^achino. 

DATHOLITE. Borusilicate of lime, called also Esmarkite and Uumboldiite. It 
18 found at Arendal in Norway and in New Jersey. 

Its chemical composition is, silica 37 '30 ; boracic acid 21*32 ; lime 35*67 s water 571. 

DATURINE. See Atropine. 

DEAL WOOD. See Pimbs. 

B 4 


DECANTATION. (Eng. and Fr.$ Abguasen, Germ.) The act of poqrinif 
off the clear liquor from any sedimexit or deposit. It is mnch employed in theehemi- 
cal arts, and it is frequently effected by means of a siphon, there being less Hak of 
disturbing the precipitate. 

DECKLE, name giren by the paper maker to a thin frame of wood fitting on tlie 
shallow mould in which the paper pulp is placed. 

DECOCTION. (Eng. and Fr. ; Zeraetzung, Germ.) The process of boiling a liquid 
with some organic body, or the liquid compound resulting from the process of boiling. 
DECOMPOSITION. The separation of bodies from each other. The methods 
employed are almost inntimerable, and usually depend on the special reactions of the 
matters under examination. We shall consider a few of the most striking cases in 
both the grand divisions of the science, riz. inorganic and organic chemistry. In 
each instance we shall, for the sake of convenience, subdivide into the three classes of 
acids, alkalies, and neutral bodies. Prerions, however, to this, we must glance at 
some of the reactions of which chemists avail themselves in separating the elementa. 
The decomposition of ordinary metallic salts, with the view of making a qualitative 
analysis of a more or less complex mixture, is a problem, in general, of extreme 
simplicity, and directions for the purpose are to be found in all the numerous works 
on qualitative analysis. The principle on which the modem methods of qualitative 
analysis are founded, is the separation of the metals in the first place into large groups 
by certain reagents, and then by means of others, to subdivide into smaller groups, in 
which the individual metals can be determined by special (esti. For the sake of 
simplicity, we shall only consider the more commonly occurring metals. The general 
reagents, by which the first subdivision is effected, are hydrochloric acid, sulphuretted 
hydrogen, sulphide of ammonium, carbonate of ammonia mixed with chloride of 
ammonium, and finally phosphate of soda. The substance in solution is treated with 
hydrochloric acid, by which mercury, silver, and lead are removed. The mercury 
will only be perfectly removed if it exists entirely in the state of a subsalt. Lead is 
only partially precipitated, and will be subsequently found in the next group. The 
precipitate by hydrochloric acid is to be boiled with water, which will remove the 
chloride of lead, and leave the chlorides of mercury and silver. The hitter may be 
separated by means of ammonia, which will dissolve the chloride of silver and 
convert the mercury into a black powder, in which the metal can be detected by 
special tests. The fluid filtered from the precipitate by hydrochloric acid, is to have 
a stream of hydrosulphuric acid gas passed through it for a considerable time, or 
until no more precipitation occurs. By this means antimony, arsenic, tin, cadmium, 
gold, mercury, silver, lead, bismuth, and copper are thrown down, and must be 
separated from each other by special processes. The filtrate from the precipitate by 
hydrosulphuric acid is to have ammonia added in slight excess, and then a solution of 
sulphide of ammonium as long aa any precipitation takes place. By this means 
nickel, cobalt, iron,''manganese, zinc, alumina and chromium, are thrown down ; also 
baryta, strontia, and lime, if they happen to be in combination with pho^horic oxalic 
or boracic acids, or if united to fluorine. From the flltrate, carbonate of ammonia 
mixed with chloride of ammonium, precipitates baryta, strontia, and lime. The filtrate 
from the last precipitate can only contain magnesia, or the alkalies. The above brief 
description of the mode of dividing the metals into groups will be sufficient to give an 
idea of the processes employed for decomposing complex mixtures into simple. ones. 

Inorganic acids are usually removed from metals by converting the latter into an 
insoluble compound, while the acid remains in solution either m the free state or 
combined with a body of such a nature as not to mask the reactions of the acid with 
reagents. This is often done in the laboratory by boiling the metallic salt with an 
alkaline carbonate. The metals are, consequently, either converted into oxides or 
carbonates insoluble in water, while the acid unites with the alkali to form a soluble 
salt capable of being obtained by filtration in such a condition ns to permit the nature 
of the acid to be made known by means of appropriate tests. It is usually necessary 
to neutralise the solution carefully before testing for the acid. 

It is seldom necessary in researches to reduce inorganic alkalies to their elements, 
their constitution being usually ascertained by converting their constituents into 
new forms capable of being weighed or measured with accuracy. If, for instance^ 
it was necessary to ascertain the constitution of sulphuric acid, it would be sufficieot 
10 determine the quantity of baryta contained in the sulphate. On the other hand, 
acids susceptible of assuming, when pure, the gaseous condition may have their con- 
stitution determined by decomposing a known volume with a substance capable 
of combining with one ingredient and liberating the other in the gaseous states 
Thus hydrosulphuric acid may be analysed by heating it with potassium, which will 
remove the sulphur and liberate the hydrogen. 

In decomposing inorganic alkalies with the view of separating the metals contained 


in them, we osoally liave to aTail oonelves of rerj poverfnl affinities. This arises 
lirom the fact, that the substances in question are, generally, produced by the nnion 
of a metal with oxygen, the metal having so strong a tendency to combine with that 
element, that mere exposure to the air is sufficient to determine their union into a 
compound of great stability. In order, therefore, to decompose the alkalies of this 
class, it is necessary to find some substance having a powerful tendency to combine 
with oxygen under certain conditions. Mow it has been found that carbon, if raised 
to an exceedingly high temperature, and employed in great excess, is capable of 
remoTing the oxygen, even ftom such bodies as potassium and sodium, tbe affinity 
of which for oxygen is very great. 

Inorganic neutral bodies are generally decomposed either by the ordinary pro- 
cesses of analysis, or, where the neutrality arises ttom the substance under examina- 
tion being a compound of an acid and a base, by separating the two by treatment 
with a reagent capable of combining with one to the exclusion of the other. This is 
a process frequently available in quantitative analysis. As an illustration, we mar 
take the decomposition of the carbonates by a mineral acid in an apparatus whicn 
permits the carbonic acid set free to be accurately estimated by weighing. (See 
Cabbonates.) Another instance of the decomposition of a neutral body, by treating 
it with a substance capable of combining with one of the constituents and separating 
the other in a free state, is the decomposition of sulphate of potash by baryta. If a 
solution of the salt be boiled with excess of solution of baryta, sulphate of baryta is 
produced and caustic potash set free. The excess of baryta is removed by boiling in 
the air until the whole of the latter base is converted into the insoluble carbonate. 
A precisely analogous process is the ordinary mode of preparing caustic potash by 
boiling its carbonate with quicklime. 

Neutral bodies are frequently, howerer, so constituted, that the neutrality does not 
arise from the circumstance of an acid being saturated with a bsse, but from the 
energies of two elements being, to some extent, satisfied by the fiict of their being in 
combination. Thus, water is a neutral substance, nevertheless it may be decomposed 
by a variety of processes, several of which are susceptible of quantitative precision. 
In the first place, it may be decomposed by passing steam over a metal capable of 
uniting with its oxygen with liberation of the hydrogen. It may also be electrolysed 
and the two gases separately obtained. 

Organic or inorganic neutral salts may, at times, be very completely and simply 
decomposed by means of the battery. Not only are the various processes in electro- 
metallurgy founded on this principle, but it has even been practically applied to the 
qoantitative estimation of the metals in ores. The electrolysis of the neutral salt of 
the great series of organic acids of the general formula C^H^O' has thrown great 
light on some previously obscure points in the radical theory. 

The decompositions undergone by organic substances in contact with reagents are 
so manifold, that the limits of this work preclude the possibility of doing more than 
glancing at a few of the most general and interesting. Perhaps of all the modes of 
inducing the breaking up of more complex into simpler substances, the application of 
heat is the most remarkable for its power and the varied and opposite character of 
the substances produced. It has been shown that, as a decomposing agent, heat 
possesses no special function. From complex organic molecules all classes of sub- 
stances are formed. Individual substances belonging to every chemical type are, 
therefore, found among products of destructive distillation. Acids, alkalies, and 
neutral bodies of every kind are formed, and some of the most interesting and beauti- 
ful bodies known to chemists are found in the uninviting looking tar of coal. Let 
us illustrate this by a glance at a few of the coal-tar products. Among the acids are 
the oxyphenic, carbolic, and cresylic. The alkaloids represented are methylamine, 
ethylamine, propylamine, butylamine, amylamine, pyridine, picoline, lutidine, coUi- 
dine, parvoline, chinoline, lepidine, cryptidine and aniline. Among hydrocarbons, 
benzole, toluole, xylole, dumole, cymole, propyle, butyle, amyle, caproyle, caproylene 
cenanthylene, naphthaline, anthracene, chrysene, pyrene, &c. &c. This list, probably, 
does not include one half of the substances produced from coal by the decomposing 
and recomposing influence of heat 

Mineral acids exercise a powerful decomposing influence on organic substances. Of 
these the nitric and sulphuric are the most commonly used. Nitric acid is especially 
active, owing to its twofold action. By virtue of its oxidising tendencies, it breaks up 
great numbers of substances into more simple and less carburetted derivatives, and the 
byponitric acid produced by the removal of one of the atoms of the oxygen^ of the 
acid frequently enters into the resulting compound, a substitution product being the 
final result. In the latter bodies produced in this manner the byponitric acid (NO*) 
generally replaces hydrogen, the original type remaining unaltered. The production of 
oxalic acid from sugar ; succinic, lipic, adipic, pimelic, suberic, &C., acids firom oily 


and &ttj ttiatters hy the action of nitric acid, are examples of its oxidising power i 
while the formation of nitrobensole, and bodies of more or less analogous character, 
present instances of the replacement of hydrogen by hyponitric acid. 

Sulphuric acid owes its decomposing power to its extreme tendency to combine 
with water. Many of the less stable organic bodies are, by this means, absolutely 
broken up, so that the resulting products are of a character too indefinite to allow of 
the changes being expressed by an equation which shall jender a true account of all 
the substances directly or indirectly formed. On the other hand, the action may be 
so controlled by the careful regulation of the temperature and strength of the acid 
that products may be eliminated which are themselves totally broken up and destroyed 
by an acid of greater strength. The production of g^pe sugar by the action of sul- 
phuric acid on starch, or lignine, may be taken as an example. It not unfrequently 
happens, that the sulphuric acid unites with the substance acted on to form a conju- 
gated compound. Benzole, and many other hydrocarbons, as well as oxidised bodies, 
behare in this manner with concentrated sulphuric acid. 

Chlorine and the other halogens are powerful decomposing agents, acting chiefly 
by virtue of their affinity for hydrogen. The principal effects produced by them are 
oxidation and substitution. The oxidising action of the halogens arises from the 
decomposition of water ; the hydrogen combining with the chlorine, &C., to form an 
bydracid, and the free oxygen uniting with the other substances present 

The above sketch will sufficiently indicate some of the most usual methods by 
which the decomposition of organic and inorganic bodies is effected ; but hundreds 
of other decomposing agencies are at the call of the chemist, when any phenomena 
involving the disruptions of compounds are to be investigated. — C. 6. W. 

DECREPITATION (Eng. and Fr ; Verknistem, Germ.) is the crackling noise, 
attended with the flying asunder of their parts, made by several minerals and salts 
when heated. Sulphate of baryta, chloride of sodium, calcareous spar, nitrate of 
baryta, and several other bodies which contain no water, decrepitate most violently, 
separating at the natural joints of their crystalline structure. 

DEFECATION. (Eng. and Fr. ; Klaren, Germ.) The freeing from dregs or 

DEFLAGRATION. (Eng. and Fr.; Verpuffung, Germ.) A rapid combustion, 
attended with much evolution of flame and vapour. When metals are burnt by elec- 
tricity, they are said to undergo deflagration. 

DEFLAGRATOR. A galvanic instrument for producing a rapid and powerful 
combustion, introduced by Professor Hare. 

DE LAINES. Properly, fine worsted fabrics. They are indeed figured muslins, 
which should always be made of wool, but they are frequently made of mixed materiaL 

DELF. A coarse species of pottery originally manufactured at Delft in Holland, 
covered with a white enamel or glase. See Pottery. 

DELIQUESCENT. (Zer/liessen, Germ.) Any solid which absorbs moisture from 
the air spontaneously, and becomes soft or liquid; such as potash, and chloride of 

DELPHINI A. The poisonous principle of the Stavesacre. 

DEMY. Paper of a particular size is so called. Drawing demy is 15 inches by 20 ; 
printing demy is 17} inches by 22^. 

DENUDATION. {Denudo, to ky bare.) The carrying away by the action of run- 
ning water of the superficial solid materials of the land, by which the lower rocks are 
laid bare. 

DEODORISERS. Bodies which have the power of depriving fetid and offensive 
effluvia of their odours. There appears to exist a general idea that these substances 
are, all of them, equally disinfectants. No greater mistake can be made than to suppose 
that because a preparation has the power of removing a disagreeable smell, that there- 
fore it has removed all the elements of infection or disease. See Disinfectant. 

To disguise unpleasant odours, fumigation is employed, many of the fhtgrant gums 
are burnt, and fumigating pastiles employed* It is also a common practice to bum 
lavender and brown paper, but these merely overpower or disguise the smell ; they do 
not in any way act upon the noxious effluvia. See Pastiles. Fumigation. 

DEPHLEGMATION. The process by which liquids are deprived of their 
watery particles. It is applied chiefly to spirituous liquors, but is now obsolete, as 
involving the alchemistical notion of a peculiar principle called phlegm. 

DEPHLOGISTICATED, deprived of phloffiston, which was for a long period 
after the time of Stiihl regarded as the principle of levity and of combustion. It may 
be regarded as synonomous with oxygenated. ** Others believe that Earih and Phlo^ 
gition are those principles which are the constituent parts of all corporeal substances.** 

" It appears from all those experiments, that in each of them phtogUUm^ the simple 
inflammable principle, is present" '* Thus much I see from the above mentioned 



experiments ; that air is composed of two different fluids, the one of which attracts 
not the phlogUiotL, and the other has the quality of attracting it.** ~^ SehetU : Experi- 
wtenJtM <m Air and Fire. 

DEFILATORl£& Preparations for removing hair from the shin. These are 
aaid to hare hcen mnch used bj the ancients. In modem times they have been used 
as cosmetics to remove superflnous hair from the face. Lime and the tersulphoret of 
arsenic (Qrpiment) are the constitnents of most of the ancient and modern depilatories; 
but the use of orpiment is dangeroos, especially if there is any abrasion of the skin. 

The best and safest depilatory is said, in Uray's Supplement to the Pharmaeopttia^ 
edited bf Redwood, to be a strong solution of sulphuret (sulphide) of barium made into 
a paste with powdered starch. It should be applied to the hair immediately after it 
is mixed, and allowed to remain there for five or ten minutes. 


DERBYSHIRE SPAR. Fluor spar, or fluoride of calcium ; which see. 

DERRICK CRANEL The term Derrick is applied to a temporary crane, con« 
sisting of a spar supported by stays and guys, carrying a purchase fbr loading or un« 
loading goods on shipboard. The Derrick crane is somewhat similar in its plan, the 
projecting iron beam, or derrick, of which can be raised or lowered to any desired 

DESICCATION. The act of drybg. 

Davison and Symiagton patented a process for dryinjif or seasoning timber, by 
carrents of heated air. Even after wood has been dried m the ordinary manner, it 
eontains much moisture, which it is still necessary to remove. The patentees have 
given some carious results of this desiccating process: — 

Temperature of air 214^. 



Wright aftor 


Moioture removed. 

6 pieces small and thin 

2 pieces larger - - - - 

2 pieces larger - - - - 



8* per cent 
10*1 do. 
9-25 do. 


. 1 - •- ^ 












Oak - - - - 


6 hour*. 


90 hours. 

30 hour*. 

38 hour*. 








Red pine - - - 
























White woody lime tree. 






Part 1400, and 

part SI 80 
after 15 houn. 

94 houn. 

84 hours. 

84 hours.* 

Per cent. 








Ka 8 exposed to the atmosphere for three weeks, weighed at the end of that time 
17-8, or had taken in 4*2 per cent, of moisture. 

jPcaifter«.^Feather beds, mattresses, blankets, and clothing, are not only dried, but 
purified by this process. A feather bed of sixty pounds weight, will have no less than 
100,000 cubic feet of mt passed through it; and at the same time beaters are made use 
of, for the purpose of removing the dust Feathers treated in this manner have their 

• It will be obterted, on referring to the last column of lime, that the wood, 
chamber exposed to heated currents for 50 hours, weighed nothing less after 
( ir*atew). One application of the deslcoiting process for timber |s Io expoM It 
heated carrenU of air, and then, in Its heated sUte, Immersmg it suddenly In 
BBUscpdcs, creosote or coal-ur. The result U. that the alr-Tessels of the wood, 
conUfn ah- at so Terr high a temperature that a ?acuum Is InstanUy formed, and 
dbtely cbarged with the cold antiacpilc la which the wood Is fannMrsed. 

although kept in the 
the first 34 hours*. 

for some hour^ to the 
enjrof the i^iprOTed 

If not entirely empty, 
e?erj pore Is imne- 


balk and elasticity so much increased, that a second tick is found almost inTariably 
necessary to put the feathers into. 

A practical proof of the extreme powers of currents of dry heated air was giren in 
Syria, by exposing to them sixty suits of clothes, which had belonged to persons who 
died of the plague. These clothes were subjected to the process alluded to, at a tem- 
perature of about 240% and afterwards worn by sixty living persons, not one of whom. 
e'ver gave the slightest symptom of being in the slightest degree affected by the malady* 
{Whiskaw.) The purification of feathers by this process is carried out in many 
large establishments. Coffee it has been proposed to dry by currents of heated air, 
and subsequently to roast it by the same process. 

Thick card-board^ used for tea-trays and papier mache, is now frequently dried by- 
heated air. By the plan adopted at one establishment, previously to the introduction 
of Davison and Symington's method, it invariably occupied from eighteen to twenty 
hours to dry a room full of paper by a heating surface equal to 330 feet ; whereas by 
the new method, the same amount of work is accomplished in four hours, and with a 
heating surface of only 46 feet, or one seventh the area required by the fonner. 

SUk. — For the purpose of drying silk, it has been usual to heat the drying chambers 
by large cast-iron globular stoves, the heat obtained thus was equal to 120^ F., but 
excessively distressing to any stranger entering these apartments. 

In one arrangement 7000 cubic feet per minute are admitted at the above temper- 
iiture through small perforated iron plates, let into the stone floor. As many as 3000 
pieces of silk are sometimes suspended at one time ; and as each piece of silk, when 
wet contains about seven ounces of water, and as the operation of drying the whole 
occupies but one hour, it follows that about ISO gallons of water are evaporated in 
that time. 

Yarfu, — In Scotland and other places they now dry yams by modified applications 
of this process; and it is indeed extensively used in bleaching establishments, in 
calico-printing works, &c See Transactions of the Society of Arts for 1847-^. 

A DRYING HOUSE IS an apartment fitted up in a peculiar manner for drying calicoes, 
and other textile iabrics. Mr. South worth, of Sharpies, a Lancashire bleacher, obtained 
a patent in 1823, for the following ingenious arrangement, which has been since gene- 
rally adopted, with certain modifications, in most of our extensive bleaching and 
printing works. Fig, 641, is a section of the drying-house, where a is a furnace and 
boiler for the purpose of generating steam; it is furnished with a safety valve in the 
tube b, at top, and from this tube the steam main c passes down to the floor of the 
basement story. From this main, a series of steam-pipes, as </ (f, extends over the surface 
of the floor, and from them heat is intended to be diffused for the purpose of warming 
the drying-house. 

Along the middle of the building a strong beam of timber e e extends, and is 
supported by cast-iron pillars ; from this beam, to bearings on the side walls, a series 
of rails are carried in a cross direction, over which rails the wet cloth is to be hung iu 
fulds, and the steam or evaporation emitted in drying is allowed to escape through 
apertures or ventilators in the roof. 

The mode in which the cloth is delivered on to the rails, on either side of the beam 
will be best understood by reference to the delivering carriage, which is shown, with 
its rollers partly in section. 

The wet cloth is first to be coiled upon a roller, and then placed in the carriage, as 
aty) with its pivots bearing upon inclined planes. The carriage is to placed at the 
commencement of the rails, running upon the middle beam, and also upon the side- 
bearings or railways extending along the side walls of the building, parallel to and 
upon a level with the same beam. It is made to travel by means of an endless band 
passing over two riggers g and A, in fig^ 604, and over pulleys and a band- wheel 
attached to the carriage, as will be explained. The rigger ^, which moves this endless 
band, is actuated by bevel gear, seen at 5, which is put in motion by a pinion at the end 
of a revolving shaft leading from a steam engine. 

in the same^^., k h, is ^e endless band passing over a pulley under tbe band-wheel, 
and over the pulley n, by which it will be perceived that the traversing of the band, as 
described, would cause these pulleys and wheels to revolve. On the action of the band- 
wheel ffi, there is a drum against which the roll of wet cloth /presses, and as this drum 
revolves, the roll of wet cloth is, by its friction, made to turn in a contrary direction, 
and to deliver off the cloth on to the periphery of the drum, whence it passes over a 
roller and descends to the rails. Upon the end of the axle of the band wheel m, there 
is a pinion which takes into the teeth of the large wheel, and upon the axle of this 
large wheel there is a pinion that actuates the intermediate wheel which turns another 
toothed wheel. This last mentioned toothed wheel takes into cogs upon the side rail- 
way, and hence, as the train of wheels moves round, the carriage to which the wheels 
are attached is slowly impelled forward. 



Ai MOD u tfae wfaeeti ^gin to more, sod tbe oirUgt to idTance, the we( clo(k 
ttegint to ODiMil, and to pan down orer the flnt roller ; ■ imall roller attached to the 
carriage, ai it puKS orer the rail in SDCceiaioa, bolda the cloth againit each rail for a 
abort apace of time, and pre* enti it fR>m alippitig, by which meam the clotb deMenilt 
in foldi or loopa between the rail*, and i> thereby made to baog in a wrie* of Told* or 
loops u sfaowD in Ibe figure. 

It will be perceived (hat a* the piTOtl of tbe cloth roller/ bear upon inclined planei, 
the roller will coDtinnallj elide down a* tbe cloth dimiiii«het in bolh, keeping in con- 
tact with the dram, and delivering the cloth from the roller od to the MTeral nil*, m 

In order to atop the carriage in any part of it* coane, or to adjnitanjofthelbldiof 
the cloth, ■ man la naoally placed npon the platlbrm travelling with the carriage, over 
vhich he hai perftet command. Thii uparatni may be alio employed for taking tha 

clotb when dried off ihe railii in which cafethecarriagemuitbemade lo travel back- 
wards, and by fint goiding the end of Ibe cloth on to the roller/; and then pntling the 
wheels in a retrograde motion, the cloth will be progreMivel; coiled opon tbe roller/, 
in s aimilar way to that by which it was oncoiled. 

I>BViHO MxcTHiira (cEHTRiruo*!,). (HfdTO-exlraeleur ,■ Mnehim i tuonr, Fr.) 
By this coatrivance, PentsoldC wa* enabled to deprive all kinda of wet dotbes in a few 

minntei of their moiitnre, wilbont compreiiion or heat Kelly, ft dyer, and Aliiolt 
■ bleacher, have since obtained a patent far the above maobine with improvementi. 
Fig, 64S, represent* \ pariial section of the mMhinc. a, a, U the frnmei b, Um 


yerdcal shaft tarning in the step a, fixed on the bridge h. This shaft bears on its 
upper part a friction cone c, from which it receives its movement of rotation, as will 
be presently shown ; c is a dmm containing two concentric compartments d e, of the 
form represented in the figure ;* this drum moves ft-eely upon the shaft b, and rests 
when it is not in motion upon two conical projections /, g<, which form a part of the 
shaft. These two compartments are each composed mainly of metal, and their 
sides consist of tinned iron wire coiled circularly at very small distances from each 
other, and soldered together crosswise by small strips of metal. The top which 
covers the inner compartment d, is secured by bolts and screws to a circle of iron 
which retains the wire sides of ihe same metal, hot that which serves as a cover to 
the little compartment s, in which alone the goods are placed, is disposed so that it 
may be removed with ease, when these are to be introduced or withdrawn. It is 
furnished with an outer and inner border, disposed so that when the top is fixed the 
inner border presses upon the convex circumference of the central compartment, while 
the exterior border falls outside of the edges of the other compartment While the 
machine is at work, the second plate is maintained in its place by pins or bolts, not 
shown in the figure. 

The sides of the outer compartment d^ are connected with the bottom by means of a 
prolongation of cross bands of metal which unite the wires and are rireted or soldered 
to the two outer plates. The wires of the interior compartment are attached by an iron 
hoop, to which they are riveted and soldered, and are united to the bottom plate by 
means of a rim upon this plate; a rim somewhat flattened upon the sides which are 
riveted and soldered. 

D, is a regulator suspended in the inner compartment d, and whose two branches A, A, 
are loaded. These two branches having room to play around the bolts which serve as 
points of attachment, and which are fixed to the upper plate, terminate in kneed 
branches whose extremities rest upon a rope g, which projects ftom the shaft, e, is 
an exterior envelope scoured to the frame a, a. It encloses the whole drum except 
at top, and serves to catch the water thrown out of the gooda At y there is a stop 
cock for the discharge of this water, and the bottom contains besides the end of a pipe 
by which hot air is introduced. 

The vertical shaft b receives a movement of rotation and carries with it the dmm. 
The more rapid this movement is the more does the centrifUgal force tend to expel 
the water contained in the clothes or yam to be dried. But as this force might also 
displace the central shaft, if the weight was not rightly distributed in the drum, and 
cause the dislocation of the machine when the great velocitv requisite for quick 
drying is given to it, the regulator d is tested to prevent accident. The branches 
of this regulator spread wider the more the velocity is increased, and raise conse- 
quently the drum c above the conical enlargements, which permits the drum to be 
somewhat misplaced and to rectify its position conformably to the inequalities of its 
load, so that its centre of gravity may always coincide with its centre of rotation. The 
drum is connected with the shidft as is shown in z, leaving it tree to take the requisite 
acUustment. To hinder it ftom rising too suddenly, a spiral spring A is fixed over the 
shaft immediately above the conical enlargement g. In order to maintain the equi- 
librium more certainly, the apparatus is surrounded with a hollow crown f, half filled 
with water, and if during the revolution of the machine the weight of the goods pre- 
dominates on one side, that of the water which accnmulates on the other side serves the 
more to counterbalance it The effect of this crown may be increased by dividing it 
into two compartments or more, o, is a larse pipe by which steam or hot air is intro- 
duced into the belly of the dmm, which is pierced in this place with a great number of 
small holes to receive it 

The rotary movement is transmitted to the dmm in the following way. 

I, is a conical disc mounted upon the extremity of a shaft k' which actuates the cone c 
and the shaft b by means of ft-iction ; l* is a cone fixed upon the extremity of the shaft. 
k' l' ** is another cone of the same dimension, but whose base fronts the top of the other, 
and which is placed on the shaft k* " commanded by the prime mover. H is the belt 
which embraces the two cones, and whose lateral displacement, effected hj means of a 
fork, permits the velocity of the machine to be regulated at pleasure, n is the pulley 
which directly receives the movement In place of a single friction disc i, another 
may be employed, if judged necessary, and placed between the two, an additional 
friction pole, in order better to equalise the friction. In this case the disc and addi- 
tional cone should turn freely upon their own shafts. We may also adopt another 
arrangement for the bottom of the vertical shaft The shaft immediately above the 
step is surrounded by a loose rim, around which a certain quantity of lead shot, or 
other granular matter, is contained in the rim in the box which serves for the step. 
The top of this box is pierced with an opening, into which, when the machine 
is at rest, a cord connected with the shaft sinks, controlled by the shaft, and when 


tlie drom is raised by the action of the TC|^1ator i^ this cord quits its place, vhich allows 
the shaft to displace the shot a little, and to take a position confonnably to the point 
of the centre of graf ity. 

Bat after all great attention should be paid to the proper working of the machine. 
There are many other drying machines used, some of which are described in the 
articles deroted to special manufactures. 

DETONATION. See Fulmiiiating, for the mode of preparing detonating powder 
fiyr the percussion caps of fire-arms. 

DETRITUS ; d^ from, tera, to rub. Matter worn off rocks, and deposited in 

DEUTOXIDE, literally means the second oxide, but is nsaally employed to denote 
n compound containing two atoms or two prime equiyalents of oxygen to one or more 
of a mietaL Thus we say deutoxide of copper, and deuto^ide of mercury. Benelins 
abbreriated this expression by adopting the principles of the French nomenclature 
of 1787 ; according to which the higher stage of oxidisement is characterised by the 
termination tc, and the lower by tmi. It is now rarely employed. 

DEVIL. The name of a spiked mill, used in Yorkshire, for tearing wooUen rags into 
fragments for the manofiicture of Shoddt. 

DEVONSHIRE BATTS. A porous flne-grained sandstone from the quarries of 
Black Down Clifb, near Collumpton, in repute as a grindstone. 

DEVONSHIRE OIL-STONE. This stone occurs near Huel Friendship Mine^ 
about three miles from Tayistoek, in the Deyonian Slates of that district It has con- 
siderable local repute for sharpening all kinds of thin-edged broad instruments ; it 
has not, howeyer, become an article of conunerce. — Knight, Troaj. Society of Art*. 


DEXTRINE. Starch Gum. There are three modes of obtaining this from starch, 
▼iz., by torrefaction, by the action of dilute acids, and by the action of diasUue. The 
impure dextrine obtained by roasting is termed roaaUd ttarck, or kieomme. British 
gum is prepared by carefully roasting wheat starch, at a temperature of 800^ Fahr. 
Another method of preparing dextrine consists in moistening 1000 parts of potato 
starch with 300 parts of water, to which 2 parts of nitric acid haye been added. The 
mixture is allowed to dry spontaneously, and is afterwards heated for two or three 
hours in a stoye, at S12 Fahr. Dextrine in many of its characters resembles or- 
dinary gum, but it is distinguishable from it by its right'handed rotation of a ray of 
pUmt polariaed light, — hence its name dextrine, — and by its yielding oxalic acid, but 
not mucic acid, when heated with nitric acid. Its chemical formula is C^H'O'fHO. 

DI ACTINIC LEN& A name proposed to be giyen to the best construction of 
lens for the photographic camera obscora. It should be transparent to all the 
chemical rays, or rather, a lens which should unite the chemical and luminous foci 
in one point The name has not been generally adopted. 

DIALLAGE. Bronzite, Ifyperstene, and SchUlertpar are ofti>n confounded nnder 
this name. The name is deriyed from 9taXKctyn, difference, alluding to dissimilar 
cleayage. It is thin, foliated, and easilpr deayable ; lamina brittle ; colour, yarious 
shades of green, grey, and brown, sometimes bronxe and penriy metallic 

Of diallage rode fine examples will be found near the Lizard Point, and beautiful 
crystals of diallage are to be discoyered in the Serpentine rocks near Oadgwith, in 
the same locality. 

DIA MAGNETISM. As this term is becoming more generally used in our lan- 
guage, it appcan necessary to giye a definition of it, although it is not our purpose 
to enter on the consideration of any purely physical subject. 

The term was introduced by Dr. Faraday, to express those bodies which did not 
act as magnetic bodies do. If n and s represent the poles of a horse*8hoe magnet, 
any bar of a magnetic character, as iron, cobalt or nickel, hong up between them^ and 
free to moye, wUl by yirtue of the attracting and repelling polar forces, place itself 

643 i^ 

y !; y 
NO r ' -J OS 

along the line joining the two poles a b, which is called the magnetic axis. If instead 
of a bar of iron we suspend in the same manner a rod of glass, of bismuth, or of 
silyer, it will arran^ itself equatorially, or across the line a 6, as shown by the dotted 
line, c d. All bodies in nature appear to exist in one of those two conditions. The 
prefix dia is ased here in the same sense as in dia-meter. See De La Bive's EUo 
tricity, for a full explanation of all the diamagnetic phenomena. 
DIAMOND (^Diamant^ Fr. ; Diamanf, Germ.) Experiment has determined that 


this beantifol gem is a peculiar (aUotropic) condition of carbon. By burning the 
diamond in oxygen gas we produce carbonic acid ; and by enclosing the gem in a 
mass of iron, and subjecting it to a strong heat, the metal is converted into steel, when 
the diamond has disappeared. It has been shown that we can, by the agency of the 
heat of the voltaic arc, convert the diamond into excellent coke, and into graphite; bat 
although portions of coke are found to be sufficiently hard to cut glass, we have not 
yet succeeded in making diamonds fVom coke. Sir Humphry Davy noticed that the 
charcoal of one of the poles of Mr. Children's great voltaic battery was considerably 
hardened, and he regarded this as an advance towards the production of that gem. 
Recently some experiments made by a French philosopher have advanced the dis- 
covery another step : one of the poles of a voltaic battery being charcoal and the other 
of platinum, it was found that the fine charcoal escaping from the carbon pole and 
depositing itself on the plat^pum pole was sufficiently hard to be used in the place of 
diamond dust for polishing gems. The formation of the diamond in nature is one ot 
the problems which " our philosophy ** has not yet enabled us to solve. Time is an 
element which enters largely into nature's works ; she occupies a thousand, or even 
thousands of years to prcSluce a result, while man in his experiments is confined to 
a few days, or a few years at most 

Although diamonds have been occasionally found in various parts of the globe, there 
are only two places which can be strictly named as diamond districts, a portion of the 
Indian Peninsula and Braail. India has been celebrated from the most remote anti- 
quity as the country of diamonds. Its principal mines are in the kingdoms of Goloondsi 
and Visapour extending from Cape Comoriu to Bengal, at the foot of a chain of moun* 
tains called the Ortro, which appear to belong to the trap rock formation. In all the 
Indian diamond soils, these gems are so dispened that they are rarely found directly, 
even in searching the richest spots, because they are enveloped in an earthy crust, whi^ 
must be removed before they can be seen. The stony matter is therefore broken into 
pieces, and is then, as well as the looser earth, washed in basins scooped out for the 
purpose. The gravel thus washed is collected, spread out on a smooth piece of ground, 
and left to dry. The diamonds are now recognised by their sparkling in the sun, and 
are picked out from the stone. 

Diamonds are also said to come fVom the interior of the island of Borneo, on the banks 
of the river Succadan, and Arom the peninsula of Malacca. It is said the principal spots 
where diamonds are found are recognised by certain small flints, generally of a black 
colour, which lie upon the surface, and also by the yellow colour of the stony soil The 
ground is dug in the presence of an overseer : all stones above 5 carats, are claimed for 
the sovereign. Diamonds are found occasionally in the rivers, seldom however of any 

The diamond mines of Brazil were discovered in 1728, in the district of Serro-do- 
Frio. The ground in which they are imbedded has the most perfect resemblance to that 
of the East Indies where the diamonds occur. It is a solid or friable conglomerate, 
consisting chiefly of a ferruginous sand, which encloses fragments of various magnitude 
of yellow and bluish quartz, of schistose, jasper, and grains of gold disseminated with 
oligist iron ore, — all mineral matters different from those that constitute the neighbour- 
ing mountains ; this conglomerate, or species of pudding-stone, almost always superficial, 
occurs sometimes at a considerable height on the mountainous table-land. The most 
celebrated diamond mine is that of Mandarga, on the Jigitonhonha, in the district of 
Serro-do-Frio to the north of Rio -Janeiro. The river Jigitonhonha, three times bz^aader 
than the Seine at P{iri8, and from 3 to 9 feet deep, is made nearly dry^ by drawing the 
water off with sluices at a certain season ; and the cosco/Ao, or diamond gravel* is 
removed from the channel by various mechanical means, to be washed elsewhere at 
leisure. This cascalho, the same as the matrix of the gold mines, is collected in the 
dry season, to be searched into during the rainy ; for which purpose it is formed into 
little mounds of 15 or 16 tons weight each. The washing is carried on beneath an 
oblong shed, by means of a stream of water admitted in determinate quantities 
into boxes containing the cascalho. A negro washer is attached to each box ; in- 
spectors are placed at regular distances on elevated stools, and whenever a negro has 
found a diamond, he rises up and exhibits it. If it weighs 17^ carats, he receives 
his liberty. Many precautions are taken to prevent the negroes from secreting the 
diamonds. Each squad of workmen consists of 200 negroes, with a surgeon and an 
almoner or priest. 

The flat lands on either side of the river are equally rich in diamonds over their whole 
surfkce, so that It becomes very easy to estimate what a piece of groand not yet washed 
may produce. 

It is said that the diamonds surrounded by a greenish crust are of the Jirst water, 
or are the most limpid when cut The diamonds received in the different mines of the 
district, are deposited once a month in the treasury of Tejuco ; and the amount of what 


vas tlios delivered ftom 1801 to 1606, may be estimated at about 18 or 19 thoosand 
carats f)er ojuitan. 

On the banks of the torrent called Rio-Pardo, there is another mine of diamonds. 
The ground presents a great many friable rocks of padding-stone, distributed in invgu lar 
strata. It is chiefly in the bed of this stream that masses of cascalho occur, peculiarly 
rich in diamonds. They are much esteemed, particularly those of a greenish-blue colour. 
The ores that accompany the diamond at Rio-Pardo differ somewhat from those of the 
washing grounds of Mandanga, for they contain no pisiform iron ore ; but a great 
many pebbles of slaty jasper. This table land seems to be very high, probably not less 
than 5,500 feet above the level of the sea. 

Toeaya, a principal village of Minas* Novas, is 84 leagues to the north-east of Tej aeo, 
in an acute angle of the confluence of the Jigitonhonlui and the Rio-Grande. In the 
bed of the streamlets which fidl westward into the Jigitonhonha, those rolled white 
topaxes are found which are known under the name of minoff moras with blve iopazes^ and 
aquamarine beryls. In the same country are found the beautiful cymophanes or chry- 
soberyls so much prized in Brazil. And it is from the cantons of Indaia and Abaite 
that the largest diamonds of Brazil come ; yet they have not so pure a water as those 
of the district of Serro-do-Frio, but incline a little to the lemon yellow. 

It is known that numy minerals become phosphorescent b^ heat, or exposure to the 
tun's light Diamonds, it has been said on doubtful authority, possess this property, 
but all not in equal degree, and certain precautions must be observed to make it mani- 
fest Diamonds need to be exposed to the sunbeam for a certain time in order to 
become self-luminous ; or to the blue rays of the prismatic spectrum, which augment 
still more the faculty of shining in the dark. Diamonds susceptible of phosphorescence 
exhibit it either after a heat not raised to redness, or the electric discharge. Many 
minerals possess the power of becoming electrically phosphorescent, which do not 
appear to be affected by the solar rays. Diamonds possess not only a great refractive 
power in the mean ray of light, but a high dispersive agency, which enables them to 
throw out the most varied and yivid colours in multiplied directions. 

Diamonds take precedence of every gem for the purpose of dress and decoration \ 
and hence the price attached to those of a pure water increases in so rapid a proportion, 
that, beyond a certain term, there is no rule of commercial valuation. The largest 
diamond that is known seems to be that of the Rajah of Mattan in the East Indies. 
It is of the purest water, and weighs 867 carats, or, at the rate of 4 grains to a carat, 
upwards of 3 ounces tro^. It is shaped like an egg, with an indented hollow near 
the smaller end ; it was discovered at Landak about 100 years ago ; and though the 
possession of it has cost several wars, it remained in the Mattan family for 90 years. 
A governor of Batavia, after ascertaining the qualities of the gem, wished to be the 
purchaser, and offered 150,000 dollars for it, besides two war brigs with their guns and 
ammunition, together with a certain number of great guns, and a quantity of powder 
and shot Bat this diamond possessed such celebritv in India, being regarded as a 
talisman involving the fortunes of the Rijah and his family, that he refused to part with 
It at any price. 

The Mogul diamond passed into the possession of the ruling family of Kabul, as 
has been invariably affirmed by the members of that family, and by the jewellers 
of Delhi and Kabid. It has been by both parties identified with the great diamond 
DOW known under the name of the Kou-i-Noor, or iNoimtom of light, — which was 
displayed by its present proprietor, her Majesty the Queen, at the Great Exhibition 
in 1851. 

The diamond denominated the Koh-i-noor, or Mountain (koh) of Light (noor), 
has long enjoyed both Indian and European celebrity, and has accordingly been the 
subject of traditionary Ihble, as well as of historical record. 

According to Hindu legend, it was found in the mines of the south of India in the 
days of the Great War, the subject of the heroic poem, the Maha'bha'raia, and was 
worn by one of Uie warriors who was slain on that occasion, Kama, king of Anga: 
this would place it about 4000 years ago, or 2100 n. a A long interval next makes 
it the property of Yikramaditya, the raja of M(jayin, 56 b.c., fh>m whom it 
descended to his successors, the ngahs of Malwa, until the principality was subverted 
by Mohamedan conquerors, into whose hands it fell, with other spoils of infinite value. 

Whatever may be thought of the legend which gives so high an antiquity to the Koh- 
i-Noor, we might expect some more trustworthy information when we come down so 
low as the beginning of the fourteenth century ; Malwa having been invaded and 
overrun by the armies of Ala-ad-din, the sultan of Delhi, in 1306, who, according to 
the autobiography of the sultan Baber^ acquired the jewel. That it did become the 
property of the sultanas of Delhi is little doubtful, but when or bow is matter of some 
uncertainty, although the grounds of the difficulty have not hitherto been investigated. 

Vol. II. C 


In 1665 Mods. Jean Baptiste Tavernier, an enterprising and intelligept trareller, 
and an eminent jeweller, although Ecnyer, Baron d'Anbonne, yisited India especially 
to purchase diamonds. His profession and his personal character seem to have re- 
commended him to the favourable attention of the nobles of the court of Delhi, and 
bigot as he was, of Aurangseb himself, by whose commands Mons. Tavemier was 
permitted to inspect, handle, and weigh the jewels of the imperial cabinet. Amongst 
them was one which for surpassed all the rest in siae and value. Tavemier describes 
it as rose-cut, of the i^pe of an egg cut in two, of good water, and weighing 319^ 
ratis, which, he says, is equal to 280 of our carats. 

There is but little doubt that the diamond examined by TaTcmier in the Delhi 
Cabinet was the Koh-i-Noor. BabeT, the Mogul emperor, obtained a diamond, cor- 
responding exactly with this, and it paseed eventually into Uie possession of the ruling 
family of Kabul Nadir Shah, on his occapation of Delhi in 1 739, compelled Mohammed 
Shah, the great-grandson of Aurangseb, to give up to him everything of value that the 
imperial treasury possessed, and his biographer and secretary specifies a pahAask, or 
present, by Mohammed Shah to his conqueror of several magnificent diamonds. 
According to the funily and popular tradition Mohammed Shah wore the Koh-i-Noor 
in front of his turban at his interview with his conqueror, who insisted on exchanging 
turbans in proof of his regard. However this might have been, we need have little 
doubt that the great diamond of Aurangseb, was in the possession of Mohammed 
Shah at the time of the Persian invasion i and if it was, it most certainly changed 
masters, and became, as is universally asserted, the property of Nadir Shah, who is also 
said to have bestowed upon it the name of Koh-i* Noor. After his death, the diamond 
which he had wrested from the unfortunate representative of the house of Timur, became 
the property of Ahmed Shah, the founder of the Abdali dynasty of Kabul, having been 
given to him, or more probably taken by him, from Shahrikh, the young son of Nadir. 
The jewel descended to the successors of Ahmed Shah, and when Mr. Elphinstone was 
at Peshawur, was worn by Sh^ Shqja on his arm. When Shah Shiga was driven from 
Kabul, he became the nominal guest and actual prisoner of Runjet Sing, who spared 
neither importunity nor menace, until, in 1813, he compelled the fugitive monarch to 
resign the precious gem, presenting him on the occasion, it said, with a lakh and 
25,000 rupees, or alMut 12,000^ sterling. According to Shah Shiga's own aocoont, 
however, he assigned to him the revenues of three villages, not one rupee of which he 
ever realised. Rui^et was highly elated by the acquisition of the diamond, and wore 
it as an armlet at all great festivals. When he was dying, an attempt was made by 
persons about him to persuade him to make the diamond a present to Jagannnth, 
and it is said that he intimated assent by an inclination of his head. The treasurer, 
however, whose charge it was, refused to give it up without better warrant, and 
Runjet dying before a written order could be signed by him, the Koh-i- Noor was 
preserved for awhile for his successors. It was occasionsdly worn by Rhurreuk Sing 
and Shu Sing. After the murder of the latter, it remained in the Lahore treasury 
until the supercession of Dhulip Sing, and the annexation of the Puyaab by the 
British Government, when the civil authorities took possession of the Lahore treasury, 
under the stipulations previously made, that ail the property of the state should be 
confiscated to the East India Company, in part payment <^ the debt due by the Lahore 
government and of the expenses of the war ; it was at the same time stipulated that 
the Koh-i- Noor should be presented to the Queen of England. Such is the strange 
history of certainly one of the most extraordinary diamonds in the world. After the 
Company became possessed of the gem, it was taken in charge by Lord Dalhousie, 
and sent by him to England in custody of two officers.— fTant** Handbook of the Great 

As exhibited at the Crystal Palace in Hyde Park, the Koh-i-Noor weighed 186^^ 

The form of the Koh-i-Noor is given in fig. 644. P is a large plane at the base of 
the diamond which is a cleavage plane, f, also a large cleavage plane, produced by 
a fructure ; this had not been polished, and being inclined to Uie plane p at an angle 
of 109° 28', affords a satisfactory means for determining the diiection of the cleavage 
planes of the stone. ▲ shows a flaw running parallel to tiie cleavage plane f. This 
constituted the principal danger to be apprehended in cutting the stone, and was most 
skilfully ground nearly out before any of the fnceta were cut. This flaw seemed to 
proceed fh>m a fracture marked b. c and b were little notches cut in the stone for the 
purpose of holding the diamond in its original setting ; n a small flaw which slmost 
required a glass to see it, evidently parallel to the plane p ; d a fracture from a blow 
or fall, showing at its base a cleavage plane — Tennant 

This fine diamond did not possess that high degree of brilliancy which was expected 
from its great reputation; it was consequently submitted to Messrs. Garrard to be 
recut. In the operation the weight was reduced more than one-third, but its brilliancy 



greatly improred. The present state of the Koh-1-Noor k shown infy$. 645 and 
646. See DiAvomMTurrnra 


After this gem, the next are: — 1. That of the emperor of Russia, hoagfat by the 
late em press Oitharine, whteh weighs 199 earats. It is said to be of the siae of a 
pigeon's egg^ and to hare been bought for 90,000^, besides an annuity to the Greek 
merchant of 4,000/L It is reported that the aboTe diamond formed one of the eyes of 
the famons statne of Sherigan, in the temple of Brama, and that a French grenadier, 
who had deserted into the Malabar senriee, found the means of robbing the pagoda of 
tius preckms gem, and escaped with it to Madras, where he disposed of it to a ship 
captain for 2,0002., who resold it to a Jew for 12,0002^ From him it wae transferred 
lor a large sum to the Ored: merchant 2. That of the emperor of Austria, ^hich 
weighs 139 esrats, and has a slightly yellowish hue. It has, howerer, been valued at 
1 00,000c 3. That of the French State, called the Regent or Pitt diamond, remarkable 
for its form and its perfSect limpidity. Although it weighs only 136 carats, its fine- 
qualities hare cansed it to be rained at 160,000/., Oiongh it cost only 100,000/. 

The largest diamond furnished by Brazil, now in possession of the Crown of Portugal, 
wdghs, according to the highest estimates, 120 carats. It was found in the streamlet 
of Abaite, in a clay-slate district 

Diamonds poss^sed of no extraordinary magnitude, but of a good form and a 
pore water, may be Talned by a certain standard rule. In a brilliant, or rose- diamond 
of regular proportions so much is cut away that the weight of the polished gem does 
not exceed one-half the weight of the diamond in the rough state ; whence the ralue of 
a cut diamond is esteemed equal to that of a similar rough diamond of double weight 
exclusiTe of the cost of workmanship. Hie weight and yalue of diamonds is reckoned 
by carats of 4 grains each ; and the comparative value of tiiro diamonds of equal 
quality, but different weights, is as the squares of these iveights respectively. The aver- 
age price of rough diamonds that are worth working, is about 2/. for one of a single 
carat ; but as a polished diamond of one carat must have taken one of tiiro carats, its pnce 
in the rough state is double the square of 2iL, or 8JL Therefore to estimate the value 
of a wrought diamond, ascertain its iveight in carats, double that weight, and multiply 
the square of tibis product by 2/. Hence, a wrought diamond of 

1 carat is worth £S 7 carats is worth £S93 

2 M 32 8 „ 512 
8 ^ 72 9 „ 612 

4 „ 128 10 M 800 

5 „ 200 20 « 3200 

6 „ 288 

beyond whieh weight the price can no longer rise m this geometrical progression, from 
the sbmH number of purchasers of such expensive toys. A very trifling ^ot or flaw of 
any kind lowers exceedingly the commercial value of a diamond. 

Diamonds are used not only as decorative gems, but for more nseAil purposes, aa 
ibr cutting glass by the glazier, and all kinds of hard stones by the lapidary. 

(Hi tiie structure of the glaaier's diamcmd we possess some very interesting obsenr* 




ations and reflections by Dr. Wollaston. He remarks, that the hardest sahstances 
brought to a sharp point scratch glass, indeed, bat do not cat it, and that diamonds 
alone possessed that property ; which he ascribes to the peculiarity of its crystallisation 
in rounded fi&ces, and curvilinear edges. For glass-cutting, those rough diamonds are 
always selected which are sharply crystallised, hence called diamond sparks ; bat cat 
diamonds are never used. The mclination to be giyen to a set diamond in catting 
fflass is comprised within very narrow limits ; and it ought, moreover, to be moved 
m the direction of one of its angles. The curvilinear edge adjoining the curved fkces, 
entering as a wedge into the furrow opened up by itself, thus ten& to separate the 
parts of the glass; and in order that the crack which causes the separation of the 
vitreous particles may take place, the diamond must be held almost perpendicular to 
the surface of the glass. The Doctor proved this theory b^ an experiment. If, by 
suitable catting with the wheel, we maJLC the edges -of a spmel ruby, or corundom- 
telesie (sapphire), curvilinear, and the adjacent ftices carved, these stones will cut glass 
as well as a glazier*s diamond, but being less hard than it, they will not preserve this 
property so long. He found that npon giving the surface of even a fragment of flint 
the same shape as that of the catting diamond, it acquired the same property ; bat« 
from its relative softness, was of little duration. The depUi to which the fissure 
caused by the glazier's diamond penetrates does not seem to exceed the two-hundredth 
of an inch. 

The following remarks by Mr. Tennant cannot fail to be of interest, and, as pointing 
out the errors which hare been frequently committed through ignorance, of great 

** By attending to the forms of the crystal, we are quite sure that we shall not find 
the emerald, sapphire, zircon, or topaz in the form of a cube, octahedron, tetrahedron, 
or rhombic dodecahedron ; nor the diamond^ spinel, or garnet in that of a six sided 
prism, and so on with other ^ems. For want of a knowledge of the crystalline form 
of the diamond a gentleman m California offered 200L for a small specimen of quartr. 
He knew nothing of the substance, except that it was a bright shining mineral, exces- 
sively hard, not to be scratched by the file, and which would scratch glass. Pre- 
suming that these qualities belonged only to the diamond, he conceived that he was 
offering a fair price for the gem ; but the owner declined the offer. Had he known 
that the diamond was never found as a six -sided prism, terminated at each end by a 
six-sided pyramid, he would have been able to detect the fkct that what he was offered 
200il for, was really not worth more than half a crown.** — Tannanft Lecture on Geme. 

The accompanying forms may serve to guide those who are ignorant of crystal- 

649 BrilUant (upper side.) 


650 Rnse. 



a, table } b, lUr-fiioets ; e, tkUl (aoets ; d, losenget ; r, giiAe. 

The following technical terms are applied to the different faces of diamonds • 

Bezilej the upper sides and comers of the briUiant, lying between the edge of the 
table and the girdle. ° 

CoUei : the small horizontal plane or face, at the bottom of the brilliant. 

Crown : the upper work of the rose, which all centres in the point at the top, and 
18 bounded by the horizontal ribs. 

Facets .• small triangular faces, or planes, both in briUianU and roses. In briUianU 
there are two sorts, tA«o or jAtff-facets, and tfor-facets. Skill-iacets are divided into 
iqtper and wider. Upper skill-fiieets are wrought on the lower part of the bezil, and 
terminate m the girdle ; under-skill facets are wrought on the pavUions, and tenninate 
in the girdle ; star-fecets are wrought on the upper part of the bezil and terminate in the 

Girdle : the line which encompasses the stone parallel to the horizon ; or, which 
determines the greatest horizontal expansion of the stone. 


Jjozemge* i are common to brUHanU and roM«. In brittianta they ar^ formed by the 
meedng of the skUl and star-facets on the heziL In ratei by the meeting of the facets 
in the horisontal ribs of the crown. 

PaviUoma : the nnder sides and comers of briUianU, lying between the girdle and 
the collet. 

Bibt : the lines, or ridges, which distingnish the several parts of the work, both in 
brWiamtt and nuet. 

TtMe : the large horiaontal plane, or fiice, at the top of the hrUUanL 
Ftg, 649 represents a brilliant, and/w. 650 a rose oat diamond. 
The rose diamond is flat beneath, like all weak stones, while the upper fkce rises 
into a dome and is cnt into facets. Most usaally six fiiceta are pot on the central 
region which are in the form of triangles, and nnite at their summits ; their bases 
abut opon another range of triangles, which bein^ set in an inverse position to the 
preceding, present their bases to them, while their summits terminate at the sharp 
margin ci the stone. The latter triangles leave spaces between them which are like- 
wise cot each into two facets. By this distribution the rose diamond is cut into 
24 facets; the surface of the diamond being divided into two portions, of which the 
upper is called the crown, and that forming the contour, bennUi the former, is called 
dmtdk (laoe) by the French artists. 

According to Mr. Jeiferies, in his Treatise on Diamonds, the regular rose diamond 
is formed by inscribing a regular octagon in the centre of Uie table side of the stone, 
and bordering it by eight right-angled trisngles, the bases of which correspond with 
the sides of Uie octagon ; beyond these is a chain of 8 trapeziums, and another of 
16 triangles. The collet side also consists of a minute central octagon, fVom tyetj 
Single of which proceeds a ray to the edge of the girdle, forming the whole surface 
into 8 trapeziumSt each of which is again subdivided by a salient angle (whose apex 
tonches the girdle) into one irregular pentagon and two triangles. 

To fashion a rough diamond into a brilliant, the first step is to modify the faces of 
the original octahedron, so that the plane formed by the junction of the two pyramids 
shall be an exact square, and the axis of the cr3rstal precisely twice the length of one 
of the sides of the square. The octahedron being ^us rectified, a section is to be 
made parallel to the common base or girdU^ so as to cut off 5 eighteenths of the whole 
height from the upper pyramid, and 1 eighteenth from the lower one. The superior 
and larger plane thus produced is called the taUc^ and the inferior and smaller one is 
called the adlet; in this state it is termed a complHe aquare table diamond. To convert 
it into a brilliant, two triangular facets are jrfaced on each side of the table, thus 
changing it from a square to an octagon ; a losenge-shaped fiioet is also placed at each 
of the four comers of the table, and another loienge extending lengthwise along the 
whole of each side of the original square of the table, which with two triangular meets 
set on the base of each lozenge, completes the whole number of &cet8 on the table 
side of the diamond ; viz. 8 lozenges, and 24 triangles. On the collet side are formed 
4 irregular pentagons, alternating with as many irregular lozenges radiating from 
the coUet as a centre, and bordered by 16 triangular facets adjoining the girdle. The 
brilliant being thus completed, is set with the table side uppermost and the collet side 
implanted in the cavity made to receive the diamond. The brilliant is always three 
times a» thick as the rose diamond. In France, the thickness of the brilliant is set 
(iff into two unequal portions ; one third is reserved for the upper part or table of the 
diamond, and the remaining two thirds for the lower part or collet (culasae). The 
table has eight planes, and its circumference is cut into facets, of which some are 
triangles and others lozenges. The collet is also cut into fkcets called pavilions. It 
is (if consequence that the pavilions lie in the same order as the upper fiicets, and that 
they correspond to each other, so that the symmetry be perfect, for otherwise the 
play of the light would be false. 

Although the rose-diamond projects bright beams of light in more extensive propor- 
tion often than the brilliant, yet the latter shows an incomparably greater play, from 
the difference of its cutting. In executing this, there are formed 32 faces of different 
figures, and inclined at different angles all round the table, on the upper side of the 
stone. On the coBet (culasse) 24 other faces are made round a small table, which 
converts the culasse into a truncated pyramid. These 24 facets, like the 82 above, 
are differently inclined and present different figures. It is essential that the fifices of 
the top and the bottom correspond together in sufficiently exact proportions to multi- 
ply the reflections and refhictions, so as to produce the colours of the prismatic 

DIAMONDS, cutting of. Although the diamond is the hardest of all known sub- 
stances, yet it may be split by a steel tool, provided a blow be applied ; but this requires 
a perfect knowledge of the structure, because it will only yield to such means in certain 
directions. This circumstance prevents the workman from forming facettes or planes 

c 3 


generally, by the procesfl of splitting ; be is tberefbre obliged to resort to die process 
of abrasion, whicb is technically called cutting. The process of cotting is effected by 
fixing the diamond to be cut on the end of a stick, or handle, in a small ball oif 
cement, that part which is to be redoced being left to project. Another diamond is 
also fixed in a similar manner ; and the two stones being rubbed against each other 
with considerable force, they are mutually abraded, flat surfisces, or iacetteo, being 
thereby produced. Other facettes are formed by shifting the diamonds into Iresh 
positions in the cement, and when a sufficient number are produced, they are fit for 
polishing. The stones, when cut, are fixed for this purpose, by imbedding them in soft 
solder, contained in a small copper cup, the part or fkeette to be polish^ bein^ left 
to protrude, 

A flat circular plate of cast-iron is then charged with the powder produoed dnriog 
the abrasion of the diamonds ; and by this means a tool is formed which is capable ai 
producing the exquisite lustre so much admired on a finely -polished gem. Those 
diamonds that are unfit for working on account of the impenection of their lustre or 
colour, are sold, for various purposes, under the technical name of Bort Stones cf 
this kind are frequently broken in a steel mortar, by repeated blows, until they are 
reduced to a fine powder, which is used to charge metal plates of yarioos kinds, for 
the use of jewellers, lapidaries, and others. Bort, in this state of preparation, is 
incapable of polishing any gems; but it is used to produce flat surfeic^ on rubies and 
other precious stones. 

Fine drills are made of small splinters of bort, which are used for drilling small holes 
in rubies, and other hard stones, for the use of watch-jewellers, gold and silver wire- 
drawers, and others who require very fine holes drilled in such substances. These 
drills are also used to pierce holes in china, where rivets are to be inserted ; also for 
piercing holes in artificial enamel teeth, or any vitreous substances, however hard. 

The following description furnished to Mr. Tennant, by Messrs Garrard, of the 
cutting of the Koh-i-noor will fully explain the peculiar conditions of the process, 
and also show that there are some remarkable differences in the physical condition of 
the gem in its different planes. The letters refer to the out of the Koh-i-noor, article 
DiAHONik,^. 644. 

**ln cutting diamonds firom the rough, the process is so uncertain that the 
cutters think themselves fortunate in retaining one-half the original weight. The 
Koh-i-noor, on its arrival in England, was merely surface cut, no attempt having been 
made to produce the regular form of a brilliant by which alone lustre is obtained. By 
reference to the figures, which are the exact size of the Koh-i-noor, it will be clearly 
understood that it was necessary to remove a large portion of the stone in order to 
obtain the desired effect, by which means the apparent surface was increased rather than 
diminished, and the flaws and yellow tinge were removed. 

** The process of diamond cutting is effected by an horizontal iron plate of about 
ten inches diameter, called a «cAjf/*, or mUl which revolves from two thousand to three 
thousand times per minute. The diamond is fixed in a ball of pewter at the end of 
an arm, resting upon the table in which the plate revolves ; the other end, at which 
the ball containing the diamond is fixed, is pressed upon the wheel by movable weights 
at the discretion of the workmen. The weight applied varies from S to 30 lbs. accord- 
ing to the size of the fkcets intended to be cut The recutting of the Koh-i-noor was 
commenced on July 16, 1862, His Grace the late Duke of Wellington being the first 
person to place it on the mill ; the portion first worked upon was that at which the 
planes p and F meet, as it was necessary to reduce the stone at that part, and so to level 
the set of the stone before the table could be formed ; the intention being to turn the stone 
rather on one side, and take the incision or flaw at e, and a fracture on the other side of 
the stone, not shown in the engraving, as the boundaries or sides of the girdle. The 
next important step was the attempt to remove an incision or flaw at c, described by 
Professor Tennant and the Rev. W. Mitchell as having been made for the purpose of 
holding the stone more flrmly in its setting, but pronounced by the cutters (after having 
cut into and examined it) to be a natural flaw of a yellow tinge, a defect often met with in 
small stones. The next step was cutting a*facet on the top of the stone immediately above 
the last mentioned flaw. Here the difference in the hardness of the stone first manifested 
itself; for while cutting this facet, the lapidary noticing that the work did not proceed so 
fast as hitherto, allowed the diamond to remain on the mill rather longer than usual, with- 
out taking it off to cool ; the consequence was, that the diamond became so hot from the 
continual firiction and grater weight applied, that it melted the pewter in which it was 
imbedded. Again, while cutting the same facet, the mill became so hot from the ex- 
treme hardness of the stone, that particles of iron mixed with diamond powder and 
oil ignited. The probable cause of the diamond proving so hard at this part is, that 
the lapidary was obliged to cut directly upon the angle at which two cleavage planes 
meet, cutting across ^ grain of the stone. Another step that was thus considered to 


be importuit by the catten was remoTing a flaw at a. Thia flaw wat not thought by 
Profewor Tennant and Mr. Mitehell to be dangeroos, becaiue if it were allowed to run 
accor^ng to the cleaTage, it woald only take off a small piece, which it waa necessary 
to remoTe in order lo acquire the fireseat shape. The cutters, however, had an idea 
that it vighi not take the desired direction, and, therefore, began to cut into it ftt>m 
botih sidea, and afWrwarda directly upon it, and thus they snooeeded in getting rid of 
it. ¥rhile cutting, the stone appeared to become harder and harder the furdier it was 
cot into, especially jost abore the flaw at ▲, which part became so hard, that, after 
working the mill at the medium rate of S400 times per minute, for six hours, little 
impreaaion had been made ; the speed waa therefore increased to more than 3000, at 
which rate the work gradually proceeded. When the back (or former top) of the 
atone was cut. It proved to be much softer, so that a hcet was made in three hours, 
which would have occupied more than a day, if the hardness had been equal to that 
on the other side i nevertheless, the stone afterwards became gradually huder, especi- 
ally underneath the flaw at ▲, which part was nearly as hard as that directly above 
H. The flaw at n did not interfere at all with the cutting. An attempt was made to 
cot out the flaw at ▲, but it was found not desirable on account of its length. The 
^iffwwi*!^ was finished on September 7th, having taken thirty- eight days to cut, working 
twelve hours per day without oessation." The weight of the Koh-i-Noor since cut- 
tiDg is 1624 carats. 

DIAMOND DUST. The use of diamond dust within a few years has increased 
very matorially, on account of the increased demand for all articles that are wrought 
by it, such as cameos^ intaglios, &c There has been a discovery made of the peculiar 
power of dmuiond dust upon steel i it gives the finest edge to all kinds of cutlery, and 
It threatened at one time to displace the hone of Hungary. Finely powdered corundum, 
however, now occupies its place. It is well known that in cutting a diamond, the 
dust is placed on the teeth <^ the saw— to which it adheres ; to Uits dust is to be 
attributed solely the power of man to make brilliants from rough diamonds. The 
dost enables the polisher to obtain the perfection of geometrical svmmetr^, which is 
one of the chief beauties of the mineral, and also that adamantine polish, which nothing 
can iigure or affect, save a substance of its own nature. 

Diamond dust, it would appear, can now be manufectured by the agency of voltaic 
electricity. See Diakond. 

DIAMOND MICROSCOPES were first suggested by Dr. Goring, and have been 
well executed by Mr. Pritehard. Previoos to grinding a diamond into a spherical 
figure, it should be ground flat and parallel upon both sides, that by looking through 
it, as opticians try mnt glass, we may see whether it has a double or triple reftvctive 
power, as many have, which would render it useless as a lens. Among the different 
crystalline forms of the diamond, probablv the octahedron and the cube are the only 
onea that will give a single vision. It will, m many cases, be advisable to grind diamond 
lenses plano-convex, both because this figure gives a low spherical aberration, and 
because it saves the trouble of grinding one side of the gem. A concave tool of cast 
iron, paved with diamond powder, hammered into it by a hardened steel punch, was 
employed by Mr. Pritehard. This ingenious artist succeeded in completing a double 
convex of equal radii, of about ^ of an inch fooos, bearing an aperture of ^ of an inch 
with distinctness upon opaque objects, and its entire diameter upon transparent ones. 
This lens gives vision with a trifling chromatic aberration ; in other respects, like Dr. 
G^ing^s Amician reflected, but without its darkness, its light is sud to be superior 
to that of any compound microsc<^ whatever, acting with the same power, and the 
aame an^le of aperture. The advantage of seeing an olgect without aberraium by the 
interposition of only a single magnifier, instead of looking at a picture of it with aii 
eye-glass, is evident We thus have a simple direct view, whereby we shall see more 
accurately and minutely the real texture of objects. 

DIAMOND TOOLS. 1. Tftc G&utsr't diamond is the natural diamond, so set that 
one of its edges is brought to bear on the glass. 

The extreuM point of any diamond will scratch ghiss, making a white streak ; but when 
the rounded edge of a diamond is slid over a sheet of glass with but slight pressure, 
it produces a cut, which is scarcely visible, but which readily extends through the mass. 

Dr. WoUaston succeeded in ^vmg to the ruby, topaa, and rock crystal forms similar 
to those of the diamond, and with thoae he succeeded in cutting glass ; proving that this 
useftd property of ihe diamond depended on its form. Although die primitive form 
of the diamond is that of a regular octahedron, the Dnke de Boumon has published 
upwards of one hundred forms of crystallisation of the diamond. The irregular octa- 
hedrona with round feeets are those proper for glaaiers* diamonds. 

Notwithstanding the hardness of the diamond, yet, in large glass works, as many as 
one and two doaens are worn out every week : from being convex, they become rapidly 
concave, and the catting power is lost. 



3. Diamond driUs are made of various shapes ; these are either found amongst im- 
perfect diamonds, or, are selected from fragments split off from good stones in their 
manufactare for jewelling. 

DIAPER is the name of a kind of cloth, used chiefly for table linen. It is known 
among the French by the name of ioiiefourri, and is ornamented with the most exten- 
sive figures of any kind of tweeled doth, excepting damask. The mounting of a loom 
for working diaper is, in principle, much the same as a draw-loom, but the figures being 
less extensive, Uie mounting is more simple, and is wrought entirely by the weaver, 
without the aid of any other person. As tweeled cloths, of any number of leayes, are 
only interwoven at those intervals when one of the leaves is raised, the woof above and 
the warp below are kept floating or flushed, until the intersection takes place. Of con- 
sequence the floating yam above appears across the fabric, and that below k>ngitudi- 
nally. This property of tweeled cloths is applied to form the ornamental figures of 
all kinds of tweeled goods, merely by reversing the floating yam when necessary. In 
the simpler patterns, this is effected by a few additional leaves of treddles ; bat when 
the range of pattern becomes too great to render this convenient, an apparatus called a 
back hameu is employed, and the doth woven with this mounting is called diaper. 
Diapers are generally five-leaf tweels, that is to say, every warp floats under foar 
threads of woof, and is raised, and of course interwoven with the fifth. This is done 
either successively, forming diagonals at 45^ upon the cloth, or by intervals of two 
threads, which is called the broken tweeL The latter is generally, if not uniyersally, 
adopted in the manufacture of diaper. The reason of preferring the broken to the 
regular tweel, where ornaments are to be formed, is very obvious. The whole depend- 
ing upon reversed flushing, to give the appearance of oUique or diagonal lines through 
either, would destroy much of the effect, and materially injure the beauty of the fitbric. 
The broken tweel, on the contrary, restores to the tweeled doth a great similarity of 
appearance to plain or alternately interwoven fabrics, and at the same time preserves 
the facility of producing ornaments by reversing the flushing. 

DIASTASE. A white and tasteless substance, obtained by moistening pounded 
malt, and squeezing the water through a bag. Albumen is precipitated from the torbid 
fluid by alcohol, and filtered. Then the diastase is precipitated by an additional qoao- 
tity of alcohol, and purified by re-solution and re-precipitation. One part of diastase 
will convert 2000 parts of starch into dextrine, and 1000 parts into sugar. 

DICHROISM. The property of exhibiting two colours. Many of the phenomena 
belong to the conditions producing Fluorescence, which see. Some of Uie pheno- 
mena have been referred to polarisation, but this requires examination. 

DIDYMIUM (Di). A metal discovered by Mosandar, in 1841, in oxide of cerium^ 
and so called as being associated in that ore as a twin brother with lanthantim» 

The oxide of Didymium (DiO) is a dark brown powder ; the salts are pink, or rose, 
and amethyst or violet 

DIES FOR STAMPING. (Cotiu, Fr.; MUnzstampdR, Germ.) The first circum- 
stance that claims particular attention in the manufacture of dies, is the selection of 
~ the best kind of steel for the purpose, and this must in some measure be left to the 
experience of the die-forger, who, if well skilled in hb art, will be able to form a tole- 
rably correct judgment of the fitness of the metal for the purpose, by the manner in 
which it works upon the anvil. It should be rather fine-grained than otherwise, and 
above all things perfectly eren and uniform in its*texture, and free ttom spots and 
patches finer or coarser than the general mass. But the very fine and uniform steel 
with a silky fracture, which is so much esteemed for some of the purposes of cutlery, 
is unfit for our present purpose, from the extreme facility with which it acquires great 
hardness by pressure, and its liability to cracks and flaws. The Tery cross-grain^, or 
highly crystalline steel, is also equally objectionable ; it acquires fissures under the 
die-press, and seldom admits of being equally and properly hardened. The object, 
therefore, is to select a steel of a medium quality as to fineness of texture, not easily 
acted upon by dilute sulphuric acid, and exhibiting an uniform texture when its surface 
is washed over with a little aquafortis, by which its freedom from pins of iron, and 
other irregularities of composition, is sufficiently indicated. 

The best kind of steel b^ing thus selected, and properly forged at a high heat into 
the rough die, it is softened by very careful anneiding, and in that state, having been 
smoothed externally, and brought to a table in the turning lathe, it is delivered to the 

The process of annealing the die consists in heating it to a bright cherry red, 
and suffering it to cool gradually, which is best effected by bedding it in a cradble 
or iron pot of coarsely-powdered charcoal In this operation it is sometimes sup- 
nosed that the die, or at least its superficial parts, becomes super-carbonised, or 
nighly converted steel, as it is sometimes called; but experience does not justify 
such an opinion, and I belieye the composition of the die is scarcely, certainly not 


materially, affected by the process, for it does not remain long enough in the fire for 
the purpose. 

The engTEver nsnally commences his labours by workii:^ oat the device with small 
ateel tools in intaglio ; he rarely begins in relief (though this is sometimes done) ; and 
haring ultimately completed his design, and satisfied himself of its general effect and 
correctness, by impressions in clay, snd dabs, or casts in type metal, the die is ready 
for the important operation of hardening, which, from rarioos causes, a few of which 
I shall enumerate, is a process of much risk and difficulty ; for should any accident 
now occur, the labour of many months may be seriously iojored, or even rendered 
quite useless. 

The process of hardening soft steel is in itself very simple, though not very easily 
explained upon mechanical or chemical principles. We kjiow by experience, that it 
is a property of this hiffhly valuable substance to become excessively hard, if heated 
and suddenly cooled ; i^ therefore, we heat a bar of soft malleable and dactile steel red 
hot, and then suddenly quench it in a large quantity of cold water, it not only becomes 
haid, but fragile and brittle. But as a £e is a mass of steel of considerable dimen- 
sions, this hardening is an operation attended by many and peculiar difficulties, more 
especially as we have at the same time to attend to the careful preservation of the 
engraving. This is effected by covering the engraved face of the die with a protecting 
face, composed of fixed oil of any kind, thickened with animal charcoal : some per- 
sons add pipe-clay, others use a pulp of garlic, but pure lamp-black and linseed oil 
answer the purpose perfectly. This is thinly spread upon the work of the die, which, 
if requisite, may be fhrther defended by an iron ring ; the die is then placed with its 
face downwards in a crucible, and completely surrounded by animal charcoal It is 
heated to a suitable temperature, that is, about cherry red, and in that state is taken 
out with proper tongs, and plunged into a body of cold water, of such magnitude as not 
to become materially increased in temperature ; here it is rapidly moved about, until 
aJl noise ceases, and then left in the water till quite cool. Li this process it should 
produce a hobbling and hissing noise ; if it pipes and sings, we may generally appre- 
hend a crack or fissure. 

No process has been found to answer better than the above simple and common mode 
of hardening dies, though others have had repeated and fair trials. It has been pro- 
posed to keep up currents and eddies of cold water in the hardening cistern, by means 
of delivery -pipes, coming fW>m a height; snd to subject the hot die, with its face 
uppermost, to a sudden and copious current of water, let fall upon it ftxnn a large pipe, 
supplied from a high reservoir ; but these means have not in any way proved more 
successful, either in saving the die, or in giving it any good qualities. It will be recol- 
lected, fVom the form of the die, that it is necessarily only, as it were, case-hardened, 
the hardest strata being outside, and the softer ones within, which envelope a core, 
something in the manner of the successive coats of an onion ; an arrangement which 
we sometimes have an opportunity of seeing displayed in dies which have been smashed 
by a violent blow. 

The hardening having been effected, and the die being for the time safe, some fur- 
ther steps may be taken for its protection ; one of these consists in a very mild kind of 
tempering, produced by putting it into water, gradually raised to the boiling point, 
till heated throo^^out, and then suffering it gradually to cooL This operation renders 
the die less apt to crack in very cold weather. A great safeguard is also obtained by 
thrusting the cold die into a red-hot iron ring, which just fits it in that state, and which, 
by contracting as it cools, keeps its parts together under considerable pressure, pre- 
venting the spreading of external cracks and fissures, and often enabling us to employ 
a split or die for obtaining punches, which would break to pieces without the protecting 

If the die has been successfully hardened, and the protecting paste has done its duty 
by preserving the face from all injury and oxidisement, or burning, as it is usually 
colled, it is now to be cleaned and polished, and in this state constitutes what is 
technically called a katbix ; it may of course be used as a multiplier of medals, coins, 
or impressions, but it is not generally thns employed, for fear of accidents happening 
to it in the coining press, and because the artist has seldom perfected his work upon 
it in this state. It is, therefore, resorted to for the purpose of fUmishing a punch, 
or steel impression for relief. For this purpose a proper block of steel is selected, of 
the same quality, and with the same precautions as before, and being carefully annealed, 
or softened, is turned like the matrix, perfectly true and fiat at the bottom, and ob« 
tusely conical at top. In this state, its conical surface is carefully compressed by 
powerful and proper machinery upon the matrix, which, being very hard, soon allows 
it to receive the commencement of an impression ; but in thus receiving the impres- 
sion, it becomes itself so hard by condensation of texture as to require during the 
operation to be repeatedly annealed, or softened, otherwise it would split into small 


saperfioial fi8SU|e«, or vould iigare the matrix; much practical skill ia therefore 
quired in taking the impression, and the panch, at each annealing, must be carefnlly 
protected, so that the work may not be ii\jured. 

Thus, after repeated blows in the die-press, and frequent annealing, the impresstoii 
from the matrix is at length perfected, or brought completely up, and having been 
retouched by the engraver, is turned, hardened, and collared, like the nuitrix, of 
which it is now a complete impression in relief, and, as we have before said, is called a 

This punch becomes an inexhaustible parent of dies, without fbrther reference to the 
original matrix ; for now by impressing upon it pluj;s of soft steel, and by pursuing 
with them an exactly similar operation to that by which the punch itself was obtained, 
we procure impressions from it to any amount, which, of course are fao-similes of the 
matrix, and these dies being turned, hardened, polished, and, if necessary, tempered, 
are employed for the purposes of coinage. 

The distinction between striking medals and common coin is very essential, and the 
work upon the dies is accordingly adjusted to each. Medals are usually in very high 
relief, and the effect is product by a succession of blows ; and as the metal in which 
they are struck, be it gold, silver, or copper, acquires considerable hardness at each 
stroke of the press, they are repeatedly annealed during the process of bringing 
them up. In a beautifhl medal, which Mr. Wyon executed for the Ro^al Naval 
College, the obverse represents the head of the King, in very bold relief; it re- 
quired thirty blows of a very poweriUl press to complete the impression, and it was 
necessary to anneal each medal after every third blow, so that they went ten times into 
tiie fire for that purpose. In striking a coin or medal, the lateral spread of the metal, 
which otherwise would ooae out as it were from between the dies, is prevented by the 
application of a steel collar, accurately turned to the dimensions of the dies, and which, 
when left plain, gives to the edge of the piece a finished and polished appearance ; it is 
semetimes grooved, or milled, or otherwise ornamented, and occasionally lettered, in 
which case it is made in three separate and movable pieces, confined by a ring, into 
which they are most accurately fitted, and so a(](justed that the metal may be forced 
into the letters by its lateral spread, at the came time that the coin receives the blow 
of the screw- press. 

Coins are generally completed by one blow of the coining-press. These presses are 
worked in the Royal Mint by machinery, so contrived that they shall strike, upon an 
average, sixty blows in a minute ; the blank piece, previously properly prepared and 
annealed, being placed between the dies by part of the same mechanism. 

The number of pieces which may be struck by a pair of dies of good steel, pro- 
perly hardened and duly tempered, not unfrequently amounts at the Mint to between 
one and two hundred thousand ; but the average consumption of dies is of course much 
greater, owing to the variable qualities of steel, and to the casualties to which the dies 
are liable; thus, the upper and lower die are sometimes struck together, owing to 
an error in the layer-on, or in that part of the machinery which ought to put the blank 
into its place, but which now and then fails so to do. This accident very commonly 
arises from the boy who superintends the press neglecting to feed the hopper of the 
layer-on with blank pieces. If a die is too haid, it is apt to break or split; and is es- 
peciallv sulject to fissures, which run from letter to letter upon the edge. If too soft, 
it swells, and the collar will not rise and fall upon it, or it sinks in the centre, and the 
work becomes distorted and fknlty. He, therefore, who supplies the dies for an exten- 
sive coinage, has many accidents and difficulties to encounter. There are eight presses 
at the Mint, frequently at work for ten hours each day, and the destruction of eight 
pair of dies per day (one pair for each press) may be considered a fhir average result, 
though they much more frequently fall short of, than exceed this proportion. It must 
be remembered, that each press produces 3600 pieces per hour ; but making allowance 
for occasional stoppages, we may reckon the daily produce of each press at 30,000 
pieces ; the eight presses, therefore, will frimish a diurnal average of 240,000 pieces. 

DIES, hardening of. See Stkel, hardening of. 

DIGESTER is the name of a copper kettle or pot of small dimensions, made very 
strong, and mounted with a safety valve in its top. Papin, the contriver of this appa- 
ratus, used it for subjecting bones, cartilages, &c. to the solvent action of high -pressure 
steam, or highly heated water, whereby he proposed to ftusilitate their digestion in 
the stomach. This contrivance is the origin of the French cookery pans, called 
autochv€8, because the lid is self-keyed, or becomes steam-tight bv turning it round 
under damps or ears at the sides, having been previously ground with emery to fit the 
edge of the pot exactly. In some autoclaves the lid is merely laid on with a fillet of 
linen as a lute, and then secured in its place by means of a screw bearing down upon 
its centre from an arched bar above. The safety valve is loaded either by a weight 
placed vertically upon it, or by a lever of the second kind pressing near its fulcrum, 


mnd aeted upon by a weight which may he made to bear upon any point of its gra- 
duated arm. 

CheTTeoi has made a naefiil application of the digeeter to Tegetable analyaif. Hib 
instrnraent conaists of a strong copper eyiinder, into which enters a tight cylinder of 
silTer, haying its edge tnmed oTer at right angles to the axis of the cylinder, so as to 
form the rim of the digester. A segment of a copper sphere, also lined with silver, 
stops the apertore of the silver cylmder, being applied closely to its rim. It has a 
conical vabre pressed with a spiral spring, of any desired force, estimated by a steel- 
yard. This spring is enclosed within a brass box perforated with four holes ; which 
may be screwed into a tapped orifice in the top the digester. A tnbe screwed into 
another hole serves to conduct away the condensible vaponrs at pleasure into a Wonlfe's 

DIKE or DYKE. A waU like division in rocks, prodooedby the Section of trapean 
matter in a fiased state ftt>m below, throogh the overlying strata. In many places 
those hard trap rocks stand out above the a^acent rocks, which have been worn 
away, presenting actually the appearance of a massive wall. 

DILATATION. The increase of size produced in bodies by the agency of heat 
See EzPANsioK. 

DILUVIUM. (i>iikmaR.) Deluge. Those accumulations of gravel and loose 
materials, which, by some geologists, are said to have been produced by the action of 
a dilnvian wave or deluge, sweeping over the surftce of tfie earth. — LyeB. 

DIMITY is a kind of cloth cotton originally imported from India, and now manu- 
factured in great quantities in various parts of Britain, especii^ in Lancashire. Dr. 
Johnson calls it dimmity, and describes it as a kind of ftistian. The distincUon between 
fustian and dimity seems to be, that the former designates a common tweeled cotton 
cloth of a stout &bric which receives no ornament in the loom, but is most frequently 
dyed after being woven. Dimity is also a stout cotton doth, but not usually of so 
thick a texture ; and is ornamented in the loom, either with raised stripes or fancy 
figures : it is seldom dyed, but usually employed white, as for bed and bed-room furniture. 
The striped dimities are the most common, they require less labour in weaving than 
the others ; and the mounting of the loom being more simple, and consequently less 
expensive, they can be sold at much lower rates. 


DIORITES. A trap or greenstone rock, in which albUe replaces or^oclase. 
Diorites are abundant in the Vosges. 

DIP. ¥rhen any stratum, mineral vein, or dike, does not lie horisontally it is said 
tod ip E. W. N. or S., as the case may be. The angle which it makes with the 
horizon^ called the angle of the dip. 

DIPPEL'S ANIMAL OIL. A fetid voktile oil obtuned when animal sub- 
stances, such as bone, are subjected to distillation. That which is found in commerce 
is obtained in the manuihcture of bone-black. 

DIPPING. Ornamental works in brass aro usually brightened by a process called 
dipping. After the work has been properly fitted together and the gretae removed, 
'either by the action of heat, or by boiling in a pearl ash lye, it is piciled in a bath of 
dilute aqua fortis. It is then scoured bright with sand and water, and being well 
washed is plunged into the dipping bath, which consists of pure nitrous acid, 
commonly known as dipping aquafortis^ for an instant only, and is then well washed 
with cold and hot water to remove every trace of acid from the snrfkce, after which 
the work is put into dry beech or box wood, sawdust, &c, well rubbed until it is quite 
dry, and then burnished and lackered with as little delay as possible. 

DISINFECTANT. A substance which removes the putrid or infected con- 
dition of bodies. It is well not to confound it with antiseptic, which applies to 
those bodies which prevent putrefaction. The word disinfectant has lately become 
somewhat uncertain in its meaning, on account of a word being used as its equiva- 
lent, viz. deodoriser. This latter means a substance which removes odours. In 
reality, however, there are no such substances known to us as a class. There are, 
of course, some substances which destroy certain others having an odour, but in all 
cases the removal of the smell and the destruction or neutralisation of the body must 
be simultaneous. There is, however, a large class of substances that destroy putre- 
faction, and the name disinfectant is therefore distinctly needed. The gases which 
rise from putrefying bodies are not all capable of bein^ perceived by the senses in 
their ordinary condition, but sometimes they are perceived. A disinfectant puts a 
stop to them and deodorises simultaneously. If any substance were to remove the 
smell of these gases, it would remove the gases too, as they are inseparable from their 
property of affecting the nose. A deodoriser would therefore be, and is, a disinfectant 
of that gas the smell of which it removes. But it has been suggested that it may 
remove Uiose gases which smell, and allow the most deleterious to pass, they having 
no smelL Whenever we find such a class of substances, it will be well to give them 


the Dame of deodorisers. There may be fiome trath in the hypothesis that metallic 
salts remove the sulphar, and by preyenting the escape of sulphuretted hydrogen cause 
less odour, vithoat complete disinfection. But it appears that the decomposition is 
a prevention of putrefaction in proportion to the removal of that gas in cases vhere 
it is given out, and it is quite certain that metallic solutions have disinfecting proper- 
ties. Any solution having the effect here supposed would at the least be a partial 
disinfectant, inasmuch as tibe decomposition would be so far put a stop to, as to prevent 
at least one obnoxious gas. How the others could remain unacted on in this case it is 
difficult to comprehend. To prevent the formation of one gas is to arrest decom- 
position or to alter the whole character of the change which is producing the 
gases. The most deleterious of emanations have no smell at all to the ordinary 
senses, and we can only judge of the evil by its results, or the fact that the sub- 
stances capable of producing it are near, or by the analysis of the air. (See Sani- 
tary Arrangehents.) The cases where sulphuretted hydrogen accompanies the 
offensive matter, are chiefly connected with fgsctX decomposition. This gas is a 
useful indication of the presence of other substances. So far as is known, the des- 
truction of the one causes the destruction of the other. But the presence of sul- 
phuretted hydrogen is no proof of the presence of infectious matter, nor is its absence 
a proof of the absence of infections matter, it being only an occasional accompaniment. 
When the infectious matter and the odoriferous matter are one, as in the ease, as far 
as we know, of putrid flesh, &c., then to deodorise is to disinfect We can find then 
no line of daty to be performed by deodorisers, and no class of bodies that can bear 
the name, although there may be a few cases where the word may be found convenient. 
If, for example, we destroy one smell by superadding a greater, that might in one 
sense be a deodorising. If we added an acid metallic salt, and removed the sulphu- 
retted hydrogen, letting loose those organic vapours which for awhile accompany 
this act, we might, to those who were not very near, completely destroy smell, and 
still send a substance into the air by no means wholesome ; but in such a case decom- 
position is stopped, at least for a while. The smelling stage is by no means the most 
dangerous, nor has the use of the word deodorise any relation to sanitary matters, 
except in the grossest sense ; it is desirable that persons should look far beyond 
the mere indications furnished by the nose, and as in science we can find no deodo- 
risers, so in practice we need not look for any in the sense usually given to the word. 
The word may be used for such substances as remove the odour and the putrefaction 
of the moment, but allow them to begin again. Even in this case deodorisers become 
temporary disinfectants, which character all removers of smell must more or less 

Antiseptics, or cclytic agents. Substances which prevent decomposition, ne words 
coiysis and coiytic come from kwXuw, to arrest, restrain, cut short. This word was proposed 
by the writer to apply to cases such as are included under antiseptics, antiferments, 
and similar words. There was needed a word for the general idea. A colytic force 
manifests itself towards living persons in anaesthetics, anodynes, and narcotics, as well 
probably, as in other ways. Colytics may probably act fh>m different causes, but these 
causes not bein^ separately distinguished, a name for the whole class can alone be 
given. The action of coiysis is entirely opposed to catalysis, which is a loosening up 
of a compound. CoUfsis arrests catalysis, as well dso as other processes of decompo- 
sition, ordinary oxidation for example. Disinfectants, in their character of restraining 
further decomposition, are included under colytics. One of the most remarkable sub- 
stances for arresting decomposition is kreasote. It has been used in some condition or 
mixture firom the earliest times. The ancient oil of cedar has been called with good 
reason turpentine, which has strong disinfecting properties, but the word has evidently 
been used in many senses, as there are many liquids to be obtained firom cedar. It is used 
for the first liquid from the distillation of wood; and Berzelius for that reason says 
that the Egyptians used the pyroligneons acid, which, containing some kreasote« was 
a great antiseptic. But a mixture of this acid with soda would be of little value in 
embalming, nor is it probable that they would add a volatile liquid like turpentine 
along with caustic soda. It is expressly said (in Pliny) that the pitch was reboiled, 
or, in other words, the tar was boiled and distilled, the product being collected in the 
wool of fleeces, from which again it was removed by pressure. In doing this the 
light oils or naphtha would be evaporated, and the heavy oil of tar, containing 
the carbolic acid, or kreasote, would remain. It was called picenum, as if made 
of pitch or pissenum, and pisselsum or pitch oil, a more appropriate name than that 
of Bunge's carbolic acid or coal-oil, and still more appropriate than the most recent, 
which, by following up a theory, has converted it into phenic acid. The distillation 
was made in copper vessels, and must have been carried very far, as they obtained 
**a reddish pitch, very clammy, and much fatter than other pitch." This was the 
anthracene, chrysene, and pyrene of modem chemistry. The remaining hard pitch 
was called palimpissa, or second pitch, which we call pitch in contradistinction 


to tar. By the second pitch, howeyer, was somethnes meant the prodoct of distillation 
instead of what iras left in the stilL Some confosion therefore exiits in the names, 
bat not more than with as. The pitch oil was resinous fat, and of yellow colonr, 
according to some. This oil, containing kreasote, was used for toothacne — a colytie 
action applied to liying bodies •— and for skin diseases of cattle, for which it is 
found yaloahle. They also osed it for preserving hams. — ('* l>inf|/0c/aato,'* by the 
Writer. Jtmr. Sec, of Att», 1857.) 

It is qnite possible that kreasote may be the chief agent in most empyrenmatic 
aabstanoes which act as antiseptics. Bat it is not the only agent Hydrocarbons of 
yarioos kinds act as antiseptics, as well as alcohol and methylic alcohol, which contain 
little oxygen. To this class belong essential oils and substances termed perfumes, 
which are nsed for fumigation, and haye also a powerful colytic action, it is 
exceedingly probable that the true theory of this action is connected with the want 
of oxygen. These substances do not rapidly oxidise, but, on the contrary, only yery 
slowly, and that chiefly by the aid of other bodies. Their atoms are, therefore, in 
a state of tension, ready to unite when assisted. As an example, carbolic acid and 
kreasote nnite with oxygen when a base is present, and form roeolic acid. We can 
scarcely suppose that an explanation, commonly resorted to in the case of sulphurous 
acid, would suit them ; yiz., that it takes up the oxygen, and so keeps it from the 
pntrescible substance. It is, therefore, much more hkely that its condition acts on 
the putrescible body. For, as the state of motion of a putrefying substance is trans- 
ferred to another, so is the state of immobility. 

In 1750 Sir John Pringle wrote his ** Experiments on Septic and Antiseptic 
Substances, with remarks relating to their Use in die Theory of Medicine.*' He 
recommended salts of yarioos kinds, and astringent and gummy parts of yegetables 
and fermenting liquors. Dr. Macbride followed him with numerous experiments. 
He speaks of acids being the long prescribed agents as antiseptics. He found them 
antiseptic even when diluted to a great extent. Alkalies also be found antiseptic, 
and salts in generaL Also " gum-resins, such as myrrh, asafcetida, aloes, and terra 
japonica," besides ** decoctions of Virginia snake-root, pepper, ginger, saffron, con- 
trayerra root, sage, valerian root, and rhubarb, with mint, angelica, senna, and 
common wormwood." Many of the common yegetables also were included as to 
some extent antiseptic ; such as horse-radish, mustard, carrots, turnips, garlic, onions, 
celery, cabbage, colewort Lime was found to prevent, but not to remove putrefac- 
tion. We are inclined at present very much to qualify some of these observations. 
Animal flaids, he observes, will remain for a long time without putridity if kept 
firom the air. He says that astringent mineral acids and ardent spirits "not only 
absorb the matter from the putrescent substances, but likewise crisp up its fibres, and 
thereby render it so hard and durable that no change of combination will take place 
for many years.** He adds also molasses to the antiseptics. In 1767 the academy of 
DQon gave a prise for the use of nitrate of potash in ventilation. This may have gifen 
the first idea to Carmicbael Smyth. Guyton-Morveau came later with a volume of 
yalnable experients on adds. 

An anUeeptic preserves fh>m patrefiietion, but does not necessarily remove the odour 
caused by tnat which has previously putrefied. Many of the substances described as 
disitdTeetants here, mij^t equally be cidled antiseptics. When they remove the putrid 
matter they are disinfectants, when they prevent decomposition they are antiseptics. 
Bat when the smell is removed by a substance which is known to destroy putrefactive 
decomposition, and to preserve organic matter entire, then we have the most thoroush 
disinfection ; then we know that the removal of the smell is merely an indication of the 
removal of the evlL 

IHein/eetanU are of various kinds. Nature seems to use soil as one of the most 
active. AU the dejecta of the animals on the surface of the earth fall on the soil, 
and are rapidly made perfectly innoxious. Absorption distinguishes porous bodies, 
and the soil has peculiar facilities for the purpose. Bat if saturated, it could disin- 
fect no longer. This is not allowed to occur ; the soil absorbs air also, and oxidises the 
organic matter which it has received into its pores, and the offensive mister is by this 
means either converted into food for plants, or is made an innocent ingredient of the air, 
or, if the weather be moist, of the water. The air is therefore, in copjuuction with 
the soil, one of the greatest disinfectants, but it acts also quite alone and independent of 
the soil. Its power of oxidising must be very great The amount of organic effluvium 
sent into large towns is remarkable, and yet it seldom accumulates so as to be 
t^rcfDfly perceptible to the senses. The air oxidises it almost as rapidly as it rises ; 
this IS hastened apparently by the peculiar agent in the air, oionc, which has a 
greater capacity of oxidation than the common air ; when this is exhausted it is 
highly probable that the oxidation will be much slower, and this exhaustion does 
take place in a very short time. So rapid is the oxidation, that the wind, even 


blowing at the rate of about fifteen to twenty miles an boor, iir entirely derived of 
its ozone by passing over less than a mile of Manchester. In J^ondon this does not 
take place so rapidly, at least near the Thames. But when the oione is removed, it is 
probable that the rate of increase of the organic matter will be maeh greater. We 
may by this means, then, readily gauge the condition of a town up to a certain point 
by the removal of the ozone : but it requires another agent to gauge it afterwards or 
thoroughly. It is in connection with each other that the air and the soil best dis- 
infect When manure is thrown upon land without mixing with the soil, it may 
require a very long period to obtain thorough disinfection, but when the atmosphere 
is moist, or rain iaUs, then the air is rapidly transferred into every portion of the 
porous earth, and the organic matter becomes rapidly oxidised. To prevent a 
smell of manure, and with it also the loss of ammonia, it is then needfbl that as soon 
as possible the manure should be mixed with the soil. The same power of oxidation 
is common to all porous bodies, to charcoal, and especially, as Dr. Stenhouse has 
shown, to platinised charcoal Disinfection by the use of porous bodies is not a pro- 
cess of preservation, but of slow destruction. It is an oxidation in which all the 
escaping gases are so thoroughly oxidised, that none of them have any smell or any 
offensive pn^rty. But being so, the body disinfected must necessarily decay, and 
in reality the process of decay is remarkabljr increased. All such bodies must there- 
fore be avoided when manures are to be disinfected, as the valuable ingredients are 
destroyed instead of being preserved. Stenhouse has employed charcoal for disin- 
fecting the air. The air is passed through the charcoal either on a large scale for a 
hospi^ or on a small scale as a respirator fbr the mouth. Care must be taken, how- 
ever, to keep the charcoal dry : wet charcoal is not capable of absorbing air until that 
air is dissolved in the water. This soluticm takes place less n^iidly in water. Wet 
charcoal is therefore a filter for fluids chiefly, and dry charcoal fbr vapours. Its destruc- 
tive action on manures will, however, always prevent charcoal fkx»m being much used 
as a disinfectant for such purposes, or, indeed, any other substance wlu^ acts principally 
by iu porosity or by oxidation. This the soil does only partially, as it has another 
power, riz. that of retaining organic substances fit to be the food of plants. Although 
air acts partly in coig unction with the soil and the ndn to cause disinnction, and partly 
by its own power, it also acts mechanically as a means of removing all noxious vapours. 
The wind and other currents of the air are continually ventilating the ground, and when 
these movements are not sufficiently rapid, or when they are interrupted by our mode 
of building, we are compelled to cause them artificially, and thus we arrive at the 
art of ventilation. The addition of one tenth of a per cent of carbonic acid to the 
air may be perceived, at least if accompanied with the amount of organic matter 
usually given out at the same time in the breath, and as we exhale in a day 20 
cubic feet of carbonic acid, we can injure the quality of 20,000 cuIhc feet of air in 
that time. The great value of a constant change of air is therefore readily proved* 
and the instinctive love which we have of fresh air is a sufficient corroboration. 

Cold is a great natural disinfectant The flesh of animals may be preserved as far 
as we know for thousands of years in ice ; putrefying emanations are completely 
arrested by freezing, but the mobility of the particles, or chemical action, is also 
retarded by a degree of cold much less than freezing. 

Heat is also a disinfectant, when it rises to about 140^ of Fahrenheit, according to 
Dr. Henry. But as a means of producing dryness it is a dinnfeotant at various 
temperatures. Nothing which is perfectly dry can undergo putrefection. On the other 
hand heat with moisture below 140° is a condition very highly productive of decom- 
position and all its resulting evils. Disinfection by heat is used at qaarantine stationiL 
Light is undoubtedly a great disinfectant} so fkr as we know, it acts by hastening che- 
mical decomposition. In all cases of ventilation, it is essential to allow the rays of light 
to enter with the currents of air. Its effect on the vitality of the fanmaa being is abun- 
dantly proved, and is continually asserting itself in vegetation. The true disinfecting 
property of light exists in all probability in the cheimcal rays which cause compo- 
sitions and decompositions. Water, however, is of all natural disinfectants the most 
managealA, and there is no one capable of taking its place actively. Wherever animals 
even human beings, live, there are emanations of organic matter, even fh>m the purest 
The whole surfhce of the house, furniture, floor, and walls, becomes coated by degrees 
with a thin covering, and this gradually decomposes, and gives off unpleasant vapours^ 
Sometimes it becomes planted with fungi, and so feeids plants of this kind. But long 
before this occurs a small amount of vapour is given off sufficiently disagreeable to 
affect the senses, and sometimes affecting the spirits and the health before the senses 
distinctly perceive it This must be removed. In most cases this fllm is removed by 
water, and we have the ordinary result of household cleanliness ; but in other cases 
when the fhmiture is such as will be injured by water, the removal is made by friction 
or by oil or turpentine, and other substances used to polish. Water as a disinfectant 


k wed ftteo in washing of clotheg, for this porpoie nothing whaterer can snpply its 

glaoe, although it requires the assistance both of soap and friction, or agitation and 
cat Water is also osed as a mechanical agent for remoring filth, and the method 
which Hercules derised of nsing a river to wash away filth, is now adopted in all the 
most adTBBced plans of cleansing towns. It is only b^ means of water that the refose 
of towns can be conveyed away in covered and impervioas passa^pes, whilst none what- 
ever is allowed to remain in the town itself. In cases where this cannot be done, it 
is much to be desired that some disinfocting agent shoold be vsed to prevent dccom* 
position. Where water is not nsed, as in water-eioseta, there most of course be a great 
amount of matter stored up in middens, and the town is of course continually exposed 
to the efilttvift. Besides these methods of acting, water disinfects partly by preventiDg 
effluvia from i|rising from bodies, simply becnose it keeps them in solution. Iliis 
action is not a perfect one, but one of great value. The water gives off the impurity 
slowly, sometimes so iriowly as to be of no injury, or it keeps it so long that complete 
oxidation takes pbMse. The oxygen for this purpose is supplied by the air, which tiie 
water absorbs without ceasing. To act in this way, water must be delivered in 
abundance ; when only existing as a moisture, water may act as a great opponent 
to disinfeetioQ bpr rising up in vapour loaded with the products of decomposition. 

Mere dry log is known to arrest deoay, as the mobility of the particles in decompo- 
sition is stayed by the want of water. We are told in Andersson^ travels in 8. Africa, 
that the Damarss cut their meat into strips, and dry it in the sun, by which OMuns it is 
preserved fresh. A similar custom is found in 8. America. Certain days prevent < 
this, and decomposition sets in rapidly. A little overclouding of the sky, or a little 
more moisture in the air, quickly stops the process. 

The above may be called natural disinfectants, or imitations of natural processes, 
charcoal being introduced as an exam|^ of a more decided character of poroos action. 
They show both mechanical and chemical action. The mechanical, when water or air 
removal dilutes, or covers the septic bodies : the chemical, when porous bodies act as 
conveyers of oxjgen : or an union of both, when oold and Ikeat prevent the mobilitjr of 
the particIeiL The action by oxidation causes a desfcruotion of the offensive material. 
The other method is antiseptic It is much to be desired that all impurities shoukl be 
got rid of bv some <tf these methods, but especially by the air, the water, and the soiL 
There are, however, conditions in which diffieolties interfere with the action. Large 
towns may be purified by water, but what is to be done with the water which contains 
all the impurity? If put upon land, it is very soon disinfected, but on its way to the 
laad it may do much mischief. It has been proposed to disinfect it on its passage, 
and even in the sewers themselves ; by this means the town itself is freed from Uie 
nuisaaoe, and the water may be used where it is needed witibout fear. This intro- 
duces artificial disinfectants. There are other cases where such are required ; when 
the refuse matter of a town is allowed to lie either in exposed or in underground 
receptacles; in this case a town is eiqKMed to an immense sorfece of impurity, and 
dxstnfeetants would greatly diminish ^e evil, if not entirely remove it There are 
besides, special cases without end continually occurring, where impurities cannot be 
at once removed, and where treatment with artificial disinfectants is required. 

Artificial disinfectants which destroy the compound, are of various kinds. Fire is 
one of the most powerful. A putrid body, when heated so as to be deprived of all 
volatile particles, cannot any longer decompose^ It is however passible that the 
vapours m^ become putrid, and if not oarefolly treated, this will happen. ^ It was the 
custom of some of the WMltfay among the ancients to bum the dead, and it is still the 
custom in India; but although the form is kept up amongst all classM, the expense is 
too great for the poor. The bodies are singed, or even less touched by nre, and 
thrown if possible into the river. This process has been recommended here, but the 
quality of the gaseous matter rising from a dead body, is most disgusting to our 
physical, and still more to our moral senses, and the amount is enormous. It is of 
course possible so to bum it, that only pure Carbonic acid, water, and nitrogen, 
shall escape, but the probability of preventing all escape is small enough to be deemed 
an impossibility, and the escape of one per cent would cause a rising of the whole 
neighbourhood. To effect the combustion of the dead of a great city, such a laige work, 
furmihed with great and powerful furnaces, would be required, that it would add one 
of the most frightful blots to modem civihsation, instead of the calm and peaceM 
churchyard where our bones are preserved as long at least as those who care for us live, 
and then gradually return to the earth. In burning the dead some prefer to bam 
the whole body to pure ash. This was the ancient method; but it is highly probable 
that the ashes which Uiey obtained were a delusion in most cases. The amount of 
ash found in the urns, is often extremely small. The body cannot be reduced to an 
infinitesimal ash, as is supposed; eight to twelve pounds of matter remain from an aver- 
age man when all is over. A seeond plan, is to drive off all volatile matter, and leave 


a cinder. This disgusting plan leaves the body black and incorruptible. It can never, 
in any time known to us, mix with its mother earth, and yet ceases at once to 
resemble humanity in the slightest degree; it will not even for a long time assist ns 
by adding its composition to the fertility of the soiL The burning of bodies never 
could have been general, and never can be general. Fire has only a limited use as a 
disinfectant. It cannot be used in the daily disinfection of the dejecta of animals, and 
is applied only occasionally, where the most rapid destruction is the most desirable, either 
because the substance has no value, or it is too disgusting to exist, or the products after 
burning are not offensive. There are two methods of using fire, charring or burning 
to ashes. The second is an act of 

Oxidation, — This is effected either by rapid combustion called fire ; by slow com- 
bustion, the natural action of the air ; or by chemical agency, sometimes assisted hy 
mechanicaL Slow oxidation in the soil is a process which is desirable in every re- 
spect, and it would be well if we could bring all offensive matter into this condition; 
the ammonia is preserved, or it is in part oxidised into nitric acid and water, both 
the ammonia and nitric acid being food for plants. Sometimes this process is hastened 
by mixing up the manure with alkaline substances, raising it in heaps, and watering, 
by this means forming nitrates, a process performed abundantly in warm countries 
upon the materials of plants and animals, and imitated even in temperate regions with 
success. This amount of oxidation destroys a good deal of the carbonaceous substances, 
and leaves less for the land. It is only valuable when saltpetre is to be prepared. 

One of the most thorough methods of oxidation, is by the use of the manganates or 
permanganates. They transfer their oxygen to organic substances with great rapidity. 
and completely destroy them. They are therefore complete disinfectants. They 
destroy the odour of putrid matter rapidly, and oxidise sulphuretted hydrogen, and 
phosphuretted hydrogen, as well as purely organic substances. As the^ do this by 
oxidation at a low temperature, they are the mildest form of the destructive disinfec- 
tants, and their application to putrid lic^uids of every kind will give most satisfiictory 
results. The quantities treated at a tmie should not be great, and the amount of 
material used must be only to the point of stopping the smell, or at least not much 
more, because both pure and impure matter act on the manganates, and an enormoua 
amount of the material may be used in destroying that which is not at all offensive. 
The manganates do not prevent decay from beginning again. Their use has been 
patented by Mr. Condy. A similar action takes place with various high oxides and 
other oxides which are not high. Sometimes, however, a deleterious gas is produced 
as a secondary result by oxidation, as when sulphuric acid in the sulphates oxidises 
organic matter, allowing sulphuretted hydrogen to escape. In this case it is highly 
probable that a true disinfection takes place, or a destruction of the putrid substance, 
and all offensive purely organic substances; still the amount of sulphuretted hydrogen 
given off, is of itself sufficiently offensive and deleterious, although not properly 
speaking an infectious or putrid gas, but an occasional accompaniment. 

Nitric acid is another agent of destruction or oxidation, although it has qualities 
which might cause it to be ranked amongst those which prevent the decomposition by 
entering into new combinations. But properly speaking, it is not nitric acid which is 
the disinfectant of Carmichael Smyth, but nitric oxide, which is a powerful oxidiser, 
and most rapidly destroys orj|;anic matter. For very bad cases, in which gaseous 
fumigation is applicable, nothing can be more rapid and effective in its action than 
this gas. Care must be taken that there is no one present to breathe it, as it has a 
powerful action on the lungs, and care must be taken that metallic sur&ees which are 
to be preserved clean, be well covered with a coating of varnish. This was used with 
great effect in ships and hospitals for some years, beginning with 1 780, and so much 
good did it do, that the Parliament in 1802 voted Dr. C. Smyth a pension for it. 
Guyton-Morveau was vexed at this, and wrote an interesting volume concerning his 
mode of fumigating by acids; but in reality acids alone are insufficient, and his fa- 
vourite muriatic acid has no such effect as nitrous fumes, which so readily part with 
their oxygen. 

Cbiorme is another destructive agent, and its peculiar action may be called an 
oxidation. When used as a gas, it has a great power of penetration, like nitrous fumes, 
and stops all putrefaction. It has a more actively destructive power than oxygen 
alone, even when its action is that of oxidation only. It decomposes compounds of 
ammonia into water and nitrogen, and as putrefactive matter is united with, or com- 
posed partly of nitrogen, it destroys the very germ of the evil. By the same power 
it destroys the most expensive part of a manure, the ammonia. It cannot therefore 
be used where the offensive matter is to be retained for manure. When chlorine is 
united with lime or soda, it may be used either as a powder in the first case, or as a 
liquid in either case. For direct application to the offensive substances a solution 
is used, or the powder. This latter acts exactly as the gaseous chlorine, but the 


pofwer of deetroying ammonia is greater. As a liquid, it acts too rapidly; as a solid, 
the cbloride of lime soon attracts moisture, and soon loses its power. Some people 
use the chloride of lime as a source of chlorine; they pour sulphuric acid on it, and so 
cause it to giye out chlorine, which escapes as a gas, and acts as aforesaid. This has 
not been found agreeable, or indeed more than partially useful. Too much is giren 
out at first, too little at last It is said to have increased the lung diseases at hospitals, 
where it was much used in Paris. When only a minute quantity of gas is given out, 
as at bleach works, it certainly causes a peculiar freshness of feeling, and the appear- 
ance of {he people is much in its favour, nor has it eyer there been known to affect the 
lungs. For violent action, in cases of great impurity, it is a great disinfectant, and to 
be preferred to nitrous fumes, probably causing a less powerful action on the lungs. 
Eau dejacelle is a chloride of potash used in Paris. Sometimes oxygen, or at least 
air, is used alone, to remoTe both colour and smell, oils haying it pumped into them. 
Sometimes acids alone are used for disinfection. As putrid compounds contain am- 
monia or organic bases, they may be removed, pr at least they may be retained in 
combination, and in this way restrained from further evaporation. This seems to 
be the way in which muriatic acid acts, and all other merely acid agents. This acid, 
so much valued at one time, is now entirely disused, as it ought to be, because it is ex- 
ceedingly disagreeable to breathe, and destructive of nearly all useful substances which 
it touches, being at the same time a yery indirect disinfectant Acids poured on putrid 
matters, no doubt destroy the true putrefiu:tion, but they cause the eyolution of gases 
exceedingly nauseous, and of course unwholesome. This evolution does not last long, 
but long enough to make them useless as disinfectants when used so strong. Vinegar 
is the best of the purely acid disinfectants ; wood yinegar the best of the vinegars, 
because it unites to the acidity a little kreasote. Vinegar is a very old and well 
established agent ; it has been used in the case of plague and various pestilences from 
time immemorial. It is used to preserve eatables of varioas kinds. For fumigation 
no acid yaponr used is pleasant except yinegar, and in cases where the impurity is 
not of the most violent kind, it may be used with great advantage. Even this how- 
ever acts on some bright surfaces, a disadvantage attending most fhmigations. 

Si^}hurous- add, or the fumes of burning sulphur, may be treated under this head, 
although in reality it does not act as a mere acid combining with a base and doing no 
more. It certainly unites with bases so that it has the advantage of an acid, but it 
also decomposes by precipitating its sulphur, as when it meets sulphuretted hydrogen. 
It therefore acts as an oxidiser in some cases, but it is generally belieyed, from its 
desire to obtain oxygen, that it acts by being oxidised, thus showing the peculiar 
characteristics of a dcoxidiser. We can certainly belieye that bodies may be disin- 
fected both by oxidation and deoxidation. The solutions of sulphurous acid act as a 
restraint on oxidation, and preserve like yinegar. Its compounds with bases, such 
as its salu of soda, potash, &c, preserve also like vinegar, saltpetre, &c. ; probably 
from their affinity for oxygen, taking what comes into the liquid before the^ organic 
matter can obtain it. But it is not probable that this rivalry exists to a great extent ; 
the presence of the sulphurous acid in all probability puts some of the particles of oxy- 
gen in the organic matter in a state of tension or inclination to combine with it, so 
that the tension of the particles which are inclined to combine with the oxygen of the 
air is removed. 

Sulphur fumes are amongst the most ancient disinfectants held sacred in early times 
from their wonderful efficacy, and still surpassed by none. With sulphur the shepherd 
purified or disinfected his flocks, and with sulphur IFlysses disinfected the suitors which 
he had slain in his house. No acid fumigation is less injurious generally, yinegar ex- 
cepted, to the lungs or fomiture, and its great efficiency marks it out as the most desirable, 
alUiough much kdd aside in modem times. The amount arising from burning coal 
most haye a great effect in disinfecting the putrid air of our streets, and rendering 
coal-burning towns in some respects less unpleasant; this is one of the advantages 
which that substance brings along with it, besides, it must be confessed, greater evils. 
It is carious that this compound of sulphur should be one of the most efficient agents 
in destroying sulphuretted hydrogen, another compound of Sulphur. Sulphurous acid 
preyents decomposition, and also preserves the yaluable principle of a manure, so that 
it belongs partly to the class of disinfectants, and partly to antiseptics. 

The peciiliar actions of sulphurous acid and kreasote have been united in that called 
** McDougall's Disinfecting Powder." Since in towns and farms, when disinfectants 
are used, it is desirable not to use liquids, these two haye been united into a powder, 
which assists also in removing moisture, as water is often a great cause of discomfort 
and disease in stables and cowhouses. When they are used in this manner the acids 
are united with lime and magnesia. When the floors of stables are sanded with the 
powder, it becomes mixed with the manure, which does not lose ammonia, and is found 
afterwards much more valuable for land. The cattle are also freed from a great 

Vol. 11. D 


amount of illness, because the air of the stable is purified. When fieoes of anj kiod 
cannot be at once removed by vater, as by the water-closet system, the use of this is 
invaluable ; but it is well to know that the instant removal of impurity by water is 
generally best for houses, however difficult the after problem may be when &e river is 
polluted. In stables and cowhouses this is not the case, and it is then that a disinfecting 
powder becomes so valuable, although it is true that so many towns are unfortunately 
so badly supplied with water-closets that disinfectants are still much wanted for the 

The inventors have proposed to disinfect sewers, as well as sewage, by the nine 
substances ; not, howeyer, m the state of a powder. They apply the acids to the 
sewage water in the sewers themselves, and so cause the impure water to pass disin- 
fected through the town ; by this means the towns and sewers are purified together. 
When the sewage water is taken out of the town it can be dealt with either by preci- 
pitation or otherwise. As it will cease to be a nuisance, covered passages for it will 
not require to be made. 

Lime is used for precipitating sewage water, and acts as a disinfectant as far as the 
removal of the precipitate extends, and also by absorbing sulphuretted hydrogen, 
which, however, it allows again to pass off gradually. The other substances proposed 
for sewers have chiefly relation to the precipitation, and do not so readily come under 
this article. Charcoal has been mentioned ; alum has been proposed, and it cer- 
tiunly does act as a disinfectant and precipitant None of these substances have been 
tried on a great scale excepting lime. An account of the Leicester experiment by lime 
will come under the article Sewage. 

Absence of air is an antiseptic of great value. The process of preserving meat, 
called Appert's process, is by putting it in tin vessels with water, boiling off a good 
deal of steam, to drive out the air, and then closing the aperture with solder. 
Schroeder and De Dusch prevented putrefaction for months by allowing no air to 
approach the meat without passing through cotton ; so also veils are found to be a 
protection against some miasmas. Salts, or compounds of acids with bases, are 
raluable antiseptics ; some of them are also disinfectants, that is, they remove the 
state of putrefaction after it has begun. An antiseptic prevents it, but does not neces- 
sarily remove it Common salt is well known as a preserver of flesh ; nitrate of 
potash, or saltpetre, is a still more powerful one. Some of these salts act in a manner 
not noticed when treating of the preceding substances, viz. by removing the water. 
Meat, treated with these salts, gives out its moisture, and a strong solution of 
brine is formed. Chloride of calcium prevents, to some extent, the putrefaction of 
wood. Alum, or the sulphate of alumina, is not a very efficient preserver ; bat 
chloride of aluminum seems to have been foxmd more valuable. It is sometimes 
injected into animals by the carotid artery and jugular vein. Meat, usually keeps a 
fortnight : if well packed, cleaned, and washed with a solution of chloride of alu- 
minum, it will keep three months. 

But in reality the salts of the heavier metals are of more activity as disinfectants. 
It has been supposed that their efficiency arose from their inclination to unite with 
sulphur and phosphorus, and there is no doubt that this is one of their valuable 
properties, by which they are capable of removing a large portion of the impure 
smell of bodies ; but they have also an inclination to combine with organic substances, 
and by this means they prevent them from undergoing the changes to which they are 
most prone. The actual relatiye value of solutions it is not easy to tell. Most expe-> 
riments have been made on solutions not sufficientiy definite in quantity. Salts of 
mercury have been found highly antiseptic. Such a salt is used for preserving wood ; 
the process is known as that of Kyan's, or kyanising. A solution of corrosive subli- 
mate, containing about 1^ per cent of the salt, is pressed into the wood either by a 
forcing pump or by means of a vacuum. The albumen is the substance most apt to 
go into putrefaction, and when in that condition it conveys the action to the wood. It 
is no doubt by its action on the albumen that the mercury chiefly acts. Thin pieces of 
pine wood, saturated for four weeks in a solution of 1 to 25 water, with the following 
salts, were found, after two years, to be preserved in this order : — 1. Wood alone, 
brown and crumbling. 2. Alum, like No. 1. 3. Sulphate of manganese, like 1. 
4. Chloride of zinc, like 1. 5. Nitrate of lead, somewhat firmer. 6. Sulphate of 
copper, less brown, firm. 7. Corrosive sublimate, reddish yellow and still firmer. 
In an experiment, in which linen was buried with similar salts, the linen was quite 
consumed, even the specimen with corrosive sublimate. Other experiments showed 
salts of copper and mercury to protect best— Gmdin, 

Nevertheless, all these metallic salts are found true preservers under other coiidi« 
tions. Chloride of manganese, a substance frequently thrown away, may be nsed, as 
Gay-Lussac and Mr. Young have shown, with great advantage, and Mr. Boucherie has 
shown the value of the acetate of iron. Mr. Boucherie's process is very peculiar. 



He feeds the tree, -when IWing, with the acetate of iron, by ponring it into a trough 
dog aroond Uie root The tree, when cut down, has its pores filled with the salt, and 
the albumen in the sap is preyented from decomposing. For preservation of yegetable 
and animal substances, sec FnTB£PAcnoN, PaETBNTioN of. 

The chloride of zinc of Sir William Burnett is also a yalnable disinfectant, and has 
more power than it would seem to possess from the experiments quoted above. 
Wood, cords, and canvass have been preserved bj it under water for many years. It 
has the advantage also of being so soluble as to take up less room than most other 
salts, although liquids generally are inconvenient as disinfectants in many places. 

Nitrate of lead is a disinfectant of a similar kind ; it lays hold of sulphur, and the 
base unites with organic compounds. All these metals are too expensive for seneral 
use, and can only be applied to the preservation of valuable materials. Even iron is 
much too dear to be used as a disinfectant for materials to be thrown on the fields 
as manure. All are apt to be very acid, a state to be avoided in a disinfectant, 
unless when it is applied to substances In a very dilute state, or in an active pntrid 
state, and giving out ammonia. — R. A.S. 

See also Sanitary Askanoehskts. 

DISTILLATION. Distillation consists in the conversion of any substance into 
vapour, in a vessel so arranged that the vapours are condensed again and collected to 
a vessel apart. 

The word is derived from the Latin dis and stillo, I drop, meaning originally to 
drop or fail in drops, and is very applicable to the process, since the condensation 
generally takes place dropwise. 

It is distinguished from gubUmatkm by the confinement of the latter term to cases 
of distillation in which the product is solid, or, in fact, where a solid is vaporiKd and 
condensed without visible liquefaction. 

The operation may simply consist in raising the temperatore of a mixture suffi- 
ciently to evaporate the volatile ingredients \ or it may mvoive the decomposition of 
the substance heated, and the condensation of the products of decomposition, when it 
is termed deatructive dutiUation ; in most cases of destructive distillation the bodies 
operated upon are so/iV, and the products liquid or gaseous ; it is then called dty dia- 

In consequence of tbe diversity of temperatures at which various bodies pass into 
vapour, and also according to the scale on which the (^ration has to be carried out, 
an almost endless variety of apparatus may be employed. 

Whatever be the variety of form, it consists essentially of three parts,— the retort 
or MtULt the etmdenser, and the receiver. 

On the tmatt ecale^ in the chemical laboratory^ distillation is performed in the simplest, 
way by means of tbe common glass retort a, and receiver 6, as in^. 651. The great 



advantages of the glass retort are that it admits of constant observation of the mate- 
rials within, that it is acted upon or injured by but few substances, and may be cleaned 
generally with facility. Its great disadvantage is its brittleness. 

The retort may be either simple, as mfig. 652, or tubulated, as in >^. 651 (a). 

Retorts should generalljr be chosen sufiKsiently convex in all parts, the degree of 
curvature of one part passing gradually into that of the neighbouring portions, as is 



repre«eDted in the figure ; the part to be heated Bhonld, moreorer, be u oniform in 
point of thickneu u possible. The inbtilaled retort ia more liable to crack than the 
plain one, od account of Ihe neceesorilj greater Ihicknen of the glua in the neigh- 
bourhood of the tubnlHture ; nevenheleu it ii very convenient on account of the 
faciliiy which it offen for the introdaction of the materiaU. 

In charging retOTl* if plain, a fnnnel with a long stent ihonld be emplojedito avoid 
soiling the oeck vlth the liquid to be diitilled : when a solid hat to be introdnecd it 
ii preferable lo emplo j a tubulated retort ; and if a powdered lolid ii to be mixed with 
a fluid it i> prefenble to introduce tbe fluid first. 

Heat ma}- be applied to Ihe retort Hither by the argud gas flame, as injt;. 651, or 
H water, oil. or sand-bath maj' be employed. 

In distilling Tarioui subataoces, t. g., sulphuric acid, great inconvenience is expe- 
rienced, and even danger incurred, hy the phenomenon termed "bumping." Thia 
coneisls in the aecumuUlion of large babbles of vapour at the bottom of Ibe liquid, 
which bursting cause a forcible expulsion of the liquid ftota tbe retort. It is pre- 
vented by the iulroduclion of a few angular fragments of solid matter of soch a nature 
as Dot to be acted upon by the liquid which is to be distilled. Nothing answer* tbi* 
purpose better than a piece of platinum foil cut into a ft'ioge, or even a coil of plati- 
num wire introduced into the cold liquid before Ihe distillation is commenced. Even 
with (his precaution the distillation of sulpbaric acid, which it is often desirable to 
perform for the purpose of its purification, is not unattended with dlfEJcnlty and 

Dr. Mobr suggests the following method*: — A glass retort of ahont two ponnds 
capacity, i> placed od a cylinder of sheet iron ia tbe Ceotre of a gmill iron furnace, 
while its neck protrudes through ao opening in tbe side of the furnace (.ffji.GSS). Ignited 
charcoal is placed round the cyliuder, without being allowed to come in contact with 
the glass, and a current of hoi air is thus Diade to play on all parts of the retort 
excepting the bottom, which is protected by its support There is a valve in the fine 
of the furnace for regulating the draaght,and three small doors in Ihe cupola or bead, 
for supplying fresh fuel on every side, and for observing the progren of tbe distil- 
Instead of the sheet Iron cyliDdcr a hessian crucible may be employed, and this, if 
requisire, elevated by phicing it on a brick. If the vapour he very readily condensed. 
Dotliingmoreis necesssry tbanio bsert the extremity of tbe retort into a g^as* receiTet 
asinj^. 651. 

If a more efficient condensing arrangement be reqaislie, nothing iamore convenient 
for use on the small scale than a Liebig's condenser, shown in ,fig. 654. It conaiatt 

simply of a long glan lube into which Ihe neck of the retort is fitted, and the opposite 
extremity of which passes into the mouth of the receiver ; round tbis lube is fitted 
another either of glass or metal, and between tbe two a current of water it made to 
flow, enlering at a and passing oat at ft. The temjieratore of this water may be 
lowered to any required degree by putting ice into the reservoir e, oi by disulving 
salts in it. (See FaEsztNo. } 

Even on the small scale it Is sometimes necessary to employ distillatory sppantiia 
constructed of other materials besides glass. 

■ MotiT (Dit RedwDsd't Prwtiul PbvmWT. 



Euthenwire retort* are now eoiulrneted of very Mmvenieiit lues ind ihapea. 
There la one ktod — vhich ii very aaefal when it is required to pui a gu into the 
retort at the nine time that the distillaCioD ii going on, u in the preparation of 

chloride of akunmimn, &c which haaatnbe paniag down into it alio made of 

eartbeovare, ai iafig. 6SS. The eloKit are of Wedgevood ware, bnt a common cla]' 
iMon maj' be made impenaeable to gatei, b^ waihing the nirface with a loliitiDn of 
borsi, then carefDlly drying and heating them, 

Betorta, or Saska witb bent tube*, which kkt in thnt {fig. 6S6), of copper, are 



employed when it ii reqniaile lo prodnce high temperBtorei, u for the preparation of 
bensole tiram benzoic acid and baryta, or in malting marsh gu from an acetate, &c. 

In diatiUing hydroflaoric acid the whole apparatua ahontd be conatmeted in leadj 
the receirer conaiiting of a U -shaped titbe of lead, which ia fitted with leaden atoppers 
so as lo aerve for keeping the ncld when prepared ; or a receiver of gutta percha may 
be employed with a stopper ofthe same mitcriat. (.Fig. 657.) 

For many purposea in the laboratory ai, for instance, the preparation of oxygen by 
heating binoxide of manganeae, — in the maau&clare of potassiom, &c. See. , where 
bigh lemperatnrea are repaired, the iron bottles in whidi mercury is imported from 




Spain may be employed, a common gnn-barrel being screwed into them to act aa a 
delivery tabe or condenser, (Fijr. 658.) 

On a large scale an almost cndiesa variety of atills have been and are still employed, 
which are constructed of diOerent mateinala. 

The common ■'stitl" coniists of a retort or still pmpcr, in which the subslance is 
heated; and a condenser commonly called a "wonn"on accnnnt of its having fre- 
qaenll; a spiral shape. The retort or still ia generally made in two parts ; the pan 
or cop/KT, which is the part to which heat is applied, and ia commonly set in a furnace 
of bricksork, and the " htad" which is generally removed after each operation, and 
nfixed and luted npon the pan when igun osed. The condenser or worm is com- 
monly placed in a tube or other veaael trf water, (See/ij, 661.) 

The Btill may be either constructed of earthenware, or, as is very conmionly the 
case, of copper, either plun or electro-plated with silver, according to circDmstances i 
lees freqoeDtly platinum is employed. 

The still is either healed by an opei^ fire, as in Jig. 656, or, as is aow vety conimoiity 


the CMC, by itrani. The >tiU-paD (jfj. 659) ii Buirounded by an outer copper jtelcet, 
and steam i« Admitted betveea them fhim a ateam boiler under any reqnired pres- 
lure. Id Ibis na; the lenperatara may be regulated vith the greatest nicety. 

Various adaptations for heating by steam hare been appropristelj arranged in a 
Tcry oonTtnieBt form by Mr. Coffey, of Bunbill Row, Finsbnry, in bis sii-CBlted 
EscuUpinD Still. It is in l^f^t a veritable mullum iaparvo, being intended to aSbrd to 
the pharmaceutical chemist the means of conducting the processes of ebullition, distilla- 
tion, eTaporalion, desiccation, &c., on the small scale, by the heat of a gns-fBrnace. 
The foUoving sat (Jig. 660) represents thia apparatus. 



valve for iliattiBg off the Meun fivm i, -when it puaet throDf^ the tabe m, other- 
wue it voold psai tbrongb l. utd comma aicate heat to the diying-cloiet o o, and 
from thsDce to the oondeaacr t t. o it * Mcond etaporalin|; pan OTer the drjtng- 
cloairt. Another ■mnguneiil for dittilling by Meam ia ihown in Jig. 061. 

Sometime* alto dinillatioD is effected b; pawing hot (team through a ironn con- 
luned KilAn the still, imtead of or in addilioD to, the application of beat from 

The vonn or eondenaer i« frcqnentlj conatmeted of earthenware, and ut in an 
earthenwaiv veMel, theie are Ttirj conienient when the operatiou is not to be con- 
docted on B very targe Kale, and only at a moderate lemperatore. They are now lo 
be obtained of alt mana&etaren of itone-wara artidca. More commonly the worm 
il of eopper, tin, or copper lined with lilver, and in aome rare case* where the liquid* 
lo b« dulilled act epon both copper and lilTcr, of platinum. {Fig. flea.) 



venel of a pritmatic form which ocoopie* bat little tpace : the water employed for 
coDdennuioTt enter* nt the bottom and pnues oat at the (op. 

Gadda'i ecndtiuer is represented in fiq. 664. Il consisli of two conical veuvls of 
metal, of nncqoal aiie the smaller being fixed within the other, and (he apace between 


them closed at the bottom. These are placed io a tub filled with cold water, which 
cornea in eoDlact with the ioner and outer Bur&ces of the codm, wbiJe the (para 
between i» ocenpied b; the vapour to be condensed. Thia condenser it lubject lo [be 
otgection which appliei to the common worm, that it ciuiQOt be eaiiJy and efficienil; 

To obviate tbii, Profeitor Mit*cherlicb hM propoied a very simple modification in 
it« foriD, in which ihe inner cone is rooTable, lo that, when talien out, the intervening 
space belween itaud the oaler cone cin be cleaned, and then the inner eona reflaeed 
previooily to commencing an operation. 

DUtdlalim of SpirilM. — In the manaractore of ardail $pirilt, the tiedholic liquor 
obtained bj fermentation of a saccharine soiulion is submitted to distillation i the 
alcohol bein^ more volatile tlinn the wsler pitsses »ier first, but invariablj a consider- 
able proportion of water is evaporated and condensed with the alcohoL To sepaMe 
this water to the required extent it is necessary either to submit the product to redis- 
tillation, or to contrive an apparatus such that the product of this fint diatillation ia 
relorned to the still until a spirit of the required strength is obtaioed. 

One oftbeearlieBt and simplest coutrivances for efiecting the latter object ii the sliU 
invented bj Dorn, which ii employed up to the present lime in Germany (Jig. GGS). 
A is the aiill, heated by Ibe direct action of the fire ; B the head, from which r txaieji 
vapour to a small refrigerator, for the purpose of testing the slrcngth of the distillate '; 
B ia an ordinary condenser containing worm, &c The intcrm^iate copper veoel 
answers mo purposes; the upper part c forming a heater for the wash, while the lover 
compartment b acts as a rectifier. The healer c, whan filled np to the level of the 

cook B, contains the exact measDrc of wish fbr charging Ihe still ; the eonients can 
be constantly agitated by the rouscr i. The still and healer being both charged, Ihe 
vapourwill at first be completely condensed in passing through the worm g, andflov- 
iog into D will close Ihe npcrlure. When the contents of c become bo hot thst no 
more condensation occurs, Ihe vapour will escape by hubblinR through the liqoid in n, 
which latter rapidly becomes healed to Ihe boiJing point, imd evolves vapours richer 
in alcohol, which in their turn are conden<ied in e. 

In thif mnoner, by one operalion, spirit containing about 60 per cent, of alcohol is 

or the recent improvements on Bom's still two only need be described :— CoH'eT■^ 
which has in a great measure replaced ail othen in thiscountry.and Dennne's, wbich 
is extensively employed in France. 

Coffey's still fnr surpasses any of those before described. It was patented in I8SS, 
and has proved mo«l valuable to the distiller, since it yields the strongest spirit thil 
can be obtained on the large scale. 

Its objects are twofold:— lat, to economise Ihe heat, as much as pooible, by ex- 
posing the liquid to a very extended healed surface ; Sud, to cause Uie evspoiation 
of the alcohol from the wash by passing a current of steam through it 

The wash is pumped from the " wash charger " into the worm tube, which passes 
{torn top to bottom of the rectifier. In circulating (hrongli ihis tnbe its temperalore 
is raised lo a cenain extent Arrived at tiie Ust convolution of the tube in the 
rectifier the wuh passes by Ihe tube mm in at the top of the "analyser." ItfnIliSDd 



oollecta apon die top shelf antil this overflowt, wheooe it falls on t« tlie leeond shelf 

ftnd so 00 to the bottom. All the while sleom is passed up rrom the steam boiler 
through fine botes in tlic ebelves, and through Tslves opeoing upwards. As the wuh 
gniduBllj descends in the aaaljser it becomea npidly weaker, panlj fVnm conden- 
sation of the steam which is pa^ed into it, and partly from loss of alcohol, either 
evaporated or expelled bv the steam ; till, when it airiTes at the bottoin, it has parted 
with the last traces of spirit. At the same time the vapour, a* it rises through each 
shelf of the analyser, becomes con^naoasly richer in alcohol, and contains less and 
leu water in consequence of its condensation ; it then passes from the top of the 
analyser in at the bottom of the lower compartmeat of the rectifier. Here it ascends 
in a similar way, babbling through the descending wash, nntil it arrives at r, above 
which it merely circulates round the earlier windings of the wash pipe, the low tern* 
peraturc of which condenses the spirit, which, collecting on the shelf at r, flow* off 
by the tube into the finished spirit condenier. 

In order Blill ftirther to economise heat, the water for supplying the boiler is nade 
to pass through a lon^ coil of pipe, immersed in boiling hot spent wash, bj which 
means its temperature is raised before it enters the boiler. In f^t the saving of fuel 
by the employment of this still is so great, that only about three-fourths of the 
quantity is consumed that would he requisite for distilling an^ given quantity of 
alcohol in the ordinary still ; and Dr. Muspratt estimates that io this way a saving 
will be effected throughout the kingdom of no less than 140,000 tons of coal per 

Very few persons have any idea of the enormoos Kse of some of the distilleries. 
One of Mr. Coffey's stills at Inverkeithing works off 3000 gallons of wash per hour, 
ftod one, more recently erected at Leilh, upwards of 3000 gallons. 

Deromt't ttill is very similar, in the prmciple of its action, to Coffey'a, differing in 
eg7 fact only in the mechanical 

details by means of wbicb the 
result is obtained. 

It conusts of two stills, A. 
and B,jSp. 667. The mlitnre 
of steam and alcohol vapour 
from A passes into the liquid 
in B, which it raises to the 
boiling point The vaponrs 
from B rise through the <iul3- 
latoiy column c, and o (the 
rectificatory column) ; bence 
they traverse the coila of 
tubing in e (the conrfeiutr and 
vine heater), and the alcohol 
is finally condensed by tra- 
versing the worm in r (the 
Ttfrigrrator), whence it is deli- 
vered at z. At the same time 
a steady current of the ori- 
ginal alcoholic liquor is ad- 
mitted from the reservoir H, 
into the exterior portion of the 
condenser f, by means of the 
tap, the flow from whicb is 
regulated by the ball cock $. 
Whilst condensing the spirit 
in the worm the waab has its 
temperature raised, especially 
ascends by the tube h into the 
heater e, by the small ori£ces 
k k, fig. GG8, where it is still 
further heated by the current 
. of healed alcohol which has 
t- risen into the worm ttom the 
stills, whilst at the same time 
ansisling in the condensation 
of the spirit After perform- 
ing its office of condensauon, 
andwEen nearly nt the boiling point, the alcoholic liquor pnsscs out by the tube^ and 


progTCM into tbe atill b, ud jet permit ^°^ 

ihe ucent of tlie itewn. In thu dis- 

tUlatoTj colDmn (c, jig. STO) it meeta 

Ihe ite&m riaog from the still b. The 

greater p&rt of itt alcohol is expelled, 

wtucfa, traTening die aeries of con- 

deosen before described, is allinuiletj 

liqaefied and collected at z; but, to 

complete Ihe rectificatioo, it descends 

into the still B, and, irben above a 

certain level (m n), into l, which stills 

being heated by a fnmace beneath, the 

final expulsion of alcohol is Mcom- 

plished, and the spent liqaor run tS 

The details of the eonstniction <A 
the apparatus employed in the dis- 
lillation of spirits have been here given, 
since this process is perhaps one of the 
Djott important of the kind ; bnt va- 
riooa modifications are employed in 
the distillation of other Iir)uids. 

In some cases, Dnasually eSeCloal 
condensing amngenieiils are required, 
as in the manufacture of Etbeh, Chu>- 
soroKM, BiBULFBiDE or Caibom, and 
BiCHLOBiDE or Cakbon. 

la others higher temperatures are 
necessary, as in the distillation of sul- 
phuric acid. 

When the liquids to be distilled are acid, or otherwise corrosive, great care has to 
be taken especially that the worm or other condenser is of a material not acted upon 
by the scid. See Acetic Acid, and Sulphdbic Agii\ 

The term distillation is sometimes applied to cases of the volatilisation and subse- 
quent condensation of the metals either in their preparation or purification. 

In cases like mercnrj, potassium, and sodium, where they are condensed in the 
liquid state, or fisibly pass through this state before volatihsation, this term is quite 
^ipropriate i but where the fusing and vaporising points nearly coincide, as in the 
ease of arsenic, Ihe term aublimation would be more suitable. 

Nevertheless it is difficult to draw a precise line of demarcation l>etweeo the two 
terms \ for in the cases of zinc cadmium, &c., the metals being melted before vola- 
tilisation, and condensed likewise in the liquid state, the term is certainly corrccl. 

For the details of construction of the distillatory apparatus we must refer to the 
articles on these several mclnls. 

Di^iilatio^ daceaum is a term improperly applied to certain eases of distiUalion 
vbetv the vapour is dense, and may be oollected by descendiog through a tube which 


has an opening in the top of the distillatory yessels, and descends through the body of 
the vessel in which the operation of evaporation is going on, being collected below. 

This is clearly merely due to the fact of the vapoar being even at a high tempera- 
ture more dense than atmospheric air, and might be performed withany body fomung 
a dense vapoar, such as mercury, iodine, zinc, &c. 

It has, however, practically been confined to the English process of refining sine. 
See Zinc. 

The two most remarkable cases in which the process of destructive distillatioin is 
carried out on a manu&cturin^ scale, are the dry distillation of wood, for the manu- 
facture of wood charcoal, acetic acid, and pyrozilic spirit (which see); and of coal, for 
the purpose of obtaining coal gas, and coke. This process will be found fully de- 
scribed in the article on Coal-oas. 

Distillation of Essential Oils or Essences, — The separation of volatile flavouring 
oils fVom plants, &c, by distillation with water, will be fUUy treated under another 
head. See Perfumest, Essences. 

Fractional Distillation, — A process for the separation of volatile organic substances 
(such as oUs) is very extensively employed in our naphtha works under this name. 

If we have two volatile bodies together, but differing appreciably in their boiling 
points, we find, on submitting them to distillation in a retort, through the tubulature 
of which a thermometer is fixed, so that its bulb dips into the liquid, that the tem- 
perature remains constant (or nearly so) at the point at which the more yolatile con- 
stituent of the mixture boils, and the distillate consists chiefly of this more volatile 
ingredient ; and only after nearly the whole of it has passed over, the temperature 
rises to the point at which the less volatile body boils. Before this point has been 
reached, the receiver is changed, and the second distillate collected apart. By sub- 
mitting the flrst product to repeated redistillation, as long as ita boiling point remains 
constant, the more volatile constituent of the mixture is ultimately obtained in a state 
of absolute purity. See Naphtha. 

This method may in fact be adopted when the mixture contains several bodies ; 
and by changing the receiver with each distinct rise of temperature, and repeating 
the process several times, a fractional separation of the constituents of the mixture may 
be etfected.— H. M. W. 

DISTILLATION, DESTRUCTIVE. Organic matters may be divided into two 
groups, founded on their capability of withstanding high temperatures without under- 
going molecular changes. Bodies that distil unchanged form the one, and those which 
break up into new and simpler forms, the other. The manner in which heat acts 
upon organic substances differs not only with the nature of the matters operated upon, 
but also with the temperature employed. We shall study the subject under the 
following heads : — 

1. Apparatus for destructive distillation, 

2. Destructive distillation of vegetable matters, 

3. Destructive distillation of animal matters, 

4. Destructive distillation of acids. 
6, Destructive distillation of bases. 
6. General rmarks. 

1. Apparatus for destructive distillation. — Destructive distillation on a large scale is 
most conveniently performed in the cast iron retorts used in gas works. Where quan- 
tities of materials not exceeding fifteen or twenty pounds are to be operated on, for 
the purpose of research, a more handy apparatus can be made fh>m one of the stout 
cast iron pots sold at the iron wharves- They are semi-cylindrical, and have a broad 
flange round the edge. The cover should be made to fit in the manner of a saucepan 
lid. The aperture by which the products of distillation are to be carried away should 
be of good size, and the^exit pipe must not rise too high above the top of the pot before 
it turns down again. This is very essential in order to prevent the less volatile portion 
of the distillate from condensing and falling back. The exit tube should conduct the 
products to a receiver of considerable capacity, and of such a form as to enable the 
solid and fluid portions of the distillate to be easily got at for the purpose of examin- 
ation. From the last vessel another tube should conduct the more volatile products 
to a ^ood worm supplied with an ample stream of cold water. If it be intended to 
examme the gaseous substances yielded by the substances under examination, the exit 
pipe of the worm must be connected with another apparatus, the nature of which 
must depend on the class of bodies which are expected to come over. If the most 
volatile portions are expected to be basic, it will be proper to allow them to stream 
through one or more Woulfe's bottles half filled with dilute hydrochloric acid. Any 
very volatile hydrocarbons of the C'H" family which escape may be arrested by 
means of bromine water contained in another Woulfe's bottle. The pressure in the 
Woulfe's bottles must be prevented from becoming too great, or the leakage between 


the flange of tlie pot and its coyer will be yery considerable. The latbg may consist 
of finely nfted Stourbridge clay, worked up with a little horse dung. A few heavy 
weights should be placed on various parts of the lid of the pot, so as to keep it close, 
and render the leakage as little as possible. For the destractiye distillation of small 
quantities of substances, I have been accustomed for a long time to employ a small 
still made from a glue pot, and having a copper head made to fit it The luting for 
all temperatures not reaching above 700 may be a mixture of jths linseed and ^th 
almond meal, made into a mass of the consistence of putty. For the apparatus em- 
ployed in the destructive distillation of wood, coal, bones, &c, on the large scale, the 
xarious articles in this work on the products obtained from those substances must be 

2. Deatruetive distillation of vegetable matters.»~-The principal vegetable matters which 
are distilled on the large scale are wood and coaL We shall consider these separately. 

Destrucdve distillation of wood, — The products obtained in the ordinary process of 
working are acetic acid, wood spirit or methylic alcohol, acetone, pyrozanthine, xylite, 
lignine, paraffine, kreosote. or phenic acid, oxyphenic acid, pittacal, several homologues 
of benzole, with ammonia, and methylamine. There are also several other b^ies 
of which Uie true nature is imperfectly known. The greater part of the above sub- 
stances are fhlly described in separate articles in this work. See Acetic Acid, Pa- 


Peat appears to yield products almost identical with those from wood. 

Destructive distillation ofcoaL — The number of substances yielded by the distillation 
of coal is astonishing. It is very remarkable that the fluid hydrocarbons produced at 
a low temperature are very different to those distilling when a more powerful heat is 
employed. The principal fluid hydrocarbons produced by the distillation and subse- 
quent rectification of ordinary gas tar are benzole and its homologues ; see Hydro- 
CARBOKS. But if the distillate is procured at as low a temperature as possible, or 
Boghead coal be employed, the naphtha is lighter, and the hydrocarbons which make 
its chief bulk belong to other series. See Naphtha. 

3. Destructive distillation of animal matters. — Bones are the principal animal sub- 
stances distilled on the large scale. The naphthas which come over are excessively 
foetid, and are very troublesome to render clean enough for use. The products con- 
tained in bone oil will be described in the article Naphtha. Horn and wool have 
recently been exammed with reference to the basic products yielded on distUlingthem 
with potash. Horn under these circumstances yields ammonia and amylamine. Wool 
I find to afford ammonia, pyrrol, butylamine, and amylamine. My experiments on 
feathers, made some years ago, although not carried so far as those on wool, appear 
to indicate a very similar decomposition. 

The products yielded by animal matters, when distilled per se^ are very different 
to those obtained when a powerful alkali is added previous to the application of 
heat. If feathers or wool be distilled alone, a disgustingly foBtid gas is evolved 
containing a large quantity of sulphur. Part of the sulphur is in the state of sulphide 
of carbon. But if an alkali be added previous to the distillation, the sulphur is re- 
tained, and the odour evolved, although powerful, is by no means offensive. During 
the whole period of the distillation of ordinary organic matters containing nitrogen, 
pyrrol is given off, and may be recognised by the reaction afforded with a slip of deal 
wood dipped in hydrochloric acid. An interesting experiment, showing the formation 
of pyrrol from animal matters, may at any time be made with a lock of hair, or the 
feather of a quill. For this purpose the nitrogenous animal matter is to be placed at 
the bottom of a test tube, and a little filtering paper is to be placed half way up the 
tube, to prevent the water formed during the experiment from returning and frac- 
turing the glass. The end of the tube is now to be cautiously heated with a spirit 
lamp, and, as soon as a dark yellowish smoke is copiously evolved, a slip of deal pre- 
viously moistened with concentrated hydrochloric acid is to be exposed to the vapour. 
In a few seconds the wood will acquire a deep crimson colour. The fact of the pre- 
sence of sulphur in wool, hair, or other albuminous compounds of that description, 
may be made very evident to an audience by the following experiment Dissolve the 
animal matter in very concentrated solution of potash in a silver or platinum basin, 
with the aid of heat Evaporate to dryness, and raise the heat at the end to fuse the 
potash and destroy most of the organic matters. When cold, dissolve in water, and 
filter into a flask half full of distilled water. To the clear liquid add a little of Dr. 
PlayiUr's nitroprusside of sodium ; a magnificent purple tint will be immediately pro- 
duced, indicative of the presence of sulphur. A very small quantity of hair or flannel 
will sufllee to yield the reaction. 

The above remarks on destructive distillation apply principally to highly complex 
bodies, the molecular constitution of which is either doubtful, as in the case of albu- 
minoos substances, or totally unknown, as with coals and shales. The destructive 




distillation of organic substances of comparatively simple constitntion, such as acids 
and alkalies, sometimes yields products, the relation of which to the parent substance 
can be clearly made out This holds more especially in the case of organic acids; the 
bases too often yield such complex results, that the decomposition cannot be expressed 
by an equation giying an account of all the products. We shall study a few cases 

4. Deatructive distillation of acids. — The destructive distillation of acids takes place 
in a totally different manner, according as we have a base present or the operation is 
carried on withoat any addition. Many if distilled per se undergo a very simple re- 
action, consisting in the elimination of carbonic acid, and the formation of a pyroacid. 
But if an excess of base be present, the decomposition often results in the formation 
of a ketone (see Acetone). We shall offer a few examples of these decompositions. 
Gallic acid, heated to about 419° Fahr., is decomposed into pyrogallic and carbonic 
acids, thus: — 

C"H«0»« « C"H«0« + 2C0» 


Gallic acid. Pyrogallic acid. 

There are cases in which the action of heat upon organic acids results in the for- 
mation of two substances, not produced simultaneously, but in two epochs or stages. 
In reactions like this, the first effect is the removal of two equiyalents of carbonic 
acid, and by submitting the resulting acid to heat again, two more are separated. 
Under these circumstances, it is the second which is generally called the pyroacid. As 
an example we will take meconic acid which breaks up in the manner seen in the 
annexed equations. 

C"H«0" =3 C*«H*0" + 2C0* C"HW« « C'»H*0« + 2C0« 

Meconic acid. Comenic acid. Comenlc acid. Pyromeconlc acid. 

It will be seen that the hydrogen remains unaffected. Perhaps the name pyroco- 
menic acid would be preferable to pyromeconlc acid, inasmuch as it is derived fmn 
comenic acid in the same manner as pyrogallic from gallic acid. 

But pyroacids are not always derived from the parent acid by the mere elimination 
of carbonic acid ; thus mucic acid, in passing into pyromucic acid, loses two equiyalents 
of carbonic acid, and six equivalents of water, thus: — 

C"H>K)'« - CWH^O* + 2C0« + 6HO 


Mucic acid. Pyromucic acid. 

It does not invariably happen that the destructiye distillation of acids perse results 
in the formation of a pyroacid, the disruption is sometimes more profound, the products 
being numerous and somewhat complex. Let us take as an illustration a case where all 
the results can be reduced to an equation. Oxalic acid, when heated in a retort withoat 
addition, yields water, oxide of carbon, carbonic and formic acids, in accordance with 
the annexed equation : — 

4(CK)«,H0) = 4C0« + 2CO + 2H0 + C«HO«,HO 

Oxalic acid. Fomilc acid. 

The admixture of sand, pulverised pumice stone, or any other inert substance in a 
state of fine division, often remarkably assists in rendering the decomposition more 
easy and definite. Thus, if pure sand be mixed with oxalic acid, the quantity of formic 
acid is so increased, that the process is sometimes employed in the laboratory as a 
means of affording a pure and tolerably strong acid. 

We have said that the destructive distillation of acids proceeds in a very different 
manner according as we operate upon the acid itself, or a salt of the acid. The dis- 
tillation of the pure salt yields different products to those which are obtained when 
the salt or dry acid is mixed with a large excess of a dry base (such as quicklime), 
before the application of heat If, in the former mode of proceeding, two atoms of 
the acid are decomposed, yielding a body containing (for four volumes of yapour, see 
Formula) the elements of two atoms of carbonic acid and two of water less than the 
parent acid, such body is called a ketone. Thus when two atoms of acetate of lime 
are distilled, the products are one atom of acetone, and two of carbonic acid. Of 
course the carbonic acid combines with the lime, thus : — 

2(C*H«CaO*) « C'HHP + 2(CaO,CO«). 

Acetate of lime. Acetone 

If, however, the salt is not of a very low atomic weight, and the quantities operated 
on are at all considerable, secondary products are formed, as in the dry distillation of 



outyrate of lime, wheD» if the substance is not in very small quantity, carbon is deposited, 
and a certain qaantity of batyral (C'H'O^) is formed, and probably other substances. 
As an illustration of the decomposition undergone irhen acids are distilled with a 
^reat excess of dry base, we shall select that of benzoic acid, which under the circum- 
stances alluded to yields benzole and carbonate of the base. 

C"H«0* - C«H« + 2 (CO«) 

Bensoic add. Beniole. 

5. Destructive dutiBaticn o^beues, — It has been found that the organic bases undergo 
a much simpler and more direct decomposition when subjected to destructiTC distiUa- 
tion in presence of alkalies than when they are exposed to heat without admixture. 
There are two bodies almost invariably found among the resulting products, namely 
ammonia and pyrroL In this respect, therefore, the organic alkalies behave like 
other nitrogenised animal and vegetable products. The decomposition is almost 
always rather complex, and it is very rare that the products are sufficiently definite 
to be arranged in the form of an equation. The most common substances found, are 
the alcohol bases, and these are almost invariably of low atomic weight One great 
difficulty connected with researches on this sulject, is owing to the fact of its teing 
seldom that the products are in sufficient quantity to enable a thorough knowledge of 
the molecuhu* constitution to be arrived at Unfortunately this information is much 
-wanted in consequence of the numerous cases of isomerism to be met with among the 
alcohol baaeSb See FoaHinLB, Chekical. Thus it is difficult, when working on 
Tery small quantities, to distinguish between bimetlfylamine and ethylamine, both of 
which have the formuhi OH'N. 

It is remarkable that thero is a great similarity between the products of the des« 
tmctive distillation of some of the most unlike nitrogenous substances. This is con- 
spicuously seen in the case of bones, or rather the gelatinous tissues of bones, shale 
and ooal naphthas, and cinchonine. An inspection of the following table, compiled 
from a paper (by the writer of this article), ** On some of tEe Basic Constituents of 
Coal Naphtha," will render this evident 

Gclatlnoas TiHoet. 

Shale Naphtha. 

Coat Naphtha. 





























• « 





It is very possible that some of the above bases, having the same fonnulie, but de- 
rived from different sources, will, in course of time, prove to be merely isomepc, sod 
not absolutely identicaL The author of this article has quite recently found that the 
chinoline of coal tar is certainly not identical with that from cinchonine. The base 
from the latter source yields a magnificent and fiist blue dye upon silk, when treated 
by a process which gives no reaction if the coal base be substituted. It is unfortunate 
that the reaction is with the latter instead of the former, as it would have added one 
more to the list of gorgeous dyeing materials yielded by coal tar. 

6. General Remarka. — The tendency of numerous researches, made during the last 
few years, has been to show that there is no organic substance, capable of resisting 
high tempeiatares, which may not be found to exist among products of destructive 
distillation. By varying the nature of the substance to be distilled, and also the cir- 
cumstances under which the operation is conducted, we can obtain an almost infinite 
variety of products. Acids, bases, and neutral substances, solid, liquid, and fluid 
hydrocarbons, organic positive, negative, and derived radicals, organo-metallic bodies, 
— all may be produced by the action of high temperatures on more or less compli- 
cated bodies. Much has already been done, but the facts at present accumulated 
relate merely to the superficial and more salient substances. On penetrating further 
below the surface fiir more valuable and interesting facts will come to light — C.G.W. 

DIYIDIYI, or Libi Davi^ is the pod of a leguminous shrub, which is an indigenous 
production of Jamaica, and some parts of South America. Mr. Rootsey obtained a 
mean produce of 6*625 grs. of leather from 60 grs. of dividivi, while the same quantity 
of the best Aleppo galls yielded only a mean produce of 4*625. It appears too 
from Sir Humphry Davy's estimate, that 60 grs. of dividivi contain 3*0476 grs. ot* 
5-079 per cent of tannin, and 60 grs. of galls, 2*12704 gniia, or 3*450 per cent 



- 229 

New Granada 

- 2,617 

Venezuela - 

- 372 

Other parts - 






Sixty gn, of oak bark yielded only 1'75 grains of leather; whence it follows that it 
contains but 0'805 of a grain of tannin to the drachm, or not more than 1 '34166. 

It has been tried as a dye instead of galls or sumach, but its use for this purpose is 
almost entirely abandoned. See Leather. 

Diyidivi imported in 1857 : — 

computed real value, 2,4 1 6 

»» »» 

»» >» 

3,153 £33,264 

DIVING BELL. As it is frequently desirable to raise objects from the bottom of 
the sea or rivers, and to lay the foundation of piers and similar structures, some con- 
trivance was desired to enable man to descend below the water, and to sustain himself 
while there. The first method adopted was the very simple one of letting down a 
heavily weighted bell vertically into the water. As the bell descended, the air got 
overpressed, and the water rose in the bell, but never to the top, and within that 
space the man was sustained for some time. The air, however, was vitiated by the 
processes of respiration, and the man had to be drawn up. It is curious to find that 
as early as 1693 a ver^ complete system of diving without a bell was devised, as the 
following quotation will show. 

A.D. 1693. ^William and Blary, by the Grace, &c &c. Whereas John Stapleton, 
gentleman, hath by his great stddy and expence invented a new and extrsordinary 
engine of copper, iron, or other mettal, with glasses for light joints, and so contrived as 
to permit a person enclosed to move and walk freely with under water, and yet so 
closely covered over with leather as sufficiently to defend him fh>m all the jumpes of it. 
Also invented a way to force air into any depth of water, whereby the person in the 
aforesaid engine may be supplied with a continual current of fresh aire, which not 
only serves him for respiracon, but may alsoe be ute/ul far continuing a lamp burning^ 
which he may carry about with him in hie hand, • • • Likewise a way to 
make the same again serviceable for respiracon, and by continually repeating the 
operacon, a man mav remain a long time under water, in either of the said engines, 
without any other air than the sayd engines do contayne, whereby he shall be pre- 
served from suffocation if any extraordinary accident should interrupt the current of 
fresh air afore menc5ned." — Letters Patent Rolls Chapel Edited by Bennet Woodcro/t 

The defects were many in this apparatus, and Dr. Halley invented a bell, the object 
of which was to remedy them. 

Dr. Halley's bell was of wood coated with lead, and having strong glass windows 
above, to allow the passage of light to the diver. In order to supply air, a barrel was 
taken with an open hole m the bottom, and a weighted hose hanging by, and fitting 
into a hole at the top. From this barrel the air of the bell was supplied as frequently 
as it became vitiated, the barrels of air being sent down from above. Spalding im- 
proved upon Halley's bell, and again Friewald made some improvements on Spalding's, 
but in principle these bells were all alike. The modem bells are usually large and strong 
iron bells, with windows in the upper part By means of an air pump, placed on the sar- 
&ce, air is sent down to the divers in the bell, and the vitiated air is as regularly 
removed from the bell bv other tubes through which it escapes. These diving bells 
are lowered by means ot cranes, and are moved about in the water by those above, 
signals being given by the men below. The difficulty of moving this machine, renden 
it still inconvenient, and recent attempts have been made to obviate this, by the con- 
struction of a diving bell upon principles entirely different. This new diving bell, 
to which the name of The NAUTiLns has been applied, has proved so useful in the 
construction of some parts of the Victoria Docks, and some works on the Seine, that m 
full description of it is appended. 

The nautilus machine is entirely independent of 6usi)ension ; its movements are 
entirely dependent on the will of those within it, and without reference to those who 
may be stationed without ; it possesses the power of lifting large weights, per m, and 
at the same time is perfectly safe, by common care in its operations. This latter ia 
the greatest desideratum of all. These advantages must strike all as combining 
those requisites of success which have been always wanting in the present known 
means for constructing works under water. 

The form of the machine is not arbitrary, but depends entirely on the nature of 
the work to be performed, adapting itself to the various circumstances attending any 
given position. By reference to the annexed figures it will be perceived that when at 
rest, being entirely enclosed, its displacement of water being greater than its own weight, 
it must fioat to the surface (see Jig. 671). Entering through a man-hole at the top 
(which is closed either from the inside or outside), yon descend into the interior of the 


mmchiBV, portloiu of whieb »re willed off on cither nde, formiDg chkinbera ; theM 
chambera are cooneeud at or near tb« bolKun of a pipe a a, vhidi opeu by ■ 

cock i, oalwnrdi to the extensl (urrouDdIng water. Aa openiog ia the bottom of 
the machine of variable dimetuions ia closed b; a door or doors luaceptible of being 
opentd or closed at pleaMin^ The chamben w w, are likewise coDoected U top hj 

a smaller pipe ee, which opeiu tbrongh the top of the machine, and to which opening 
is affised a flexible pipe, with coits of wire spirally enclosed. Branches on this 
Utter pipe T, allow also commnnicBtlon with the larger or working chamber. 

At the surface of [be water placed on a float or vessel for the pnrpase, is a receiver 
of variable dimensions, to which is attached at one end a hoUow dram or reel, to the 
barrel of which is affixed the other end of the flexible pipe a, leading to the top of 
the naatilns. At the other end of, and In connection with the receiver, is a powerful 
air -condensing pump. This combination represents the nancUus as adapted to 
engineering work. 

At to the wndia operaitdi: — The operator with his ssiislanta enters the maehlaa 
through the top, which is then closed. To dcKend, the water-cock b ii opened, and 
the external water flows into the chambers w w ; at the same time a cock, on a pipe 

Vol. IL E 



opening from the chambers outwards, is opened, in order that, the mr escaping^, an 
nntnterrapted flow of water may take place into the chambers. The weight of water 
entering the chambers caoses a destraction of the buoyancy of the machine, and 
the nautilus gradually sinks. As soon as it is fairly under water, in order that 
the descent may be quiet and without shock, the water-cock &, is closed. The re- 
ceiver at the surface being previously chMiged by the air pump to a density scnne- 
what greater than that of the water at the depth proposed to attfun, one of the 
branch-cocks on the pipe c r, connecting the chambers at top, is opened, and the air 
rushes into the working chamber, gradually condensing until a density equal to the 
density of the water without is attained; this is indicated by proper air and water 
gauges. These gauges marking equal points, showing the equilibrinm of forces 
without and within, the cover to the bottom z is removed or raised, and commonica- 
tion is made with the under water surface, on which the nautilus is resting. In order 
to move about in localities where tides or currents do not affect operations, it is only 
necessary for the workman to step out of the bottom of the nautilus, and placing the 
hands against its sides, the operator may move it (by pushing) in any direction. 

Where currents or tides, however, have sway, it becomes necessary to depend upon 
fixed points from which movements may be made in any direction. This is accomplished 
by placing, in the bottom of the nautilus, stuffing boxes of peculiar construction (m m, 
fig. 672), through which cables may pass over pulleys to the external sides, thence 
up through tubes (to prevent their being worn), to and over oscillating or swinging 
pulleys, placed in the plane of the centre of gravity of the nautilus, and thence to 
the points of affixment respectively (Jig. 673). The olgect to be gained by having 



the swinging pulleys in the plane of the centre of gravity of the masB, is to hold the 
machine steady and to prevent oscillation. Within the machine, and directly over the 
above stuffing boxes, are windlasses for winding in the cables. By working these 
windlasses movement may be effected, and of course the number of these cables will 
depend on the variable character of the situation to be occupied. Having thus 
secured the means of descending, communicating with the bottom, and of movement, 
the next point is to ascend. Weight of water has caused a destruction of buoyancy 
at first, and consequent sinking ; if then any portion of this water is removed, an 
upward effort will at once be exerted exactly proportionate to the weight of water 
thrown off.^ The sir in the receiver at the surface being constantly maintained at a 
higher density than that of the water below, if we open the water cock on the top 
pipe, c, c, throwing the condensed air from the receiver above directly on to the 
surface of the water in the chambers, movement and consequent expulsion of the 
water must take place, and an upward movement of the machine itself, which will 
rise to the surface. 

It is evident that if, previously to the expulsion of the water, the nautilus be affixed 
to any object below, the power exerted on that object will be exactly proportionate to 
the weight of water expelled, and the power will continue increasing until, there 


being no fiffther weight to be throirn off, the maximam effect is prodaced. To applj 
this power to lifting masses of stone or rock, proper arrangemeDts are affixed to the 
centre of the opening in the bottom, by which connection can be made with the 
weight, admitting, at the same time, the swinging around of the object suspended, 
so that it may be placed in anj required position. In the construction of permanent 
work, or the movement of objects whose weight is known, or can be estimated, a 
water, or, so called, lifting tube is placed on the side of the water chamber, which in- 
dicates the lifting power exercised by the nautilus at any moment The adyantsge 
of this gauge will be recognised, inasmuch as without it the closest attention of the 
operator, working very cautiously, would be necessary to determine when the weight 
was overcome ; by its aid, however, the operator boldly throws open all the valves 
necessary to develope the power of the nantilos, watching only the gauge. The 
water, having reached the proper level indicating the required lifting power, he knows 
the weight must be overcome, or so nearly so that the valve or cocks may be at once 
closed, m order that the movement may take place horixontallyk A moment's re- 
fieetioii will show that* if there were not an index of this character, carelessness or 
inattention on die part of the operator, by leaving the cocks open too long, might 
develope a power greater than required, and the nautilus would start suddenly up- 
ward. The expansive power of air, acting upon the incompressible fluid, water, 
through the opening in the bottom, gives a momentum which, by successive de- 
velopments of expansion in the workmg chamber, is constantly increasing in ve- 
locity, until, in any considerable depth of water, the result would be undoubtedly 
of a very serious character. Take, for exemplification, the nautilus in thirty-three 
feet of water, and bottom covers removed, and an equilibrium, at fifteen pounds 
to the inch, existing between the air and the water at the level of the bottom of 
the machine. Upward movement is communicated the instant the machine rises 
in the slightest degree, the existing equilibrium is destroyed, and the highly elastic 
qualities of air aasome preponderance, exerting, from the rigid surface of the water 
below, an impulsive effort upward in the direction of least resistance. At each suc- 
cessive moment of upward movement the impelling power increases, owing to the 
increasing disparity between the pressure of air within struggling for escape. The 
machine, thus situated, becomes a marine rocket (in reality), in which the propelling 
power is exhausted only when the surface is reached, and a new equilibrium is ob- 
tained. It will readily be seen that, were this difficulty not overcome, it would be 
impossible to govern the nautilus ; for, rising with great velocity to the surface, 
the machine is carried above its ordinary flotation, or water line, a little more air 
escaping owing to the diminished resistance as thajt level is passed ; the recoil, or 
surging downwards, causes a condensation of the air remaining in the chamber ; 
a portion of the space previously occupied by air is assumed by water ; the buoyant 
power becomes less, the machine settles slightly more by condensation of the air, a 
larger space is occupied by water, and the nautilus redescends to the bottom with a 
constantly accelerating movement, seriously inconveniencing the operator by filling 
more or less with water, according to depth. For many months the difficulties just 
enumerated baffled all attempts at control. A weight attached could be lifted, bat 
the instant it was entirely suspended, — before the valves could be closed, — upward 
movenaent was communicated beyond control This difficulty so fatal has been over- 
come by an arrangement at ike bottom of the nautilus, with channels which 
radiate fh>m the opening in an inclined direction, debouching at the sides of the 
machine. The moment then that the air, by its expansion f^om diminished resist- 
ance, or by the introduction fh>m above of a greater volume than can be sustained 
by the water* below, reaches, in its downward passage, the level of these chambers, 
following the direction of least resistance, it passes through these channels and 
escapes mto the surrounding water, without of course affecting the movement of the 
machine in the least 

The pump for supplying air to the diving bell or other suitable vessel is represented at 
fig». 674 and 675, and is constructed as follows : — d is a cylinder, opening at the upper 
part into a chamber or chambers r f, separated by a partition s. On the side of 
each of these chambers there is a valve h h, opening inwards, and at the upper 
part of the same are two valves 1 1, opening outwards into the valve chamber g. 
Outside the opening for each of the valves h, h, there is a cup, into which the end 
of the water supply pipe K passes ; by this means a small stream of water is supplied 
to the cup, and is drawn f^om it into the chamber 7 to supply the waste in the opera- 
tion of pumping. The valve chamber o is covered with a jacket A, having a space 
between it and the valve chamber that is filled with water fh>m the water pipe m, 
which affords a stream of cold water to carry off the heat fh)m the condensed air 
which is forced into the chamber. The water thus supplied circulates through the 
tubes in the chamber and round them in the jacket, and thus cools the Air in these 

E 2 


IB thereby Btled with vUer, aod 
thus the air is expelled therefrom ■ smsll quan- 
tily or (h« wnter pimsiiig with it and coieriog the 
TaWcs hj which means they are kept tight and 
■wet TTie air nnd -water thna diieharped, after 
passing around the siidlU tuheG m the ralre 
chamber and beine cooled are forced outward 
and conveyed to the condenser On the r«tnrD 
stroke of the piston, the other chamber r is filled. 
and air and water expelled from it m like manner 
through its Talve into the Talve chamber. There 
is alvays a sufficient quantity of water in the cy- 
linder D and chamber f to fill the latter when 
the -water is all expelled ftom the cylinder, by 
the piston c haTing been driven to one end of it, 
and when the piston returns to the opposite end 
of the cylinder the irtiter flows in behind it, and 
draws in its equivalent in bulk of air and water 
through the valve h. On its return, this is forced 
out throngh the valve A into the chamber i, as 
Dienliooed above. The water being non-elaHic, 
le parts are kept cool enough to avoid raising 
n, this procen may be continoed for any length 
o> time. A transverse aectioD of this appiiatua is 
shown in Jij. 67S. 

Figs. 676 and 677 reprMent the tfeakiog tabe 
and alarm bell above referred to. The conatmfi- 
tion of this mcchsnism is as follows : — There is 
a hollow csEting, one portion of which is trian- 

if the I 


ga]»z in form, (torn one end of whi 
■ projt ■ " 

screw cut on . 
■creved iolo tb« top of the 

from the iniide, and pro- 
ject* through it to allow 
the coupling of ft flexible 
or other hose to he at 
tached to it. At tlie op 
pnsite angle, and in a line 
with a, there is a tnbnlsr 
projection b, prorided with 
a, screw to receive a cap J" 
to which is to be attached 
a I»ece of hose. Withm 
the tuhe/, and at its janc 
tioD with b, ie placed a thin 
diaphragm of metal oi 
oth«r laitaUe material c, 
for which pDTpote, how- 
ever, a thin silver plate (hat 
just fits (he bore of the cap 
/" ia preferred. This dia- 
phrwm closet all commn- 
Tesael and the external air. 
By this means it is eaa; to 
coDverse (hrongh aay re- 
qniredlengtliof tnbing. I( 
Diaj be desirable to Gt a 
■top-cocfc into the tnboUr 

projection &, as a precsDtioaarymeBns of preventing the (scape of air in (he event of a 
mptnre of the diaphragm. The apper part of the triangnlar enlargemem of ihe 
speaking tnbe is ts|iped for a stuffing box at g, withb which there is an aiii A, which 
rao* frcan side to side of the said enlargement, and through (he ataSng box st one side. 
On this uis i is fixed a lever i within the said enlargement, which lever communicates 
with the Enrfaee of the water by means of a wire Gxed at its reversed eod, and ninning 
throngh the whole length of pipe. On the oater eitremitf of the axis h ia affixed a 
hammer, which strikel oti a bell k conoecled to the tube, as shown in the drawing. 
Br tbia means the attention of the operator below may be drawn to the ipeaking tube 
when it is required to convene with him from the sarfkce of the water, and the men 
wboae duty it is to attend to the operator beh>w can, by placing their ear at the end of 
Ihe tabe, hear the bell struck be- 
low at a signal (or commanicntioil "° 
wltfi them at the snrftce. 

The only parts of the apparatus 
not vet described are the saw for 
catting the (ops of piles to an oni- 
furm level, the pump which enables 
the divers tbeinselves to rise to the 
surface in Ihe event of the flexible 
bose being detached or iqjured, 

1 the« 

an eje bolt into the tide of the 
SDoken vessels. 

The arrangement of the saw- | 
fVame and connections are shown 
in fiff. 678. Only u much of the 
botium of the Nautilus is shown 
■■ will render the pcaition of the 
saw imderstood. p is a pile which 
is repaired to be out down to Ihe 
«ame level a« the others, e is the 
blade of the saw, n the framing 
by which it is stretched, c, d, the 

handle which resu on the cross bar K ; to whicb is attached the upright part of the 
handle which is laid hold of by the workman inside when working the i*v. b, a, r. 



a bent lever ^ith two friction rollers at f which gaides the saw forwards whUe 

making the cut . v • i. 

Thf pump for ascending in case of accident to the air hose is not shown m the 
drawing. It is a simple force pump placed in the working chamber, by whicli the 
ballast water in w w, fig. 672, can be pumped out so as to lighten the apparatus «iiB- 
cientlj to allow of its ascent 

The apparatus for fixing the eye bolts is shown in fig. 679. The operation of this 
apparatus is as follows : — It will be observed the chsunber d opens outwards to the 
water, so that when the sliding partition or valve y is forced down by the lever g, the 
communication of the water with the chamber c is cut off. The lid z being removed, 
a bolt i ^or other operating tool or instrument) is placed within the chamber c ; the 
rod k is forced through the stuflBng box / until the recessed end of the rod contains 
the end of the bolt ; the small rod j is then screwed through the stuffing box n, until 
the screw on the end of this rod has become affixed to the end of the bolt contained 
within the recess at p. The lid z of the chest is then fastened on, and the partition 
or valve y raised, the stuffing box m preventing the escape of air. Communication is 
thus opened between the chambers a and d, the latter b«ingopen outwards. The rod 
i is now pushed outwards by pressing on the handle k through the stuffing box /, 
nntil the vessel or object to be operated upon is reached, when the operation is per- 



s - 
» - 

1 - 

> — 

I - - 

> r •■ 


ibrmed as required. It will be observed that the stuffing box prevents the escape of 
air out of the bell or the admission of water into it, the stuffing box n having the same 
tendency. After the operation with the tool or instrument is complete, the rod k is dis- 
connected by unscrewing the rod j, and is drawn into the chamber a by means of the 
handle k ; the partition or valve y is again lowered, and the operations above described 
arc repeated. It will hence be obvious that a number of eye bolts might in this manner 
be successfully inserted in the side of a sunken vessel from the diving bell, so that bj 
hooking on the ** camels *' the strain would be so distributed as to prevent injory by 
the process of lifting the toid vessel. 

DOCIMACY. !Brom the Greek AoKifta^'w, I prove (^Docimasie, Fr. ( Probierhaui, 
Germ. ), is the art by which the nature and proportions of an ore are determined. 
The art of assaying minerals, the separation of the metaL This analjrtical examina- 
tion was originally conducted in the diy way, the metal being extracted from its mine- 
ral isers* by means of heat and certain fluxes. But this method was eventually found 
to be insufficient and even fallacious, especially when volatile metals were in question, 
or when the duxes could absorb them. The latter circumstance became a very serions 
evil, whenever the object was to appreciate an ore that was to be Worked at great ex- 
pense. Bergmann first demonstrated, in an elaborate dissertation, that the humid ana* 
lysis was much to be preferred ; and since his time the dry way has been devoted 
chiefly to the direction of metallnrgic operations, or, at least, it has been employed 
merely in concert with the humid, in trials upon the small scale. 

AfWr discovering an ore of some valuable metal, it is essential to ascertain if its 
quantity and state of combination will justify an adventurer in working the mine, and 
smelting its products. The metal is rarely found in a condition appfoadiing to purity ; 
it is often disseminated in a ^angue far more bulky than itself; and more frequently 
still it is combined with simple non-metallic substances, such as sulphur, carbon, 
ehlorine, oxygen, and acids, more or less difficult to get rid of. In these compound 
states its distinctive characters are so altered, that it is not an easy task either to re> 
cognise its nature, or to decide if it can be smelted with advantage. The assaycr. 


without neglecting any of the external characters of the ore, teeks to penetrate, so to 
speak, into its interior ; he triturates it to an impalpable powder, and then subjects 
it to the decomposing action of powerful chemical reagents ; sometimes, with the aid 
of alkalies or salts appropriate to its natnra, he employs the dry way by fire alone ; at 
others, be calls in the solvent power of adds with a digesting heat ; happy, if after a 
series of labours, long, Taried, and intricate, he shall finally succeed in separating a 
notable proportion of one or more metals either in a pure state, or in a form of com- 
hioation such that from the amount <^ this known compound, he can infer, with 
precision, the quantity of fine metal, and thereby the probable value of the mine. 
The blow-pipe, skilfully applied, affords ready indications of the nature of the me- 
tallic constituents, and it is therefore usually the preliminary test The separation of 
the several constituents of the ore can be effected, however, only by a chemist, who 
joins to the most extensive knowledge of the habitudes of mineral substances, much 
experience, sagacity, and precision in the conduct of analytical operations. Under 
the individual metals, as also in the articles BiiOWpzPB, Assay, Metalldrgt, Minks, 
and Ores, are presented such a copious and correct detail of docimatic processes, as 
will serve to guide the intelligent student through this labyrinth. 
DOEGLING TRAIN OIL. The oil of the Balana rostrata, or Bottle-nose whale. 
DOGWOOD. Comtu sangumea, a small underwood known as the wild cornel, 
and as the conunon Dogwood. Little splinters of this wood are used by the watch- 
makers for cleaning out the pivot-holes of watches, and by the optician for cleaning 
deeply-sealed small lenses. Its peculiarity is that it is remarkably free from silex. 
Toothpicks are also manufiictured from dogwood. 

DOIXY. DOLLY TUB. A minim^ term applied to a tub fitted with a perforated 
bcMird, the doXbf^ to which a circular motion is given by a winch-handle, and thus im- 
pe^ts a similar motion to the ore. See Minino and Ores, Drbssino of. 

DOLOMITE. JUagnesian Limestone. This rock occurs in very (p'eat abundance 
in various parts of England, especially in Yorkshire, Nottinghamshire, and Somerset. 
It is largely employed as a building stone. 

Karsten infers, from his numerous analysles of dolomite, that in those which are 
crystallised, the carbonate of lime is always combined in simple equivalent propor- 
tion with another carbonate, which may be carbonate of magnesia fdone, or together 
with carhonates of iron or manganese, and sometimes both. In the uncrystallised 
varieties of dolomite, the diversity in the proportion of lime and magnesia is inde- 
finite, but such masses must be regarded as mere mixtures of true dolomite and car- 
bonate of lime. Acids do not produce a perceptible effervescence with dolomite, 
except when digested with it in fine powder. Karsten found that dilute acetic acid 
extracts from dolomites, at a temperature below 32^ Fahr., only carbonate of lime, 
while a dolomitic mass remains undissolved. Hence he regards them as mixtures of 
dolomite with unaltered carbonate of lime. — Buckof. 

Sulphate of magnesia has been manufactured from dolomite on the large scale. 
Dr. William Henrv, of Manchester, patented a process of the following kind : — 
Calcine magnesian limestone so as to expel the carbonic acid ; then convert the 
caustic lime and magnesia into hydrates by moistening them with water ; afterwards 
add a sufficient quantity of hYdrochloric, nitric, or acetic acid, or chlorine to dissolve 
the lime, but not the magnesia, which, after being washed, is converted into sulphate 
by sulphuric acid, or, where the cost is objectionable, by sulphate of iron, which is 
easily decomposed by magnesia. Or the mixed hydrates of lime and magnesia are 
to be added to bittern : chloride of calcium is formed in solution, while two portions 
of magnesia (one from the bittern, the other from the magnesian lime) are left unacted 
CO. Hydrochlorate of ammonia may be used instead of bittern : by the reaction of 
this on the hydrated magnesian lime, chloride of calcium and caustic ammonia remain 
in solution, while magnesia is left undissolved ; .the ammonia is separated from the 
decanted liquor by distillation. 

In some chemical works on the Tyne, the dolomites fW>m the coast around Marsden 
are treated with sulphuric acid, and the sulphate of magnesia {Epsom salts) separated 
from the sulphate of lime by crystallisation. 

The dolomite has also been employed by the late Hugh Lee Pattinson for the ma- 
nufacture of the Carbonate of Magnesia, which see. 

DONARIUM. Dr. Bergmann received through Mr. Krantz a mineral from 
Brerig in Norway, which is found in the same zircon-syenite that contains wohlerite 
and eukolite, and he discovered in it the oxide of a new metal combined with silicic 
acid. This metal he calls Donarhtm, after the god Donar, and he assigns to it the 
symbol — Do. 

The silicate of the oxide of Donarinm, Do*0»,SiO» + 2HO, is yellowish red, in 
some fragments passing into brown, in others into yellow ; when scratched or pow- 
dered, it is light orange. In thin films it is almost transparent, the thicker ones 

S 4 


transladd. Some pieces have a distinctly laminated stracture, in others the fractare 
is more fiat, or conchoidal. Its hardness is between that of finor spar and apatite ; its 
specific gravity «» 5*397. 

Small films heated in a platina spoon break down into a dark brown* mass, which 
reassumes an orange colour when cold; the larger pieces lose their transparency. By 
heating it in a glass tube, watery vapour is driven oS, Fragments held by the pla- 
tina forceps in the flame of a spirit lamp decrepitate. Heated by the blowpipe on 
charcoal, it does not melt, a slight vitrification being sometimes observed on the 
edges, perhaps in consequence of the intermixture of some foreign substance. Fused 
with soda, the silicic acid is dissolved. The other constituents are seen in the non- 
transparent mass, by the help of a glass, as small yellow particles. Borax yields a 
yellow bead, which is colourless when cold. The phosphates produce in the external 
part of the flame a reddish glass, which is colourless when cold ; in the inner part of 
the flame the bead becomes yellow, and when cold is colourless. 

The mineral, containing donarium, is readily decomposed by acids, and yields when 
treated by hydrochloric acid a clear and transparent gelatinous matter. At the same 
time some carbonic acid is evolved. The colour of the solution is deep yellow, like that 
of a concentrated solution of iron. The mineral is also affected by diluted acids, even 
by tartaric acid. After having been exposed to a strong heat, the essential parts of 
mineral are no longer acted upon even by concentrated acids. 

The analysis showed tho presence of lime, water, and the new oxide, also some 
traces of magnesia, manganese, carbonate of soda, and iron. 

The oxide of donarium belongs to the class of earthy bodies, and ranks next to 
zirconia and yctria. The hydrate, which is thrown down by ammonia of a beautiful 
white colour, becomes yellow, and at Isst yellowish red, losing its hydrate water in the 
air. B}*^ heat the latter is completely removed, and the oxide, which is insolnble in 
muriatic acid, can be perfectly deprived by this acid of the contained iron. Analysis 
showed the constituents to be : — 

Silicic acid -----. 17*625 

Oxide of donarium - - - * . 71 •247 

Carbonate of lime ...... 4*042 

Oxide of iron - - - . . 0*310 

Magnesia and oxide of manganese < - - 0*214 

Potash and soda . - . . . 0*303 

Water ---..- 6*900 


See Ure*8 Dictionary of Chemistry, 

DONKEY ENGINE. A very small engine employed to pump water into boilera. 
If the use of the donkey engine was more usual than it is we should hear less of steam 
boiler explosions. • 

DOOt^ARA RESIN. A resin obtained in considerable quantities in the East Indies 
from the Vateria Indica, which is used as a fragrant incense in the temples, makes 
an excellent varnish, and is sometimes called JSast Indian Copal^ or Gum Ptiuy. 
— Simmonds, 

DORNOCK, is a species of figured linen of stout fabric, which derives its name 
f^om a town in Scotland, where it was first manufiictured for table-cloths. It is the 
most simple in pattern of all the varieties of the diaper or damask style^ and therefore 
the goods are usually of coarse quality for common household wear. It receives the 
figure by reversing the flushing of the warp and woof at certain intervals, so as to 
form squares, or oblong rectangles upon the cloth. The most simple of these is a suc- 
cession of alternate squares, forming an imitation of a checker board or mosaic work. 
The coarsest kinds are generally woven as tweels of three leaves, where every thread 
floats over two, and is intersected by the third in succession. Some of the finer are 
tweels of four or five leaves, but few of more ; for the six and seven leaf tweels aie 
seldom or never used, and the eight leaf tweel is confined almost exclusively to 

DOWN. See Feathers. Down imported in 1857, 5,208 lbs. 

DRAGON'S BLOOD {Sang dracon, Fr. ; Drachenbfut, Germ.) is a resinous 
substance, which comes to us sometimes in small balls of the siae of a pigeon's egg, 
sometimes in rods, like the finger, and sometimes in irregular cakes. Its colour, in 
lump, is dark-brown red; in powder, bright red ; friable ; of a shining fracture; specific 
gravity 1*196. It contains a little benzoic acid, is insoluble in water, but dissolves 
readily in alcohol, ether, and oils. It is brought from the East Indies, Africa, South 
America, as the produce of several trees, the Dracana draco, the Pterocarpus santa- 
Unu8, Pterocarpus draco, and the Calamus rotang. 


Dragon's blood is used chiefly for Ungeing spirit and turpentine Tarnishes, for pre* 
paring gold lacquer, for tooth tinctures and powders, for staining marble. Sec Ac* 
cording to Herbenger, it consists of 9*07 parts of red resin called X>racoiitii, 2 of fixed 
oil, 3 of benaoic acid, 1 -6 of oxalate, and 3*7 of phosphate of lime. According to 
Johnstone, the resin of lump dragon's blood has the formula C^H'^O*, that of reed 
dragon's blood, C*H«»0». 

Pereira, enumerates the following varieties of this substance found in commerce: — 

1. Dmgon^M biood in the reed; Dragon's Uood in sticks; Siinguis Draconis in 

2. DragtnCs Hood in oval masses; DragotCs Wood m drops; Sanguis Draconis in 

3. Dragon^s blood in powder. 

4. Dragon's Wood in the tear ; Sanguis Draconis in grants. 

5. Lump Dragon^s Wood ; Scmguis Draconis in massis. 

Besides these, there are Dragon*s Wood in cakes, and False Dragon*s Wood in oval 

DRAINING TILES. Burnt clay tiles, generally shaped in section like a horse 
shoe, about one foot long and two or three inches broad. These are much used in 
agricultural draining. See Stoivb-warb. 

DRAWING CHALKS. Chalks or crayons are frequently nothing more than the 
natural production reduced to a conrenient form : they are, however, sometimes pre- 
pared artificially ; a few of these manufactures are named. 

The brothers Joel, in Paris, employ as crayon cement the following composition : 
6 parts of shellac, 4 parts of spirit of wine, 2 parts of turpentine, 12 parts of a 
colouring powder, such as Pru$sian>blue, orpiment, white lead, vermilion, &c., and 
12 parts of blue da^. The clay being elutriated, passed through a hair sieve, and 
dried, is to be well incorporated by trituration with the solution of the shellac in the 
spirit of wine, the turpentine, and the pigment ; and the doughy mass is to be 
pressed in proper moulds, so as to acquire the desired shape. They are then dried 
by a stove heat. 

In order to make cylindrical crayons, a copper cylinder is employed, about 2 inches 
in diameter, and 1^ inch long^ open at one end, and olosed at the other with a per- 
forated plate, containing holes corresponding to the sizes of the crayons. The paste is 
introduced into the open end, and forced through the holes of the bottom by a piston 
moved by a strong press. The vermicular pieces that pass through are cut to the 
proper lengths, and dried. As the quality of the crayons depends entirely upon the 
fineness of the paste, mechanical means must be resorted to for effecting this object in 
the best manner. The following machine has been found to answer the purpose 
exceedingly welL 

JFig. 680 is a vertical section through the centre of the crayon milL Fig. 681 is a 
view of the mill from above, a, the mill tub, whose bottom b must be a hard flat plate 
of cast-iron ; the sides a being of wood or iron at pleasure. In the centre of the 
bottom there is a pivot c, screwed into a socket cast upon the bottom, and which may 
be strengthened by two cross bars d, made fast to the fhime e. r, the millstone of 
cast-iron, concave, whose diameter is considerably smaller than that of the vessel 
A; it is furnished within with a circular basin of wood a, which receives the mate- 
rials to be ground, and directs them tot he holes h, which allows them to pass down 
between the under part of the muUer, and the bottom of the tub, to undergo tritur- 

By the centrifagal motion, the paste is driven towards the sides of the vessel, rises 
over the sides of the muller, and comes again through the holes n, so as to be 
repeatedlv subjected to the grinding operations. This millstone is mounted upon an 
upright shaft i, which receives a rotatory motion from the bevel-work k, driven by 
the winch i. 

The furnace in which some kinds of crayons, and especially the factitious black- 
lead pencils, are baked, is represented in^^r. 682, in a fW>nt elevation ; and in^. 683, 
which is a vertical section through the middle of the chimney. 

A A, six tubes of greater or less size, according as the substance of the crayons is a 
better or worse conductor of heat These tubes, into which the crayons intended for 
baking are to be put, traverse horizontally the laboratory b of the furnace, and are 
supported by two plates c, pierced with six square holes fbr covering the axles of the 
tubes A. lliese two plates are hung upon a common axis d ; one of them, with a 
ledge, shuts the cylindrical part of the furnace, as is shown in the figure. At the 
extremity of the bottom the axis d is supported by an iron fork fixed in the brick- 
work ; at the front it crosses the plate c, and lets through an end about 4 inches square 
to receive a key, by means of which the axis d may be turned round at pleasure, and 
thereby the two plates c, and the six tubes a, are thus exposed in succession to the 
action of the fire in an equal manner upon each of their sides. At the two extremities 


fuel u iotrodaced ; Q,Jig. 683, the uh-pit ; b, the flre-pUce ; i holes of the gnoe 
irhich Bcparate the flre-plsce from the ash-pit ; e, brickwork exterior to the furnace. 

General Lomet proposes the following composition for red crayoni. He tikei the 
■oftcst fariDntiCe, grinds it upon a porphfrj (lab ; and then earefullj elatnates it. He 
makes it into plastic paste arith gum arabic and a little irbite soap, which he forms by 
moulding, as aboTe, through a sjriage, and drying JQto crayons. The proportioot 
of tlie ingredients require to be carefully studied. 

Chiyuns or Chalks, lithographic. Vuioua formnlie have been given fbrthe fonna- 
tion of these crayons. One of these prescribes nhite wax, 4 parts ; hard tdlow-soap, 
shellac, of each S parts; lamp black, 1 part. Another is, dri^ (allow-soap and «bite 
wai, each n parts ; lamp black, 1 part. This miiture being fused with a gentle heat, 
is lo be cast into moulds for forming crayons of a proper size. See LiTnooRAPor, 

DRUGGET is a coarse, but rather slight, wooUen nbric, used fbr covering carpets, 
aod as an article of clothing by females of the poorer classes. — Vrt. 

The manofncture of druggets of various kinds has been of late years considerably im- 
proved, and carpets, many of them handsomely figured, are now found in common 

DRY GRINDING. The practice of employing dry_ stones has been long adopted 
for the purpose of quickening the processes of sharpening and polishing stwl goodie 
Tbe dry dusi from the sand-stone, mixed with the tine particles of steel, being inhaled 
by the workmen, produces diseases of the pulmonary organs to such an extent, that 
needle and fork grinders are reported rarely to lii~e beyond the ages of twenty-five or 

Mr, Abraham, of Sheffield, Grst invented magnetic guards, which, being placed 
close to the grindstone, attracted the particles of steel, and thos protected the men 
from their influences. Still they suffered from the effects of the fine sand-durt, »nd 
the grinders heedlessly abandoned the use of them altogether. 

Mr. Abraham devised another plan, which is employed, although only partially, in 
the Slieffield works. The grindstone is enclosed in a wooden case, which only ex- 
poses a portion of the edge of tbeslonei a horizontal lube proceeds as a tangent from 
the opper surface of the circle to the external atmosphere. The current of air gener- 
ated by the stone in rapid revolution, escaping through the tube, carries off with it 
nearly all the dust arising fVom ttie process. It is curious to find so simple a cMi- 
trivsnce frequently rrjecled by Ibe workmen, notwithstanding that sad experieoc* 
teaches them, that they are (hereby exposing themselves to the influenee* of an atmo- 
■phere which produces slowly but snrely their dissolution. 



DRYING OILS. When oilt, especially linieed and nut oik, are boiled with litharge 
or oxide of lead, ihey acqnire the property of solidifying or drying quickly on expo- 
sure to the atmosphere. These are very useful to the painter, as without them the 
pigments with which they are mixed would remain soft. The oxide of lead appears 
to estaUish a state of more easy oxidation in the oils, so that they assume readily the 
conditions of a resin. 

DRY ROT. A peculiar decomposition which takes place in wood, dependent upon 
a process of oxygenation. See Wood. 

DTJCTlLlTi (Sireckiarckeit, Germ.) is the property of being drawn out in length 
without breaking, possessed in a pre-eminent degree by gold and silver, as also by many 
other metals, by glass in the liquid state, and by many semifluid, resinous, and 
gammy substances. The spider and the silkworm exhibit the finest natural exercise 
of ductility upon the peculiar viscid Mcretions firom which they spin their threads. 
¥rhea a body can be readily extended in all directions under the hammer, it is 
said to be malleable, and when into fillets under the rolling press, it is said to be 

Talkie of the DvctiUty and MaUeahUity of Mttah. 

Metflto Ductile and 

Brittle MetaU 

MetaU In the Order 

MeUl« in the Order 

Malleable in Alpha- 


of their AViredrawing 

of their Laminable 

beCkal Order. 

AlphabeUcal Order. 
















Cerium ? 












Columblum ? 














Palladium ? 




Cadmium ? 












There appears to be therefore a real difference between ductility and malleability ; 
fcr the metals which draw into the finest wire are not those which afford the thinnest 
leaves under the hammer or in the rolling press. Of this fact iron affords a good 
illustration. Among the metals permanent in the air, 17 are ductile and 16 are brittle. 
Bat the most ductile cannot be wire-drawn or laminated to any considerable extent 
without being annealed from time to time during the progress of the extension, or 
rather the sliding of the particles alongside of each other, so as to loosen their lateral 

DCLSE. The jRhodomefiia palmata. See AixiiB. 

DUNES. Low hills of blown sand, which are seen on the coasts of Cheshire and 
Cornwall, in this country, and also in many places skirting the shores of Holland and 

DUNGING, in calico-printing, is the application of a bath of cowdnng, diffused 
through hot water, to cotton goods in a particular stage of the manufacture. Dunging 
and scouring are commonly alternated, and are two of the most important steps in the 
process. See Calico Printiho. 

DUTCH LEAF or FOIL, a composition of copper and lime, or of bronze and 
copper leaf. See Allots, Brass, and Bronze Powdsrs. 

DUTCH RUSH. EquUetum Hyemah, This rush is known also as the Large 
hranchleu Horse'tail. The dried stems are much employed for polishing wood and 
metal. For this purpose they are generally imported from Holland. 

DYEING (Teinture, Fr. ; Fiirberei, Germ.) is the art of imparting to and fixing 
upon wool, silk, cotton, linen, hair, and skins any colour, with sufficient tenacity, not 
to be removed by water or the ordinary usage to which these fibrous bodies are 
exposed when worked up into articles of raiment or furniture. We shall here consider 
the general principles of the art, referring, for the particular dyes and the manner of 



opening from the chambers ontwards, is opened, in order that, the air escaping, an 
uninterrupted flow of water may take place into the chambers. The weight of water 
entering the chambers causes a destrnction of the buoyancy of the machine, and 
the nautilus gradually sinks. As soon as it is fairly under water, in order that 
the descent may be quiet and without shock, the water-cock &, is closed. The re- 
ceiver at the surface being previously charged by the air pump to a density some- 
what greater than that of Uie water at the depth proposed to attain, one of the 
branch-cocks on the pipe c c, connecting the chambers at top, is opened, and the air 
rushes into the working chamber, gradnally condensing until a density equal to the 
density of the water without is attained ; &is is indicated by proper air and water 
gauges. These gauges marking equal points, showing the equilibrium of forces 
without and within, the cover to the bottom z is removed or raised, and communica- 
tion is made with the under water surface, on which the nautilus is resting. In order 
to move about in localities where tides or currents do not affect operations, it is only 
necessary for the workman to step out of the bottom of the nautilus, and placing the 
hands against its sides, the operator may move it (by pushing) in any direction. 

Where currents or tides, however, have sway, it becomes necessary to depend upon 
fixed points from which movements may be made in any direction. This is accomplished 
by placing, in the bottom of the nautilus, stuffing boxes of peculiar construction (m m, 
fig. 672), through which cables may pass over pulleys to the external sides, thence 
up through tubes (to prevent their being worn), to and over oscillating or swinging 
pulleys, placed in the plane of the centre of gravity of the nautilus, and thence to 
the points of affi&ment respectively (Jig. 673). The olgect to be gained by having 


the swinging pulleys in the plane of the centre of gravity of the mass, is to hold the 
machine steady and to prevent oscillation. Within the machine, and directly over the 
above stuffing boxes, are windlasses for winding in the cables. By working these 
windlasses movement may be effected, and of course the number of these cables will 
depend on the variable character of the situation to be occupied. Having thus 
secured the means of descending, communicating with the bottom, and of movement, 
the next point is to ascend. Weight of water has caused a destruction of buoyancy 
at first, and consequent sinking ; if then any portion of this water is removed, an 
upward effort will at once be exerted exactly proportionate to the weight of water 
thrown off. The air in the receiver at the surface being constantly maintained at a 
higher density than that of the water below, if we open the water cock on the top 
pipe, c, c, throwing the condensed air from the receiver above directly on to the 
surface of the water in the chambers, movement and consequent expulsion of the 
water must take place, and an upward movement of the machine itself, which will 
rise to the surface. 

It is evident that if, previously to the expulsion of the water, the nautUus be affixed 
to any object below, the power exerted on that object will be exactly proportionate to 
the weight of water expelled, and the power will continue increasing until, there 


Leing no fiother weight to be throirn off, the maximam effect is produced. To applj 
thia power to lifting masses of stone or rock, proper arrangeoients are affixed to the 
centre of the openiDg in the bottom, bj which connection can be made with the 
weight, admitting, at the same time, the swinging around of the otgect suspended, 
so that it may be placed in any required position. In the construction of permanent 
work, or the moTcment of objects whose weight is known, or can be estimated, a 
water, or, so called, lifting tube is placed on the side of the water chamber, which in- 
dicates the lifting power exercised by the nautilus at any moment The adrantage 
of this gauge will be recognised, inasmuch as without it the closest attention of the 
operator, working Tery cautiously, would be necessary to determine when the weight 
was overcome ; by its aid, howerer, the operator boldly throws open all the yalves 
necessary to develope the power of the nautilus, watching only the gauge. The 
water, having reached the proper level indicating the required lifting power, he knows 
the weight must be overcome, or so nearly so that the valve or cocks may be at once 
closed, m order that the movement may take place horizontally^ A moment's re- 
fleetioii will show that, if there were not an index of this character, carelessness or 
inattention on the part of the operator, by leaving the cocks open too long, might 
develope a power greater than required, and the nautilus would start suddenly up- 
ward. The expansive power of air, acting upon the incompressible fluid, water, 
through the opening in the bottom, ^ves a momentum which, by successive de- 
velopments of expansion in the working chamber, is constantly increasing in ve- 
locity, until, in any considerable depth of water, the result would be undoubtedly 
of a very serious character. Take, for exemplification, the nautilus in thirty-three 
feet of water, and bottom covers removed, and an equilibrium, at fifteen pounds 
to the inch, existing between the air and the water at the level of the bottom of 
the machine. Upward movement is communicated the instant the machine rises 
in the slightest degree, the existing equilibrium is destroyed, and the highly elastic 
qualities of air assome preponderance, exerting, from the rigid surface of the water 
below, an impulsive effort upward in the direction of least resistance. At each suc- 
cessive moment of upward movement the impelling power increases, owing to the 
increasing disparity between the pressure of air within struggling for escape. The 
machine, thus situated, becomes a marine rocket (in reality), in which the propelling 
power is exhausted only when the surface is reached, and a new equilibrium is ob- 
tained. It will readily be seen that, were this difficulty not overcome, it would be 
impossible to govern the nautilus ; for, rising with great velocity to the surface, 
the machine is carried above its ordinary flotation, or water line, a little more air 
escaping owing to the diminished resistance as thajt level is passed ; the recoil, or 
surging downwards, causes a condensation of the air remaining in the chamber ; 
a portion of the space previously occupied by air is assumed by water ; the buoyant 
power becomes less, the machine settles slightly more by condensation of the air, a 
larger space is occupied by water, and the nautilus redescends to the bottom with a 
constantly accelerating movement, seriously inconveniencing the operator by filling 
more or less with' water, according to depth. For many months the difficulties just 
enomerated baffled all attempts at control. A weight attached could be lifted, but 
the instant it was entirely suspended, — before the valves could be closed, — upward 
movement was communicated beyond control This difficulty so fatal has been over- 
come by an arrangement at the bottom of the nautilus, with channels which 
radiate from the opening in an inclined direction, debouching at the sides of the 
machine. The moment then that the air, by its expansion fh>m diminished resist- 
ance, or by the introduction from above of a greater volume than can be sustained 
by the water below, reaches, in its downward passage, the level of these chambers, 
following the direction of least resistance, it passes through these channels and 
escapes into the surrounding water, without of course affecting the movement of the 
machine in the least 

The pump for supplving air to the diving bell or other suitable vessel is represented at 
fiS9, 674 and 675, and is constructed as follows : — d is a cylinder, opening at the upper 
part into a chamber or chambers f f, separated by a partition e. On the side of 
each of these chambers there is a valve h h, opening inwards, and at the upper 
part of the same are two valves 1 1, opening outwards into the valve chamber o. 
Outside the opening for each of the valves h, h, there is a cup, Into which the end 
of the water supply pipe K passes ; by this means a small stream of water is supplied 
to the cnp, and is drawn firom it into Uie chamber f to supply the waste in the opera- 
tion of pumping. The valve chamber o is covered with a jacket K, having a space 
between it and &e valve chamber that is filled with water fi-om the water pipe m, 
which affords a stream of cold water to carry off the heat from the condensed air 
which is forced into the chamber. The water thus supplied circulates through the 
tubes in the chamber and ronnd them in the jacket, and thus cools the ftir in these 

E 2 


nounced as a dangerous drug, and forbidden to be used, by our parliament in the r«gn 
of Queen Elizabeth. An act was passed authorising searchers to bum both it and log^ 
-wood in every dye-house where they could be found. This act remained in full force 
till the time of Charles II. ; that is, for a great part of a century. A foreigner might 
have supposed that the legislators of England entertained such an affection for their 
native woad, with which their naked sires used to dye their skins in the old times, 
that they would allow no outlandish drug to come in competition with it. A most 
instructive book might be written illustrative of the evils inflicted upon arts, manu- 
factures, and commerce, in consequence of the ignorance of the legislature." 

More recently another class of dye-drugs have been introduced, and have super- 
seded some of those of the former century ', these are bichromate of potash, red and 
yellow prussiate of potash, manganese, catechu, arsenic, &c. 

Colours are not, properly speaking, material ; they are impressions which we receive 
from the rays of light reflected, in a decomposed state, by the surfaces of bodies. It is 
well known that a white sunbeam consists of an indeterminate number of d^erently 
coloured rays, which, being separated by the refractive force of a glass prism, form the 
solar spectrum, an image divided by Kewton into seven sorts of rays ; the red, orange, 
yellow, green, blue, indigo, and violet Hence, when an opaque body appears ocJoored, 
for example, red, we say that it reflects the red rays only, or in greatest abundance, 
mixed with more or less of the white beam, which has escaped decomposition. Accord- 
ing to this manner of viewing the colouring principle, the art of dyeing consists in 
fixing upon stuffs, by means of corpuscular attraction, substances which act upon light 
in a different manner from the surfaces of the stuffs themselves. The dyer ought, there- 
fore, to be familiar with two principles of optics ; the flrst relatively to the mixture of 
colours, and the second to their simultaneous contrast. 

Whenever the different coloured rays, which have been separated by the prism, are 
totally reunited, they reproduce white light. It is evident, that in this composition 
of light, if some rays were left out, or if the coloured rays be not in a certain proportion, 
we should not have white light, but light of a certain colour. For example ; if we 
separate the red rays from the light decomposed by a prism, the remaining coloured 
rays will form by their combination a peculiar bluish green. If we separate in like 
manner the orange rays, the remaining coloured rays will form by their combination 
a blue colour. If we separate from the decomposed prismatic light the rays of greenish 
yellow, the remaining coloured rays will form a violet. And if we separate the rays of 
yellow bordering on orange, the remaining coloured rays will form by their union an 
indigo colour. 

Thus w% see that every coloured light has such a relation with another coloured light 
that, by uniting the first with the second, we reproduce white light; a relation which 
we express by saying that the one is the complement of the other. In this sense, red 
is the complementary colour of bluish green ; orange, of blue; greenish yellow, of 
violet ; and orange yellow, of indigo. If we mix the yellow ray with the red, we 
produce orange ; the blue ray with the yellow, we produce green ; and the blue with 
the red, we produce violet or indigo, according as there is more or less red relatively 
to the blue. But these tints are distinguishable from the orange, green, indigo, and 
violet of the solar spectrum, because when viewed through the prism they are reduced 
to their elementary component colours. 

If the dyer tries to realise the preceding results b^ the mixture of dyes, he will 
succeed only with a certain number of them. Thus, with red and yellow he can make 
orange; with blue and yellow, green; with blue and red, indigo or violet. These 
facts, the results of practice, have led him to the conclusion that there are only three 
primitive colours ; the red, yellow, and blue. If he attempts to make a white, by 
applying red, yellow, and blue dyes in certain quantities to a white stuff, in imitation 
of the philosopher's experiment on the synthesis of the sunbeam, far ftom succeeding, 
he will deviate still further from his purpose, and the stuff will by these dyes become 
coloured of a depth varying according to the quality of the stuff used ; until a full 
black is produced. Nevertheless, the principle is applicable, and in many cases 
adopted in practice by blending the yellow, red, and blue rays in order to produce or 
improve an otherwise imperfect white. When a little ultramarine, cobalt blue, 
Prussian blue, or indigo is applied to bleached goods with the view of giving them 
the best possible white, if only a certain proportion be used, the goods will appear 
whiter after this addition than before it In this case the violet blue forms with the 
brown yellow of the goods a mixture tending to white, or less coloured than the 
yellow of the goods and the blue separately were. For the same reason a mixture of 
Prussian blue and cochineal pink, or archil and cudbear, is used for whitening of 
silks in preference to a pure blue, for on examining closely the colour of the silk to be 
neutralised, it was found by the relations of the complementary colours, that the 
violet was more suitable than the pure blue alone. The dyer should know, that 


when lie applies aeiwenX different coloaring matters to stuff, as yellow and Mae 
separately, &ey will appear green, not because the colouring matters have combined, 
but because the eye cannot distinguish the points which reflect the yellow from those 
which reflect the blue, and it is this want of distinction that produces the combined 
colour. With such a dye the colour will appear of different tints, the blue or yellow 
prevailing according to the position in which it is placed to the eye, whether seen 
by reflected or transmitted, light, but when the dye applied to the stuff is in chemical 
union, producing a green, such as arsenite of copper the yellow and blue rays cannot 
be thns distinguish^ Otber instances of mixed colours will be seen by examining 
certain grey substances, such as hairs, feathers, &c« with the microscope, by which 
it is seen grey colour results fh>m black points disseminated over a colourless or 
slightly coloured surfiioe. The microscope may be thus usefully applied by the dyer 
to distinguish whether a colour be the result of a mixed or a combined dye. 

The dyer should also be acquainted with the law of the simultaneous contrast of 
colours. When the eye views two colours close alcmgside of each other, it sees 
them differing most, in the height of their tone, when the two are not equally pale or 
fuU^bodied. They appear most different, when the complementary of the one of them 
is added to the colour of the other. Thus, put a green alongside of an orange, the 
led colour complementary of green being added to the orange, will make it appear 
redder. And in like manner, the blue complementary of orange being added to the 
green, will make it appear more intensely blue. 

It is not sufficient to place complementary colours side by side to produce harmony 
of colour, the respective intensities having a most decided influence ; thus, pink and 
light green agree, red and dark green al»o ; but light green and dark red, pink and 
dark green do not, therefore, to obtain the maximum of effect and perfect harmony, 
the following colours must be placed side by side, taking into account their exact 
iBtensity and tint 

FrimUir« Coloar. Secondary Coloan. 

{Light blue 
Blue - - - Orange - - - ^ Yellow 

Yellow orange » - Indigo 
Oreenish yellow - Violet 
Black - - White 

4 Red 







The mixed contrast gives the reason why a brilliant colour should never be looked at 
for any length of time, if its true tint or brilliancy is to be appreciated; for if a person 
looks, for example, at a piece of red cloth for a few minutes, green, its complementary 
colour is generated in the eye, and adding itself to a portion of Uie red, produces 
black, which tarnishes the beauty of the red. This oontrast explains why the shade 
of a coloar, may be modified according to the colour which the eye has previous 
looked at, either favourably or otherwise. An example of the first instance is noticed, 
when the eye first looks to a yellow substance, and then to a purple one ; and as 
exemplifying the second case looking at a blue and then at a purple. 

The relations of dyeing with the principles of chemistry, constitute the theory of 
the art, properly speaking ; this theory has for its basis the knowledge — 

1st. Of the nature and properties of the bodies which dyeing processes bring into 

2nd. Of the circumstances in which these bodies are brought together, facilitating 
or retarding their action. 

3rd. The phenomena which appear during their action ; and, 

4th. Properties of the coloured combinations which are produced. 

The first of these generalities embrace a knowledge of the preparations, which 
stuff necessarily undergoes previous to dyeing, and also the preparations of the dye- 
drug before bringing it into contact with the stuff. 

The operations to which stuffs are subjected before dyeing, are intended to separate 
from them any foreign matters which may have become attached, or are naturally 


inherent in the staff. The former are sach as have been added in the spiDiiiog, 
weaving, or other manipulations of the manufacture, and are all removed by 
steeping in an alkaline lye and washing. The secondare the natural yellow coloQring' 
substances which coat some of the various 6bres, both vegetable and animal ; and the 
chlorophylle, or leaf-green of vegetables The removal of these is generally effected 
by boiling in soap and alkaline lyes. A weak bath of soda, in which the stuff is 
allowed to steep for some time, and then washed in water, is generally the only pre- 
paration required for wool, in order that it may take on a uniform dye. 

To remove the gummy or resinous matter from silk, it requires boiling in soap lye; 
however, its removal is not essential to the stuff combining with the dye, as silk is often 
dyed while the gum remains in it, in which case it is only rinsed in soap lye at a very 
moderate heat, to remove any foreign matters imbibed in the process of manufactore. 

Vegetable fibre, as cotton, has such natural resinous matters that retard the re- 
ception of the dye removed by boiling, either with or without alkaline lyes ; bat the 
natural dun colour of the fibre is not removed, which from the laws of light and 
colour already referred to, would interfere with the production of bright light tints; 
under these circumstances, the natural colour of the fibre has to be previously removed 
by bleaching, for which see the article. Bleaching. 

The necessary preparation of the dye-drugs within the province of the dyer, is to 
obtain the colour in a state of solution, so as to allow the fibre to absorb it, and to 
produce chemical combination, or to get the dye or colour in such a minute state of 
division as it will penetrate or enter into the fibre of the stuff. These preparations 
embrace the formation of decoctions, extracts, and solutions, and also in some cases of 
precipitation, previous to immersing the stuff into the bath. Stu£^ chemically 
considered, have but a feeble attraction for other matters, so as to combine with them 
chemically; still that they do possess certain attractions is evident from varions 
phenomena observed in the dyeing processes, and that this attraction is possessed 
with different degrees of intensity by the different fibres, is also evident from the ease 
and permanence that woollen stuff will take up and retain dyes compared with 
cotton ; and also, that certain dyes are retained and fixed within or upon one kind of 
fibre and not at all in another. This may be determined by plunging the dry staff 
into solutions of the salts, and determining the density of the solution before the 
immersion and after withdrawing the stuff. Wool abstracts alum from its solution, 
but it gives it all out again to boiling water. The sulphates of iron, copper, and 
zinc, resemble alum in this respect Silk steeped for some time in a solution of 
protosulphate of iron, abstracts the oxide, and gets thereby dyed, and leaves the 
solution acidulous. Cotton in nitrate of iron produces the same effect. Wool put in 
contact with cream of tartar, decomposes a portion of it ; it absorbs the acid within its 
pores, and leaves a neutral salt in solution in the liquor. Ck>tton produces no such 
, effect with tartar, showing by these different effects that there are certain attractions 
between the stuff and dyes. This attraction, however, may be more what is termed 
a catalytic influence, the fibres of the stuff producing a chemioil action with ihe salt 
or dye, with which it is in contact This attraction or affinity of the fibre for the 
dye-drug, does not produce a very extensive effect in the processes of dyeing. More 
probably the power of imbibing and retaining colours possessed by the fibre is more 
dependent upon a mechanical than a chemical influence. 

All dye-drugs must in the first instance be brought into a state of solution, in order 
that the dye may be imbibed by the fibre ; but if the fibre exerts no attraction for the 
colour so as to retain it, it is evident that so long as it remains capable of dissolving 
in water, the stuffs being brought into contact with water, will soon lose their colour. 
A colour thus fonhed does not constitute a dye, however strongly stained the stuffs 
may appear to be, in or out the dyeing solution; in order to form a dye, the colour 
must be fixed upon or within the stuff, in a condition insoluble in water. Hence 
the mere immersion of the stuff into a solution of a colour will not constitute a dye, 
except where the stuff really has an attraction for the colour and retuns it, or causes 
a decomposition by which an insoluble compound is fixed upon it, such as referred to 
by potting stuffs into solutions of iron. The abstraction of the colour fh>m a solution 
by the immersion of the stuff, is often the result of a mechanical attraction possessed 
by porous substances, enabling them to absorb or imbibe certain colouring matters 
from solutions that are held by a weak attraction by their solvents. On this principle, 
a decoction of cochineal, logwood, brazil-wood, or a solution of sulphate of indigo, 
by digestion with powdered bone black, lose their colour, in consequence of the 
colouring particles combining by a kind of capillary attraction with the porous carbon, 
without undergoing any change. The same thing happens when well scoured wool 
is steeped in such coloured liquids; and the colour which the wool assumes by its 
attraction for the dye, is, with regard to most of the above coloured solutions, but 
feeble and fugitive, since the dye may be again abstracted by copious washing with 


simple water, whose attraetive force therefore OYercomea that of the wool. The aid 
of a high temperature, indeed, is requisite for the abstraction of the colour from the 
wool and the bone-black, probably by enlarging the sise of the pores, and increasing 
the soWent power of the water. 

Those dyes, whose colouring matter is of the nature of extractive, form a fiister 
combination with stuffs. Thus the yellow, fawn, and brown dyes, which contain 
tannin and extractive, become oxygenated by contact of air, and insoluble in water ; 
by which means they can impart a durable dye. When wool \b impregnated with 
decoctions of that kind, its pores get charged by capillurity, and when the liquid 
becomes oxygenated, they remain filled with a colour now become insoluble in water. 
The fixation of iron oxide and scTeral other bases also depends on the same change 
within the pores or fibre, hence all salts that have a tendency to pass readily into the 
basic state are peculiarly adapted to act as a medium for fixing dyes ; however, this 
property is not essential. 

hx onier to impart to the stuffs the power of fixing the colour in an insoluble form 
upon it, recourse is had to other substances, which will combine with the soluble and 
form with it an insoluble colour ; and it is not necessary that this new substance 
should haTC an attraction for the stuff, or be capable of passing into a basic form, any 
more than the original colour, but it is necessary that it be rendered insoluble while 
in contact with the stuff. 

Such substances used to unite the colour with the stuff hare been termed mordants, 
which meant that they had a mutual attraction for the stuff and colour, and combining 
with the stuff first, they afterwards took up the colour ; but this is only so in some 
instances. A few examples will illustrate the bearing of these mordants. If a piece 
of cotton stuff is put into a decoction of logwood, it will get stained of a depth accor- 
ding to the colour of the solution, but this stain or colour may be washed from the 
cotton hj putting it into pure water, the colour being soluble. If another piece of 
cotton stuff be put into a solution of protosulphate of iron, and then washed from this, 
a portion ot the iron will have undergone oxidation, and left the acid, and become 
fixed upon the fibre and insoluble in water. Whether this oxidation is the result of 
an influence of the stuff, or the effect of the oxygen of the air and water in which the 
goods are exposed, it does not matter meantime, only this fixed oxide constitutes an 
example of a mordant by its combining with the stuff. If this stuff is now put into 
a decoction of logwood, the colouring matter of the logwood will combine with the 
oxide of iron fixed upon the fibre, and form an insoluble colour, which after washing 
will not remoTC from the stuff. If, instead of washing the stuff from the sulphate of 
iron solution in water, it be passed through an alkaline lye of soda or potash, the 
acid hblding the iron in solution is taken hold of by the alkali, and removed. The 
oxide of iron is thus left upon the stuff, in a much larger quantity than in the 
former case, and as firmly fixed, although not by any attraction between it and the 
fibre, but simply being left within it. And this stuff being now put into the logwood 
liquor, will form a dye of a depth according to. the quantity of iron thus fixed upon 
the stuff, and equally permanent with that which had been fixed on the stuff by the 
oxidation in working. 

Such then are the methods of fixing within the stuff insoluble colours from soluble 
compounds, and from these remarks the necessity of having the dye in solution will 
also be erident 

Suppose again that the sulphate of iron be mixed with the logwood decoction, there 
will be produced the same colour or .dye as an insoluble precipitate : if the cotton 
stuff is put into this, no colour worthy of the name of a dye will be obtained, as the 
cotton wUl not imbibe within its fibre this precipitate. Place woollen stuff in the same 
liquid, there is formed a very good dye» the woollen fibre having imbibed a great por- 
tion odT the solid precipitate, probably owing to woollen fibres bein^ much larger than 
those of cotton. Thus, with cotton and other stuff that will not imbibe freely solid pre- 
cipitates, the mordant must be fixed within the fibre previous to applying the colouring 
substances, such as the vegetable decoctions. It will also be seen that the dye which 
is the product of combination between the mordant and colour is not that of the natural 
colour of the drug, but the colour of the compound. Hence the great variety of tints 
capable of being produced from one dye-drug, by varying either the kind or intensity 
of the mordanL So that in the above instances, it is not the colour of the hematoxylin 
fixed on the stuff, but its compound with iron, or tin, or alumina, as the case may be, 
all of which give different tints. 

It is upon this principle of rendering bases insoluble while within the fibre by 
chemical means, that has brought to the use of the dyer a great number of mineral 
dyes which in themselves, whether separate or combined, have no attraction whatever 
for the fibre ; such as solutions of sulphate of copper, and yellow prussiate of potash, 
nitrate of lead, and bichromate of potash, &c Suppose the stuff to be dyed a yellow 

Vol II. • F 


by the two last named salts, was first put into the solution of lead and then washed 
previous to being put into the bichromate solution, the greater portion of the lead 
would be dissoly^ Arom the stuff, and a very weak colour would be obtained. If the 
stuff from the lead solution was put directly into the bichromate solution, a Tery good 
dye would be the result ; but the portion of the solution remaining upon the suHSm^c of 
the stuff will combine with the chrome and form a precipitate which the fibre cannot 
imbibe, but will form an external crust or pigment upon the surfiice, which blocks up 
the pores, and exhausts to no purpose the dye, causing great waste : hence the stuff 
from the solution of lead is put into water containing a little soda or lime, and the 
lead is thus reduced to an insoluble oxide within the fibre. The goods may now be 
washed from any loose oxide adhering, and then passed through the bichromate 
solution, when the chromic acid combines with the ozideof lead, forming a permanent 
yellow dye. Thus it will be seen that whether the combination of the colour with 
the stuff be chemical or mechanical the production of the dye which is fixed upon the 
fibre is certainly a chemical question, anid the dyer should be familiar with the natnre 
and principles of these reactions. 

There are a few instances where the dye produced docs not come within the sphere 
of these principles, there being no mordants required, nor any combination of the 
colour formed within the stuff, but the dye-drug in its natural hue is fixed within the 
fibre. Such colours^iave been termed substantive^ to distinguish them from those pro- 
duced by means of mordants, which are termed adjective. Amongst this class of dyes 
and dye-drugs stands pre-eminent indigo blue. Indigo in its natural state is entirely 
insoluble in water, and is of a deep blue colour. The composition of this blue indi^ 
is represented as — 

Carbon - - - 16 | Nitrogen - - I 
Hydrogen - • 5 | Oxygen - » - 2 

But it is found capable of parting with a portion of the oxygen, and by so doiog, 
losing entirely its blue colour ; and in this deoxidised condition it is soluble in alkaline 
lyes and lime water ; this colourless compound is termed indigogene. The opinion 
of Liebig upon the constitution of this substance is, that indigo contains a salt radical, 
which he terms Ani/le^ composed of 0"H*N. He considers that indigogene or white 
indigo is the kydrated protoxide of this radical, and that blue indigo is the peroxide, 
represented thus — 

C H N O Water. 
Salt radical, anyle - - -16 5100 

Indigogene - - - -16 5111 

Blue indigo - - - -16 5120 


Advantage is taken of this property of indigo, of parting with its oxygen and becom- 
ing soluble, to appl^ it to dyeing, and it is effected by the following means, when for 
the purpose of dyemg vegetable stuff, as cotton ; and fi-om the circumstance of these 
operations being done cold, the method is termed the cold vat, which is made up as 
follows: — The indigo is reduced to an impalpable pulp, by being ground in water to the 
consistence of thick cream. This is put into a suitable vessel filled with water, along 
with a quantity of copperas, and newly slaked lime, and the whole well mixed by 
stirring. After a short time the indigo is deoxidised and rendered soluble by a por- 
tion of the lime which is added in excess, the reaction being represented thus : 

1. Indigo, composed of [Jj5^^|^«®°*; ; • 7 Dyeing Solution. 

{Protoxide of Iron • ^ — ^ .. ._ 
Sulphuric Acid . 

^ ,. fj^;™« / "^ Cr^ ' Sulphate of Lime. 

3. Lime- - - JLime. .... ^-f- -=^ Sulphate of Lime. 

The peroxide of iron and sulphate of lime are precipitated to the bottom, and the indi- 
gogene and lime form a solution of a siraw colour, with dark veins through it 

The operation of dyeing by this solution is simply immersion, technically, dipping. 
The stuff by immersion imbibes the solution, and when taken out and exposed to 
the air, the indigogene upon and within the fibre rapidly takes oxygen fh)m the atmo- 
sphere, and becomes indigo blue, thus forming a permanent dye, without any 
necessary attraction between the indigo and the stuff. 

ITie indigo vat for wool and silk is made up with indigo pulp, potash, madder, and 


tmD. In tbis vat the extracts of madder and bran perform tbe deoxidising functions 
of tbe copperas in tbe cold vat, by undergoing a species of fermentation. 

Pastel and wood, eitber alone or witb tbe addition of a little indigo, is also used for 
the dyeing of wool and silk stuff, tbe deoxidation being effected by tbe addition of 
bran, msdder and weld. In dyeing witb tbese vats, tbe liquor is made warm, and they 
require mucb skill and experience to* manage, in consequence of their complexity, 
being always liable to go out of condition, as the dyeing goes on, by tbe extraction of 
tbe indigogene and tbe modification of the fermentable matter employed to deoxidise 
tbe indigo to supply that loss. The alkaline solvent also undergoes change, so there 
must be snecessiTe additions of indigo and alkali ; tbe principal attention of the 
dyer is tbe maintaining tbe proper relation of these matters, as too much or too little 
of either is iiijarions. 

Sulphate of indigo forms an intense blue solution, unaffected also by mordants. 
Vegetable stuffs dipped in this retain no dye, for the washing off the acid in order to 
preseire the fibre removes tbe colour ; but animal fibre, such as woollen and silk, 
becomea dyed ; a portion of tbe blue remains upon the stuff after washing off the acid, 
being retained by capillary attraction. This dye is termed Saxon blue, but it has very 
little of tbe permanence of indigo or vat blue^ although it is also a substantive colour. 
Another truly substantive colour is that dyed by cartbamus or safflower, but the 
fixation of tbis dye npon'tbe stuff differs from any of those referred to. Like indigo, 
it has no affinity for any base or substance capable of forming a mordant ; its solvent 
is an alkali, but in this dissolved state it does not form a dye. Tbe mode of 
proeeedinp; in dyeing witb cartbamus is first to extract the dye from the vegetable 
in whicb it is found, by soda or potash, which is afterwards neutralised by an acid 
previous to dyeing, whicb renders the colour insoluble, but in so fine a state of division 
that no precipitation can be seen for some time and the stuff immersed in this imbibes 
the colour within its fibre, its lightness assisting tbis action, as the precipitate will 
remain suspended in water for days before it will subside. Vegetable fibre takes up 
tbis dye as easUy as animal, but whether by an attraction for tbe stuff, or by a 
mechanical capillary attraction of the fibre is not so easily determined. A piece of 
stuff suspended in a vessel filled witb water, having in it some insoluble carthamine, 
all tbe colouring particles will flow to and combine witb the fibre from a considerable 
distance, giving a proof of tbe existence of some force drawing them together. 

Such then are tbe various conditions and principles involved in the processes of 
fixing tbe dye within or upon tbe stuff. 

During the operations of dyeing there are certain circumstances which have to be 
attended to^ in order to fiicilitate and effect certain hues or tints of colour. Thus, 
witb many of the colouring substances, beat not only favours but is necessary for 
the solution of tbe dye, and also its combination witb tbe stuff or mordant Decoctions 
of woods are always made by hot water, and the dyeing processes with decoctions are 
in bot liquor. When the colouring matter of quercitron bark is extracted by boiling 
water, tbe colour produced upon tbe stuff wUl be a rich amber yellow, but if tbe 
extract be made by water at 180^ Fabr., a beautiful lemon yellow will be the dye pro- 
duced by it, unng tbe same mordant in each case. Colours dyed by madder and 
Barwood must be done at a boiling beat during the whole process, or no dye is effected. 
Sumach, another astringent substance, is most advantageously applied at a boiling 
heat; and in order to have a large body of this dye fixed upon the stuff, it should be 
immersed in the liquor while hot and allowed to cool together, during which the 
tannin of tbe dye undergoes some remarkable change in contact witb the stuff. 
Sai&ower dyes are kept cold, so are tin bases, Prussian blues, and chrome yellows : by 
applying heat to the last a similar result is effected to that witb bark; instead of a 
lemon yellow an amber yellow will be obtained. Almost all colours are affected less 
or more by tbe temperature at which they are produced. Some mordants are fixed 
upon the stuff by beat, such as acetate of alumina; the stuff being dried from a solution 
of this salt at a high temperature loses part of tbe acid by being volatilised, and there 
remains upon tbe fibre an insoluble suboxide, which fixes tbe dye. These remarks 
respecting tbe methods apply more particularly to vegetable stuffs, as cotton, and in 
many cases also to silk, but wool is always dyed at a high beat Although wopl 
seems to have a mucb ^ater absorbing power than cotton, the latter will absorb and 
become strongly dyed m a cold dye bath, in which wool would not be affected ; but 
apply heat and (he wool will be deeply dyed, and the dye mucb more permanent than 
the eotton. 

The permanence of colours is another property to be carefully studied by tbe 
practical dyer, as the colour must not be brought under circumstances that will 
destroy its permanency during any of the operations of the dyebouse. The word 
permanent, however, does not mean fast^ which is a technical term applied to a colour 
that will resist all ordinary operations of destruction. As for instance, a Prussian 


blue U a pemianeDt colour but not a fast coloar, as any alkaline matter will destroy 
it, or a common black is permanent, although any acid matters trill destroy it ; 
while Turkey red is a fast colour and not affected by either acid or alkaline matters. 
A few of the circumstances affecting colours in the processes they are subjected to may 
be referred to in this place. If, for instance, the air in drying the dyed stuff in a 
hot chamber be moist, there is a great tendency to the colour being impaired in 
these circumstances. For example, a red colour dyed with safflower will pass into 
brown, a Prussian blue will pass into a grey lavender, chrome yellows take an amber 
tint Mostly all colours are affected less or more by being subjected to strong heat 
and moisture; even some of those colours termed fast are affected under sach 
circumstances. A dry iieat has little or no effect upon any colour, and a few colours 
are made brighter in their tint by such a heat, as chrome orange, indigo blue, on 
cotton, &c. 

Some of these effects of heat and moisture differ with different stuff; thus indigo 
blue upon cotton is not so much affected as indigo blue upon silk, while safflower red 
upon cotton will be completely destroyed before the same colour upon silk will be 
perceptibly affected. The same colouring matter fixed by different mordants upon 
the same stuff is also differently affected under these conditions. 

Light is another agent effecting a great influence upon the permanence of colours, 
which should be also considered by the dyer. Reds dye^ by a Braxil wood and a 
tin mordant, exposed to the light, become brown ; Prussian blue takes a purple tint ; 
yellow becomes brownish ; safflower red, yellowish, and these changes are facilitated 
by the presence of moisture ; such as exposing them to strong light while drying from 
the dye bath, either out or within doors. The direct rays of the sun destroy all 
dyed colours ; even Turkey red yields before that agency. 

Boiling was formerly prescribed in France as a test of fast dyes. It consisted in 
putting a sample of the dyed goods in boiling water, holding in solution a determinate 
quantity of alimi, tartar, soap, and vinegar, &c Dufay improved that barbarous test 
He considered that fast*dyed cloth could be recognised by resisting an exposure of 
twelve hours to the sunshine of summer, and to the midnight dews; or of sixteen da js 
in winter. 

In trying the stability of dyes, we may offer the following rules : — 

That every stuff should be exposed to the light and air ; if it be intended to be 
worn abroad, it should be exposed also to the wind and rain ; that carpets moreover 
should be subjected to friction and pulling, to prove their tenacity ; and that cloths 
to be washed should be exposed to the action of hot water and soap. However, such 
tests are not at all applicable to most of the colours dyed upon cotton stuff. Not 
many of them can stand the action of hot water and soap, or even such acids as the 
juice of fruits. Indigo blue, one of the most permanent dyes on cotton, yields its 
intensity to every operation of washing, even in pure water. 

DelavaFs observations on the nature of dyes may be thus summed up. In tran- 
sparent coloured substances, the colouring substance does not reflect any light ; and 
when, by intercepting the light which was transmitted, it is hindered fVom passing 
through substances, they do not vary from their former colour to any other colour, 
but become entirely black ; and he instances a considerable number of coloured 
liquors, none of them endued with reflective powers, which, when seen by transmitted 
light, appeared severally in their true colours ; but all of them, when seen by incident 
light, appeared black ; which is also the case of black cherries, black currants, black 
berries, &c., the juices of which appeared red when spread on a white ground, or 
otherwise viewed by transmitted instead of incident light ; and he concludes, that 
bleached linen, 8cc "when dyed with vegetable colours, do not differ in their 
manner of acting on the rays of light, from natural vegetable bodies ; both yielding 
their colours by transmitting, through the transparent coloured matter, the light which 
is reflected from the white grobnd : " it being apparent, from different experiments, 
" that no reflecting power resides in any of their components, except in their white 
matter only," and that "transparent coloured substances, placed in situations by which 
transmission of light through them is intercepted, exhibit no colour, but become 
entirely black." 

The art of dyeing, therefore (according to Mr. Delaval), " consists principally in 
covering white substances, from which light is strongly reflected, with transparent 
coloured media, which, according to their several colours, transmit more or less 
copiously the rays reflected from the white,*' since " the transparent media them- 
selves reflect no light ; and it is evident that if they yielded their colours by reflect- 
ing instead of transmitting the rays, the whiteness or colour of the ground on 
which they are applied would not in anywise alter or affect the colours which they 

But when any opaque basis is interposed, the reflection is doubtless made by it, 

. DYEING. 69 

rather than by the substance of the dyed wool, silk, fte., and more especially when 
such basis consists of the white earth of alum, or the white oxide of tin § which, by 
their strong reflective powers, greatly augment the lustre of colours. There are, 
moreover, some opaque colouring matters, particularly the acetous, and other solu- 
tions of iron, used to stain linen, cotton, &c., which must necessarily themselves 
reflect instead of transmitting the light by which their colours are made perceptible. 

The compound or mixed colours are such as result from the combination of two 
differently coloured dye stuffs, or from dyeing stuffs with one colour, and then with 
another. The simple colours of the dyer are red, yellow, blue, and black, with which, 
when skilfully blended, ho can produce every variety of tint Perhaps the dun or 
fawn colour might be added to the above, as it is directly obtained from a great many 
vegetable substances. 

1. Bed with yellow, produces orange; a colour, which upon wool is given usually 
with the spent scarlet bath. To this shade may be referred flame colour, pome- 
granate, capuchin, prawn, jonquil, ctusis, chamois, cq/if au lait^ aurora, marigold, 
orange peel, mordores, cinnamon, gold, &c. Snuff, chestnut, musk, and other shades 
are produced by substituting walnut peels or sumach for bright yellow. If a little blue 
be added to orange, an olive is obtained. The only direct orange dyes are annotto, 
and subchromate of lead. See Silk and Wool Dteino. 

The latter is never used for dyeing orange upon silk and wool, while the former is 
now never used for cotton. An orange with annotto is very fugitive, even uiton the 
animal fibre ; but much more so upon cotton. Subchromate of lead is produced upon 
cotton by dyeing it first a deep chrome yellow by acetate of lead and bichromate of 
potash, as already noticed, and then passing the stuff so dyed through a hot solution 
of an alkali or lime, which changes the dye from the yellow chromate to the state of 
subchromate, which is deep orange. 

2. Red with blue produces purple, violet, lilac, pigeon's neck, mallow, peach- 
blossorm, iUu de rot, lint-blossom, amaranth. 

' Thus a Prassian blue dyed over a safflower red, or vice versa, wUl produce any of 
these tints by varying the depth of the red and blue according to the shade required ; 
but the same shades can be produced direct by logwood and an aluminous or tin 
mordant; the stuff being steeped in sumach liquor previous to applying the tin 
mordant produces the reddish or purple tint when such is required. 

3. Bed with black ; brown, chocolate, maroon, &c. These tints are produced by 
various processes. To dye a deep orange by annotto liquor, and then form over it a 
black by sumach and sulphate of iron, gives a brown ; or dye the stuff first a rich 
yellow by quercitron and a tin mordant, and then over the yellow produce a purple by 
passing it through logwood ; chocolates are thus produced. A little Brazil wood with the 
logwood gives more of the red element AYhen maroon is required, the red is made 
to prevail, and so by a judicious mixture, these various tints are produced. Brown, 
especially upon cotton fibre, is more often produced direct by means of catechu. 
Steep the stuff in a hot solution of catechu, in which the gummy principle has been 
destroyed by the addition of a salt of copper ; then pass through a solution of bichro- 
mate of potash at boiling heat, when a rich brown is obtained. 

4. Yellow with blue ; green of a great variety of shades ; such as nascent green, gay 
green, grass green, spring green, laurel green, sea green, celadon green, parrot green, 
cabbage green, apple green, duck green. 

Green is essentially a mixed dye, and produced by dyeing a blue over a yellow or 
It yellow over a blue. In almost all cases the blue is dyed first, and then the yellow, and 
according to the depth of each or any of these are the various tints of green produced. 
With silk and wool, one kind of green dye may be produced simultaneously by 
putting sulphate of indigo into the yellow dye bath, and then working the previously 
prepared or mordanted stuff in this. With cotton, an arsenite of copper (Scheele*s 
green) may be produced by working the stuff in a solution of arsenite of potash or 
soda, and then in sulphate of copper, which produces a peculiar tint of green. 

5. Mixtures of colours, three and three, and four and four, produce an indefinite 
diversity of tints : thus, red, yellow, and blue form brown olives and greenish greys; 
in which the blue dye ought always to be first given, lest the indigo vat should be 
soiled by other colours, or the other colours spoiled by the alkaline action of the vat. 
Red, yellow, and grey Cwhich is a gradation of black) give the dead-leaf tint, as well 
as dark orange, snuff colour, &c. Red, blue and grey give a vast variety of shades ; 
as lead grey, date grey, wood-pigeon grey, and other colours too numerous to 
specify. See Brown Dye. 

Care must be taken, however, in mixing these colours, to study the depth of the 
tint required ; as, for instance, were we wishing to dye a slate grey, and to proceed 
first by dyeing a blue, then a red, with a little of the grey, we would produce, instead 
of a slate grey, a purple or peach. The arrangement referred to, applies only to the. 



elements of the coloan that enter into the composition of the varioos tints, so that a 
slate grey is^a blae with a small portion of red, and a still smaller portion of Uie black 
element, that produces the grey tint Thus, dye the staff first a deep sky bine by the 
Tat, then by passing through a solution of sumach, with a small quantity of logwood, 
Brazil wood, copperas, and alum, grey will be produced. The Brasil wood gives the 
red tint, sumach and copperas the black tint, the logwood assisting in this, and with tlie 
aid of the alum throwing in the puce or dore neck hue ; and thus by the Tariatioo of 
these hues by such arrangements, any of the grey tints can be produced. See Cauco 

DYER'S ALKANET, Alkanna tinctoria. See Alkanet. 

DYER'S MADDER, Bubia tinctorium. See Madder. 

DYER'S OAK, Qttercus infectoria. See Galls and Oak. 

DYER'S ORCHELLA WEED, RocceUa tinctoria. See Archil, Obchella. 

DYER'S SAFFLOWER, or Bastard saffron. The Carthamus tinctorius. The 
flowers are of a deep orange colour, but they are used for dyeing various shades of 
red. The flowers of the carthamus are employed in Spain for colouring dishes and 
confectionery. See Safflower. 

DYER'S WOODROOF. Asperula tinctoria. The roots of this plant are used in 
some parts of Europe, particularly Dalmatia, instead of madder, for dyeing wool and 
cloth of a reddish colour ; but in bulk the crop obtained is inferior to that of the 
madder. — .Lawwn, 


EARTHS. (TVrref, Fr. ; Erden, Germ.) It has been demonstrated that the sob- 
stances called Earths, and which, prior to the electro-chemical career of Davy, were 
deemed to be elementary bodies, are all compounds of certain metallic bases and 
oxygen. Five of the earths, when pure, possess decided alkaline properties, being 
more or less soluble in water, having (at least three of them) an acrid alkaline taste, 
changing the purple infhsion of red cabbage to green, most readily saturating the 
acids, and affording thereby neutro-saline crystals ; these are baryta^ Mtrontici^ Ume 
(calcia\ magneaiay and litkia. The earths proper are alumina,, gludna^ yttritt^ zireomia, 
and thorina; these do not change the colour of infusion of cabbage or tincture of 
litmus, do not readily neutralise acidity, and are quite insoluble in water. 

EARTHY COBALT. See Wad. A manganese ore, in which the oxide of cohalt 
sometimes amounts to thirty-three per cent — Dana, 

EARTHY MANGANESE. See Wad and Manoakbse. 

EAST INDIA' BLACK WOOD. The Sit Sal of the natiTes of India. The Dal- 
bergia iati/olia. It is a wood of a greenish black colour, with light coloured Teins. It 
takes a fine polish, and is very heavy. 

EAU DE COLOGNE. See Perfuuert. 

EAU DE LUCE. See Perfcmert. 

EBONY. Of this black wood three kinds are imported:-- 

The Mauritius Ebony, which is the blackest and finest grain. 

The East Indian Ebony, which is not of so good a colour. 

The African Ebony, which is porous and bad in point of colour. 

The ebony of the Mauritius is yielded by the Diospyrua Ebenus, Colonel Uoyd 
says, this ebony when first cut is beautifully sound, but that it splits like all other 
woods from neglectful exposure to the sun. The workmen who use it immerse it in 
water as soon as it is felled for from six to eighteen months ; it is then taken out, and 
the two ends are secured fh)m splitting by iron rings and wedges. Colonel Lloyd 
considers that next to the Mauritius, the ebony of Madagascar is the best, and next 
that of Ceylon. 

The Mauritius ebony is imported in round sticks like scaffold poles, about fourteen 
inches in diameter. The East Indian variety comes to us in logs as large as twenty- 
eight inches diameter, and also in planks. The Cape of Good Hope ebony arrives in 
England in billets, and is called billet wood, about from three to six feet long, and two 
to four inches thick. 

The uses of ebony are well known. 

White Ebony comes from the Isle of France, and is much like box wood. See 
Green Ebont. 

EBULLITION. (Eng. and Fr. ; Kochen, Germ.) EoUing. When the bottom of 
an open vessel containing water is exposed to heat, the lowest stratum of finid imme- 
diately expands, liecomes therefore specifically lighter, and rises through the colder 
and heavier particles. The heat is in this way diffused through the whole liquid 



mass, not by simple eommimicatioiiof that power from particle to particle as in solids, 
— called the amductioH of caloric,— bat bj a translation of the several particles from 
the bottom to the top, and the top to the bottom, in regular succession. This is deno- 
minated the carrying powers of fluids, being common to both liquid and easeons bodies. 
These internal moTements may be rendered very conspicuous and instructive, by 
mingling a little powdered amber with water, contained in a tall glass cylinder, stand- 
ing upon a sand-bath. That this -molecular translation or locomotion is almost the 
sole mode in which fluids get heated, may be demonstrated by placing the middle of a 
pretty long glass tube, nearly filled with water, obliquely over an argand flame. The 
upper half of the liquid will soon boil, but the portion under the middle will continue 
cool, so that a lump of ice may remain for a considerable time at the bottomv When 
the heat is rapidly applied, Uie liquid is thrown into agitation, in consequence of 
elastic vapour being suddenly generated at the bottom of the Tessel, and being as 
suddenly condensed at a little distance above it by the surrounding cold column. 
These alternate expansions and contractions of Tolume become more manifest as the 
liquid becomes hotter, and constitute the simmering, vibratory sound which is the 
prelude of ebullition. The whole mass being now heated to a pitch compatible with 
its permanent elasticity, becomes turbulent and explosive under the continued in- 
fluence of fire, and emitting more or less copious volumes of vapour, is said to boiL 
The further elevation of temperature, by the influence of caloric, becomes impossible 
in these circumstances with almost all liquids, because the vapour carries off from 
them as much heat in a latent state as they are capable of receiving from the fire. 

The temperature at which liquids boil in the open ur varies with the degree of 
atmospheric pressure, being higher as that is increased, and lower as it is diminished. 
Hence boUing water is colder by some degrees in an elevated situation, with a de- 
pressed barometer, tiian at the bottom of a coal-pit in fine weather, or, when the 
barometer is elevated. A high column of liquid also, by resisting the discharge of 
the steam, raises the boiling point As we ascend from the sea level, the boiling point 
becomes lower, the following table illustrates this. 

Yudi Inches of Boiling 

high. pretture. point. 

Farm of Antisana - - 4488 17'87 187-34 

Quito - - - - 3170 20-74 194*18 

Mexico .... 2490 22-52 198*14 

StGothard - - - 2302 2802 199*22 

Brianfon - - - - 1423 25*39 203*9 

Monte Doie - - - 1136 26*26 205*7 

Madrid - - . - 665 27*72 208*04 

Moscow - . - - 328 28*82 210*2 

Lyons . . - - 177 29*33 210*92 

Paris .... 71 2969 211*46 


In vaetiOf all liquids boil at a temperature about 124° F. lower than under the 
average atmospheric pressure. For a table of elasticities, see Vapoub. Gay-Lassac 
has shown that liquids are converted into vapours more readily, or with less turbu- 
lence, when they are in contact with angular or irregular, than with smooth surfaces ; 
that they therefore boil at a heat 2^ F. lower in metallic than in glass vessels, pro- 
bably owing to the greater polish of the latter. For example, if into water about to 
boil in a glass matrass, iron filing ground glass, or any other insoluble powder be 
thrown, such a brisk ebullition will he instantly determined, as will sometimes throw 
the water out of the vessel ; the temperature at the same time sinking two degrees F. 

The following table exldbits the boiling heat, by Fahrenheit's scale, of the most 
important liquidi : — 

Ether • Graham ... 96** 

Ether, specific gravity 0*7365 at 48° 100 

Carburet of sulphur -.-....-..113 

do. ------ . Graham - - - 118 

Alcohol, sp. grav. 0*813 - . - - - lire - - - - 173*5 

Nitric acid, do. 1*500 .... - Dalton ... 210 

da do. 1*42 Graham - - - 248 

Water 212 

Saturated solution of Glauber salt . . - Biot - - - - 213| 

do. do. Acetate of lead - - do. - - - - 21 5| 

do da Sea salt .... do. ---- 224} 

do da Muriate of lime - - Ure - - " - 285 

da do. do. 1+ water 2 do. - » ** - 230 



Saturated Bolation of muriate of lime, 35-5 + water, 64-5 Ure ... ass** 

Ammonia -- ..---- Graham - - 140 

Crystallised chloride of calciam - - - - do. - - - S02 

Saturated solution of muriate of lime, 40*5 + water, 59-5 Ure - - . 240 

Muriatic acid, sp. grav^. 1-094 - - - - Dalton - - - 232 

do. do. 1127 ... - do. - - - 222 

Nitric acid, do. 1*420 . - - - da - - - 248 

do. do. 1-30 - - - - do. - - - 236 

Rectified petroleum ------ Ure - - - 306 

Oil of turpentine - - - - - - do. - - - 316 

Sulphuric acid, sp. grav. 1-848 - - - - Dalton - - - 60O 

do. do. 1-810 - - - - do. - - - 473 

do. do. 1-780 - - - - do. - ■ - - 435 

do. do. 1-700 - - - - do. - - - 374 

do. do. 1-650 - - - - do. - - - 350 

do. do. 1-620 . - - - do. - - - 290 

do. do. 1-408 - - - - do. - - - 260 

do. do. 1-300 - - - - do. - - - 240 

Phosphorus ------- do. - - - 554 

Sulphur do. --- .'i70 

Linseed oil ------- do. - . - 640 

Whale oil Graham - - 630 

Mercury Dulong - - - 662 

do. -------- Crighton - - 656 

Saturated solution of acetate soda, containing 60 per cent . Griffiths - - 256 

do. Nitrate of soda, 60 do. - - - 246 

do. Rocheliesalt, 90 do. • - - 240 

do. Nitre, 74 do. - - - 238 

do. Muriate of ammonia, 50 do. - - - 236 

do. Tartrate of potash, 68 do. - - - 234 

do. Muriate of soda, 30 do. - - - 224 

do. Sulphate of magnesia, 57*5 do. - - - 222 

do. Borax, 52-5 da - - - 222 

do. Phosphate of soda, ? do. - - - 222 

do. Carhonate of soda, 7 do. • - - 220 

do. Alum, 52 do. - - - 220 

do. Chlorate of potash, 40 do. - - - 218 

do. Sulphate of copper, 45 do. - - - 216 


EBULLITION ALCOHOLMETER. That the boiling temperature of water i« 
increased by holding neutro-saline and saccharine substances in solution has been long 
known, and has been the subject of many experiments, made partly with the Tiew of 
ascertaining from that temperature the proportion of the salt or sugar, and partly with 
the view of obtaining a practical liquid bath. But it seems to have been reserved for 
the "Abbe Brossard-Vidal, of Toulon, to have discovered that the boiling temperature 
of alcoholic liquors is, in most cases, proportional to the quantity of alcohol, im*spec- 
tively of the quantity of neutro-saline or saccharine matter dissolved in them. When, 
however, such a quantity of dry carbonate of potash, or sugar, is added to a spirituous 
liquor as to abstract or fix in the solid state a portion of the water present, then the 
boiling temperature oiTthat mixture will be lowered in proportion to the concentration 
of the alcohol, instead of being raised, as would be the case with water so mixed. 
But, generally speaking, it may be assumed as a fact, that the boiling point of an 
alcoholic liquor is not altered by a moderate addition of saline, sacchai ine, or extrac- 
tive matter. On this principle, M. Brossard-Vidal constructed the instrument repre- 
sented in Jig. 684, for determining by tluit temperature the proportion of alcohol 
present His chief object was to furnish the revenue b«mrds of France with a means 
of estimating directly the proportion of alcohol in wines, so as to detect the too 
common practice of introducing brandy into their cities and towns under the mask of 
wine, and thereby committing a fraud upon the octroi; as the duty on spirits is much 
higher than on wines. 

'J'he above iostrument consists of a spirit-lamp, surmounted by a small boiler, into 
which a large cylindric glass bulb is plunged, having an upright stem of such calibre 
that the quicksilver contained may, by its expansion and ascent when heated, raise 
before it a little glass float in the stem, which is connected by a thread with a similar 
glass bead, that hangs in the air. The thread passes rouud a pulley, which turning 
with the motion of the beads causes the index to move along the graduated circular 
scale. The numbers on this scale represent per centages of absolute alcohol, so that 


the nnmber oppodEe to vbich the index stops, vhcn the liquor in the cjUnder orer 
the lamp bnili britkly. deaDles tbe per eeuu^e of ilcohol io it. 

Dr. tire iiitcodiic«d oQolber form ofiiutnuaeDl (jSj. 895V It is thm deieribed Iiy 
tlic inTeutor: — 

It miuiats, I, of a flat apiril-tanip a, inrroaaded by a taaeer for rontiinioft 
cold watfr to ke?p tlie liuop cool, should innny eiperimentB require la he mude in *iic- 
ccsaion; S, of the boiler B. vhieb fits by it« bottom cnge c, upon the ciue of the 
. lamp. At the point c. Is seen the edge of the damper-plate for modifying the flame 
<,t the lamp, or eitinguiBhJng il wh«D the experiiueut is completed, c is the thermo- 
meter, made with s Terj minute bore, in the manner of the Rev. Mr. Wollaslon'i in- 
(LtrumeDt for measuring the height of a mountain by the boiling point of water OD it* 
summiL The bottom nf the scale in the ebullitioa thermometer, is marked p for 
proof OD the left tide, aod 100 (of proof spirit) on the rijrht side. It correspondi 
to 1786 Fahr. very nearly, or the boiling point of alcohol of O'SaO specific gravity. 
The following table gives the boiling poinla coirespoDding to the indie Hted densities i — 

SpcclSc griTltr- Temp. Fi 






10 U. P. 



ao „ 



30 „ 


40 „ 


0-9665 SO U. P. 


The above table is the mean of a great man; experiments. When alcohol is 
stronger than 92, or the excise proof, its boillag point variea too little vitb Its 
progressiTe increase of strength to rend^ that lest applicable in practice. In fact, 
even for proof spirits, or spirits approaching in strength 10 proof, a more exact 
indication may be obtained by dilulinj: them with their own bulk of water, before 
ascertaining their strength and then doubling it. 

The boiling point of any alcoholic liquor is apt to rise if the heal be long continued, 
and thereby to lead into error in using this instrument. This source of fallacj maj 
be. io a fcreat roeainre avoided by adding to the liquor iii the little boiler about a 
teaapooDfal (thiny-fiTc grains) of common enlinary talt, whicli haj! the curious eCEect 
of arresting the mcrcary in the Ihcnaomcter at the true boiling point of the spirit. 


wine, or beer, to enable a correct reading to be had. The small measure marked m 
holds the requisite quantity of salt 

The thermometer is at first adjusted to an atmospheric pressure of 29*5 inches. 
When that pressure is higher or lower, both water and alcohol boil at a somewhat 
higher or lower temperatare. In order to correct the error which would hence 
arise in the indications of this instrument under different states of the weather, 
a barometrical equation is ftttachod, by means of the subsidiary scale e, to the ther- 
mometer x>. 

Having stated the principles and the construction of the ebullition of the alcohol- 
meter, I shall now describe the mode of its application. 

First — ^Light the spirit lamp a. 

Second. — Charge the boiling vessel b, with the liquid to be tested (to within an 
inch of the top), introducing at the same time a paper of the powder ; then place the 
vessel B (the damper plate being withdrawn) on to the lamp a« 

Third. — Fix the thermometer d on the stem attached to b, with its bnlb immersed 
in the liquid. The process will then be in operation. 

The barometrical scale indicated on the thermometer is opposite the mean boiling 
point of water. Prior to commencing operations for the day, charge ^the boiler b 
with water only, and fix the instrument as directed ; when the water boils fireely, the 
mercury will become stationary in the stem of the thermometer, opposite to the true 
barometrical indication at the time. Should the mercury stand at the line 29-5 this 
will be the height of the barometer, and no correction will be required ; but should 
it stand at any other line, above or below, then the various boiling poiBts will bear 
reference to that boiling point. 

In testing spirituous or fermented liquors of any kind, when the mercnry begins 
to rise out of the bulb of the thermometer into the stem, push the damper-plate half- 
way in its groove to moderate the heat of the flame. When the liquor boils freely 
the mercnry will become stationary in the stem ; and opposite to its indication, on the 
left, the underproof percentage of spirit may be read off at once, if the barometer 
stand that day at 29 '5 inches; while on the right hand scale, the percentage of 
proof spirit is shown; being the difference of the former number from 100. The 
damper-plate is to be immediately pushed home to extinguish the flame. 

The alcoholmeter will by itself only indicate the percentage of alcohol contained 
in any wine, but by the aid of the hydrometer, the proportionate quantity of sac- 
charum in all wines may be readily and easily determined. The hydrometer will 
show the specific gravity of the liquid upon reference to table Na I, annexed. In 
testing a sample of wine, first take the specific gravity, and suppose it to be 989, 
then charge the boiler of the alcoholmeter with the wine, as directed, and at the 
boiling point it indicates the presence of alcohol at 69*6 per cent**'', whose specific 
gravity will be found to be 979 ; deduct that gravity f^om the gravity of the bulk, 
or 989, and 10 will remsfln, which 10 degrees of gravity, upon reference to the wine 
table, will be found to represent 25 lbs. of saccharine or extractive matter in every 
1 00 gallons, combined with SO^th gallons of proof spirit 

Sikes*s hydrometer will only show the sp. gr. of liquids lighter than water (or 
1000), and for wines in general use, the gravities being lighter than that article, will 
answer every purpose ; but there are wines whose gravities are heavier than water, 
such as mountain, tent, rich Malagas, lachrymas Christi, &c., to embrace which 
additional weights to the hydrometer will be required, as for cordialised spirits, &c. 
In testing a sample of rich mountain, its sp. gr. was found to be 1039, or 39 degrees 
heavier than water ; that wine at the boiling point indicated the alcohol 72'5 per 
cent"*p* ; but 980 deducted f^om 1039 leaves 39 degrees of sp.^.; against 59 
of the wine tables will be found 147-5 or 147^ lbs. of saccharine or extractive 
matter, combined with 27 1 gallons of proof spirit to every 100 gallons. 

Should the barometer for the day show any other Indication above or below 
the standard of 29*5, the thermometer scale will then only show the apparent strength, 
and reference must be had to the small ivory indicator, e, it being the counterpart 
of the barometrical scale of the thermometer; thus, should the barometer indicate 
30, place 30 of the indicator against the boiling point of the liquid, and opposite the 
line of 29*5 will be found the true strength. « 

Exomple 1. — ^Barometer at 30. — Suppose the mercury to stop at the boiling-point 
72"*»', place 30 of the indicator against 72 on the thermometer, and the line of 29*5 
will cut 69 '6"'*, the true strength. 

Example 2. — Barometer' at 29.~Suppose the mercury to stop at the same point, 
72.«*p% place 29 of the indicator against 72 on the thermometer, and the line of 29*5 
will cut 74*3-*'P', the true strength. 

For nuUted liquors. — To all brewers and dealers in fermented liquors, this principle, 
by its application, will supply a great desideratum, as it will not only show the alcohol 
created in the wort by the attenuation, as well as the original weight of the wort prior 










• c 

« i 


























10 1199 


























































































































































































































r- 1 














































































































































No. 2. 

TABLE, showing the lbs. of Sugar per Gallon in Cordialized Spirits, with Per 
to be added to the indicated Strength, per the Alcobolmeter. 

DlSbrence or 










Diflerenoe of 

Lbt. of Sagar 
per Gallon. 

4 ox. 

or 85 

to 100 

6 ox. 
to 100. 

8 01. 


to 100. 

10 OS. 
to 100. 

12 Of. 

to 100. 

14 01. 


to 100 




IJm. ofSttgar 
per Gallon. 

Np. Orav. 



of SiiiriU 










fjp. Gxmv. 












































3 1 












2 '2 












































5 9 














































































































42 5 

































3 9 

















































































62 '5 












3' I 

















70 • 

































































82 5 


































































« m 














m * 










to fermentatioD, but it will indicate the valae of malt liquors in relation to their com- 
ponent parts. It will likewise be a ready means of testing the relative value of worts 
from sugar compared with grain, as well as being a guide to the condition of stock 
beers and ales. 

To ascertain the strength of malt liquors and their respective values, the instrument 
has been supplied with a glass saccharometer, testing-glass, and slide-rule. Commence 
by charging the testing-glass with the liquid, then insert the saccharometer, to ascertain 
its present g^vity or density per barrel, and at whatever number it floats, that will 
indicate the number of pounds per barrel heavier than water. 

Example 1. — Suppose the saccharometer to float at the figure 8, that would indicate 
8 lbs. per barrel ; then submit the liquid to the boilin;? test, with the salt as before 
directed, and suppose it should show (the barometrical differences being accounted for) 
90 *'»', that would be equivalent to 10 per cent of proof alcohol. Refer to the slide rule. 


and plape A on the slide against 10 on the upper line of figures, and facing b on the 
lower line will be 18, thus showing that 18 Ihs. per barrel haTe been decomposed to 
constitute that percentage of spirit; then, by adding the 18 lbs. to the present 8 lbs. 
per barrel, the result will be 26 lbs., the original weight of the irort after leaying the 

Example 2. — The saccharometer marks 10 lbs. per barrel, and at the boiling point it 
indicates 8S*'** equivalent to 12 gallons of proof spirit per cent. ; place a agulnst 12, 
and opposite B will be 21 ^ lbs. per barrel, when, by adding that to the 10 lbs. present, 
^1^ lbs. will be the result. 

To <ucertain the relative value, — Suppose the price of the 26 lbs. of beer to be S6«. per 
Varrel, and the 31^ lbs. beer to be 40«. per barrel, to ascertain which beer will be the 
cheapest place 26 on the opposite side of the rule against 36, and opposite 3 Ij^ Ilk )• will 
be 43*. 7dL, showing that the latter beer is the cheapest by 3«. 7</. per barreL 

By taking an account of the malt liquors by this instrument prior to stocking, it 
may be ascertained at any time whether any alteration lias taken place in their condition, 
either by an increase of spirit by after fermentation and consequent loiw of saccharum, 
or whether, by an apparent loss of both, acetous fermentation has not been going on 
towards the ultimate loss of the whole. 

This instroment will likewise truly indicate the quantity of spirit per cent created 
in distillers* vorts, whether in process of fermentation or ready for the still ; the only 
difference will be in the allowances on the slide- rule. 

N.B. — The saccharometers applicable to the foregoing rules for beer, ales, &c., 
haTe been adjusted at the temperature of 60^ Fahrenheit, and will be found correct for 
general purposes; but where extreme minuteness is required, the Tariation of tempe* 
rature must be taken into account ; therefore for every 10 degrees of temperature above 
60, -jiyths of a pound must be added to the gross amount found by the slide-rule ; on the 
contrary, for every 10 degrees below 60, ^ths of a pound must be deducted. 

For cordiaiised Spirits. — The operation in this instance is somewhat different from 
that of beers, which have the alcohol created in the original worts $ whereas, in cor- 
dial ised spirits, gins, &c., the alcohol is the original, and the saccharine matter, or 
'sugar, is an addendum. 

If 100 gallons of spirits are required at a given strength, say 50 per cent under proof, 
50 gallons of proof spirit, with tbe addition of fifty gallons of water, would effect that 
object, and upon testing it by the alcoholmeter, it would be found as correct as by the 
hydrometer. But in cordialising spirits it is different, for to the 50 gallons of proof 
spirit 50 gallons of sugar and water would be added, thereby rendering the hydrometer 
useless, except for taking the specific gravity of the bulk, and according to the quantity 
-of sugar present, so a relative quantity of water must have been displaced ; and as the 
sugar has no reducing properties, the alcoholmeter will only show the strength of the 
cordial in relation to the water contained in it, as the principle indicates, irrespectively 
of saccharine or extractive matter present 

Suppose, in making 100 gallons of cordial at 50"^*, 3 lbs. of sugar are put to the 
gallon, or 300 lbs. to the 100 gallons, that 300lbs., displacing 18^th gallons of water, 
only 31fg(th gallons of water instead of 50 have been applied ; the sugar, without 
reducing properties, making up the bulk of 100 gallons, which is meant to represent 
60 per cent '•^. 

The alcoholmeter will only show at the full point of ebullition the alcoholic strength 
in relation to the water in the 100 gallons of the mixture, or 35 per ccnt"'i", leaving 15 
per cent to be accounted for on the bulk. 

As the quantity of sugar present must be determined before that percentage 
can be arrived at, a double object will be effected by so doing, namely eliciting in all 
instances the quantity of sugar present, as well as the percentage of spirit to be ac- 
counted for. 

Example 1. — In taking the sp. gr. of a cordial, suppose it to be found 1076, then 
submit the liquid to the boiling point, and having ascertained the percentage of alcohol, 
and it proves to be 35"*i>% the sp. gr. of alcohol at that strenffth will be found to be 956 ; 
deduct 956 from the sp. gr. of the bulk, or 1076, and 120 will remain ; refer that to its 
amount en the head line of the table No 2, namely, 120, under which will be found 3, 
representing 3 lbs. of sugar to the gallon ; and by running the eye down its column to 
opposite the alcoholic strength indicated (35"i>') will be found l4-9,which represents the 
percentage of water displaced by the sugar, and which amount of 14-9, added to the 
35 per cent ascertained, makes the total upon the balk 49*9 per cent ■*!**, with 3 lbs. of 
sugar to the gallon. 

Far Gins, ^-c. — Example 2. In taking the sp. gr., suppose it to be found 957 ; then 
submit to the boiling point, and it proves to be 14"P', whose sp. gr. is 937, which 
deducted from 957, leaves sp. gr. 20 ; on the head-line of table No. 2, under 20, will 
be found 8.oz., or ^ lb. of sugar to the gallon, and on running the eye down to opposite 


U* 1", will be found 3*0, which added to the 14, makes the total on the hulk 17 per 
cent." p% with 50 Ihs. of sugar to the 100 gallons. 

To chemists for their tinctures, &c., this instrument will be found essentially uiefuL 

N.B.->Care must be taken that the mercury is entirely in the bulb of the thenuo- 
meter before it is fixed on the stem for operation, and in all cases (except for water) 
the salt must be used. 

EDGE TOOLS ; more properly cutting tooU^ of which the chisel may be regarded 
as the type. Holtzapffel, whose book on Mechanical Maniptilation is the best to be 
found in any language, divides cutting tools into three groups, — namely paring tooli, 
scraping tools, and shearing tools. 

Firtt Paring or splitting tools, with thin edges, the angles of which do not exceed 
sixty degrees ; one plane of the edge being nearly coincident with the plane of the 
work produced (or with the tangent in circular work). These tools remove the 
fibres principally in the direction of their length, or longitudinally, and they produce 
large coarse chips, or shavings, by acting like the common wedge applied to mecha- 
nical power. 

Secondly, Scraping tools, with thick edges, that measure from sixty to one handred 
and twenty degrees. The planes of the edges form nearly equal angles with the 
surfiiee produced, or else the one plane is nearly or quite perpendieolar to the fhee 
of the work (or becomes as a radius to the circle). These tools remove the fibres 
in all directions with nearly equal fitciiity, and they produce fine do8t*like shaTiogi 
by actina; superficially. 

Thir<&f, Shearing, or separating tools, with edges of from sixty to ninety degree 
generally duplex, and then applied on opposite sides of the substances. One plaae of 
each tool, or of the single tool, coincident with the plane produced. 

Mr. James Bouydell introduced a process which professes to produce cheap edge 
tools of excellent quality. We believe the result has not been so satisfactory as the 
patentee expected. He welds iron and steel together in such a manner thst when 
cut up to form edge tools, the steel will constitute a thiu layer to form the catting 
edge. He piles a slab or plate of steel upon two or more similar plates of iroo, heats 
in a furnace to a good welding heat, and then passes between grooved or other 
suitable rollers, to convert it into bars ; the steel being in a thin layer either on one 
of the outer surfaces of the bar, or between two surfaces of iron according to the kind 
of tool to be made therefrom. The bars thus produced are cut up and manafactared 
into the shape of the desired articles by forging. If the cutting edge is to extend 
but a short distance, the steel is applied only near one edge of the pile. The componnd 
bars which have the steel on one side are suitable for chisels and other tools, which 
have a cutting edge on one side, the iron being ground away when making or sharpen- 
ing the tool. See Cutlery; Steel. 

EDULCORATE (Edulcarer, Fr.; AustuMen, Germ.) is a word introdoeed by the 
alchemists to signify the sweetening, or rather rendering insipid, of acrimonious poi- 
verulent substances, by copious ablutions with water. It means, in modem language, 
the washing away of all particles soluble in water, by agitation or trituration with this 
fluid, and subsequent decantation or filtration. 

EFFERVESCENCE. (Eng. and Fr. ; Aufhrnusen, Germ.) When gaseous matter 
is suddenly extricated witii a hissing sound during a chemical mixture, or by the 
application of a chemical solvent to a solid, the phenomenon, firom its resemblance to 
that of simmering or boiling water, is called effervescence. The most familiar ex- 
ample is afforded in the solution of sodaic powders ; in which the carbonic acid gas of 
bicarbonate of soda is extricated by the action of citrio or tartaric acid. 

EFFLORESCENCE (Eng. and Fr.; Verwittern, Germ.) is the sponlaineons con- 
version of a solid, usually crystalline, into a powder, in consequence either of the 
abstraction of the combined water by the air, as happens to the crystals of sulphate 
and carbonate of soda ; or by the absorption of oxygen and the formation of a salme 
compound, as in the case of alum schist, and iron pyrites. Saltpetre appears as an 
efflorescence upon the ground and walls in many situations. 

EGGS, HATCHING. See Incubation, AnTincxAL. 

EIDER-DOWN U so called because it U obtained from the £u/er-duck. These 
birds build their nests among precipitous rocks, and the female lines them with fine 
feathers plucked from her breast, among which she lays her five eggs. The nauves 
of the districts frequented by the eider-ducks let themselves down by cords among 
the dangerous cliffs, to collect the down from the nests. It is used to fill coverlets, 
pillows, cushions, &c. 

ELAINE (called also Olsine) is the name given by Chevreul to the thin oil, which 
may be expelled from tallow and other fats, solid or fluid, by pressure either in their 
natural state or after being saponified, so as to harden the stearine. It may be extraeted 
also by digesting the fat in seven or eight times its weight of boiling alcohol, specgrav- 



0-79S, till it dittolyes the whole. Upon cooling the solution, the itearine falU to the 
bottom, while the elaine collects in a layer like olive oil, upoa the surface of the super- 
natant solution, reduced by evaporation to one eighth of its bulk. If this elaine be now 
exposed to a cold temperature, it will deposit its remaining stearine, and become pure. 
Bracoanot obtained it by exposing olive oil to a temperature of about 21^ F. in order 
to cause the congelation of the margarine or stearine (?). The elaine was a greenish 
yellow liquid ; at 14^ F. it deposited a little margarine. See Oils and Stsakine. 

ELASTIC BANDS. ( Twtu AuOquet^ Fr. ; Federharz-zeige, Germ.) See Caout- 
chouc and Braimiio Machine. 

ELASTICITY. The property which bodies possess of occupying, and tending 
to occupy, portions of space of determinate volume, or determinate volume and figure, 
at given pressures and temperatures, and which, in a homogeneous body, manifests 
itself equally in every part of appreciable magnitude (NichM). The examination of 
this important subject in Kinetics does not belong to this work. A few remarks, 
and some explanations, only are necessary. 

Ehstie Pre$9wre is the force exerted between two bodies at their surface of contact. 

Compresaicn is measured by the diminution of volume which the compressible 
(elastic) body undergoes. 

7%e Modulut or Coefficient of Elasticity of a liquid is the ratio of a pressure applied 
to^ and exerted by, the liquid to the accompanying compression, and is therefore the 
reciprocal of the compressibility. The quantity to which the term Modulus of 
Elaatieitjf was first applied by Dr. Young, is the reciprocal of the extensibility or 
longitudmal pliability. (See the Edinburgh Transactions, and those of the Royal 
Society, for the papers of Barlow, Maxtcellj and iZanAine, and the British Association 
Reports for those of Fairhaim^ HodgkinsouL, &c.) 

Yarions tables, showing the elssticity of metals, glass, &c., have been constructed, 
and will be found in treatises on mechanics. The following notices of the mecha- 
nical properties of woods may prove of considerable interest The experiments were 
by Chevaadier and Wertheim. 

Rods of square section 10 mm in thickness and 2 m in length were prepared, being 
cut in the direction of the fibres, and the velocity of sound in them was determined by 
the longitudinal vibrations, thmr dasticity from their increase in length, and their co- 
hesion by loading them to the point of rupture. Small rods were cut in planes per- 
pendicular to the fibre grain (in directions radial and tangential to the rin^s of growth) 
and their elasticity and sound volocity were measured by the lateral vibrations. It was 
thus again established, that the coefficients of elasticity, as deduced from the vibrations, 
come out higher than those derived from the elongation. 

Name* of the woods. 

Fir - 
Oak . 
Holm- Oak 
Pine - 
Sycamore - 
A&h . 
Elm . 


Soond Telocity. 

Coefficients of elns- 






































































— - 




















































16 80 










12 36 



























L refers to rods cut lengthwise with the grain, 
R to those cut In a direction radial, and 
T to tbo^e tangential to the annual rings. 

EL ATEBIUM. A peculiar extract obtained from the juice of the wild cucumber. 
(^Momordica daterivrn), 

ELDER. (Samlmeus nigra, Sureau, Fr. ; Hohlunder, Germ.) Pith balls for elec- 
trical purposes are manufactured fh)m the pith of the elder tree, dried. The wood is 
employed for inferior turnery work, for weaver*s shuttles, netting pins, and shoe- 
makers* pegs. Its elasticity and strength render it peculiarly fitted for these 
latter purposes. 

ELECTIVE AFFINITY. iWahherwandtschafty Germ.) See Decomposition, 

ELECTRIC CLOCKS. The application of electricity as a motive power to 
docks, and as a means of transmitting synchronous signals or time, is naturally inti- 



matelj connected with the attempts (not yet realised in an economic point) to apply it 
as a motive power to machinery, and with its application, so fully realised (see article 
Electro-telegrapht), to telegraphy proper ; and it has grown up side by side with the 
latter. Prof. Wheatstone's atteniion wasdirected to it in the very early days of telegraphy. 
Without entering upon the history of electric docks, it will suffice to describe tvo 
principles on which they have been constructed, and which are best known,— Bains 
and Shepherd 8. In the former, electricity maintains the pendulum in motion, and the 
pendulum drives the clock-train ; in the latter, the motion of the pendulum is maintained 
by electricity, but the clock-train is driven by distinct currents, sent to it by means of 
pendulum contacts. 

The bob of Bain's pendulum consists of a coil of wire, wound on a bobbin with a 
hollow centre.- The axis of the bobbin is horizontal. Bar magnets, prescnf:n/r 
similar pules, are fixed on each side of the coil, in such a position that, as the pendnlom 
oscillates right and left, the poles on either side may enter the coil of wire. It is one 
of the laws of electric currents, when circulating in a helix, or spiral, or coil, or even 
in a single ring, that each face of the coil presents the characters of a magnetic pole, 
of a south pole if the current circulates in the direction in which the hands of a 
watch move, of a north pole, if it circulates in the reverse direction. Things are so 
arranged in Bain's pendulum that a battery current is alternately circulating in and 
cut off from the coiL When the current is circulating, the coil has the character of a 

686 magnet, with a north end and a south end; if 

the permanent magnets present north poles, the 
north end of the coil- bob will be repelled from 
one of the magnets, while its south end will be 
attracted by the other magnet This consti- 
tutes the impulse or maintaining power in one 
direction. Now the connections are sach that, 
when the arc of vibration is complete and the 
pendulum ready for the return vibration, the 
pendulum rod pushes aside a golden slide, by 
which the electric circuit had been completed, 
and the current is cut off; the pendulamisthns 
able to make its return vibration by mere 
gravity. It starts to repeat the above operations 
by mere gravity; but, ere it completes the arc, 
the rod pushes back the slide, and again com- 
pletes the electric circuit, and gives rise to a 
second impulse, and so on. A small annount of 
magnetic attraction is sufficient to supply the 
necessary amount of maintaining power. One 
pair of zinc-copper, buried in the moist earth, 
has been found ample. 

In an ordinary clock, the train is carried hy 
a weight or by a spring, and the time is regn- 
lated by the pendulum. In Bain's the time is 
regulated and the train is driven by the pendu- 
lum. The rod hangs within a crutch in the 
usual way ; the crutch carries pallets of a par- 
ticular kind, acting in a scape- wheel ; and from 
the latter, the motion is transmitted to a iraia 
of the usual character; but much lighter. For 
large clocks, Mr. Bain proposes a modification 
of the slide, which shall invert the current at 
each oscillation, so as to have attraction as a 
maintaining power in both oscillations. The 
general arrangement of the pendulum is shovn 
in Jig. 686. B is the pendulum bob, ▼ith >» 
coil of wire, the ends of which pass up on either 
side of the rod. z and c are the battery pla^ 
w ith their attached wires d and d'. The arrows 
o show the course of the voltaic current firom the 
plate c by the wire d^, thence down the pendaj 
lum rod by the right hand wire, through the coil 
B, up by the wire on left side of rod, then hy 

^ -• ' ' the wire c, along the slide at e, and by the 

wire D to the zinc plate z. When the slide e is in position, the circuit is complete, 
and the bob is attracted by the n pole of one of the magnets, and repelled by the a 


pale of the other. When IlieaUdeU ditpUecd, the UtnctloneeMM, tad tlupatdnlnm 
n left to the mere action otgn-ritj. 

Sfaepberd'a electric clock has m, Temontcdr eMapemmt. Then U no direct ocnin«>~ 
tion betveen the dectric tbree and the pendulDin, or helween the pendnliun and the 
clock Inio. The attTiu:tiTe power, deriTCd trtmt the electric eorrent, ii llnplf em- 
plojcd lo nice the nme nnall weight to the nine bmght i tai the clock-tnun it 
carried by the attrKetire force derived from electric cnrrcnta, whose eireoiu are com- 
pleted bj the peDdnlmn tonchiag contact ipringa. The pendolnm ii thua protected 
from the infloeoee of change in the fbree of the cnrrent, or IVom Irrenlar reaiataocet 
ia the train. Fig-tSI U a penpectiTe view of ibia peodalun, wiu batteries ■ m, 

attached, and the dock coanectioDi and thou of iu batteries, $t*t, thown. The 
electricinr teavet the pendnlam bMterj by the wire a, and retnraa to it b; the wire w. 
Vol. iL O 


There is only one break in this circnit, namely, at s, which is a slender spring &oed 
with platinum, that is in contact with platinum on the pendulum at the extreme of its 
right Tibration, but at no other time. The wire ▲ reaches the pendulum from the 
battery by the coils b, the plate o, and the frame d ; the wire F goes direct from the 
spring E to the zinc z. From this arrangement, it happens that eyery time the con- 
tact at E is completed, the iron core, of which the ends m s are visible, ooDtained 
within the coils b, becomes a magnet, and when the contact at b 14 broken, the 
magnetism ceases. The poles n b have, therefore, a power alternately to attract aad 
to release a, which is a plate or armature of soft iron, moving on an axis, as shown 
in the figure, and to which is attached a bar b, with a counterpoise t. We have nid 
that the office here of the electric force, is merely to raise a weight; the fall of the 
weight maintains the pendulum in motion. When the armature a is attracted, the 
lever b is raised; this raises the wire c into a horizontal position, and its other part 
d into a vertical position; the latter is caught and retained by the latch or detent e; so 
that when the magnetic attraction ceases, the counterpoise t descends with the lever 
b ; and so the armature a leaves the electro-magnet n s. But the wire d remaiB$ 
vertical, and its other part with the small weight e remains horizontaL Now, when 
the pendulum makes its left hand oscillation, the point of the screw /impinges upon 
the stem g, and carries it a little to the left ; this raises the detent e, and liberates the 
piece d c, which descends into its original position by gravity ; the small ball c adds 
to its weight. In descending, the vertical piece c strikes against the point of the 
screw ht and gives a small impulse to the pendulum p. The ball c is not larger than 
a pea, and its fall is not an eighth of an inch; but the impact is sufficient to keep the 
pendulttm in motion; and it is constant, being this same body falling through the 
same space; and is independent of any variation in the battery power, which latter is 
only concerticd in raising the ball. The arc of the pendulum's vibration is regulated 
by adjusting the small b^l to a greater or less distance from the centre. Provision is 
thus made fbr maintaining the pendulum in motion, and giving it an impact of con- 
stant value. If this arrangement is in connection with a compensating mercurial pen- 
dulum, extreme accuracy of time-keeping is attained. The next step is to transfer 
the seconds, thus secured, to a dial or clock. The same movement of the keeper a 
with its counterpoise i, has sometimes been made to impart motion to the seconds 
wheel of a clock train; but more commonly the clock train is distinct, as shown in the 
drawing, and is carried by a special electro-magnetic arrangement, in connection with 
separate batteries, z c, zc^ the contacts of which are, however, under the control of 
the pendulum. Insulated springs, k and ^ are fixed near the top of the rod ; from k 
a wire leads to the silver s, of the left hand battery ; and from / another wire leads to 
the zinc z, of the right hand battery. The other metals of the respective batteries are 
connected by a wire with an electro-magnet within the clock, the other end of the said 
electro-magnet being connected with the metal bed and frame of the pendulum. When, 
therefore, the pendidum oscillates to the right, the circuit is completed at k ; and the 
current of the left hand battery circulates from 9 through the wire k ; and thence 
through the metal frame and by the wire to the clock, and so to the zinc z. When 
the oscillation is to the left and 1 is in contact, the right band battery is in action ; and 
the current circulates from « through the clock, to the metal fhune, and thence to / 
and to the zinc z of the battery. In one case, a voltaic current enters the clock by 
the wire shown below, and leaves it by the upper wire ; and, in the other case, it 
enters by the upper and leaves by the lower wire. There is a double set of electro- 
magnets within the clock, showing four poles in all ; there are also two magnetised 
steel bars, mounted see-saw fashion, with their poles alternate, and facing the four 
electro-magnetic poles. When the current enters the clock from below or in one 
direction, the bars oscillate this way; when it enters from above or in the reverse 
direction, they oscillate that way. They are both fixed at right angles to aad upon 
the same axis ; which axis carries a pair of driving pallets, that act on a scape- wheel, 
and so the clock-train is driven. It will be seen at a glance, that two or more clocks 
may be connected in the same circuit, as readily as one ; it being merely necessary in 
such case to modify tHe battery power, to correspond with the work to be done. 
For instance, three such clocks have been going for several years at Tonbridge by 
the same pendulum ; several are actuated in like manner at the Royal Observatory, 
Greenwich. Nor is it necessary that the clocks should be in the same room with the 
pendulum, or in the same building, oir even in the same parish. All the clocks above 
referred to, are variously distributed ; and one of the Observatory clocks is six miles 
distant from its penduliui, being at the London Bridge Station of the South-Eastem 

In cases where it has not been found convenient to drive the dock train, especially 
in the case of a public one, the movement of which is heavy, great advantage has 
been derived for regulating the oscillations of the pendulum of the large clock, by 
means of electric currents, under the control of a standard pendulum. Mr. Jones 


hjM adopted thif method* and it is likely to meet with much fiiTour. The turret 
clock, under this arrangement, is driven hy weights in the usoal way, and the time is 
regulated hy a pendulum. The hoh of the pendulum is placed under a condition 
anulogoaB to that of Bain's (Jig, 686), the permanent magnet, however, heing attached 
to tlie pendulum, and the electro-magnet fixed facing it If currents are made to 
circulate syncfarononsly in the latter, by means of a standard pendalum, the oscillations 
of the pendulum of the turret-clock are constratoed to accord with those of the 
standard, and a very perfect s^rstem of time-keeping is obtained. This is practised at 
LiTerpool ; and has just been introduced at Greenwich. 

Under the abore arrangements the dock is controlled by the standard pendulum 
second by second, and the two keep time together throughout the day. There are 
cases in which it is sufficient, and also more convenient, to correct a clock once a dar 
only by means of a telegraph signal transmitted from a standard clock. This is 
managed in several ways. There is a dock at the Telegraph Office in the Strand ; 
a good r^ulator, adjusted to gain a second or two during the twenty-four hours, and 
to stop at 1 P.M. A telegraph signal is sent from the Royal Observatory precisely at 
one, that drops a time-ball at the Strand office, which, in &iling, staru the clock. 
At Ashford, seventy-three miles from Greenwich, there is an electric clock which has 
a gaining rate, and which is so constructed that the liattery circuit is opened at one 
o'clock by means of pins and springs attached to the movement, and the clock there- 
fore stops. At 1 P.M., Greenwich mean time, a signal is sent through the Ashford 
clock from the Royal Observatory, which starts it at once at true time. At the Post 
office, Lombard Street, there is a clock which, in the course of the twenty-four hours, 
raises a weight At noon a telegraph signaJ is sent from Greenwich, which passes 
thro«|^ an electro-magnet t the latter attracu an armature of soft iron and liberates 
the ball, which Ihlls, and in £Uliag it encounters a crutch, or lever, attached to the 
second's hand, and thrusts it this way or that, as the case may be ; but so as to bring 
k io sixty seconds on the dial, and thus to set the dock right 

Intermediate between the one method of sending a signal every second to regulate 
a dock, and the other method of sending it once a &y, we have the followlog arrange 
ment of Bain's for sending it once an hour. Fig, 6tf8 shows the arrangement, with 
part of the dial removed* to show the position of the electro-magnet The armature 
IS below ; it carries a vertical stem, terminating ^ 

above in a fork. Its ordinary position is shown 
by the dotted lines. The minute hand (partly 
removed from the cut) carries a pin on its back 
surface. When the hand is near to sixty mi- 
nutes, and an electric current is sent through 
the magnet the armature is attracted upwa^ 
and the fork takes the position shown by the 
fnli^ lines at the top of the dhU, and, in doing 
so, it enoonnters the pin and forces the hand 
into the vertical position, and sets the clock 
to true time, providing the signal comes from 
a standard dock, or is sent by hand at true 
time. A dial of moderate character keeps so 
near to time, that once or twice a day would 
be, for all common purposes, often enough to 
correct it * 

Fig. 689 is an arrangement of Bain's, by 
which a principal dock, showing seconds, 
sends deetric currents at minute intervds to other docks, and causes the hand to 
move minute by minute, a is a voltaic battery ; b is the prindpaldock, which may 
be an electric dock or not at pleasure} o and h are two out of many subordinate 
docks. The seconds hand of the principd clock completes a voltaic circuit twice 
(for the case of two docks) during the minute; at the 80 seconds for the dock o, 
and at the 60 seconds for the dock h. The clock h shows time in leaps from one 
minute to the next; and the dock o from one half minute to the next half minute. 
As many more contacts per minute may be provided for the seconds hand of the 
prime dock as there are subordinate clocka 

Next akin to the time signals above described, and which act automatically upon 
docks, either to drive the dock-train or to correct the dock errors, are mere time 
signals, which are extensivdy distributed throughout the country by the ordinary tele- 
graph wires, and are looked for at the various telegraph stations, in order to oompare 
the office dials with Greenwich mean time, and to make the necessary correction; 
tbcy are also re-distributed b^ hand the moment they appear, through sub-distriots 
branching from jnaetion stations. Large black balls, hoisted in oonipionous stations, 




are also dropped dailj by electric currents in yarioos places, for the general infor- 
mation of the pablic, or of the captains of ships. — G. V. W. 


ELECTRICITY /or Blattmg in Mines and Quarries, Professor Hare was the fint 
who entertained this idea, bat Mr. Martin Roberts devised the following process, u 
order not to be called upon to make aAresh a new apparatus for each explosion, Mr. 
Roberts inyeuted cartridges, which may be constract^ beforehand. With this new, 
two copper wires are procured^ about a ten^ of an inch in diameter, and three yaiw 
in length, well covered with silk or cotton tarred, so that their insulation mBj be 
very good. They are twisted together (fg. 690) for a lf?8"lj 
six inches, care being taken to leave their lower extremities nee. 
for a length of about half an inch (separating them about ban ia 
inch), from which the insulating envelope is removed, inorder tostietca 
between them a fine iron wire, after having taken the precanuon 
of cleaning them welL The upper extremities of the two eopptf 
wires are likewise separated, in order to allow of their being plMM 
respectively in communication with the conductors, that abut npoQ 
the poles of a pile. The body of the cartridses is a tin tube, three 
inches long, and three quarters of an inch in diameter, the solaeringi 
of which are very well made, in order that it may be perfectly imper* 
meable to water. A glass tube might equally well be em^oyed, 
were it not for its fragility, which lus caused a tin tube to be pj^ 
ferred. The system of copper wires is introduced into ^^^ 
fixing them by means of a stem that traverses it at such a beig 
that the fine iron wire is situated, in the middle of the tin wie, 
so arranged that the ends of the copper wire do not ^/^^[! 
touch the sides of the tube (Jig, 691). The cork is firmly ww» 
the upper extremity of the tube witn a good cement Mr. "frfr 
recommends for this operation, a cement composed of one part ^°^ 
wax and two parts of resin ; the tube is then filled with P^^^^^ ^ 
its other extremity, which is likewise stopped with a cork, ^"^ 
cemented in the same manner. Figwre 692 indicates the ""**' 
in which the cartridge is placed in the hole, after having ca 
fully expelled all dust and moisture \ care must be taken ^^^ 
cartridge is situated in the middle of the charge of powder tbai 
introduced into the hole. Above the powder is placed s P'*^^ 
straw or tow, so as to allow between it and the powder a smtU apjf 
filled with air ; and above the plug is poured dry sand, untU the ikn« 
is filled with it The two ends of the copper wires that «>»* ** y^ 
the cartridge are made to communicate with the poles of the p • 
by means of conductors of sufficient length, that one id<^3[ ^ ^ 
tected ftum all dangers arising fh)m the explosion of the ^"^^ ^ 
M. Ruhmkorff, and after him, M. Verdu, have successfully tried to 'v^^ij^llof 
induction spariL /or the incandescence of a wire, in order to bring about the ^^^^ 
the powder. This process, besides the considerable economy that it presents-'^ 
instead of fW>m fifteen to twentv Bunsen's pairs, necessary for causing tbe Mff^"^ 

ELECTRlCnr. 85 

of the win, il reqairei but ■ riagle ooa for producing the iDdaetioa ipcrk, — poMcuei 
th« adruitages of being le« loiceptibLe of dermngemeiit. Ontj it tu neccsur; to 

clrcDJt preienn too grett ■ reaiituiee, the induction apark ia able to pM* throagh 
the powder without influnmg it. M. Ruhmkorff fani eoneeiTed the bippv idea of 
teekmg for ■ medium, wbicb, more euily inflsnunable b; the spark, may bring About 
the ignition of the powder in all pouible couditioni. He found it in Statham'i fiue«*, 
which are prepared bj taking two end* of copper wire covered with ordidarj gotta 
pereha ; thej are twiited (^.693), ud the euds are bent m> aa to make them eater 
mto an en'riope of vnleaoiied (lolphured) gntta percha, which hai been cut and 
drawn off from a copper wire that had been for a bog time covered with it. Upon 
Ihia envelope a sloping cut a, i, is formed; aod after hariug maintained the ex- 
tremitiei of the cop^r wire* at aboat the eighth of an inch fh>m each other, their 
points are covered with fnlminaU: of mercur;, in order to render (he ignition of the 
powder more earf. The cut is filled with powder, and Ibe whole is wrapped round with 
a piece of caoulcbonc tube, e, d, or else it is placed in a cartridge filled with powder. 
In the Btatham fiuee*, it is the aDlphide (sulphuret) of copper adhering to the wire, 
produced by the action of the Tnlcaaised gutta percha which is removed from the 
copper wire that it covered, which by being iufiamed under the action of the induction 
spark bringi about an explosion, Bnt it is neceisary to take care wbeu tbe fusee has 
been prepared, as we have pointed oat, to try it in order to regulate the extent of the 
lolntian of coolianitj. It might, in fact, happen that while sliU belonging to tbe same 
envelope of a copper wire, th« idiealh oF a vulcanised gutta percha wi& which the 
foaee is furnish^, maybe more or le« impregnated with sulphide of ropperi 
DOW, it the solphlde of copper is in too great quantity, it becomes too good a 
eoodnctor, and prevents the spark being produced; if, on the conltary, it is not in a 
■officiently Urge quantity, it does not tn^cleutly facilitate the discharge. 

The Erst trials on a large scale of the application of tbe proct^i that we Just 
deaeribed, were made with RohmkorS's ioduction apparatus, by the Spanish colonel, 
Verdo, in tbe workshops of M. Uerkmas, manufacturer of gatla percha covered wire, 
at La Villette, near Paria. Experinieiita were made luccesaively upon lengths of 
wire of «00, GOO, 1000, SOOO, and up to S6,000 metres (ofS'Za feetji and the success 
was always complete, whether with a circuit composed of two wires, or replacing one 
of the wire* by the earth i two ordinary Bunsen's pairs were sufficient for producing 
the induction spark with Rubmkorff's apparatus. Since his first researches with 
H. Ruhmkorff, M. Verdu has applied himself 1o fresh researches in Spain ; and he 
«ai satisfied, by many trials, that of all explosive substances, not any one was nearly 
so sensitive as fulminate of mercury; only, in order to avoid (he danger that arises 
from the fiwylily of explosion of this componnd, he takes the precaution of intro- 
dncing the extremity of the fhsecs into a small gutta percha tube, closed at the end. 
After having filled with powder this species of little box, and having closed it 


hermetieaUy, the fhsees may be carried about, may be handled, may be allowed to 
fall, and even squeezed rather hard, withoat danger. The elastic and, leather-like 
nature of gutta percha, which has been carefully softened a little at the fire, preserves 
the fulminate f^om all chance of accident We may add, that with a simple Bunsen's 
pair, and by means of Rahmkorff *s induction apparatus, M. Verdu has succeeded in 
producing the simultaneous explosion of six small mines, interposed in the same 
circuit at 320 yarda from the apparatus. He has not been beyond this limit ; but he 
has sought for the means of acting indirectly upon a great number of mines, by 
distributing them into groups of five, and by interposing each of these groups in a 
special circuit The fusees of each group are made to communicate by a single wire, 
one of the extremities of which is buried in the ground, and whose other extremity 
is near to the apparatus. On touching the induction apparatus successively with each 
of the free ends that are held in the hand, which requires scarcely a second of time, 
if there are four wires, that is to say, four groups and consequently twenty mine% 
twenty explosions are obtained simultaneously at considerable distances. There are 
no limits either to the distance at which the explosion may take place, or to the 
number of mines that may thus be made to explode. 

ELECTRIC LIGHT. Various attempts have been m»le, fVom time to time, to 
employ electricity as an illuminating power ; but hitherto without the desired success. 
The voltaic battery has been employed as the source of electricity, and in nearly all 
the arrangements, the beautiful arc of light produced between the poles, from the 
points of the hardest charcoal, has been the illuminating source. One of the great 
difficulties in applying this agent arises from the circumstance that there is a trans- 
ference of the charcoal from one pole to the other, and consequently an alteration in 
the distance between them. This gives rise to considerable variations in the intensity 
and colour of the light, and great want of steadiness. Various arrangements, many 
of them exceedingly ingenious, have been devised to overcome these difficulties. 

The most simple of the apparatus which has been devised U that of Mr. Staite, 
which has been modified by M. Archereau. Two metal columns or stems, to which 
any desired form can be given, are connected together by three cross pieces, so as to 
form one solid frame *, one of these cross pieces is metallic, it is the one which occupies 
the upper part of the apparatus ; the others must be of wood. These latter serve as 
supports and points of attachment to a long bobbin placed parallel to the two columns 
and between them, and which must be made of tolerably thick wire, in order that the 
current, in traversing it without melting it, may act upon a soft iron rod placed in the 
interior of the bobbin. This iron rod is soldered to a brass stem of the same calibre, 
and of the same length, carrying at its free extremity a small pulley. On the opposite 
side the iron carries a small brass tube, with binding screws, into which is introduced 
one of the carbons, when the entire rod has been placed in the interior of the bobbin. 
Then a cord fixed to the lower cross piece, and rolling over a pulley of large diameter, 
is able to serve as a support to the movable iron rod, running in the groove of the 
little pulley. For this purpose, it only requires that a counterpoise placed at the end 
of the cord shall be enabled to be in equilibrio with it. The metal cross piece which 
occupies the upper part of the apparatus, carries a small brass tube, which descends 
perpendicularly in front of the carbon that is carried by the electro-magnetic stem, 
and into which is also introduced a carbon crayon. By means of a very simple ad- 
justment, this tube may besides be easily regulated, both for its height and for its 
direction } and consequently the two carbons may be placed very exactly above one 
another. The apparatus being adjusted, we place one of the two metal columns of 
the apparatus in connection with one of the poles of the pile, and cause the other 
pole to abut upon the copper wire of the bobbin (one end of which is soldered upon 
Its socket). The current then passes from the bobbin to the lower carbon by the rod 
itself that supports it, and passing over the interval separating the two carbons, it 
arrives at the other pole of the pile by the upper cross piece of the apparatus and the 
metal column, to which one of the conducting wires is attached. 

So long as the current is passing and producing light, the bobbin reacts upon the 
iron of the electro*magnet rod, which carries the lower carbon and attracts it on 
account of the magnetic reaction that solenoids exercise over a movable iron in their 
interior. It is this which gives to the carbons a separation sufficient for the luminous effect 

But immediately the current ceases to pass, or is weakened, in consequence of the 
consumption of the carbons, this attraction ceases, and the movable carbon, acted on 
by the counterpoise, is found to be drawn on and raised until the current passes 
again ; equilibrium is again established between the two forces, and the carbons may 
be employed again. Thus, in proportion as the light tends to decrease, the coun- 
terpoise reacts; and this it is that always maintains the intensity of the light equal. 

M. Breton has an apparatus which differs somewhat from the abovs, and M. 
Foacault has also devised a very ingenious modification. 



H. Daboacq bH made b7 fkr the moat neecMfiil mmagtmeat, tat m dctcription of 
wluch we are indebted to Z?e Is A'ra'i TVulin oil £J(eMi%, (TuuLated ti]' C. V. Wftlker. 

The two cmrbooi, between which the light i* dereloped, bora in conuuit with the 

>ir. and ihorten «t each iutant; a mechaDiim ii conaeqnently neecMaiy, which 

bringi them near to each other, propoTtionalt j to the pro g re ii of the Miabaftion g 


ud lince the ponliTe carbon mffen a more rapid oombnltian than the negative, it 
moM travel more rapidlj in hce of thla latter ; and this in a relation which Tariea 
with the thiekneu RQd die natnre of the carbon. The meehaniim mn*t MtJify all 
theae exigencies. The two carbooi are nnceasingl; «olicited towarda each other, 
the lower carbon bj a (pir&l ipring, that caoies it to rite, and the upper carbon bj 
itt weight, which Cftmeg il to deecend. The nune axii i« common to them. 
The galTUiic current ii prodnced by a Bnnaen'i pile of from 40 ti 


It arriTes at the two carbons, as in apparatus already known, passing throagh a liollov 
deetro-magnet} concealed in the column of the instrument. When the two carbons 
are in contact, the circuit is closed, the electro*magnet attracts a soft iron, placed at 
the extremity of a lever, which is in gear with an endless screw. An antagonist 
spring tends always to unwind the screw as soon as a separation is produced between 
the two carbons ; if it is a little considerable, the current no longer passes, the action 
of the spring becomes predominant, the screw is unwound and the carbons approach 
each other until the current, again commencing to pass between the two carbons, the 
motion that drew them towaids each other is relaxed in proportion to the return of 
the predominance of the electricity orer the spring ; the combustion of the carbons 
again increases their distance, and with it the superior action of the spring ; hence 
follows again the predominance of the spring, and so on. These are altematiyes of 
action and reaction, in which at one time the spring, at another time the electricity, 
has the predominance. On an axis, common to the two carbons, are two pulleys: 
one, the diameter of which may be varied at pleasure, communicates by a cord with 
the rod that carries the lower carbon, which corresponds with the positive pole of the 
pile ; the other, of invariable diameter, is in connection with the upper or negative 
carbon. The diameter of the pulley, capable of varying proportionately to the using 
of the carbon, with which it is in communication, may be increased from three to 
five. The object of this arrangement is to preserve the luminous point at a con- 
venient level, whatever may be the thickness or the nature of the carbons. It is only 
necessary to know that at each change of kind or volume of the carbon, the diameter 
of the pulley must be made to vary. This variation results from that of a movable 
drum, communicating with six levers, articulated near the centre of the sphere ; the 
movable extremity of the six arms of the lever carries a small pin, which slides in 
cylindrical slits. These slits are oblique in respect of the sphere ; they form inclined 
planes. A spiral spring always rests upon the extremity of the levers ; so that, if 
the inclined planes are turned towards the right, the six levers bend towards the 
centre, and duninish the diameter. If, on the contrary, they are turned towards the 
left, the diameter increases, and with it the velocity of the translation of the carbon, 
which communicates with the pulley. We may notice, in passing, that this apparatus 
is marvellously adapted to the production of all the experiments of optics, even the 
most delicate ; and that, in this respect, it advantageously supplies the place of solar 
light As it is quite impossible to describe accurately the minute arrangements of 
this instrument, the letters of reference have not been used in the text 

Dr. Richardson informs us, that although Mr. Grove calculated, some years ago, 
that for acid, zinc, wear and tear, &c. of batteries, a light equal to 1444 wax candles could 
be obtained for about Ss, 6d. per hour, the cost of the light employed for about five 
minutes at Her Majesty*s Theatre, as an incident in the ballet, which was obtained by 
employing 75 cells of Callan's battery of the lar^st size, was said to be 2/. per night 
or at the rate of 20/. per hour. In this calculation we expect we have not a fair re- 
presentation of all the conditions. To obtain a light for ten minutes, a battery as 
large must be used as if it were required to be maintained in activity for hours — and 
probably the battery was charged anew every evening. There can be no doubt but 
the cost of light or of any other ybrcc from electricity, with our present means of pro- 
ducing it must be greatly in excess of any of our ordinary means of producing illu- 
mination. For a consideration of this subject, see Electro- motite Enginxs. Mr. 
Grove proposed a light which should be obtained from incandescent platinum, but the 
objection to this was, that after a short period, the platinum broke up into small par- 
ticles, the electric current entirely disintegrating the metal. Mr. Way has lately 
exhibited a very continuous electric light, produced from a constant flow of mercury 
rendered incandescent by the passage of the electric current 

ELECTRIC WEAVING. M. Bonelli devised a very beautiful arrangement by 
which alt the work of the Jacquard loom is executed by an electro- magnetic arrange- 
ment The details of the apparatus would occupy much space in the most concise 
description, and as the invention has not passed into use, although M. Froment has 
modified and improved the machine, we must refer those interested in the subject to 
the full description given in De la JRive's Treatise on Electricity by Walker, 


ELECTRO-METALLURGY. The art of working in metals was carried on 
exclusively by the aid of fire until the year 1839. At that epoch a new light dawned 
upon the subject ; considerable interest was excited in the scientific world, and much 
astonishment among the general public by the announcement that electricity, under 
proper mana^ment and by most easy processes, could' supersede the furnace in not 
a few operations upon metals ; and that man^ operations with metals, which coold 
scarcely be entertained under the old condition of things, might be placed in the 
hands of a child, when electricity is employed as the agent 


PaUic attention was first directed to the important discovery bj a notice that 
appeared m the Atheiutum of May 4, 1SS9, that Professor Jaoobi of St Petersbarg 
had ** found a method of conyerting any line, however fine, engraved on copper, into 
a relief by galvanic process^** Jacobi's own aoeonnt of the matter was that, while at 
Dorpat, in Febrnary, 1837, prosecating his galvanic investigations, a striking phe- 
oomenon presented itself, which fnmished him with perfectly novel views. Official 
dades prevented his completing the investigation, thus opened ont to him, daring the 
same year; and it was not until Octobers, 1838, that he communicated his dis- 
coveiy, accompanied with specimens, to the Academy of Sciences at St Petersburg ; 
an abstract of which paper was published in the Oerman News of the same place on 
October 30 of the same year. And in a letter of Mr. Lettsom, dated February 5, 
1839, the nature of the discovery is thus given in the following March number of the 
AMmak of Electricity, Speaking of a recent discovery of Professor Jacobi's he says, 
" Ue observed that the copper deposited by galvanic action on his plates of copper, 
eoold by certain precauUons be removed fh>m those plates in perfect sheets, which 
presented in relief most accurately every accidental indentation on the original plate. 
Following up this remark, he employed an engraved copper-plate for his battery, 
caosed the deposit to be formed on it, and removed it by some means or other ; he found 
that the engraving was printed thereon in relief (like a woodcut) and sharp enough 
to print frmn." This paragraph does not appear to have caught the eye of the 
public so readily as the briefer note that appeared a couple of months later in the 

On May 8, or four days after the appearance of the notice in the Atheiuntm^ Mr. 
Thomas Spencer gave notice to the Polytechnic Society of Liverpool that he had a 
commnnication to make to the society relative to the application of electricity to the 
arts. He subsequently desired to communicate the result of his discoveries to the 
British Association whose meeting was at hand ; but, for some cause, which does not 
appear, the commui^cation was not made ; and it eventually was made public, as at 
first proposed, through the Polytechnic Society of Liverpool, on September 12, 1839. 
In the meantime, namely on Bfay 22, Mr. C. J. Jordan, referring to the notice in the 
.^l/sAemnnn, wrote to the Mechanics* Magazine that, at the commencement of the 
summer of 1838, he had made " some experiments with the view of obtaining im- 
pressions from engraved copper-plates by the aid of galvanism.** His letter de« 
scribing this process appears in the numl]«r for June 8. It occurred to him, fh>m 
what he had gathered from previous experience, that an impression might be ob- 
tained from an engraved surfsice ; and so it was, ** for on detaching the precipitated 
metal, the most delicate and superficial markings, from the fine particles of powder 
used in polishing to the deeper touches of a needle or graver, exhibited their cor- 
respondent impressions in relief with great fidelity." 

Mr. Spencer in lus communication^ besides noticing the fidelity with which the 
traces on an original plate were copied, recorded the case of a copper-plate that had 
become covered with precipitated copper, excepting in two or three places, where by 
accident some drops of varnish had fallen; whence it occurred to him, and experiment 
confirmed his conjecture, that a plate of copper might be varnished, and a design made 
through the varnish with a point, and copper might be deposited upon the metal at 
the exposed part, and thus a raised design be procured. 

In the Philomiphical Magazine for December, 1836, Bfr. De la Rue, after describing 
a form of voltaic battery, refers to the well-known condition on which the properties 
of the battery in question mainly depend, that ** the copper-plate is also covered with 
a coating of met^c copper, which is continually being deposited ; " and he goes on 
to describe that ** so perfect is the sheet <^ copper thus formed, that being stripped 
o«it, it has the counterpart of every scratch of the plate on which it is deposited.'* 
Daniell himself, whose battery is here in question, noticed as he could not fail to 
do in common with all who had employed his battery to any extent, the same pecu- 
liarities ; but it does not appear that either he or De la Rue, or any one else, to whom 
the phenomenon presented itself before Jacobi, Jordan, or Spencer, caught the idea of 
its applicability in the arts. It would also appear that the impression came with the 
greater vividness to the two latter ; for, while but little time seems to have been lost 
to them in realising their idea, twenty long months elapsed between the time when 
the ** perfectly novel views *' first presented themselves to Professor Jacobi, and the 
time when his '^ well -developed galvanic production'* was communicated to the 
Imperial Academy of Science. But, on the other hand, neither Mr. Jordan nor Mr. 
Spencer appear, as far as we are aware, to have been so sensible of the importance 
of the results to which they had arrived as to have taken any steps to secure them 
aa an invention or to publish them, until their attention was aroused by the previous 
publication of the successes of Jacobi. 

Jacobi's '^Galvano-plastik,'* Smee's and also Shaw's "Electro-metallurgy,*' Walker*s 


" ElectrotTp* IfoDipalatioii,'' fonr well-known works on the sd1:ij«c( befbre ns, praotl 
the different nsmea under vhieb the art is known ; uid from which Et is gatbertd 
that metali mif become, M it were, pltutic ander the agency of galTanic eleclricilf, 
■ud may be worked and moulded into form. Voltaie pairs are described in geneTml 
tenns in the article on Ei.E(;rao-TELEOKAPBT. The particular TOltaic pair which ledlo 
tho diBcoreries now before na, here requires special notice ; because, on the one band, 
while in use for other purposes, it was the iostrument which first directed attenlioa 
forcibly to the bduTiour of metals ander certain conditions of electric current ; and, 
on the other hand, it baa been itself eztensively oaed in eleclmtj'pe operations. 
Professor Dsniell first described his mode of arranging a Toltaic pair in the Pkiia- 
taphical Traiuaclioiu for 1836. Fig. 695 shows one cell complete of Dujiell's com- 
bination, which trotn its behaviour is called a constant battery, a is a cc^per vessel ; 
B » rod of line, contained in a tube c of porous earthenware. 
695 The liquid within the tube c it itdt and water, io which case the 

cine is in its natural stale ; or, snlphnric acid and water, in 
which case the xino is amalgamated ; the lstt«r arrangement being 
the more active of the two. The liquid in the onier vessel a, coo- 
•ista of crystals of mlphate of copper, diaaolved in water. Al c 
is • perforated shelf of copper below the lurfnoe of the liquid, 
DpoD which are placed spare crystals of sulphate of copper, which 
o dissolve as requirrd, and serve to keep up the strength o( the 
solution in proportion as the copper already there is eitmeted by 
the voltaic action hereafter to be described, a and b are screws, 
to which wires may be attached, in order to connect ap the cell 
and coDTCj the current f^om it into any desired apparatus. Certain 
chemical changes take place when this instrument is in action ; 
oiygen from the water within the porons tube combines with 
ainc, making oxide of zinc, which enters into combioation with 
sulphuric acid, producing as a final result sulphate of sine; hydro- 
gen is liberated ft^im water in the outer cell, and itself liberatH 
oxygen from oxide of copper, and combines with it prodncing 
water, and leaving copper free. As far as the metals are con- 
cerned, line is consumed /root the rod b, at the one end, and copper is liberated 
upon the plate A, at the other eod. These actions are slow and continuous ; and 
the copper, as it is liberated atom by atom, appears upon the inner surface of the 
cell; and after a tafficient quantity has been accumulated, may be peeled off or 
removed ; when it will be found to present the marks and features of the surftce 
from which it has been taken, and which, as we have already said, arrested the 
696 attention of many into whose hands Ibis instrument fell. A slight 

modification of the above arrangement gives v» a regular eleeUo- 
type apparatus. The cell c in tbi^ arrangemeut (fig, 696), is of glass 
or porcelain, or gutta percha, filled as before with a saturated aolutioa 
of sulphate of copper, to which a tittle free acid is generally 
added; it ia provided with a shelf or other means of suspending 
cryatnls of snlphate of copper. A line rod i ia placed in a porous 
tube p, OS already described; and m, the other metal of the voltuc 
e pair, is suspended in the copper solution and connected with the 
tine z by the wire w. The electric cnrrent now passes ; line is 
consumed, as in fig. 695, but copper is now deposited on the metal 
in fi'onC and back, and on as much of the wire to as may be in the 
liquid ; or, if Mr. Spencer's precaution is taken of varnishing the 
wire and the back of the metal m, all the copper that is liberated 
will be accumulated on the ^e of m. If salt and water or very 
weak acid water is contained in the porous tube p, and the iloc x 
does not considerably exceed in size the metal n, the conditions will be complied 
with for depositing copper in a oompacl regnline form. 

It is obvious that, with this arrangement, m may be a mould or other form in 
tnetal, and that a copy of it may be obtained iu copper. Fusible metal, consisting 
of 8 perls of bismuth, 4 of tin, 5 of lead, and 1 of anlimany ; or S parts bismuth, 
S tin, and S lead, is much used for taking moulds of medals. The ingredients aie 
well melted together and mixed ; a quantity sufficient for the object in riev is 
poured upon a slab or board and stirred together till about to set ; the film of dross 
is then qnicklj cleared trom the surface with a card, and the cotd medal is either 
projected upon the bright metal, or lieing previously fitted in a block of wood if 
applied with a sudden blow. Moulds of wax or stearine Tanously combined, M 
more recently and better io many cases, moulds of gotta percha, are appHeable to 
many purposee. Bat, as none of these latter materiiJs conduct electricity, it ia m- 



oessftry to provide tbem with a eondneteoos snT&ee. Plumbago or black lead \» 
almoat imiTenallj employed fbr this parpo«e ; it is rubbed orer the sarfaoe of the 
mould widi a piece of wool on a soft brash, care being taken to continue it as fkr as 
to the coadiieting wire, bj which the mould is connected with the sine. With 
moulds of solid metal, the deposit of copper commences throughout the entire sur- 
ftce at once ; but, with moulds having only a film of plumbago for a conductor, 
the action commences at the wire and extends itself gradually until it has been de- 
veloped on all parts of the surface. 

The nature of the electro-chemical decompositions that are due to the passage of 
voltaic currents through liquids, especially through liquids in which metal is in cer- 
tain forms contained, can be best understood by studying the arrangement that is 
most commonly used in the arts, wherein the voltaic apparatus, firom which the 
electric current is obtained, is distinct and separate from the vessel in which the 
electro-metallurgical operations are being brought about Such an arrangement is 
shown in fig 697, where ▲ is a Daniell's cell, as m fig. 695 ; and B a trough filled with 


an acid solution of sulphate of copper ; m is a metal rod, on which the moulds are hung ; 
and c a metal rod, upon which plates of copper are hung facing the moulds ; the 
copper-plates are connected by the wire z with the copper of the battery cell, and 
the moulds by the wire x with the zinc rod. The voltaic current is generated in the 
ceU A, and its direction is from the zinc rod, through the solutions to the copper of 
the cell ; thence by the wire z to the plates of copper c ; through the sulphate solu- 
tion to Uie moulds m ; and thence by the wire x to the zinc rod. In this arrangement, 
no shelf is necessary in the trough b for crystals of sulphate of copper to keep up the 
strength of the solution ; for the natare of the electro-chemical decompositions is 
such, that in proportion as copper is abstracted and deposited upon the moalds m, 
other copper is dissolved into the solution from the plates c. Water is the prime 
subject of decomposition. It is a compound body, consisting of the gases oxygen 
and hydrogen, and may be represented by fig. 698, where /^^ 698 

the arrows show the direction in which the current, by 
the wire p, enters the trough b of ^. 697 by the plate of 
copper c and passes through the water in the direction 
shown, and leaves it after traversing the mould by the 
wiren. Two a/onu of water o h and o' H',as bracketed 
1 and 3, are shown to exist before the electric current 
passes ; and two atoms, one ofwater h & ^bracketed I'), 
and one of oxide of copper o c, exist after the action. On 
the one hand an atom of copper c has come into the solation ; and, on the other hand, 
the atom of hydrogen h', belonging to the second atom of water, is set tree and rises 
in the form of gas. The explanation is to show that oxygen is liberated where the 
current enters, and combines there in its nascent state with copper ; it would not have 
combined, for instance, with gold or platinum. We might easily extend this sym- 
bolical figure, and show how that, when free sulphuric acid is in the solution, the 
oxide of copper on its formation combines with this acid to produce the sulphate of 
copper required ; and how, when free sulphate of copper is present, the hydrogen, 
instead of being freed in the form of gas, combines with oxygen of the oxide of cop- 
per, and liberates the metal, which in its nascent state is deposited on the mould, 
and produces the electrotype copy of the same. One battery cell is sufficient for 
working in this way in copper ; it is increased in size in proportion to the size of the 
object operated upon. And, although for small subjects, such as medals, a vertical 
arrangement will act very well ; for large objects, it has been often found of great 


kngEment, placing the moald beoetiUi the ctqiper- 
. ^ . idU soluCioQ in the vertical arnuigemeDt U not 

without its effect upon the nature of the depocit, both on its character aud ita relative 
thicknen. This has been in some iaMauee* obviMed, and the advantage of the ver- 
tical method relained bf keeping the lolution in motion, atber by atining or by a 
contiDDDOB flow of liquid. 

We have deicribed principally Daniell's battery aa the generating' cell in Electro- 
metallnrgical operalioni ; but Mr. Smee'i more limple arrangciDent of platiuiied 
silver and linc. eieiied with dilated gulpharic acid, hat been found in practice more 

Fig. G99 is aSmee's cell ; a vessel of wood, glass, or earthenmre, eontains diluted 
sulphuric acid, one in eight or ten, a pUtinised silver plate a, soetuned b; a piece <^ 
e99 wood ID, with a pUte of line z E on each tide, so as tn turn to useful 

account both sides of the silver plate. The zinc places are connected. 
by the binding screw b. Platiuization consists in applying plati- 
num in fine powder to the metallic Barfu:c. When hydrogen is 
liberated by ordinary electric action upon a sarftce so prepared, it 
has no tendency to adhere or cling to it; but it at once rises, and in 
fact gets out of the way, so that it never, by its presence or linger- 
ing, interferes with the prompt and ready continuance of the electrie 
action ; and in this way, the amount of aapply is well kept up. 

PlslinizatiOD is itself another illnstratioo of working in metal bj 

electricity. A few crystals of chloride of platinuia are disaolvt^ 

in diluted sulphuric acid. A voltaic carrent is made to enter this 

solution by a plate of platinum and to come out by a silver plate. 

Two or three DbuieU's or Smee's cell* are necessary for the ope- 

' ration. The chloride of plalinum is decomposed, and the metal is 

deposited upon the siNer plnte ; not, however, in the regaline 

compact form, as in the case of copper, but in a state of black powder in no way 

coherent. This aCTords also an illustrstion of the different behcvioiir of meIkU 

under analogous circnmsCances. Copper is of all metals the most manageable ; 

platinum is among the more nnmsnageable. 

Mr. C. V. Walker has, with groat advantage, sabstitnted graphite for silver. The 
material is obtained from gas retorts, and is cut into plates a quarter of an inch thick, 
or thicker, when plates of a larger size are cut. He platinizes these plates in the 
Qsual way as above described, and deposits copper on their upper parts, also by elec- 
trotype process, and solders a copper slip to the electrotype copper, in order to make 
the necessary connection. 

With the exception of silver and gold, copper is the metal which has been most 
eztenaively worked by these processes. 

Seals are copied by obtaining impressions in sealing-wax, pressing a warm wire 
into the edge for a connection ; rubbing blacklead over the wax to m^e the inrface 
conducteous ; &stening a slip of zinc to the other end of the wire t wrapping the line 
in brown paper, and putting the whole into a tnmbler containing sQlpbate of copper, 
B little salt-water having been poured into the brown paper celL 

FLAsTEit or Pabis MsDAi-uatiB may be saturated witli wax or stearioe, and then 
trested, if small, like seals ; if large, in a distinct trough, ss in j!^. 697. In [bis case 
the copy is in intaglio, and may be used as a mould for obtaining the facsimile of the 
cast. More commonly, the cast is saturated with warm water, and a mould of it 
taken in wax, stearine, or gutta percba. This is treated with blacklead, and in other 
respects the same as seals. 

WooDcDTB are treated with blacklead, and a copper reverse is deposited npon 
them, Tbis is used as a mould to obtain electrotype duplicates, or as a die for 
striking off duplicates. 

Stehbotvpe Plates are obtained in copper by taking a plaster copy of the type, 
treating it plaster fashion, depositing a thm piste of copper upon it, and giving 
Btreug^ by backing up with melted lead. 

Old Brasses may be copied fay the intervention of plaster. 

Enbdbsed cards OB PAPBB may be copied by first saturating with wax and then 
using blacklead. 

Fbuit may be copied by the intervention of moulds, or may be covered with 
COTper. Leaves, twigs, and bhancbes may have copper deposited upon them. 

Leaves and flowers are famished with a conducting surface by dipping them into 
a lolotion of phosphorus in biaulphurel of carbon, and then into a solntiou of nitrate 
of silver. Silver is thus released in a metallic state upon their surface. 


Flabtbk Buns, ftc, haye been copied in copper, by first depositing copper on 
the plaster prepared for this operation ; when thick enough, the original bnst is de- 
stroyed, the copper shell is filled with sulphate of copper, as in ^.697, and copper 
is deposited on its inner sor&ce till of sufficient thickness s the outer shell is then 

Tubes and yessels of capacity do not appear to have been profitably multiplied 
by electrotype. 

Pultes haye been prepared for the enoratsb to work on by depositing copper 
OD polished copper-plates, and remoTing the deposits when thick enough. 

For the multiplication of enobatbd cofpeb plates, the electrotype process has 
been yery extenslYely adopted. A reyerse of the plate is first obtained by the depo- 
sition of copper ; this seryes as a mould, from which many copies of Uie original 
plate are obtained by depositing copper upon it, and then separating the twa 
The mode practised by the Duke of I^uchtenberg is to print from an engrayed plate 
on yery thin paper with a mixture of resin of Damara, Kd oxide of iron, and essence 
of turpentine. While the impression va wet, the paper face downwards is prMsed 
upon a polished plate of copper. MThen dry the paper is washed away, and Uie im- 
pression remalus. An electrotjrpe copy from this is obtained in intaglio, and is fit 
for the use of the printer. 

GALyANOOBApHT is a picture drawn originally in yamish on the smooth platen 
and then treated in a similar way to the aboye. 

The PLATES on rollers used by cauoo pbihtbbs haye been multiplied like en- 
grayed plates. 

Gltpboqbapht is a name giyen by Mr. Palmer to his process. He blackens a 
fiiir copper-plate with snlphnret of potassium, coyering it uniformly with a coating of 
wax and other things, then draws the design through me wax with fine tools. From 
the plate thus prepared, an electrotype is taken in the usual way, and is backed up 
and mounted as an electro-glyphic cast to print from as from a wood block. For a 
stereo^yphic cast to work from as a stereotype plate, a plaster copy is taken of the 
original drawing, the high lights are cut out, and then an electrotype copy is made. 

Elbctbo-timt is done by drawing with wax or yarnish any design on a fair 
copper-plate, and making an electrotype copy for the printer's use. 

^BN-LBAYES, &C., are copied by being laid on a sheet of soft gutta percha, pressed 
into the sur&ce by a smooth plate to which pressure is applied, and then removed in- 
order to subject die gutta percha mould to the electrotype process. This is Natubb 
Pbintino, which see. 

MM. Aner and Worring haye copied lace, embboidebt, flowers, leaves of trees^ 
entire plants, fossils, insects, &c., in their natural relief, by laying the objects upon a 
plate of copper, after having soaked them in spirits of wine and turpentine so as to fix 
them. A plate of clean lead is laid oyer, and, on being pressed, an intaglio copy is 
produced on it of the object. From this an electrotype is obtained. 

Undebcut medallions, &c., are copied in elastic moulds made of treacle and 
glue in the proportions of 1 to 4. Masks and busts may also be obtained in such 

£lec?tbo-cloth was made by saturating the fibre of canvass or felt, making it con- 
ducteons in the usual way *, it was proposed in place of tarpaulins as a water-tight 
cover. • 

Rbtobts and cbucibles, &c., of glass or porcelain, have been successfully 
.coated with electrotype copper by first varnishing or otherwise preparing the snrfitoe 
to retain the black lead, and then treating them as usuaL 

SoLDEBiNO COPPBB surfaccs has been accomplished by galvanic agency. The ends 
to be united are placed together in the solution of sulphate of copper, and connected 
with the battery as for ordinary deposition. Parts not included in the process are 
protected off by varnish ; copper is Uien deposited, so as to unite the separate pieces 
into one. 

Ibon may be coated with coppeb. But here a new feature comes into view. 
Sulphuric acid leaves the copper of the sulphate, combines with iron and deposits 
copper on its surfoce without the aid of the yoltaic apparatus. The iron surface is im- 
perfectly coyered with copper, no firm perfect deposit occurs. In order to obtain solid 
deposits <k copper on iron, it is necessary to use a solution that has no ordinary 
chemical reaction upon iron. Cyanide of copper is used, which may be obtained by 
dissolying sulphate of copper in cyanide of potassium. This solution requires to be 
raised to and retained at a temperature not greatly below 200^, in order to give good 

Electbo-zincino is applied to surfaces of iron, in order to protect them fWmi 
corrosioD» A solution is made of sulphate of zinc, which is placed in a trough b» 


fig, 697. Two or three battery cells are required. The iron to be aineed if eomieeted 
with the ainc end of the batterj, and a plate of ainc with the copper end. 

Voltaic brass does not appear to haTe been obtained in a solid distinet Ibnii, 
but has been snccessAiUy produced as a coating upon a copper sar&oe. Sepvate 
solutions are made of sulphate of copper and of sulphate of sine in cyanide of 
potassinm. The two solutions are then mixed, and placed in a decomposing trongli. 
Two or three cells of a battery are used, and a brass plate connected with the copper 
end. An electrotype copper medal or other prepared surface is connected with the 
sine. Brilliaot and perfiMst brass soon appears, and will deposit slowly for some 
hours ; but alter a while, the character of the solution changes, and copper appears in 
place of brass. 

This hasty glance at the leading applications of this art will giye an idea of its 
utility. It alM> comes into play in cases where least suspected. Pins were tinned 
by electrotype long before the art was known. Brass pins are thrown into solution 
of tin in cream of tartar, and are unchanged ; but when a lump of tin is thrown 
among them, a Toltaic pair is formed, and tin is deposited on all the heapw Any 
stray pins detached from the mass, escape the influence. Space would fail us were 
we to go through the list of crystalline and of simple bodies formed by these pro- 
cesses ; as for instance, octahedral crystals of protoxide of copper ; tetrahedral 
crystals of proto-chloride of copper; octahedral crystals of sulphide of silTcr; 
crystals of subnitrate of copper ; bibasic carbonate of copper, and others too nnmerooa 
to name, have all been formed by slow Toltaic actions. The alkaline metala, po- 
tassium, sodium, &C., were first obtained b^ Davy in the galvanic way; magnesium, 
barium, aluminium, calcium, &c., are obtained by M. Bunsen by operating upon the 
chlorides of these metals either in solution or in a state of fusion. 

Electro-etchino is produced at the place where the current enUn the decom- 
posing trough, as at the copper-plates c of jig. 697. A plate of copper is prepared as 
if for the graver ; its face is then covered with an etching ground of asphalte, wax, 
black pitch, and burgundy pitch ; and its back with Tarnish. The design is then 
traced through the etching ground with a fine point ; the plate is then placed in the 
trough B, containing either sulphate of copper or simply diluted sulphuric acid, and 
connected with the copper of the battery. After a few minutes it is removed, and 
the fine lines are stopped out with varnish ; it is then replaced, and again, after a 
few minutes is removed, and the darker shades are stopped out ; the parts still ex- 
posed are again subjected to the action, and the etching is complete. When the 
ground is removed, the design will be found etched upon the copper-plate ready for 
the printer. 

Dagctkrreottpe etching is a delicate operation, and requires much care. The 
solution employed by Professor Grove was hydrochloric acid and water in equal 
parts, and a battery of two or three cells. 

Platinized silver is used in face of the daguerreotype, instead of copper. The result 
comes out in about half a minute. An oxy-chloride of silver is formed, and the 
mercury of the plate remains untouched. 

A Photo-oalvano-graphic Company has been formed in London for carrying 
out the process of Paul Pretsch. He makes solutions of bichromate of potash in glue 
water, or in Mlntion of gelatine, instead of in pure water. He then treats the glass or 
plate with these, and in the usual way takes a picture. He washes the gelatine pictoie 
with water, or solution of borax or carbonate of soda, which leaves the picture in 
relief; when developed, he washes with spirits of wine, and obtains a sunk design. 
The surfaces thus prepared, or moulds made from them in one or other of the modes 
already described, are placed in a galvano-plastic apparatus for obtaining an en- 
graved plate from which to print See Photo-oalvanographt. 

The Duke of Leuchtenberg prepares a plate for etching by leaving the design on 
the ground, and removing the ground for the blank parts. When his electrotype 
operation is complete, the design is in relief instead of being in intaglio as in ordi- 
nary etching. 

MbtaIiLo-cbromes consist of thin films of oxide of lead, deposited sometimes oa 
polished plates of platinum, but most commonly on polished steel plates. The colours 
are most brilliant and varied. Nobili is the author of the process. 

A saturated solution of acetate of lead is prepared and placed in a horisontal 
trough. Three or four battery cells are required. A steel plate is laid in the 
acetate of lead with its polished surface upward, and is connected with the copper of 
the battery. If a wire is connected with the zinc end of the battery, and held over 
the steel plate in the solution, a series of circles in brilliant colours, arise from the 
spot immediately beneath the wire, and expand and spread, like the circles when a 
stone is thrown into a pond. Silver-blond is the first colour ; then fiiwn-colottr, fol- 
lowed by the various shades of violet, and indigocs and blues ; lake, bluish lake, 



green and orange, greeniah Tiolet, and pasaisg tbroagb reddiah yellaw to roae-lake, 
which JB the hat colonr in the aeries. 

According to the shape of the metal by which the carrent enters — be it a point, 
a allp, a crosa, a concave, or a convex disc — so is the form of the coloared ngnre 
▼aried. And i^ in addition to this, a pattern in card or gutta percha is cut out and 
interposed between the two aur&ees, the action is intercepted by the portions not 
removed, and the design is produced on the steel plate, in colours, that may be 
greatly varied, according to the duration of the experiment The different coloura 
are due to the different thicknesses of the thin films of peroxide of lead. 

M. Becquerel propoaed the deposit of peroxide of lead, and also the red peroxide of 
iron, for protecting metals from the action of the atmosphere. For the latter, proto- 
sulphate of iron is dissolved in ammonia solution, and operated upon by two or three 

The most important application of electro-metaQurgy in the arts has been for 
FLATDio and gujdxmo, which is most extensively carried on both at home and abroad. 
Results that were unattainable, and others attainable only at great cost, are readily 
produced by this mode of manipulating. The liquids most in use are the cyanide 
solutions, first introduced by Messrs. Elkingtons. They are prepared in various 
ways. Cyanide of potassium is added carefully to dilute solution of nitrate of silver ; 
and the white deposit of cyanide of silver is washed, and then dissolved in other 
cyanide of potassium ; or lime water is added to the nitrate aolution, and the brown 
deposit of oxide of silver is washed and, while moist, is dissolved in cyanide of 
potassium; or common salt is added to the nitrate solution, and the white deposit of 
chloride of silver is washed and dissolved in cyanide of potassiuuL Or a solution of 
cyanide of potassium is placed in the trough n^fig. 697 ; and the current from three 
or four cells is passed into it from a silver plate at c, which combines with and is 
dissolved into the liquid, converting it into a cyanide of silver solution. To prevent 
silver being abstracted by deposition at m, as the current leaves the trough, the 
metal at m is placed within a porous cell of cyanide solution, so as to limit the action. 

Gold solution is obtained by dissolving the anhydrous peroxide of gold in cyanide 
of potassium, or by treating chloride of gold with cyanide of potassium, or by using 
a gold plate and a voltaic current with a solution of cyanide of potassium in the same 
way as described for silver *, and allowing the action to continue until the solution is 
sufficiently strong of gold. With these solutions electro-plating and gilding are 
readily accomplished. There are other solutions more or less valuable, which will be 
found in the books that treat upon the subject. 

Fig. 700 shows a single cell arrangement for plating. The zino is outside, and ia 
bent to embrace both sides of the porous celL The article to be plated ia within thia 

cell ; because, being the vessel of smaller capacity, less of the more valuable silver 
solution is required, and there is less of loss or waste. The same holds good in a 
greater degree of gold. In a few minutes, the article is covered with silver. If a few 
drops of sulphuret of carbon are added to the silver solution, the silver is deposited 
bright. Gold does not come down quite so rapidly as silver. 

Except for mere experiment, these operations are better accomplished and with 
leas waste by using distinct batteries, as a, >f^. 701, the solution of gold or silver being 
in a distinct trough 6, plates of silver or gold, as the cases may be, being suspended 
in ftront of the article to be coated. One or two cells, acconUng to the results re- 
quired, are used for plating ; and three or four for gilding. But gilding is never so 


arrangement for operationi on a saiall scale. The Te»e1 a £, conlsinuiK the gold 
Bolutlan, resti otct a anmll itore or apirit-lunp. The objects to be gilt are aupeodtd 
bf irirei to the couductiug rod d, in connection with the zinc end of the battery ; and 
the gold wire or plate cii connected with the other end. Atemper«ture of from 100° U 
!00°ii desirable ; the higher Cemperaturea require fewer batteiy cells ; with the highest, 
one will ufflce. The solulion of coune eraporalei onder the influence of heat; and 
distilled water mnit be added to supply the loss, before each ftcsh operation. 

Plaling and gilding is successfullj and, in point of economy, advantagtonslj 
carried an at Birmingham, in more thiLn one manafactorr, by means of magneto- 
electricity. In the article on Eleotbic-Teleobaphi will be found a description of this 
farm of electric force ; and the means by which it is produced. An electro-magnet ii 
(et in motion in fh>nt of the poles of a permanent magnet, in such a manner that tbe 
soft iron core of the electro-magnet becomes alternately a magnet and not a magnet ; 
in the act of becoming a magnet, it iBi»e> up a corrent in one direction in the aire 
with which it is wound; in Uie act of ceasing to be a magnet, it raises ap a cnrreat in 
the rtrerte direction. The ends of the wire are ledaway and iniukled. Theinttm- 

ent i* fitted with a wmnnutaloi, so adjusted that it collecli the currents tro 
id* of the wire, and goidea them in a uniform direction into the Teasel that eo 
le Mhilion and articles to be gilded or phited. In practice, a tingle tnaoliint at 


of many electro-magnets grouped together, and many powerful magnets for exciting 
them ; by -which means a continuous flow of a large amount of electricity is ob- 
tained. Fig, 703 is an illustration of such an arrangement as adapted by Mr. Woolrich : 
a aaa are four clusters of permanent steel magnets, seen from above ; b bb b bis the 
frame-work of the machine \ c c c c are four bars of soft iron, wound with large sixe 
insulated copper wire ; </ is a circular disc, on which they are mounted, and which 
rotates on a Tertical axis, of which f shows the upper end ; e is the commutator, 
from which two wires are led off to the solution to be operated upon. The permanent 
magnets are U shaped ; one pole only of each bundle is yisible ; the other is beneath 
the disc di, and its freight of electro- magnets c c, &c. The axis is set in rotation by 
a strap passing over the drum of a shaft of the steam-engine, that does the ordinary 
work in a factory ; and the disc carries the electro-magnets between the poles of the 
permanent magnets, and exposes them to the most fi&vourable action of these poles. 
The number of coils and magnets vary in proportion to the work required. By this 
arrangement, not only does each coil pass under the influence of many magnets, but 
each magnet acts successively on many coils ; and a proportionate supply of electri- 
city is the result — C. V. W. 

ELECTBO-HOTIVE ENGINES. The following remarks on this subject are an 
abstract of a communication read by the editor to the Inatitution, of Civil ^ngineers^ 
for which they awarded him their Telford Medal. ' 

Numerous electro-magnetic machines have been made, but a few only of these 
Te«|uire to be described. In 1832, Sal vatore Dal Negro published an account of the at- 
tempts made by him in this direction. As Dal Negro's engine was of a very simple 
and effective kind, the Professor's description of it may be quoted : — **As I had been 
soccessfbl in producing temporary magnets of very great power, with very small elec- 
tro-motors, I endeavoured to apply this power to moving noachinery. I will now 
briefly state by what means I endeavoured to set a lever in motion. I first used a 
magnetic steel bar, placed vertically between one end of a temporary magnet The 
bar vibrated from the attractions and repulsions which took place between its north 
pole and the north and south poles of the electro-magnet. In the same way a motion 
may be effected in a horizontal plane. I also set in motion a similar bar, by allowing 
a piece of iron, set free from the magnet at the moment when its power became « o 
to fall on one of its ends, after this it was immediately re-attracted. This can be ef- 
fected in two ways : the one may be employed when a quick motion is to be produced 
and the second when a greater force is wanted ; in the first case the weight falls only 
just out of the power of the magnet's attraction, and the instant the weight has fallen 
upon the bar, or lever, it is re-attracted b^ the magnet that the action may be re- 
peated : It is always small in comparison with that which the magnet cannot support 
whilst in contact. In the second case the whole weight which the magnet can carry 
is employed, and use is made of the force which draws it to the magnet" Upon this 
was founded several other attempts, particularly one by Dr. Schulthess, who was so 
satisfied with the result, that he wrote in 1833 : — " If we consider that electro-magnets 
have already been made, which were capable of carrying 20 cwts., and that there is 
no reason to doubt that they may be made infinitely more powerful, I think I may 
boldly assert, that electro-magnetism may certainly be employed for the purpose of 
moving machines." Professor Botto of Turin, also employed ** a lever put in motion 
(in th^ manner of a metronome) by the alternating of two fixed electro-magnetic 
cylinders, exerted on a third movable cylinder, connected with the lower arm of the 
lever, the upper part of which maintains a metallic wheel, serving in the ordinary 
way, as a regulator in a continuous gyratory motion." It will be evident to any one 
who has observed the motion of manv of the electric clocks, that this is in several 
respects similar to the pendulous motions adopted. 

In 1835, Professor .lacobi, of St Petersburg, published an account of his experi- 
ments, which were carried out on a large scale, regardless of cost, at the expense of 
the Emperor Nicholas. His first idea was to employ the attractive and repellant 
powers of magnetic bars, so that he might obtain an advancing and receding motion, 
which could be easily changed into a continuous circular motion. A great many 
machines have been made upon this principle ; but Jacobi, alone, as far as can be 
learned, has pointed out the true cause of their failure. *' We know," he says, ** the 
ill effects of shocks in the movements of machines, but there is here, another incon- 
venience which IS not simply mechanicaL The soft iron, by these repeated shocks 
and vibrations, gradually acquires at the surface of contact the nature of steel ; there 
will be a considerable permanent magnetism, and the transient magnetic force which 
alone produces the movement, will be weakened in proportion. A number of ex- 
periments, which I have made upon the magnetic force of a bar of soft iron, bent 
into a horseshoe form, has shown me the great disadvantage of often repeated shocks, 
proceeding firom the sudden contact of the armature." 

Vol- II. U 


Jacobi, finally setting aside all oscillating motions, prodnced a machine giving conti- 
nuous circular motion, by fixing eight electro-magnetic bars on a disc, movable round an 
axis—and eight fixed bars similarly arranged upon a fixed platform. The arrange- 
ment of the bars admitted of mach variety, provided it was exactly symmetrical, uid 
that it allowed the poles to approach each other as nearly as possible. Arrangements 
were made, with much ingenuity, by which the poles of the magnets were inverted 
directly, and so that that inversion should take place precisely at that point where 
the bars were opposite each other. One hundred and forty-four inversions in the 
second were readily effected, and Jacobi declared it would be easy with his apparatus 
" to change, or to completely interrupt, the electric current, one thousand, or more, 
times in a second/' 

A machine constructed upon this principle was, at the desire and at the cost of an 
Imperial Commission, put on board a ten-oared shallop, equipped with paddle-wheels, 
to which the electro-magnetic engine communicated motion. The boat was 88 feet 
long, and 7^ feet in width, and drew 2^ feet of water. In general, there were ten or 
twelve persons on board, and the voyage on the Neva was continued during several 
entire days. By these experiments Jacobi was led to the conclusion, that a battery 
of 20 square feet of platinum would produce power equivalent to one horse ; and tlie 
vessel went at the rate of four miles an hour. In 1839, Jacobi tried another experi- 
ment, with a battery of 64 platinum plates, each having 36 square inches of sur&ce; 
when the boat, with a party of 14 persons on board, went against the stream at the 
rate of 3 miles an hour. 

In 1837, Mr. Thomas Davenport, of the United States, constructed a rotary engine, 
in which permanent and electro-magnets were employed. Mr. Taylor, in 1839, 
patented an electro*magnetic engine, both in America aud in this country, the prin- 
cipal novelty in which was, that instead of changing the poles of the magnets, the 
electric action was, at fixed rapid intervals, entirely suspended. In 1837, Mr. David- 
son, of Edinburgh, constructed an engine, in which he produced motion by simply 
suspending the magnetism, without a change of the poles. Mr. Robert Davidson 
placed an electro-magnetic locomotive on the Edinburgh and Glasgow Railway ; the 
carriage was 16 feet long, and 6 feet broad, and weighed about 5 tons. All the 
arrangements appear to have been very complete, but when put in motion on the 
rails, It was not possible to obtain a greater speed than four miles an hour. 

Professor Page's electro-magnetic engine was for some time looked upon as a 
triumph. The fundamental principle of it is thus described : *' It is well known 
that when a helix of suitable power is connected with the poles of a battery in action, 
an iron bar, within it, will remain held up by the induced magnetism, although the 
helix be placed in a vertical position ; and if the bar is partly drawn out of the helix 
by the hand, it goes back with a spring, when the hand lets go its hold. This power, 
»-the action of the helix upon the metallic bar within it, — is the power used in Page's 
engine." Professor Page exhibited one of his engines, of between 4 and 5 horse- 
power, at the Smithsonian Institution ; the battery to operate with being contained 
within a space of 3 cubic feet. It was a reciprocating engine of 8 feet stroke* and 
the whole, including the batter}', weighed about one ton. Professor Page stated, that 
the consumption of 3 lbs. of zinc per day would produce one horse-power. This 
statement requires further investigation. 

Many similar attempts have been made, to construct effective machines 'to be 
moved by the power of the voltaic battery. Among others, Mr. Henley constructed 
an electro-magnetic engine of considerable power, for Mr. Talbot, and another for 
Professor Wheatstone. In these there were manv ingenious mechanical arrange- 
ments, invented to overcome some of the difficulties hitherto encountered ; but the 
physical conditions were similar to those already described. Mr. Talbot's engine 
was 3 feet 6 inches long, and 2 feet 6 inches wide ; when excited by a Grove's 
battery, consisting of four cells with double plates of zinc, 9 inches by 6^ inches, 
platinum plates 9 inches by 5^ inches, excited by diluted sulphuric acid in the pro- 
portions of 1 to 4, and concentrated nitric acid, it drove a lathe, with which was 
turned a gun-metal pulley 5 inches in diameter ; but in three quarters of an hour the 
battery was quite exhausted. 

Mr. Hjorth, a few years since, exhibited in London a large machine, constructed 
somewhat on the principle of Page's ; this, however, fkiied to produce any great me- 
chanical effect, and it appears to have been abandoned. Dr. Lardner stated, in 1851, 
that M. Gustave Froment,of Paris, was using, with much advantage, an electro-mag- 
netic engine in his workshops for turning lathes, planing machines, &c. Its use, 
however, appears to have been abandoned, on account of the great cost of the battery 

Haukel and Fessel, on the Continent, the Rev. James William M'Gauley, Dr. 
Kemp, and others, in Great Britain, have, at different times, excited much attention 
by the ingenious machines which they have constructed. 


Notwithstanding these numeroiis trials, and, connected with them, an almost infi- 
nite amount of experiment, it does not appear, that an j satisfactory explanation has 
ever been given of the causes which have led to the abandonment of the idea of em- 
ploying electricity as a motive power. It was mainly with the view of directing atten- 
tion to these canses, that the essay read was written. 

Electro-magnetism undoubtedly affords an almost unlimited power. An electro- 
magnet may be constructed which shall have a lifting power equal to many tons. 
It is probable, that there are limits beyond which it would not be possible to increase 
the power of electro-msgnets ; those limits have not yet been reached ; but supposing 
them to be attained, there is nothing to prevent the multiplying of the number of 
electro-magnets in the arrangements. It may be stated, in connection with this part 
of the subject, that from experiments made with Hearder's magnetometer, it appears 
that the development of magnetism in iron observes some special peculiarities. These 
may be thus stated : — With the same electro -magnet there is, as the voltaic pairb in 
the battery are increased, a gradual increase of magnetic force. With from one to 
seven elements there appears an average excess of 31 lbs. ; after this point, with the 
increase of batteiy power, by the addition of pair after pair of sine and platinum 
elements, the production of power bears a decreasing ratio to the power employed, 
and at last, the addition of five elements was not found to produce an increase of ef- 
fect equivalent to the value of one element In all experiments, therefore, on elec- 
tro-magnetic machines, the experimentalist has first to determine the utmost power 
which the soft iron is capable of assuming, in relation to, — 1st. The number of coils 
of wire on the iron ; and 2nd, the number of elements employed in the exciting 
source — the voltadc battery. The length of the iron and its thickness are also points 
demanding special considerations ftom the constructor of an electro-magnetic machine. 

There remains now to examine the production of the power, Electro- Blagnetism. 

The eleetro-mechanician is dependent upon his battery, in the same way as a 
steam engineer is dependent upon his fire and his boiler, for the production of me* 
cbanical effect. 

Voltaic batteries vary in their effects, and hence arise statements which differ 
widely from each other, as to the result obtained, by the destruction (? change of 
form) of a given quanti^ of metal in the battery. 

Dr. Botto states, that 45 lbs. of zinc, consumed in a Grove*s battery, are sufficient to 
work one-horse power electro-magnetic engine for twenty-four hours. 

Mr. Joule says the same results would have been obtained, had a Daniell*s battery 
been used, by the consumption of 75 lbs. of sine 

It is impossible, on the present occasion, to enter into the theory of the voltaic 
battery, or to describe the varieties of arrangescent which have been adopted for gene- 
rating (developing) electrical force in the form of a current, with the greatest effect, 
at the smallest cost. 

On this point the evidence of Jacobi may be quoted : — " With regard to the 
magnetic machine, it will be of great importance to weaken the effects of the counter 
current, without at the same time weakening the magnetism of the bars. It is the 
alternate combination of the pairs of plates in the voltaic pile, which permits us to 
increase the speed of rotation at will We know the magnetic power of the current 
is not sensibly augmented by increasing the number of the pairs of plates, but the 
coanter current is considerably weakened by its being forced to pass through a great 
many layers of liquid. In fiict, on using twelve voltaic pairs, each, half a square 
foot, instead of four copper troughs, each with a surfiice two square feet, which I 
had hitherto used, the speed of rotation rose at least 250 or 300 revolutions in a 

Mechanical force, whether obtained. in the form of man-power, horse-power, 
steam-power, or electrical-power, is the result of a change of form in matter. In the 
animal, it is the result of muscular and nervous energy, which is maintained by the 
due supply of food to the stomach. In the steam-engine, it is the result of vapour 
pressure, which is kept up by the constant addition of fuel to the fires, under the 
boilers. In the magnetic machine, it is the result of currents circulating through 
wires, and these currents are directly dependent upon the chemical change of zinc 
or of some other metal in the battery. Then, 

Animal power depends on food. 
Steam power depends on coal. 
Electrical power depends on zinc. 

An equivalent of coal is consumed in the furnace — that is, it unites its carbon 
with oxygen to form carbonic acid, and its hydrogen with oxygen to form water, 
and during this change of state the quantity of heat developed has a constant relation 
to the chemical action going on. 

H 2 


Mr. Joule has proved hy a series of most satisfactory experiments, that : ** The 
quantity of heat capable of increasing the temperature of a pound of water by one 
degree of Fahrenheit's scale is equal to, and may be converted into, a mechanical 
force capable of raising 838 lbs. to the perpendicular height of one foot.** 

Mr. J. Scott Russell has shown that in the Cornish boilers, at Huel Towan and the 
United Mines, the combustion of one pound of Welsh coal evaporates of m-ater, from 
its initial temperature, 10*58^ and 10'48^ rt^pectively. "But,** says Mr. «loule, '*we 
have shown that one degree is equal to 838 lbs. raised to the height of one foot 
Therefore the heat evolved by the-combustion of one pound of coal is equivalent to the 
mechanical force capable of raising 9,584,306 lbs. to the height of one foot, or to 
about ten times the duty of the best Cornish engines." 

Such are the conditions under which heat is employed as a motive power. An 
equivalent of zinc is acted on by the acid in the cells of the battery, and is oxidised 
thereby. In this process of oxidation a given quantity of electricity is set in motion ; 
but the quantity available for use, falls very far below the whole amount developed 
by the oxidation of the zinc. The electricity, or electrical disturbance, is generated 
on the surface of the zinc ; it passes through the acidulated fluid to the copper plate 
or platinum plate, and in thus passing from one medium to another, it has to overcome 
certain mechanical resistances, and thus a portion of the force is lost. This takes place 
in every cellof the voltaic arrangement, and consequently the proportion of zinc which is 
consumed, to produce any final mechanical result, is considerably greater than it should 
be theoretically. 

Joule gives as the results of his experimAts, the mechanical force of the current 
produced in a Danieirs battery as equal to 1,106,160 lbs. raised one foot high, per 
pound of zinc, and that produced in a Grove's battery as equal to 1,843,600 lbs. raised 
one foot high, per pound of zinc. 

It need scarcely be stated, that this is infinitely above what can be practically ob- 
tained. A great number of experiments, made by the Author some years since, 
enabled him to determine, as the mean average result of the currents, produced bj 
several forms of battery power, that one grain of zinc, consumed in the battery, 
would exert a force equal to lifting 86 lbs. one foot high. Mr. Joule and Dr. Scoresby 
thus sum up a series of experimental results : ** Upon the whole, we feel ourselTes 
justified in fixing the maximum available duty of an electro-magnetic engine, worked 
by a Danieirs battery, at 80 lbs. raised a foot high, for each grain of zinc consumed." 
This is about one-half the theoretical maximum duty. In the Cornish engines, doing 
the best duty, one grain of coal raised 143 lbs. one foot high. The difference in the 
cost of zinc and coal need scarcely be remarked on. The present price of the metal 
is 35/. per ton, and coal can be obtained, including carriage to the engines, at less 
than U. per ton ; and the carbon element does two- thirds more work than can possi- 
bly be obtained from the metallic one. 

By improving the battery arrangements, operators may eventually succeed in 
getting a greater available electrical force. But it must not be forgotten, that the 
development of any physical force observes a constant law. Whether in burning coal 
in the furnace, or zinc or iron in the battery, the chemical equivalent represents the 
theoretical mechanical power. Therefore, the atomic weight of the carbon atom being 
6, and that of the zinc atom being 32, it is not practicable, under the best possible ar- 
rangements, to obtain anything like the same mechanical power from zinc which can 
be obtained from coal. Zinc bums at an elevated temperature ; in burning a pound 
of zinc there should be obtained, as heat, the same amount of mechanical power which 
is obtained as electricity in the batteiy. The heat being more easily applied as t 
prime mover, it would be far more economical to bum zinc under a boiler, and to use 
it for generating steam power, than to consume zinc in a voltaic battery for generating 
electro-magnetical power. 

ELECTRa PLATING AND GILDING IRON. Professor Wood, of Springfield, 
liassachusetts, in a paper, which he has communicated to the Scientific Americanj recom- 
mends the following as useful recipes for the electro-metallurgist He says, ^ I believe it 
is the first time that a solution for plating direct on iron, steel, or Britannia metal has been 
published. In most of the experiments I have used Smee's battery ; but for depositing 
brass I prefer a battery fitted up as Grove*s, using artificial graphite — obtained from 
the inside of broken coal-gas retorts — in the place of platinum. With one large cell 
(the zinc cylinder being 8x3 inches, and excited with a mixture of one part sulphuric 
acid and twelve parts water, the graphite being excited with commercial nitric acid) 
I have plated six gross of polished iron buckles per hour with brass. I have also 
coated type and stereotype plates with brass, and find it more durable than copper- 

To prepare Cyanide of Silver, — 1. Dissolve 1 oz. of pure silver in 2 oz. of nitric 
acid and 2 oz. of hot water, after which add 1 quart of hot water. 2. Dissolve 


5 oz. of the cyanide of potassiam in 1 qoart of water. To the first prei>aration add 
by de^ees a email portion of the second preparation, until the -whole of the tiWer is 
precipitated, which may be known by stirring the miztnre and allowing it to settle. 
Then drop into the clear liquid a very small quantity of the second preparation fVom 
the end of a glass rod ; if the clear liquid is rendered tnrbid, it is a proof that the 
-whole of the silver is not separated ; if^ on the other hand, the liquid is not altered, it 
is a proof that the silver is separated. The clear liquid is now to be poured off, and 
the precipitate, which is the cyanide ef silver, washed at least four times in hot 
water. The precipitate may now be dried and bottled for use. To prepare Cffanide 
of Gold — Dissolve 1 oz. of fine gold in i'4 oz.' of nitric acid and 8 oz. of muriatic 
acid ; after it is dissolved add 1 quart of hot water, and precipitate with the second 
preparation, proeeeding the same a» for the cyanide of silver. To prepare Cyanuiee 
of Copper and Zine, — ^For copper, dissolve I: oz. of sulphate of copper in 1 pint of hot 
water. For zinc, dissolve 1 oz. of the sulphate of zinc in 1 pint of hot water, and 
proceed the same as for cyanide of silver. The electro-plater, to insure success in 
plating upon all metals and metallic alloys, must have two solutions of silver ; the 
first to whiten or fix the silver to such metals as iron, steel, Britannia metal, and 
German silver ; the second to finish the work, as any amount of silver can be deposited 
in a reguline state from the second solution. First, or Whitening Solution. — Dissolve 
2^ lbs. (troy) of cyanide of potassium, 8 oz. carbonate of soda, and 5 oz. cyanide of 
silver in one gallon of rain or distilled water. This solution should be used with 
a compound Iwttery, of three to ten pairs, according to the size of the work to be 
plated. Second, or Finiehing Solution, — Dissolve 4 J oz. (troy) of cyanide of potas- 
sium, and 1^ oz. of cjranide of silver, in 1 gallon of rain or distilled water. This 
solution should be used with one large cell of Smee's battery, observing that the silver 
plate is placed as near the surface of the artides to be plated as possible. — N.B. By 
using the first, or whitening solution, you may insure the adhesion of silver to all 
kinds of brass, bronze, red cock metal, tjpe metal, &c., without the use of mercury, 
which is so iigurioos to the human system. To prepare a Solution of Gold. — 
Dissolve 4 oz. (troy) of cyanide of potassium, and 1 oz. of cyanide of gold, in 1 
gallon of rain or distiUed water. This .solution is to be used warm (about 90^ Fahr.) 
with a battery of at least two cells. Gold can be deposited of various shades to suit 
the artist, by adding to th3 solution of gold a small quantity of the cyanides of silver, 
copper, or zinc, and a few drops of the hydro-sulphuret of ammonia.'' . 


ELECTRO-SORTING APPARATUS. — M. Froment has devised an apparatus 
for the separation of iron firom matters by which it may be accompanied. The ap» 

?iratns consists of a wheel carrying on its circumference eighteen electro-magnets, 
he iron ore reduced and pulverised is spread continually upon one of Uie extremities 
of a cloth drawn along with it, and passed under the electro-magnets in motion. The 
iron in the ore which has of course been brought into a magnetic state by any of the 
processes by which this may be effected, is separated by the magnets, and the 
imparities carried onward. See De la Hive's Electricity, 

ELECTRO-TELEGRAPHY. The simultaneous appearance of the electric spark 
at the respective ends of a long conducting wire forcibly arrested the attention of 
electricians in the early days of the science. 

A series of remarkable experiments were made by Dr. Watson, commencing on 
July 14th, 1747; when he passed an electric discharge fh>m the Thames bank at 
Westminster to the opposite bank at Lambeth, by means of a wire suspended to 
Westminster Bridge. He continued his researches; and, on August the 5th of the 
following year, he arranged 12,276 feet of wire at Shooter's Hill, the beginning, the 
middle, and the end of which were led into the same apartment He found out that 
the electric signs at the middle of the wire coincided in time with the discharge at the 
two ends, proving that the passage, at least in such a length of wire, was instantaneous. 
In reference to these results Professor Muschenbrock wrote to Dr. Watson; ^'Mag^ 
nificenttssimis tuis experimentis, superasti conatns omnium." 

The idea of applying this property to the transmission afar of telegraph signals 
proper was an early and natural result of these discoveries. But many onward steps 
were necessary before the idea could assume any definite ibrm ; and further advances 
in knowledge were essential before the idea could be realised. 

It would far exceed our limits were we to attempt the most hurried sketch of the 
history of this art ; we shall therefore content ourselves with illustrating the leading 
doctrines, that have been realised in the telegraph systems which are most in favour 
at the time in which we write. 

Locked op, as it were, in all bodies, is a large store of electric force,- the equilibrium 
of which is disturbed in a greater or less degree by a variety of causes, some extremely 
simple, others more complex ; and, according as one or other cause is in operation, 

u 3 


the conditions under which the electric force is manifested vary ; some conditions 
being very unfavourable, and others very favourable to the object in view. 

Friction is a well known means of producing electric effects. Amber (in Gretk 
electron) was the first substance on which they were noticed in a special manner, and 
hence the name. Light bodies, such as gold leaf, or feathers, are attracted by rubbed 
amber ; the leaf gold is quickly repelled again, the feathers not so readily. In doe 
course it was discovered that this difference of behaviour is due to the gold conducting 
electricity, and (he feathers not so; the one allowing the force to diffuse itself about it, 
the other receiving and retaining it only in or near the points of contact ; if the former 
property were universal it would be impossible to collect electricity ; if the latter, it 
would be impossible to get rid of it Conduction is well illustrated and turned to 
useful account in the iron and copper wires, by which distant telegraph stations are 
connected with each other ; inflation, by the glass or porcelain articles with which 
the said conducting wires are suspended to the poles above ground, and by the gutta 
percha with which tho subterranean or submarine wires are covered. 

The rapidity with which electric force traverses conductors depends upon the cir- 
cumstances under which the conductors are placed; in one case, as in that of wire 
suspended in the air, the electric force has little else to do than to travel onward and be 
discharged from the far end of the wire ; in the other case, as in that of buried wire, 
it has to disturb the electric equilibrium of the gutta percha as it travels onward, and 
thus suffers considerable retardation. The greatest recorded velocity of a signal 
through a suspended copper telegraph wire is 1,752,800 miles per second, by M. 
Hipp ; the lowest velocity through a buried copper wire, 750 miles per second 
by Faraday. Intermediate velocities are recorded, for which the nature of the wire 
or the conditions under which it was placed were different Wheatstone found the 
velocity of electricity under different conditions fVom the above to be 288,000 miles per 
second. His wire was copper, and was wotmd on a fhtme. The electricity that was 
employed by Mr. Wheatstone in these experiments was obtained from the friction of 
glass against an amalgam of tin. The various Telocities are due partly to the con- 
ditions under which the conducting wire is placed, and partly, no doubt, to the 
varied properties of electricity from various sources. And the very different methods 
of reading off the velocities In this and in other cases may have an influence over the 
respective values. 

Electricity is obtained from other sources than friction with so much greater faci- 
lity, and in forms so much more applicable and manageable for telegraphic purposes, 
that frictionid electricity has not been applied in real practice. It must not, however, 
be passed over in this place, because one of the earliest telegraphs, perhaps the very 
first in which a long length of wire was actually used, was actuated by this form of 
electricity. In 1816 Mr. Ronalds established, in the grounds attached to his residence 
at Hammersmith, eight miles of wire suspended by silk to dry wood, besides 175 
yards of buried wire in glass tubes embedded in pitch and enclosed in troughs of 
wood. He obtained his electricity from a common electrical machine, and his signals 
from the motion of light bodies, balls of elder pith, produced under circumstances 
analogous to those to which we have already referred. At the far end of his tele- 
graph wire two pith balls were suspended close together. Electricity applied at the 
home end of the wire at once diffused itself throughout the conducting system, 
including the pair of light balls. Just as we have seen gold leaf recede after having 
approached rubbed amber, and acquired an electric charge ; so the pith halls, each 
being charged with electricity, derived from the same source, recede finom each other ; 
and this in obedience to the fundamental laws of static electricity, for which we 
must refer readers to treatises on the subject Here, then, we have one solitary 
signal. The manner in which Mr. Ronalds turned it into language was ingenious^ 
He pressed time into his service, and by combining time and motion he obtamed a 
language. He provided a clock movement at each station ; the clocks were so regu- 
lated as to be synchronous in their movements ; each of them carried, in lieu of a 
hand, a light disc, having the letters of the alphabet and other signals engraved on it. 
The disc was hidden by a screen, in which was one opening. It is obvious that if 
the clocks were started together, and had uniform rates, the same letter at the same 
time would be visible through the opening in each screen ; and letter by letter would 
pass seriatim and simultaneously before the respective openings. If absolute unifor- 
mity is difficult for long periods, it is practicable for shorter. The sender of a mes- 
sage watched the opening of his screen ; the moment the letter approached that he 
desired to telegraph he charged the wire with electricity, and the balls at the far 
station moved ; the letter then visible there corresponded with the one at the home 
station, and was read off The sender watched till the next letter he required came 
round, and so on. 
Let us now pass on to some of the leading features of electro-telegraphy, as it has 


been realiaed of late yean, and to a description of lome of the tel^raph instruments 
that are moet in use. 

Chendcal action is the most fertile sonree of electricity. If a silyer fork and a 
Btpel knife are connected together by a piece of wire, and the fork is thnut iDto a 
piece of meat, say a hot mutton chop, the moment an incision is made in the meat 
with the knife, electricity will pass along the wire, and continue to do so while the 
abore disposition of things remains. Upon the proper test being applied, the elec- 
tricity is readily detected. This is the current form of electricity. The amount of 
force in circulation in this particular combination is not yery great, and its power of 
travelling to a distance is not yery high, but still it is quite capable of producing good, 
signals, on a delicate arrangement of the needle instrument (of which more here&er) 
with which in England we are so femiliar. 

The amount of electricitjr obtained b^ means of chemical action, is increased to 
the reqmred extent by a judicious selection of metals, and of the liquid or liquids in 
which they are immersed. Zinc is inyariably used as one of the metals ; it is repre- 
sented by the iron of the knife in the aboye experiment Copper, siWer, and platinum 
or graphite (gas carbon) is selected for the other metaL When the two metals are 
immersed in a same liquid, a mixture of sulphuric acid with salt-water, or fresh, is 
employed. When two liquids are used, they are separated by a porous partition ; 
the sine is usually placed in the sulphuric acid solution, and the other metal in a 
solution yarylng with the nature of the arrangements proposed. Zinc is naturally 
soluble in the acid solution in question $ and would fiierefore waste away and be 
consumed at the expense also of the acid, unless precautions were taken to make it 
resist the ordinary action of the solyent When zinc is dissolved in mercury it is not 
attacked, under ordinary circumstances, by sulphuric acid solution. Hence the plates 
of zinc employed in all good yoltaic combinations, as they are called, into which 
this acid, in a free state, enters, are protected by being well amalgamated, that is, 
they are dipped in a strong acid mixture and well washed ; and are then dipped into 
a mercury bath, and are placed aside to drain. The operation is generally repeated 
a second time ; and, in the best arrangements, the further precaution is taken of 
standing the zinc plate, while in the acid water, in some loose mercury, placed either 
in the bottom of the containing vessel, or in a ^tta percha cell : by the latter arrange- 
ment, mercury is economised. In single liquid arrangements, it is desirable to select 
a metal that is not attacked by the acid. Copper has been extensively used, and is 
yery yalnable ; but it possesses the defect of being slowly attackable. The waste, 
however, that it suffers in itself from this cause, is of small moment compared with 
certain secondary results, which terminate in the consumption of the acid and the 
zinc, and the destruction of the functions of the apparatus. Gold or platinum are 
free from these defects, but are too costly. Silver, is to a great extent free fi-om 
them, and has been much and successfblly used, especially when platinised, that is, 
having its snrfiice covered with finely divided powder of platinum. The corrosion 
from gas retorts, cut into plates, and similarly treated, fonns with amalgunated zinc 
one of the cheapest and most effective combinations. 

A single pair of plates, no matter what their character, is unable to produce a fbrce 
that can overcome the resistance of a wire of any^ length, and produce an available 
result at a distant station; and hence a series of pairs are employed in the telegraphic 
arrangements, s {/ig, 704> represents a common mode of arranging a series of pairs of 
plates. It consists of a wooden trough made water-tight, and divided into water-tight 
cells. The metals are connected in pairs by copper bands ; each pair is placed astride over 
a partition, and all the zincs face one way. When the plates (copper-zinc) are placed 
in, and the cells are filled up with pure white sand, and the acid water poured in, we 
have the very portable battery that was originally used by Mr. Cooke, and is still 
much employed in England. When batteries of a higher dass are employed, the 
cells are distinct pots or jars ; and great precautions are taken to prevent any conduct- 
ing communication existing between the neighbouring cells, save by means of the 
copper band. Jn the trough form there is a leakage and loss of force from cell to 
eelL The c or copper is the positive end of such a series, and the z or zinc, the 
negative; and both are in a condition to discharge, either each to the other, by means 
of a wire led from one to the other, or each to the earth, one by a wire leading to 
the earth at the place where the battery stands, and the other by a long wire (say a 
telegraph wire), leading to the earth at a distant place. The resistance to be over- 
come is, in the former case, less ; and the current of force in circulation is propor- 
tionately greater. Under whatever circumstances a wire takes part in promoting the 
discharge of an apparatus of this kind, the whole of the said wire is in a condition to indi- 
cate the presence of the force that is pervading it ; and as the force may be presented to 
the wire in either of two directions, that is to say, the copper or the zinc, namely, the 
positive or the negative end of the battery, may be presented to the given end of the 

H 4 


telegraph wire, the relatiTe condition or tbe wire will be modified aecordiDgtj. Not 

odIj can tbe direction of tliii current foKe b« iiiTertedat pleanire, but it cao be 

;04 maintained for 007 

length of time, gmt 

range men t>, which are 
the kejg, com matalors, 
or bBodiei of the i^a- 
TioDj telegraph instm- 
ment< (of which more 
hereafter), and are 
often tbe onlr part 
presenting any tarn- 

Eleiity about them. 
ii/$.;04, the source of 
electricitj, e, ve bait 
already deacribedi the 

tkbnormal lUte of the 
wire, that i* la isj. 
tbe telegnph prmer. 
is tbe part a.. The 
complex iiart, ctmuit- 
ing of ipringa, cj- 
linden, and ilnds, 
ihown below a, it 
nothing more than 
the neccsaarj mecha- 
nical arrangement for 
directing kt pleamrt 
the CDirent tnuo the 
battery s, in either 
direction thmngb tbe 
wire, and throogh the 
part A. By followbg 
the letters in the order here given, tbe conrie of the cnrrent may be trjced from iu 
leaving, any tbe positive or copper end of the battery, till its return to the line 
or negative end iCf/nwwDAZ'iBE. If« companion Instmment were io any 
part M the circuit of the wire w w, it wouM corropond in ite signals with the home 
iDsImmeatijiij. 704. 

One of the propertiea possessed by a wire, during the C of discbarging a Toltaic 
battery, is to deflect a magnetised needle. If the two are parallel in tbe normal stale 
of the wire, [he needle is deflected this way or that, when the wire is in tbe aboonnal 
state ; and if the needle ia very delicate, and a large enough amoiuit«f electricity is 
rircalating through the wire, the needle reaches the maximum deflection of SU" 
This is an extreme case, and cannot be approached in practice. Indeed, the deflectioa 
of any ordinary needle, under the action of an ordinary telegrapb wire, would not be 
appreciable. But, as ecay foot of tbe wire has tbe tame amount of reaction, we liave 
merely so to arrange things that many feet,- n long length of the wire, shall be made 
to react upon the needle at the same time, and thus the effect is moltipllcd in propor- 
tion to the length of wire so concentrated. This is managed by covering a con- 
siderable quantity of fine wire with illli or cotton, and winding it on a frame A (^j/- 
704), suspending tbe needle within tbe f^ame- Such an instrument is colled, from ita 
properties, a mullipUtr. It is seen at a glance that the wire of the multiplier is an 
addition over and above the length of the actual telegraph wire required for reaching 
the distant station, and thus it practically iitcreases tbe distance (0 be traversed: its 
amallness adds to this. Tbe multipliers commonly used add a resistance equal to aix 
or seven miles of telegraph wire. 

Let us now turn to the face of the instnmient. Here we have a dial and an index, 
which is on the same axis as the magnetised needle above described, capable of being 
d^ectcd to the right or left, and Umitcd in its motion by ivory pins.- We have a 
handle fbr working the mechanical part so couuected that, sb it moves to tbe right, it 
directs a current into tbe wire such that the needle moves to tbe right, and dim Turaa. 


An ilplimliet u conitnieted from the combinalioD of iheit tiro elemeoUrj notimu, 
oae or more of either or both luodi of deflectioa being med for the vtrion* letlsn, 
ks Ehown OB the engraved dial. Thia ^dj 

is Cooke u>d TnieUKoDe's lingle 
needle iiutnunent, ^. 70S. 

TlM form ud chnnurter of Ibeir 
double needle instrament is sbowD in 
yfy. T0«. It it precisely a duplicate of 
the former i two haadlei, and their 
TespeetiTe apriDgl, itudi, and cjlia- 
ders, two moltlplien, and two mag- 
netiKd needles, with their eztereal 
iDdcxea,Bnd twotetegraphwirei. One 
batterj, hoverer, it taffleieuL One 
or more of either or both kindj of de- 
flection of either or both needles, 
according to the code engrared on 
the dial, constitDlei the alphabet. Thii 
iutnunent ia very eiienaiTel^ em- 
ployed I menages are tent by it with 
extreme rapidity. 

Another property poMened by a 
■wire coDTeyiug a nureBt ii that of 
converting aoft inxi, for the time, into 
» magnet. The attraclive power, 
which can ihm be given to, and with- 
drawn from, the aoA iron at pleanire 
is tnnied to osefiil acconnt, either in 
prodneing direct meehanicBl action, 
or in litieratiag the detents of a rlock 
movement. Here alao the effect of the 



nAituy wire i* inappreciable, ukI many convolutions aroimd the iron are neeettar^ 

in order to obtain a QMful result. 

The umpUst application of thia principle it shown injt^ TOT. Here are two brais 
reels, filled with cotton- 
707 CDTered copper wire ia one 

length. The7 are hollow, 
and a U-Kbaped bar of iron 
pastes through them, pre- 
senting its ends at the lace 
turned toward lu in ihe 
drawing. This bar be- 
comes magnetic, — forms 
wliat is called an elictro- 
magntt eietj time and at 
long at an electrical cur- 
rent eirculatei inthewirej 
atid its ends become re- 
tpectiTclj north and south 
poles. A narrow plat« of 

termed, is moonled on 
pivots in front of the ends 
or poles of the magnet ; 
it came* a vertical tten 
upon which Ibe hammer is 
fixed. Ever^ time the 
iron bar is mngnetic the armature is attracted, and the hammerstrike* the bell. The 
spring or coutact-malier for inlroducicg the current of clectricitf into Ihe cirmit, i» 
shown in f)-ont on the right hand side. This is Mr. Wall^er'g bell for signalUng 
railway trains from station to stalian. The langoage consists of one or more blows. 
One, two, and three blows sre the signalB for common porpoees, half a doien blows is 
the limit. The acknowledgment of a ligcai is its repetition. Bj a limple arrange- 
ment of an index, that moves in fellowship with the nammer, the eye, M well as the 
ear, may read the bell signals. 
Fig. 706 shows another apphcation of the direct action of an electro-magnet in pro- 

ducing telegraph signals. It is Morse's printing telegraph, very generally used in 
America, and used to no small extent in Europe. The coils of wire are shown at 
M, (he armature at h, fixed at one end of (he lever p, which is itself carried on centres 
at c. The range of motion here is email in order to produce rapid utterance ; it is 
reflated by the screws d and i. The reaction of the spiral spring /restores Ihelevcr 
to Its normal position each time the magnetism ceasea. The signals consist of dotsiw 
dasbes, varioosly combined, made by the pointed screw I upon the slip of paper p, 
running from tiie drum at the right in the direction of the arrows ; a few sach 
signals are shown upon the end of the paper slip. We have described Ihe telegraph 
proper, which is seen to t>e extremely simple. The only parts at all complex are, as 
with the needle Inslnimenti already described, the mechaaical parts, namely the train of 
wheels for carrying on the paper band, and the key or contact.maker, not shown in 
the figure. The amount of pressure required from the point t in order to produce ■ 


tnsTk, it inch that il cannot conTraientl; be prodooed bj the migneCie attraction, 
deriTed trmo a current of elMlriciljr that haa come from a far dialant glation in order 
to circulate in th« coilt of wire N. This diScnlly doel not prevail in tlir signal-bell* 
J&f. 707, which are, at moat, not retioired to be mora than eight orlen milei apirt.and 
ID irUeh alao momentam can be and is accnmnlBted «o ai lo coiupire in producing 
the final reinlL Mone hai, therefore, had reconrae to a rdaif, ai he calli it. Tbia, 
ia principle, ii pretty mnch the wne thing ai the initrnmeot itwlf ; bnt it bai no 
bea.Ty woil to do, no mails to make ) it has merely to aet the part of a eontaet- 
maker or kej ; it can hence be nude lerj delieate, so a« to act veil by sach cnrrenll 
aa woold not produce any motion in uie instrument itself. The batteries which 
fnmiah the electricity for doing the actual printing work in Morse's telegraph, are in 
tbe aame italion with the inttrumeat itself The office of the relay is lo receive tb« 
signals ttaai afar, and to make the necessary connections with the local battery and 
instrument so aa to print off the signals on the paper in the usual way. It is obvious 
tbat the motions of the instrument and the relay are sympathetic, and that what a 
trained eye can read off (Vom the one a trained ear can read off from the other. The 
relays ara constructed with mnch finer wire than Is required for the instmrnent 
itself, so that the cnrrent circulating in them, although Tery low in force, is multiplied 
by a very high number, and becomes equal to the delicate duty require4 of it. 

F'$- 709 is another illDstration of the direct application of the electro-magnet without 

adTentitioni aid. It represents a detent of McCallnm's Olobolype for recording 
signals. The long lube contains small glnxs balls, which are retained therein by a 
detent attached to the armature of an electro-magnet Every time the armature il 
attracted mu hall is liberated and runs down into a grooTed dial, where it remuDS tbr 
iDspectian. One or more tubes aod detents are used, according lo the nature of the 
signal required. As applied lo the signal bell 0^- 707) three tubes are used ; one 
charged with black balls, for indicating the number r^ bell strokes made i one with white 
balls, for indicating the bell signals sent ; one with spotted balls, for marking ofiT the 
time in quarters of faaun or intervals of less length. 
The balls, when liberated, all run into the same dial ' "* 

and arrange themselves seriatim. 

We may here refer to the case of another bell or 
ahirum, in which the magnetic alCroction derived from 
the current that arrives, is not equal lo the mecha' 
nical work of striking a blow and sounding a bell; 
but which ia able to raise a detent, that had restrained 
a train of wheels ; and bo allow tbe mechanism of the 
latter to do the work required. This arrangement 
is shown in Cooke and Wbeatstone'saUnim,;^. 710 | 
I is the bell ; ■■ n, is the doable headed hammer, which 
is io &CI the pendulnm, attached to the pallets J^ which 
work in a scape-wheel hidden in the figure, and in 
gear in tbe usual way with a colled spring in the 
boi i, by the train r„ r„ r^ r. The electro-mag- j 
Dctic part here, as in other instmmenta, is simple 
eaongh ; a c is a lever moving on a centre above I, ) 
having at one end an armature a, facing the poles 
of the electro-magnet < ; and at (he other end c, a 
hook which fiices the wiieel r, and by catching in a 
notch on its circtunference, keeps the train at rest 
But when a current circulates Ihrongh the coils e, 
the armatnre is attracted, the hook is raised, the 

train i« liberated, and the pendulum -hammer vibrates and strikes a tncceision of 
blowa Bi« a support carrying a small spring, which rcaclson the lever, and restores 



it to itt noTnul poiitioD when the magnetiim cnaea. Thii alanua u nMd for calling the 
attention of tel^japh clerks. It re<iiures • liule attention lo keep np tbe proper 
adjostment betifeeii the spring on toe one band, and the magnetic attraction on the 

The telegraph originsllj adopted and ttill laigtlj lued b; the French Adminia- 
tratioo, ia lomewhat akin to the alanun jnat deacnbed. It ha* a train of wheeli, a 
acape-wheei villi foar teeth, and a pur of palleta. There ii, however, no pnida- 
Inni ; but the pallet! are connected with the armatare of an electro-magiiet, in sncb a 
manner that, for each attraction or repulsion of the aimaniTe, the icape-vheel it 
Uberated half a tooth ; for an attraction and a repoluon a whole tooth ; ao that fonr 
BQCcessive enrrenta, prodncing of coone four coniecntiTe altrsctioni and repnluoni, 
prodoce a whole reTOlution of the ccape-wheeL The axia of the latter pniject* 
thrangh the dial of the initmment (jip. Til) and cairiea an arm a or bUig.yiS^wbkh, 

followiag the motion of the wheel, a able to ii«snme eight distinct podtiona. The 
apparatus li geneially double, as shown in the flgnre ; and the signals are made up irf 
the various combinations of the eight positions of each of the two arms. The aim is 
half blsck, the other half while. The position of the black portion is read off; the 
white portion is merelj a counterpoise. When onlj one half of the dial, or one 
index is in use, the combisalions are shown bj producing with the one index sue- 
ceasively the positions of the two, whose combination makes the signal, always giving 
first the position of the left hand index, then that of the right The handles shown 
in fhint are the contact-makers ; and are so constructed that the position of the arm 
on the dial comcides with the position given la the handle. Fig. 713 is a front view 
119 of the two arms 1 part of the dial is 

supposed to be removed, so as lo ei- 
pose the four-toothed- wheel already 
mentioned, and the pulletii x andii 
which, in their movement to and fm, 
allow of the semi-tooih advances of 
the wheel 

In these variouG applications of the 
eleclro-mBgnet, the armature haabeen 
of soft iron, and the only action of 
the eleclro-magDet has been to attract 
it. It has bees withdrawn from the magnet after the electricity has ceased lo circalile, 
intherby its own gravity, by a counterpoise, or by a reacting spring. We now come to a 
telegraph that is well known and much used, Henley's magneto- elect ric telegraph, in 
which there is no reacting spring ; and in which the movement or signal is produced 
by the joint action of attraction and repulsion i and the return to iu normal state by 
the same joint action. Each pole of Henley's electro-magnet has a doable instead 
of the single termination, that we have been considering in all preceding cases. A 
piece of soft iron, like a crescent, is screwed npon each of the poles ; the homs or 
cusps of the respective crescents are being and near to each other ; and a magnetised 
•teel needle is balanced between them. This arrangement is somewhat Tike the 


fbllosiDg { I ). So long as no cairent ia cirrulating in the coilg of the eltctro- 
magnet, the crescents are impassive son iron, and no one point of either of them 
Ws more tendency than any other point to attract either end of the magiiL-tiied needle 
that U belvecD them. Bat while a current is circulatlDg-, one of Iho creicenta is 
endowed with north magnetic polaritr. xhlch ii especinllj developed at its hornt, 
and ihe other with soath polarity. Suppose the boms of the right hand crescent 
are nortb poles, those of the left saalh poles, and Ihe top end of the needle is 
north. Four forces will conspire to move the needle to the left. Its lop will be 
attracted by the left hand crescent and repelled by Ihc right j its bottom will be 
repelled by the left, and attracted by the right. When Ibis current ceases to eir- 
colate. the aimple attraction between the nta^etised needle and the soft Iran of the 
crescent tends to retain it in a deflected portion. This tendency is increased by 
a little residoal magnetism, that is apt to remain in the best iron, notwithstanding 
ercry care in Its preparation. In order, therefore, to restore the needle to its normal 
position, a short quick carrent in the reverse direction Is given. These instniments 
are single or double. Only one kind of deflection of the needle Is svsilsble for 
actual signals ; the other motion being merely the return to the nonnsl stale. The 
single needle alphabet Is composed of deflections of a short or a long duration ; these 
■re produced by holding on the current for an instant or for more than an instant ; 
and the varloas combinations r>f short and long correspond to Morse's dot and dash 
system. The double needle alphabet consists of combinations of the deflection of 
either or both needles. 

Fit). 7 ISshows Henley's instrument, and, incompleting the description of it, we have 

to describe another source of electric current to which no allaslou has been hitherto 
made. The electricity here employed Is obtained neither by (Hetion nor by ehemical 
action, bnl by means of magnetism and motion. If a piece of metal is moved in the 
preaence of a magnet, or a msgnet is moved in presence of a piece of metal, a carrent 
ofeleetrleily is generated in the metal. The results are multiplied when the metal is 
■ colt of covered wire i so that we have here the eonverse of the electro- magnet ; in 
the one case electricity had produced magnetism, In the other magnetism produces 
electricity ; hence the name mngnelo-eleetric telegraph. We have here a powerful 
set of steel magnets a a, all the north ends pointing in one direction, and bound 
together with a, plate of iron, and all the south ends similarly arranged in the other 
direction. Facing each end, but not qnite in front when at rest, is an electro- 
magnet proper, a b, consisting of the U-shaped iron rod and the coil of covered wire, 
as described in fig. 707. Each electro- magnet is monoted upon an axis, c is a short 
lever or key ; on depressing this the electro-magnet moves from its normal position 
In a region of lesser magnetic force, into a new position in the region of greatest 
magnetic force, and thus is the doable condition, enunciated above, complied with ; 
the copper wire is moved In the presence of a magnet, and this under the most 
ftvoorable coodiiioas; and the U Iron, rising from a feeble to a strong magnet, its 
lines of magnetic force move in presence of the copper wire. Just as a current, 
eosti'n^fVtMn a longdistance, had to be received in Morse's arrangement (_fig. 7D8) in an 
electro-magnet of a long coil of fine wire, so as to be much multiplied in order to 
do its work, so here a magneto-electric current, that has to be mi to a long distance, 
must be generated in a long coil of very fine wire in order to have electro-motive 
force sufficient to overcome the resistance opposed to it. In like manner the electro- 
mignets of the instrument d, in which It la received at the far-off station, have the 
same mnlliplying eharacterislics. The magneto-electric corrent eilats onl^ duiing 
the motion of the electro-magnet in front of the steel magnets, and this motion must 
be rather brisk, or the change of place is slow and the currecit feeble ; but the corrent 
ceases with the motion. The needle, however, remains deflected from causes to which 
we have already rrferred, and if the hand ia raised gently, so that the coils return 



slowly to their normal position, the needle will remain deflected ; but, if the hand is 
so removed that the colls return quickly from the region of greatest to one of leaser 
magnetic force, a reverse current of lesser force than the original is generated, which 
releases the needle from its deflected position and restores it to its normal place, ready 
for making the next signal. In a recent form of this instrument Mr. Henley has 
obviated the necessity of moving the electro-magnets, still retaining the same funda- 
mental principles. He uses a set of large U-shaped permanent magnets, and places 
the electro-magnet in the space between the branches of the permanent magnet, and 
so that the four poles of the two magnets, the permanent and the electro, shall be 
flush with each other or in the salne plane. A couple of iron armatures are mounted 
on a disc in front of the magnets. The disc has a motion on a centre ; the armatures 
are curved or crescent-shaped. Their form is so adjusted to the relative positions of 
the poles of the respective magnets that, in their normal or ordinary position, one 
crescent connects the N. pole of the magnet with one, say the upper pole of the 
electro-magnet, and the other crescent connects the S. pole of the permanent magnet 
with the lower pole of the electro-magnet On pressing a key the dUsc moves, and the 
armatures so change in position that the N. pole of the magnet is connected with the 
lowert and the S. pole with the upper poles of the electro-magnet B^ this arrange- 
ment the polarity of the electro-magnet is reversed at pleasure, and m its transition 
from being a magnet with poles in one direction, to becoming a magnet with poles in 
the reverse direction, an electric current is generated in the wire with which it is 
wound, and the direction of the current is this way or that according as the transition 
is from this direction of polarity to that This form of magneto-electric machine 
allows of larger electro-magnetic coils being used, and gives the manipulator com- 
paratively very little weight to move in signalling. 

We have shown how an electric current generates magnetism, and how magnetism 
generates another electric current ; it would follow logically that one electric current 
should therefore generate another electric current; for the magnetism produced by a cur- 
rent circulating in one^ire, must have all the properties of magnetism, and among them, 
that of producing another current in another wire; and so it is. A few convolutions of 
a large sized wire are coiled round an iron rod ; and outside the larger wire is a very 
great length of finer wire. The current from the battery is called the primary current 
in this arrangement ; and the moment it begins to circulate in the large wire, it 
magnetises the iron and generates a current, called secondary, in the fine wire, which 
is able to penetrate to a very great distance. When the primary current ceases, 
magnetisation ceases, the lines of magnetic force disappear, and a reverse secondary 
current is produced. This was the method proposed for obtaining the secondary cur- 
rent for traversing the Atlantic Ocean from Ireland to Newfoundland. The large 
wire is not necessarily first coiled on ; in the coils for the Transatlantic telegraph it 
was coiled outside. Nor is the presence of iron essential to obtaining secondary 

It will have been noticed in all the arrangements which have hitherto been 
described, that the signals are produced by motions, — that the electric current on 
reaching the far station is multiplied by being directed through many convolutions of 
wire, and is made to act upon either a piece of soft iron or a piece of magnetised steel, 
and to move them, the motion being turned to account directly, or by the intervention 
of mechanism. We have yet another property of electricity, that has been very 
successfully applied to the production of telegraphic signals by Mr. Bain, in his 
electro-chemical telegraph. If a current of electricity is led into a compound fluid 
body, say into water by one wire and out of it by another wire, the body is decom- 
posed into its constituent elements, one of which, the oxygen in the case in question, 
makes its appearance at one wire and the other — the hydrogen makes its appearance 

714 at the other wire. The same holds good 

with bodies of a more complex character in 
solution in water. The compound selected 
by Mr. Bain is cyanide of potassium. With 
a solution of this, he saturates a long ribbon 
of paper, similar, to that employed in Morse's 
telegraph. He causes the paper b {Jig, 
7 14) to pass over a drum of brass r, between 
the metal of r and an iron point or stylus 
p. The electric current enters the appa- 
ratus by the point p, passes through the so- 
lution of cyanide of potassium, with which 
the paper b is saturated, and out by the 
spring p', which is in metallic contact with the drum b. Decomposition takes place 
and the well known cyanide of iron (Prussian blue) is formed at the point of contact 



of the iron stylos p with the paper, the iron of the compoaDd being sopplied by the 
stylus Itself. The paper is carried on by ordinary mecluinism ; and a dot and dash 
alphabet is formed, according to the duration of coutacts at the sending station. There 
is a single wire and a double wire code ; and the signals appear as deep blue marks 
upon the paper. Sopplies of paper saturated with the solution are kept in reserve. 
This is unquestionably a telegraph of extreme simplicity. It has been employed with 
much success. 

Mr. Whitehonse prepared for the Atlantic Telegraph a system in which motion 
and chemical action each play their part. The secondary currents that he employed 
were not able to produce ihe chemical decomposition that he requires for his signals. 
He therefore receiyed them in a very sensitiye relay, either an electro-magnet or a 
multiplier. The relay was a contact-maker, and connected the necessary number of 
local batteries with the printing apparatus, which consists of a ribbon of paper, satu- 
rated with a chemical solution and passing between a drum and a steel point 

We should exceed our limits, were we to attempt the description of some of the many 
other forms that have been proposed. The above are good illustrations of the leading 
principles, and are all in successful nse. Some telegraphs will print in ordinary cha- 
racters ; this result is only attained by much complexity ; and its yalue is more than 
qaestionable,it being as easy to learn a new code as anew alphabet ; and telegraph clerks 
read their signals as readily as they read ordinary writing or printing, and they acquire 
their knowledge in a yery short time. Hence probably it is that telegraphs to print 
in ordinary characters are but little known in real practice ; nevertheless, some very 
promising instruments of the class have been produced, by House, and especially one 
more recently by Hughes, both of the United States. The following table has been 
drawn ont as an illustration of the codes of some of the chief instruments that have 
been the subject of this article. It shows the number and nature of the signals (de- 
flections, dots, dashes) for producing the name of the great discoverer of electro- 
magnetism, which is the foundation of electro-telegraph. The figures on the right are 
the number of marks or signs in printing and in each kind of telegraph. 

1. Single 1 Cooke 

I and 
f Wheat- ^ 

2. Double J stone. 

3. Single 1 

I Henley 

4. Double J 

5. Morse 


6. Single ' 

7. Double 










/ //////// 

//W /\\\/ 

• — • 




• • 

















— • • 



• • — 


— " 

•_^ i— 


The Rheo-dectro-atatie system of telegraphy was first described by M. Botto, in 1848. 
It is applicable to some but not to all forms of telegraph. It has been applied on iJie South 
Eastern Railway to the signal-bells {Jig, 704), for the purpose of reducing the amount 
of battery power required under other circumstances to be maintained. The wire, by 
which a pair of bells are connected, is in its normal state in permanent connection 
with the similar pole, say the positive, of batteries of equal power at the respective 
stations, so that two currents of equal power are opposed to and balanced against each 
other. Under these circumstances, the wire is in a null, or rheo-electro-static state ; 
neither current circulates. If the connection of one of the batteries is reversed, so 
that its negative pole is presented to the wire, then the currents of both batteries are 
in the same direction, and they circulate as one current, equal in value to the combined 
foree of the two •batteries. The application is obvious ; that, whereas, under the 
ordinary system, a whdfe battery, of force sufficient to traverse the distance and do 
effective work, must be at each station, under this system only half such battery is 
necessary at each station, for producing the same effective work. Also, if a little 
more battery power is placed at each station than is necessaryfor the actual work 


required, ligntle of higher power are obtained under common cireanutances ; itnd 
also Ihe eqailibrium of (he tvo opposed currents may be disturbed at any place 
between Ihe two statioas. and signals may be made by merely making a conneclioD 
belween (he line-wire aod the earth ; because the negalive pole at each station is fitted 
np in penmrnent connection with the earth ; and, as the poeilJie poles are in like 
conncclioQ with the liue-irire, eacli battery current is made to circulate throagh iti 
own signal-belt every time the earth and line-wire are placed in connection. By Ihii 
means the guard of a train can make signals of distress to the nearest station without 
the aid of portable apparatus. Considerable care is required to obtain good commoni- 
catloD with the earth ou the open railway for making distress signals, or otherwise the 
discharge is imperfect, and no signal is made. Fish-jointed rails are very valuable for 
this purpose ; in their absence, especially at embankments, metal must be bnrit^ for 
the purpose at intervals in the moist earth, and a wire attached fbr nte. Coalact 
springs ou the telegraph poles are proposed. 

Telegraph wires are suspended to polea by in- 
'"^ sulators of earthenware, glass, or porcelain; the 

material and shape varying according to the ex- 
perience of the engineer and the length of lioe 
to be insulated. In very short lengths, the battery 
power required for overcoming the recistance ii 
not great ; it will therefore not overeome tbe reaist- 
ance of an insulator of moderate quality, and escape 
to the pole and thence to the earth ; but the battery 
power required to oiereome the resistance of very 
long lengths of wire is equally able to overcome 
the resistances presented by inferior iasulatorc, and 
to escape in considerable quantities at every pole; 
BO that tbe force which reachea tbe Car 
TIG station would not be equal to ita vork. 

i-^~^ It >< for these long lines that the 
S-^rfj greatest ingenuity has been expended 
Qt:°^D in constructing iasulators. Fine porce- 
\^'(y laio is most in favour from its present- 
^^' iag a very smooth surface, snd being 

""^^ less bygroaietric than glass i snd it is 
distorted into most mysterious looking 
shapes in order to present as great a 
distance, and one as much sheltered ai 
possible, between the part, with vhich 
the line-wire is in contact, and the 
pail that is in contact with the pole. 

For fiublerranean and submarine 
wires still greater care is neceseary, 
becaoie they are in tbe very bosom (>f 
the earth or sea, to which the correut 
will escape, wbtn and where it can, 
in order to cotnplcte the discharge. 
Fig. 715 represents the cable that hat 
been lying in the British Channel be- 
tween Dover and Calais, since Sep- 
tember, 1851. It contains fonr Ko. 
16 copper wires, each wire is donbly 
covered with gutta-pereha. The four 
wirts are then twisted into a rope ; 
and the rope is thickly covered, firat 
with hemiK'n yarn, tarred, and finally 
with a jacket often No. 1 iron vires. 
The cable is shown in perspective and 
in section, i^'ij. 716 shows the per- 
specLive and section of Ihe Irish, a 
single wire cable. It consists of a 
single ccnttal conductor, of one No, 
16 copper wire, dojibly covered with 
gutia percba, then with hempen yam 
as before ; and finally with a protecting 
jacket of ten No. 8 iron wire*. The 
Calais cable weighs 7 tons pet mile; iLc Irish, 2 tons per mile. The Atlantic 


telegraph caUe* of which nearly 3000 miles were prepared, is in section, just the siie 
of a siWer threepenny piece. It is a single wire cable, the wire was a strand of seven 
Mow 22 copper wires, trebly coTered with gutta percha, then with yam, and protected 
with eighteen strands of seven wires each, of No. 22 iron wire. It weighs 19 cwt. 
to the mile. This cable is lost The iron jacket is in disrepate now for deep sea 
cablea Hemp is preferred. 

Telegraph signals pass with &r less rapidity through baried and through subma* 
rino wires, than along the ancient aerial wires. The slow travellings mentioned 
above, were through wires of this kind. We must refer to treatises on Electricity 
for fhll details of the conditions presented by a telegraph cable. In practice it is 
found that on first sending a signal into a snbmergal wire, the electricity is de- 
layed on its road, in order to proiduce a certain electrical condition upon the surface 
of the gutta percha that is in immediate contact with the conducting wire. Nor is 
thiaaU ; before a second distinctive signal can be sent, it is necessary that the con- 
dition produced by the first signal shall be destroyed ; and this is an operation, 
requiring even more time than was consumed in the mere act of producing it These 
two clnsws of retardation, especially the latter, were lar^ly manifested in the Atlantic 
cable; and have called forth all the ingenuity of electricians, in order to mitigate or 
to modify them.— a V. W. 

ELECTRUM, or ELECTRON. The ancient Electrumwas an alloy of gold with \ 
part silver. The Electrum of Kalproth is gold 64 silver 36. The ancient name of amber. 
The modem Electrum is an alloy of copper, zinc, and tin, with sometimes nickel. 

ELEMENTS. See Equtvalbnts, Chemical. 

ELEML This appears to be the resinous product of various terebinthinous 
trees. The Edinbur^ College, states it to be a ** concrete resinous exudation ft*om 
cme or more unascertained plimts." And the London Pharmacopoeia describes it, as a 
concrete turpentine derived ftx>m an unknown plant In the former edition Amyria 
Elemifera was named as the plant producing this resin. This error was due to Lin- 
niens, who confounded under one name two distinct plants. The larger quantities of 
Eiemi come to us from the Dutch settlements through Holland. It is imported in ** the 
lump,'* and in masses weighing from one to two pounds each enveloped in a pahn leaf. 

Bonastre ^ives the oonstituents of Elemi : 

Volatile oil 125 

Resin soluble in hot and cold alcohol • - - - 60O 
Resin soluble in hot but not in cold alcohol - - - 24*0 
Bitter extractive - - - - - - -20 

Impurities -------- i'5 

The resin soluble in cold alcohol consists according to Johnston of C*H"0*, while 
the latter {EHmine) is composed of C^H"0. 

Elemi is employed in making lacquer. See Vabnish. 

ELEUTRIATE. (Soittirer, Fr., Sehlemmen, Germ.) When any insoluble powder 
such as chalk is diffused through a large body of water, and then allowed to subside 
slowly, of course the larger particles will by their pavity be the first to subside. If 
then the supernatant liquor is poured off, or better, if drawn off by a siphon, the finer 
powder will be collected in the next vessel ; and by repeating this process an impalpable 
powder may be obtained. This process is called Elutriation, 

ELIASITE. An ore of Uranium, a mineral allied to pitch blende, but differing from 
It widely m its large proportion of water and lower specific ^vity (4*086 to 4-237> 

It ooenn with fluor, dolomite, quarts, &c., at the Elias mme, Joachimstal, in large 
flattened pieces, sometimes half an inch thick, of a dull reddish-brown colour, 
approaching to hyacinth-red on the edges. 

It is subtranslucent, with a greasy subvitreons lustre, and affords a dull streak, 
varying from wax-yellow to orange. Hardness between calcite and fluor spar. 
It is composed of Peroxide of Uranium - - • 61*33 
,, Alumina ----- 1'17 

„ Peroxide of iron - - - - 6*63 

fp Protoxide of iron - - . - i*09 

„ Lime .----- 3*09 

M Magnesia • - • • - 2*20 

„ Oxide of lead ... - 4*62 

„ SUica 5*13 

„ Carbonic acid .... 2*52 

Phosphoric acid - - • - 0*84 

n Water ..... 10-68 


Vo(L.IL 1 


Before the blowpipe it affords a reaction like pitchblende, I>eooinpQMd hj 
muriatic acid. — H. W. B, 

£LIXIR OF VITRIOL, a preparation of sulpharic acid, with some aromatics, 
ELM. ( Ulmut. Orme, Fr. ; Uime^ Ger.) Of this European timber tree there ire 
five species. The Ulmua CampesirU, the English Elm, is regarded in this coontry as 
one of the finest of European decidnous trees for park scenery; it lives for upwards of 200 
years, forming a remarkably straight tall trunk. The quality o£ timber depends a good 
deal on the soil in which it is grown, being always best on a dry, loamy soil, and 
plenty of air. The Ubtuts motUanth the Mountain-Scots or Wych Elm : the trunk 
is not so lofty nor the wood so heavy as the English Elm ; and though coarse gruned 
is ver^ highly prized by shipbuilders and cartwrights. It possesses great longitudiul 
adhesion, and is consequently one of oar stiffest and straightest timbers. These 
woods are not liable to split, and bear the driving of nails or bolts better than any 
other timber, and are exceedingly durable when constantly wet They are therefore 
much used for the keels of vessels, and for wet fonndations, waterworks, piles, pumps, 
and boards for coffins. On account of its toughness it is sdected for the oaves of wheds. 
. and for the gunwales of ships. 

ELVANS. Granitic and felspathio prophyritio rocks, which are frequently found 
traversing both the granite and slate rocks. 

'* The Elvans or veins of quartsiforous porphyry, that is, a granular crystalline 
mixture of feldspar and quarts which are common both in Cornwall and Devon, and 
near the granite of the south-east of Ireland, are probably in reality granite veins, or 
veins proceeding from a granitic mass." — Jukes, 

** When these granite-veins are of a large size they are termed Elvan courses ; indeed 
this is the only distinction between these two forms of elongated masses of granitic 
rock. In composition these eWans are either shorl-rock, eurite, felsparite, or even 
varieties of fine-grained granite.** — Boose, 

EMAIL OMBRANT, a process whidi consists in flooding coloured but transparent 
glazes over designs stamped in the body of earthenware or porcdain. A plane surfocc 
18 thus produced, in which the cavities of the stamped design appear as shadows of 
various depths, the parts in highest relief coming nearest the surface of the glaxe,aBd 
thus having the effect of the lights of the picture. This process was introdnced by 
the Baron A. De Tremblay of Rubelles, near Melnn. 

EMBALMING. (^EnUKiumement, Fr. ; Emhalaomen^ Germ.) An operation employed 
by the ancients to preserve human bodies from putrefaction. From their using haisams 
in the process, the name was derived. See Disinfection, Pvtbsf action. 

EMBOSSING. One of the plans introduced for embossing cijOTH by machinery 
which appears to be the most effective, is that of Mr. Thomas Greig, of Rose Bank, 
near Bury. This machine is thus constructed. 

Figs, 71 7, 718 represent three distinct printing cylinders of copper, or other suitable 
material a, b, c, with their necessary appendages for printing three different cokmrs 
upon the fabric as it passes through the machine ; either of these cylinders a, b, or c, 
may be employed as an embossing cylinder, without performing the printing proceo, 
or may be made to effect both operations at the same time. 

The fabric or goods to be operated upon being first wound tightly upon a roller, 
that roller is to be mounted upon an axle or pivot, bearing in arms or brackets at the 
back of the machine, as shown at d. From this roller the fabric aaaavi conducted 
between tension rails, and passed under the bed cylinder or paper bowl £, and from 
thence proceeds over a carrier roller f, and over steam boxes not shown in the drawing, 
or it may be conducted into a hot room, for the purpose of drying the colours. 

The cylinders A, B, and c, having either engraved or raised suifoces, are connected 
to feeding rollers 6, 6, 6, revolving in the ink or coloured troughs c,c^c\ or endless 
felts, called sieves, may be employed, as in ordinary prioting machines, for supplying 
the colour, when the device on the surface of the cylinders is raised ; these cylinders, 
may be furnished with doctors or scrapers when required, or the same may be applied 
to endless felts. 

The blocks have adjustable screws g, g^ for the purpose of bringing the cylinders up 
against the paper bowl with any required degree of pressure*, the cylinder b is 
supported by its gudgeons running in blocks, which blocks slide in the lower parts 
of the side fhtmes, and are connected to perpendicular rods t, having a^jus^le, 
screw nuts. 

The lower parts of these rods bear upon weighed levers A, k^ extending in front of 
the machine ; and by increasing the weights /, /, any degree of upward pressure maybe 
given to the cylinder b. 

The colour boxes or troughs c, c, c, carrying the feeding rollers 5, 6, 5, are fixed (m 
boards which elide in grooves in the side frames, and the rollers are adjusted and 
brought into contact with the surface of the printing cylinders by screws. 


If k Umck clbtli (liiwld b« nqaired to ba introduced batweeo the cylindrical brd or 
paper bowl K,u>d thchbriesao,** theordiaarjIeUor blanket, i( maj, fiH' printing 
and embcMaing cotton, lilk, _ . 

or paper, ba of linen or 
(H>naa ; bat if woollen 
gooda an to be operated 
npon, a cap of felt, or some 
■ueh material, moat be ' 
bonnd rmind tbe paper 
bovl, and the felt «r 
blanket mnit be need for 
the back cloth, vhicb ia U 
be conducted otot tbe 
ToUera h and l 

For tbe porpoae of em- 
boaiing the G^nic, either 
of tbe rollen A, b, or c^ 
majr be employed, obaerr- 
lag that Ihe anrhce of tba 
roller maat be cat, ao ai to 
leave tbe pattern or dcTJoe 
elevated Tor emboaaing 
TelTeta, plain dotha, and 
papers -, bnt for voolleni . 
tbe device moH be eica- 
Tated, tbM ia, cat in re- 7U 

The pattern of tbe em- 
boaaing ejlindet -will, bf 
the operatii>n, be partially 
marked throogb the Gihnc 
on to tbe aurhce of the 
paper bowl e ; to ohllie- 
rale which nuriia fVora 
the anrfiue of the bowl, a* 
it IcTnlvva, the iron cylin- 
der roller o it employed; 
bnt aa in the emboasing of 
the same putemi on paper, 
B cooDter roQer i» reqnired 
to prodnee tbe pattern per- 
fectly, the iron roller ii in 
that cue dispensed with, 
the impreadoD givea to the 
paoer bowl being req aired 
to be retained on ita anrface nntil the operation is 6nished. 

In thia case the relative eircamferencea of the embossing Dvlinder, and of tbe paper 
bowl, mast be exactly proportiMied to each other; that is. [he circa nifertnee of the 
bo* I most be equal, exactly, to a given number of circumferences of the embowing 
Cylinder, very accnratelj meamred in order to prewrve a perfect register or cnii>- 
odi^ce, aa they continae revolving between the pattern on the surrace of the em< 
bossiug cylinder and that indented into the snrbce of the piper bowL 

The axle of tbe paper bowl e, turns in brasses fitted inloslots in Ihe side framea. and 
It may be railed i^ hand th>m its bearings, when required, by a lever i, extending in 
fronL This lever is affixed to theend of a horirontal shaft L.i^ cnwsing (he machine 
•een in the figures, at tbe back of which shaft there are two segment levers i>, p, to 
which bent rods q, q, are attached, having books at their lower ends, passed under the 
aile of the bowl. At the reverse end of the shaft i. a ratchet-wheel r, is affixed, aitd 
a pall or click mounted on the side of the frame lakes into the teeth of tbe wheel r, 
and thereby holds up the paper bowl when reqnired. 

When the iron roller a, is (o be brought into operation, the vertical screws (, t, 
monnled in tbe upper parts of the side fhunes. are turned, in order to bring down the 
bniaes H, which carry the axle of that roller and slide in slots in the side ftames. 

The cyliodera i., n, and c, are represented hollow, and may lie kept at any desired 
temperature daring the operation of printing, by introducing steam into them i and 
ni>der the colour boxes c, c, c, hollow chambers are also made for the same pnrpost 
Tba degree of temperatare required to be given to these must depend opon tbe nature 


of tbe colouring material, and of the goods operated upon. For the purpoae of con- 
ducting steam to these hollow cylinders and colour boxes, pipes, as shown at o, r, r, 
are attached, which lead from a steam boiler. But when either of these cylinders is 
employed for embossing alone, or for embossing and printing at the same time, and 
particularly for some kinds of goods where a higher temperature may be required, a 
red-hot heater is then introduce into the hollow cylinder in place of steam. 

If the cylinder B, is employed as the embossing cylinder, and it is not intended to 
print the fabric by that cylinder simultaneously with the operation of embossing, the 
feeding roller b, must be remoyed, and also the colour box c, belonging to that cylin- 
der ; and Uie cylinders A and c are to be employed for printing the iabric, the one 
applying the colour before the embossing is effected, the other after it. It is howerer 
to be remarked, that if a and c are to print colours on the fabric, and b to emboss it, 
in that case it is preferred, where the pattern would allow it a and c are wooden 
rollers havmg the pattern upon their surfaces, and not metal, as the embossing cylin- 
ders must of necessity be. 

It will be perceived that this machine will print one, two, or three colours at the 
same time, and that the operation of embossing may be performed simultaneously with 
the printing, by either of the cylinders a, b, or c, er the operation may be performed 
consecutively by the cylinders, either preceding or succeeding each other. 

The situations of the doctors, when required to be used for removing any snper- 
fluous colour from the surface of the printing cylinder, are shown at d,d,di those 
for removing any lint which may attach itself, at «, e, e. They are kept in their 
bearings by weighted levers and screws, and receive a slight lateral movement to and 
fro, by means of the vertical rod m, which is connected at top to an eccentric, on the 
end of the axle of Uie roller h, and at its lower end to a horizontal rod mounted at 
the side of the frame ; to this horizontal rod, arms are attached, which are connected 
to the respective doctors ; and thus by the rotation of the eccentric, the doctors are 
made to slide laterally. 

When the cylinders a, b, or c, are employed for embossing only, those doctors will 
not be required. The driving power is communicated to the machine from any first 
mover through the agency of the toothed gear, which gives rotatory motion to the 
cylinder b, and from thence to the other cylinders a, and c, by toothed gear shown in 

fg- nr. 

EMBOSSING LEATHER. Beautiful ornaments in basso-relievo for decorating the 
exteriors or interiors of buildings, medallions, picture-frames, cabinet work, &c., have 
been recently made by the pressure of metallic blocks and dies by M . Claude Sdimth. 
The dies are made of type metal, or of the fusible alloy with bismuth, called d'Arcets. 
The leather is beaten soft in water, then wrung, pressed, rolled, and fulled as it were, 
by working it with the hands till it becomes thicker and quite supple. In this state 
it is laid on the mould, and forced into all its cavities by means of a wooden, bone, or 
copper tool. In other cases, the embossing is performed by the force of a press. The 
leather, when it has become dry, is easily taken off the mould, howeyer deeply it may 
be inserted into its crevices by virtue of its elasticity. 

EMBOSSING WOOD. iBossa^e, Ft. i Erhabenes, Arheit, Germ.) Raised figures 
upon wood, such as are employed m picture-frames, and other articles of ornamental 
cabinet work, are usually produced by means of carving, or by casting the pattern in 
plaster of Paris, or other composition, and cementing, or otherwise fixing it on the 
surface of the wood. The former mode is expensive ; the latter is inapplicable on 
many occasions. The invention of Mr. Streaker may be used either by itself or in aid 
of carving, and depends on the fact, that if a depression be made by a blunt instrument 
on the surface of Uie wood, such depressed part will again rise to its origind level by 
subsequent immersion in the water. 

The wood to be ornamented having been first worked out to its proposed shape, is in 
a state to receive the drawing of the pattern ; this being put on a blunt steel tool, or 
burnisher, or die, is to be applied successively to all those parts of the pattern intended 
to be in relief, and, at the same time, is to be driven yery cautiously, without breaking 
the grain of the wood, till the depth of the depression is equal to the intended pro- 
minence of the figures. The ground is then to be reduced by planing or filing to the 
level of the depressed part ; after which, the piece of wood being placed in water, 
either hot or cold, the part previously depressed will rise to its former height, and will 
then form an embossed pattern, which may be finished by the usual operations of 
carving. See Carving bt Machinbrt. 

Another process which may be regarded either as carving or embossing wood, is 
that patented by Messrs. A. S. Braithwaite and Co. 

Oak, mahogany, rose- wood, horse-chestnut, or other wood, is steeped in water for 
about two hours ; and the cast iron mould containing the device is heated to redness, 
or sometimes to a white heat, and applied against the wood, either by a handle, as a 
branding iron, by a lever press, or by a screw-preFs, according to cireumstances ; the 


moalds are made by the iron^ftmoder from plaster casta of the original models or 

Ebd not the wood been saturated with water, it would be ignited, but until the 
moisture is evaporated, it is only charred ; it gives off volumes of smoke, but no flame. 
After a short time the iron is returned to the Aimace to be re-heated, the blackened 
wood is well rubbed with a hard brush to remove the charcoal powder, which being 
a bad conductor of heat, saves the wood from material discoloration ; and before the 
reapplication of the heated iron, the wood is a^pun soaked in water, but for a shorter 
time, as it now absorbs moisture with more facility. 

The rotation of burning, brushing, and wetting is repeated ten or twenty times, or 
upwards, until in fact the wood fills every cavity in the mould, the process being 
materially influenced by the character and condition of the wood itself, and the degrees 
to which heat and moisture are applied. The water so far checks the destruction of 
the wood, or even its change of any kind, that the burned surfiice, simply cleaned by 
brushing, is often employed, as it may be left either of a very pale or deep brown, 
according to the tone of colour required, so as to match old carvings of any age ; or 
a very Uttle scraping removes the discoloured surface. Perforated carvings are 
burned upon thick blocks of wood, and cut off with the circular saw. 

EMBROIDERING MACHINE. (Machine a broder, Fr. ; Steckmaschine, Germ.) 
This art has been from the earliest times a handicraft employment, cultivated on 
account of its elegance by ladies of rank. But M. Heilman, of Mulbouse, invented a 
machine of a most ingenious kind, which enables a female to embroider any design 
with 80 or 140 needles as accurately and expeditiously as she formerly could do with 
one. A brief account of this remarkable invention will therefore be acceptable to 
many readers. It was first displayed at the national exposition of the products of 
industry in Paris for 1834. 130 needles were occupied in copying the same pattern 
with perfect regularity, all set in motion by one person. 

Several of these machines are now mounted in France, Germany, and Switzerland, 
and, with some modifications, in Manchester, Glasgow* and Paisley. 

The price of a machine having 130 needles, and of consequence 260 pincers or 
fingers and thumbs to lay hold of them, is 5000 francs, or 200/. sterling; and it is 
estimated to do daily the work of 15 expert hand embroiderers, employed upon the 
ordinary fhune. It requires merely the labour of one grown-up person, and two 
assistant children. The operative must be well taught to use the machine, for he has 
many things to attend to : with the one hand he traces out, or rather follows the design 
with the point of the pantograph ; with the other he turns a handle to plant and pull 
all the needles, which are aeixed by pincers and moved along by carriages, approaching 
to and receding firom the web, rolling all the time along an iron railway ; lastly, by 
means of two pedals, upon which he presses alternately with the one foot and the 
other, he opens the 130 pincers of the first carriage, which ought to give up the needles 
after planting them in the stuffy and he shuts with the same pressure the 130 pincers 
of the second carriage, which is to receive the needles, to draw them fh>m the other 
side, and to bring them back a^ain. The cluldren have nothing else to do than to 
change the needles when all their threads are used, and to see that no needle misses 
its pincers. 

This machine may be described under four heads : 1. the structure of the frame ; 2. 
the disposition of the web $ 3. the arrangement of the carriages; and 4. the construction 
of the pincers. 

1. The ttructtare of the frame, — It is composed of cast-iron, and is very massive. 
F'ig. 719 exhibits a front elevation of it The length of the machine depends upon 
the number of pincers to be worked. The model at the exposition had 260 pincers, 
and was 2 metres and a half (about 100 inches or 8 feet four inches English) long. 
The figure here given has been shortened considerably, but the other proportions are 
not disturbed. The breadth of the frame ought to hs the same for every machine, 
whether it be long or short, for it is the breadth which determines the length of the 
thread to be put into the needles, and there is an advantage in giving it the full breadth 
of the model machine, fully 100 inches, so that the needles may carry a thread at least 
40 inches long. 

2. Dispoeition o/thepiece to be embroidered, — We have already stated that the pincers 
which hold the needles always present themselves opposite to the same point, and that 
io consequence they would continually pass backwards and forwards through the same 
hole, if the piece was not displaced with sufficient precision to bring successively op- 
posite the tips of the needles every point upon which they are to work a design, such 
as a flower. 

The piece is strained perpendicularly upon a large rectangular fVame, whose four 
sides are visible in Jig, 719; namely, the two vertical sides at r f, and the two hori- 
zontal sides, the upper and lower at f' r". We see also in the figure two long wooden 



rtntioed to reccWe the embroidery, it vonod and kept Tcrlicall j itntched to ■ proper 
degree, ft>r eachof theae besmi bears upon iu end aimall ratchet wb eel g.g; the teeth 
of ODe of them beiog iDeliDed in the opposite direction to those of the other. Brudei 
the ijitna of lover be&mi, there ii another of two upper beami, which ia hoirever bot 
imperfectly aeen in the figure, on Bccoont of the interference of other part* in thia riew 
of the maehine. One of these sjstema preaenta the web to the inferior needln, and 
the other to the npper needlea. As the two beama are not in the aame vertical plane, 
the plane of the web wonld be preaented obliquelj to the needlea were it not for a 
atraight bar of iron, roand whose edge the cloth paasea, and which reodera it 
▼ertical. The piece is kept in lenaion erosawise by small brass templets, to which the 
Itrinn 9" >re attached, and by which il ia pulled towards the sides of [he fhimer. It 
renivna to show br what iDgenions means this frame may be abilUd in every poasiblc 
direction. H. Heilmann has employed for thia pnrpoae the pantograph which dranghta- 
men nae for redaclng or enlarging their plana in detenninate proportions. 
b V f t/' (Jig. 719) represent o parellelogram, of which the foar angles (, i', /". 


. C are Jointed in in^ a way that th«j may become Tery acute or very oMaie at plea- 
sure, while the aides of coarse continne of the same length \ the sides b b' and & 6^' are 
prolonged, the one to the point d, and the other to the point c, and these points e and 
d are chosen under the condition that in one of the positions of the parallelogram, the 
line c d which Joins them passes through the point/} this condition may be fulfilled 
in an infinite number of manners, since the position of the parallelogram remaining 
the same, we see that if we wished to shift the point d ftirther from the point b\ it 
would be sufficient to bring the point c near enough to hf', or v»e« ucrtd ; but when we 
hare once fixed upon the distance &' d^ it is CTident that the distance A'' c ii its neces- 
sary consequence. Now the principle upon which the eonstruction of the pantograph 
restt is this ; it is sufileient that the three points r^/, and e be in a straight line, in 
one only of the positions of the parallelogram, in order that they shall remain always 
in a straight line in erery position which can possibly be giren to it 

We see in the figure that the side b e has a handle ^' with which the workman 
puts the machine in action. To obtain more precision and solidity in work, the sides 
of the pantograph are joined, so that the middle of their thickness lies exactly in the 
▼erticai plane of the piece of goods, snd that the axes of the Joints are truly perpendi- 
cular to this plane, in which consequently all the displacements are eflfected. We 
arrive at this result by making fiut to the superior great cross bar z/' an elbow piece 
df'^ having a suitable projection, and to which is adapted in its turn the piece <f , which 
receiyes in a socket the extremity of the side b d; this piece <f is made fast to df' by 
a bolt, but it carries an oblong hole, and before screwing up tiie nut, we make the 
piece adTanee or recede, till the ihlorum point comes exactly into the plane of the 
weh. This condition bdng fulfilled, we have merely to attach the frame to the angle 
/*of the parallelogram, which is done by means of the pieoe r". 

It is now obvions that if the embroiderer takes the handle b" in his hand and makes 
Che pantograph move in any direction whatever, the point /will describe a figure 
similar to the figure described by the point c, and six times smaller, but the point/ 
cannot move without the frame, and whatever is upon it moving al«>. Thus in tiie 
movement of the pantograph, every point of the web describes a figure equal to that 
described by the point/ and consequently similar to that described by the point e, but 
six times smaller ; the embroidered olijeot being produced upon the cloth in the position 
of that of the pattern. It is sufficient therefore to give the embroidering operative who 
holds the handle n" a design six times greater than that to be executed by the machine, 
and to afford him at the same time a sure and easy means of tncmg over with the 
point «, all the outlines of the pattern. For this purpose he adapto to e, perpendicularly 
to the plane of the parallelogram, a small style terminated by a point e^, and he fixes 
the pattern upon a vertical Ublet s, parallel to the plane of the stuff and the parallelo* 
gram, and distant from it only by the length of the style e d* \ this tablet is carried by 
the iron rod /» which is secured to a cast iron foot b', serving also for other purposes, 
as we shall presently see. The frame loaded with its beams and tto doth forms a 
pretty heavy mass, and as it must not swerve from its plane, it needs to be lightened, 
in Older that the operative may cause the point of the pantograph to pais along the 
tablet without straining or uncertainty in its movements. l£ Heilmann has accom- 
plished these objecte in the fbllowing way. A cord e attached to the side 6 e of the 
pantograph passes over a return pulley, and carries at ito extremity a weight which 
may be graduated at pleasure ; this weight equipoises the pantograph, and tends 
slightly to raise the frame. The lower side of the frame carries two rods h and h, 
each attached by two arms A A, a little bent to the left i both of Uiese are engaged in 
the grooves of a pulley. Through this mechanism a pressure can be exeroised upon 
the frvne fkrom below upwards which may be regulated at pleasure, and without pre- 
renting the frame firom moving in all directions, it hinden it from deviating from the 
primitive plane to which the pantograph was adjusted. The length of the rods H 
ought to be equal to the amount of die lateral movement of the frame. Two guides 
t ^ carried by two legs of cast iron, present vertical slits in which the lower part of the 
frame v' is engaged. 

3. DigponUon ofUu earriag€$, — The twocarriages, which are similar, are placed the 
one to thie right, and the other to the left of the ftwne. The carriage itself is com - 
posed merely of a long hollow cylinder of east iron l, carrying at either end a system 
of two grooved casUxrs or pulleys l', which roll upon the horixontal rails k ; the pulleys 
are noounted upon a fbrked piece f, with two ends to receive the axes of the pulleys, 
and the piece r is itsdf bolted to a prcjecting car / cast upon the cylinder. 

This assemblage constitutes, properly spitaking, the carriage, resting in a perfectly 
stable equilibrium upon the rails k, upon which it may be most easily moved back- 
wards and forwards, carrying its train of needles to be paned or drawn through the 

H. Heifanann has contrived a mechanism by which the operatire^ without budging 



from his place, may condact the carriages, and regulate aa he pleaaes the extent of 
their coarse, as well as the rapidity of their moyements. By taming the axes m" in 
the one direction or the other, the carriage may be made to approach to, or recede 
from, the web. 

When one of the carriages has advanced to prick the needles into the stof^ the other 
is there to receive them ; it lays hold of them with its pincers, polls them through, 
performs its coarse by withdrawing to stretch the thread, and close the stitch, then it 
goes back with the needles to make its pricks in retom. * During these movements, 
the first carriage remains at its post waitmg the return of the second. Thus the two 
chariots make in succession an advance and a return, bat they never move together. 

To effect these movements M. Heilmann has attached to the piece o' made Ast to 
the two uprights a c and a d of the frame, a bent lever nonf tf*, movable round the 
point i the bend n' carries a toothed wheel o', and the extremity n" a toothed wheel 
o'' ; the foor wheels m, x', o', and o'', have the same number of teeth and the same 
diameter ; the two wheels o' and o'^ are fixed in reference to each other, so that it is 
sufficient to turn the handle N to make the wheel o" revolve, and consequently the 
wheel o' ; when the lever n o is vertical, the wheel </ touches neither the wheel m nor 
the wheel m' ; but if it be inclined to the one side or the other, it brin^ the wheel o' 
alternately into gear with the wheel x or the wheel yf. As the operative has his two 
hands occupied, the one with the pantograph, and the other with the handle of impol* 
sioQ, he has merdy his feet for acting upon the lever n o, and as he has many o&er 
things to do, M. Heilmann has adapted before him a system of two pedals, by which 
he executes with his feet a series of operations no less delicate than those vhich he 
executes with his hands. 

The pedals p are movable round the axis p, and carry cords p' wound in an opposite 
direction upon the pulleys p' ; these pulleys are fixed upon a movable shaft P' sup- 
ported upon one side by die prop e', and on the other in a piece k' attached to the two 
great uprights of the frame. In depressing the pedal p (now raised in the figureX the 
upper part of the shaft p" will turn from the left to the right, and the lever n o will 
become inclined so as to carry the wheel & upon the wheel if', but at the same time * 
the pedal which is now depressed will be raised, because its cord will be forced to 
wind itself upon its pulley, as much as the other cord has unwound itself; and thus 
the apparatus will be ready to act in the opposite direction when wanted. 

4, DUposition of the pincers. — The shaft t/ carries, at regular intervals of a semi- 
diameter,, the appenda^ q q cast upon it, upon which are fixed, by two bolta, the 
curved branches q destined to bear the whole mechanism of the pincers. When the 
pincers are opened by their appropriate leverage, and the half of the needle, which is 
pointed at each end, with the eye in the middle, enters the opening of its plate, it gets 
lodged in an angular groove, which is less deep than the needle is thick, so that when 
the pincers are closed, the upper jaw presses it into the groove. In this way the needle 
is firmly held, although touched in only three points of its circumference. 

Suppose now, that all the pincers are mounted and a^iusted at their proper distances 
upon their prismatic bar, forming the npper range of the right carriage. For opening 
all the pincers there is a long plate of iron, u, capable of turning upon its axis, and 
which extends from the one end of the carriage to the other. This axis is carried by a 
kind of forks which are bolted to the extremity of the branches q. By turning that 
axis the workman can open the pincers at pleasure, and they are again closed by 
springs. This movement is performed by his feet acting upon the pedals. 

The threads get stretched in proportion as the carriage is run out, but as this tension 
has no elastic play, inconveniences might ensue, which are prevented by adapting to 
the carriage a mechanism by means of which all the threads are pressed at the same 
time by a weight susceptible of graduation. A little beneath the prismatic bar, which 
carries the pincers, we see in the figure a shaft t, going from one end of the carriage 
to the other, and even a little beyond it ; this shaft is carried by pieces y which are 
fixed to the arms q, and in which it can turn. At its left end it carries two small bars 
y and u/, and at its right a single bar^, and a counterweight (not visible in this view); 
the ends of the two bars ^ are joined by an iron wire, somewhat stoat and perfectly 
straight When the carriage approaches the web, and before the iron wire can touch 
it, the little bar w presses against a pin u/, which rests upon it, and tends to raise it 
more and more. In what has preceded we have kept in view only the npper range 
of pincers and needles, but there is an inferior range quite similar, as the figure shows, 
at the lower ends of the arms q. In conclusion, it should be stated, that the operative 
does not follow slidingly with the pantograph the trace of the design which is upon 
•the tablet or the picture, but he must stop the point of the style upon the point of the 
pattern into which the needle should enter, then remove it, and put it down again upon 
the point by which the needle ought to re-enter in coming from the other side of the 
piece, and so on in succession. To facilitate this kind of reading off, the pattern upon 
the tablet is composed of right lines terminated by the points for the entrance and 



return of tbe needle, so that the openttire (uraally a child) has continaaUy ander her 
ejes the series of broken luiee which most be followed by the pantograph. If she 
happens to qoit this path an instant, without haTing left a mark of the point at which 
ahe had airiTed, she is under the necessity of looking at the piece to see what has been 
already embroidered, and to find by this comparison the point at which she most 
resume her woriL, so as not to leave a blank, or to repeat the same stitch. 

JSxpUination of Figure, 

A, lower cross ban, which unite the legs of the two ends of the fhune. 
a, the six feet of the front end of the fhune. 
of J the six feet of the posterior end of the frame, 
a", curved pieces which unite the cross bars a" to the uprights. 
b", handle of the pantograph. 
h, y<t Vj three angles or the pantograph. 
£, point of the side b h" on which Uie point is fixed. 
d', point of the pantograph. 

d", cross bar in form of a gutter, which unites the upper parts of the firame. 
d^ fixed point, round which the pantograph turns. 
s, tablet upon which the pattern to be embroidered is put 
s', support of that tablet. 

e, coid attached at one end to the side 6 c of the pantograph passing oyer a guide 
pulley, and carrying a weight at the other end. 

e', iron rod by which the tablet b is joined to its support b'. 

T, p, uprights of the cloth-carrying firame. 

f', r', horiaontal sides of the same frame. 

G, four roll beams. 

o^', the piece of doth. 

^\ the strings, which senre to stretch the cloth laterally. 

This machine has not been applied for embroidering nets or muslins, as these fabrics 
are not sufiiciently close to hold the needles ; it has been hitherto used for embroidering 
cloth for Tests and other purposes, and silk for ladies' dresses. We learn, however, 
that some very satisfactory experiments have been made by the Messrs. Houldsworth 
of Manchester, which promise shortly to lead to the successfhl application of these 
machines to the finer description of fiibrics. 

EMERY. This mineral was long regarded as an ore of iron ; and was called by 
Haiiy /er oxidi qwartziftre. It is, however, a massive granular or compact variety of 
corundum, more or less impure. It is very abundant in the island of Naxos, at Cape 
Emerl, whence its name. From this place it is imported in large quantities. It occurs 
also in the islands of Jersey and Guernsey, at Almaden in Poland, Saxony, Sweden, 
Persia, &c. Its colour varies from red brown to dark brown ; its specific gravity is 
about 41)00 ; it is so hard as to scratch quartz and many precious stones. 

We have recent accounts of emery discoveries in Minnesota, but nearly all that is 
used at present in the arts comes from Turkey, near ancient Smyrna. Dr. Lawrence 
Smith, tiie American geologist, made a discovery of a deposit of emery while residing 
in Smyrna, and he mi^e an examination of the locality in 1847. Dr. Smith having 
reported his discoveries to the Turkish government, a commission of inquiry was 
instituted, and the business soon assumed a mercantile form. The monopoly of the 
emery of Turkey was sold to a mercantile house in Smyrna, and since then the 
price has diminished in the market. 

The following analyses are quoted by Dana fh>m an elaborate paper by J. Lawrence 
Smith, in the American Jovmal of Science. 



being 100. 



Oxide of 









































8 13 


































The mining of the emery is of the simplest character. The natural decomposition 
of the rock in which it occurs facilitates its extraction. The rock decomposes into an 

122 EMERY. 

earth, in whicli the emery is fband imbedded. The quantity procnred under tUese cir« 
camstances is so great that it is rarely necessary to explore the rock. The earth in the 
neighbourhood of the block is ahnost always of a red coluar, and serves as an indication 
to those who are in search of the mineral. Sometimes, before beginning to excsTate, 
the spots are sonnded by an iron rod with a steel point, and when any reaistanee is 
met with, the rod is rubbed in contact with the resisting bodr, and the effect pro- 
duced on the point enables a practised eye to decide whether it has been done by 
emery or not The blocks which are of a convenient size are transported in their 
natural state, but they are frequently broken by large hammers ; when they resist the 
action of the hammer, they are subjected to the action of fire for several honra, and on 
cooling they most commonly yield to blows. It sometimes happens that large miisci 
are abandoned, from the impossibility of breaking them into pieces of a cooTenient 
size, as the transportation, either on camels or horses, requires that the pieces shall 
not exceed 100 lbs. each in weight. 

When reduced to a powder, emery varies in colour from dark grey to black. The 
colour of its powder affords no indication of its commercial value. The powder ex- 
amined under the microscope shows the distinct existence of two minerals, oomndnm 
and oxide of iron. Emery, when moistened, always affords a very strong argillaceoos 
odour. Its hardness is its most important property in its application to the arts, and 
was ascertained by Mr. Smith in the following manner: — Fragments were broken 
from the piece to be examined, and crushed in a diamond mortar with two or three 
blows of a hammer, then thrown into a sieve with 400 holes to the inch. The powder 
is then weighed, and the hardness tested with a circular piece of glass, aboot four 
inches in diameter, and a small agate mortar. The glass is first weighed, and placed 
on a piece of glazed paper ; the pulverised emery is then thrown upon it at intervals, 
rubbing it against the glass with the bottom of the agate mortar. The emery is 
brushed off the glass from time to time with a feather, and when all the emery has 
been made to pass once over the glass, it is collected, and passed through the same 
operation three or four times. The glass is then weighed, again subjected to the 
same operation, the emery by this time being reduced to an impidpable powder. This 
series of operations is continued until! the loss sustained by the gUss is exceedingly 
smalL The total loss in the glass is then noted, and when all the specimens of emery 
are submitted to this operation under the same circumstances, an exact idea of their 
relative hardness is obtained. The advantages of using glass and agate are, that the 
latter is sufficiently hard to crush the emery, and in a certain space of time to reduce 
it to such an impalpable state, that it has no longer any sensible effect on the glass ; 
and, on the other hand, the glass is soft enough to lose during this time sufiicient of 
its substance to allow of accurate comparative results. By this method, the best 
emery was found capable of wearing away about half of its weight of conunon French 

In the ordinary process, the lumps of emery ore are broken up in the same manner 
as stone is for repairing macadamised roads, and into lumps of similar size. These 
lumps then crushed under stampers, such as are used for pounding metallic ores, 
driven by water or by steam power. It is supposed that the stampers leave the frag- 
ments more angular than they would be if they were ground under runners, a mode 
which is sometimes employed. The coarse powder is then sifted through sieves of 
wire cloth, which are generally cylindrical, like the bolting cylinders of com -mills; 
but the sieves are covered with wire cloth, which vary from ninety to sixteen 
wires to the inch. No. 16 sieve gives emery of about the size of mustard-seed ; and 
coarser fhigments, extending nearly to the size of pepper-corns, are also occasionally 
prepared for the use of engineers. The sieves have sometimes as many as 120 wires 
in the inch ; but the very fine sizes of emery are most commonly sifted through lawn 
sieves. The finest emery that is obtained tnm. the manufacturers is that which floats 
in the atmosphere of the stamping-room, and is deposited on Uie beams and shelves, 
from which it is occasionally collected. The manu&cturers rarely or never wash the 
emery *, this is^ mostly done by the glass-workers, and such others as require a greater 
degree of precision than can be obtained by sifting. 

The following table shows the number of wires nstially contained in the sieyes, and 
the names of the kinds respectively produced by them : — 

Com emery - - - - 1 6 

Coarse grinding emery - - 24 

Grinding emery - - - 36 

Fine grinding emery - - 46 

Superfine grinding emery - 53 

Wirei. Wittt. 

Coarse fiour emery - - 60 

Flour emery - - • - 70 

Fine flour emery - • - 80 

Superfine flour emery - - 90 

£M£BY. 123 

Washing emery by hand is far too tediom for those who require Tery large quanti- 
ties of emery, each as the manufacturers of plate glass and some others, who generally 
adopt the following method: — TweWeor more cylinders of sheet copper, of the common 
height of about two feet, and yarying from about three, fiTc, eight, to thirty or forty 
iDches in diameter, are placed exactly leTel, and oommunicating at their upper edges, 
each to the next, "bj small troughs or channels; the largest yesselhas also a waste-pipe 
near the top« At the commencement of the process, the cylinders are all filled to the 
brim with clean water ; the pulrerised emery is then churned up with abundance of 
water in another ? essel, and allowed to run into the smallest or the three-inch cylinder, 
through a tube opposite the gutter leading to the second cylinder. The water during 
its short passage across the three-inch cylinder, deposits in that Tessel such of the 
coarsest emery as will not bear suspension for that limited time ; the particles next 
finer are deposited in the five-inch cylinder, during the somewhat longer time the 
mixed stream takes in passing the brim of that Tessel ; and so on. Eventually the 
water forms a very languid eddy in the largest cylinder, and deposits therein the very 
fine particles that have remained in suspension until this period ; and the water, 
lastly, escapes by the waste-pipe nearly or entirely free from emery. In this simple 
arrangement, time is also the measure of the particles respectively deposited in the 
manufiiccure to which the emery is applied. When the vessels are to a certain degree 
filled with emery, the process is stopped, the vessels are emptied, the emery is care- 
fully dried and laid by, and the process is recommenced. 

Holtzapffel informs us that he has been in the habit, for many years, of employing 
emery of twelve degrees of fineness, prepared by himself by washing over. 

For optical purposes, Mr. Ross mixes four pounds of the flour of emery of com- 
merce, with one ounce of powdered gum-arabio, and then throws the powder into two 
gsiilons of dear water ; and he collects the deposit at the end of 10" and SCV', and 2' 
!& 2(y and 6<y, and that which is not deposited by one hour's subsidence is thrown 
away as useless for grinding lenses. 

£mery paper is prepared by brushing the paper over with thin glue, and dusting the 
emery-powder over it fh>m a sieve. There are about six degrees of coarseness. 
Sieves with thirty and ninety meshes per linear inch, are in general the coarsest and 
finest sixes employed. When used by artisans, the emery-paper is commonly wrapped 
round a file or a slip of wood, and applied just like a file, with or without oil, accord- 
ing to circumstances. The emery-paper cuts more smoothly with oil, but leaves the 
work duIL 

Emery cloth only differs from emery-paper in the use of thin cotton doth instead of 
paper, as the material upon which the emery is fixed by means of glue. The emery 
cloth, when folded around a file, does not ply so readily to it as emery-paper, and is 
apt to unroll. Hence smiths, engineers, and others, prefer emery-paper and emery- 
sticks; bat for household and other purposes, where the hand alone is used, the 
greater durability of the cloth is advantageous. 

Emery-sticks are rods of board about eight or twelve inches long, planed up square ; 
or with one side rounded like a half round file. Nails are driven into each end of the 
stick as temporary handles ; they are then brushed over one at a time with thin 
glue, and dabbed at all parts in a heap of emery powder, and knocked on one end to 
shake off the excess. Two coats of glue and emery are generally used. The emery- 
sticks are much more economical than emery-paper wrapped on a file, which is liable 
to be torn. 

Emery-cake consists of emery mixed with a little beeswax, so as to constitute a 
solid lump, with which to dress the edges of buff and glass wheels. The ingredients 
should be thoroughly incorporated by stirring the mixture whilst fluid, after which it 
is frequently poured into water, and thoroughly kneaded with the hands, and rolled 
into lumps before it has time to cooL The emery-cake u sometimes applied to the 
wheels whilst they are revolving; but the more usual course is, to stop the wheel 
and rub in the emery cake by hand. It is afterwards smoothed down by the 

Emery-paper, or patent razor-strop paper, an article in which fine emery and glass 
are mixed with paper pulp, and made into sheets as in making ordinary paper ; the 
emery and glass are said to constitute together 60 percent of the weight of the paper, 
which resembles drawing-paper, except that it has a delicate fawn colour. The emery- 
paper is directed to be pasted or glued upon a piece of wood, and when rubbed with a 
hole oil, to be used as a rasor-strop. 

In 1842, Mr. Henry Barclay took out a patent for a method of combining 
powdered emery into diact and Japs of different kinds, suitable to grinding, cutting, 
and polishing glass, enamels, metals, and other hard substances. The process of 
manufacture is as follows:^ Coarse emery -powder is mixed with about half its 
weight of pulverised Stourbridge loam and a little water or other liquid, to make a 


thick paste ; this is pressed into a metallic moald by means of a screw-press, and after 
having been thoroughly dried, is baked or burned in a muffle or close receiver at a 
temperature considerably above a red heat and below the full white heat. In this 
case, the clay or alumina serves as a bond, and unites the particles very completely 
into a solid artificial emery- stone, which cuts very greedily, and yet seems hardly to 
suffer perceptible wear. 

Superfine grinding emery is formed into wheels exactly in the same manner as the 
above, but the proportion of loam is then only one-fonrth instead of one-half that of the 
emery. Those emery stones, which are of medium fineness, cut less qoickly, but 
more smoothly than the above. 

Flour-emery, when manufactured into artificial stones, requires no uniting sub- 
stance, but the moistened powder is forced into the metal mould and fired ; some 
portions of the alumina being sufficient to unite the whole. These fine wheels render 
the works submitted to them exceedingly smooth, but they do not produce a high 
polish on account of the comparative coarseness of the flour-emery. 

The alumina of emery is believed to be aggregated to the same degree of hardness 
as in corundum or adamantine spar ; which is one of the hardest minerals known. 
Emery is extensively employed for grinding metals, glass, &c. ; for which parpose it 
is reduced to powders of different degrees of fineness by grinding and elutriation. 

EMERALD (^Emeraude, Fr. ; Smaragd, Germ.), is a precious stone of a beantiful 
green colour ; valued next to diamond, and in the same rank as oriental ruby and 
sapphire. It occurs in prisms with a regular hexagonal base; sp. grav. 2*7; scratches 
quartz with difficulty ; is scratched by topaz ; fhsible at the blowpipe into a frothy 
bead ; the precipitate afforded by ammonia, from its solution, is soluble, in a great 
measure, in carbonate of ammonia. Its analysis is given very variously by different 
chemists. It contains about 14 per cent of glucina, which is its characteristic con- 
stituent, along with 68 of silica, 16 of alumina, a very little lime and iron. The beau- 
tiful emerald of Peru is found in a clay schist mixed with some calcareous matter. A 
stone of 4 grains weight is said to be worth from 4/. to 5/. ; one of 8 grains, lOiL; one 
of 15 grains, being fine, is worth 60/; one of 24 grains fetched, at the sale of M. de 
Dree's cabinet, 2400 francs, or nearly lOOL 

The beryl is analogous in composition to the emerald, and is employed (when of the 
common opaque kind, found near Limoges) by chemists for procuring the earth 

Fine emeralds are found in a vein of dolomite, which traverses the hornblende 
slate at Muzo, north of Santa Fe de Bogota. A perfect hexagonal crystal from this 
locality, two inches long, is in the cabinet of the Duke of Devonshire ; it measures 
across its three diameters 2 J in., 2| in., 1{ in., and weighs 8 oz. 18 dwts: — owing to 
flaws, it is but partially fit for jewellery. A more splendid specimen, though some- 
what smaller, weighing but 6 oz., is in the possession of Mr. Hope; it cost 500/. 
Emeralds of less beauty, but much larger, occur in Siberia. One specimen in the 
royal collection measures 14j inches long and 12 broad, and weighs 16) lbs. troy ; 
another is 7 inches long and 4 inches broad, and weighs 6 lbs. troy. — Dana. 

The emerald is generally believed to derive its colour from the presence of a minute 
quantity of oxide of chrome, the beryl from oxide of iron. 

This mineral has been recently examined with great care by M. Lewy, from 
whose conununication to the Academy of Sciences we abstract the following : — 

** M. Lewy visited a mine called Muzo, in New Granada, Mexico, and obtained some 
fine specimens of emeralds, and of the rocks in which those precious stones are found, 
lie observed that the largest and finest emeralds could be reduced to powder by a 
slight squeezing or rubbing between the fingers when first obtained, but that they 
acquired hardness after a certain time and repose. It has been commonly stated 
that the colouring matter of the emerald is chrome, but M. Lewy attributes it to an 
organic colouring matter, analogous to chloropkyle. He states that the emerald ex- 
posed to heat loses all colour ; whereas minerals coloured by chrome, do not lose 
their green colour by ignition. His analysis of the Mexican mineral b as fol- 
lows : — 

Silica -•-....• Q7*9 

Alumina - - . . . - 17*9 

Glucina •.-.-. i2*4 

Magnesia - - - . . - 0*9 

Soda - - - - • - - 0-7 

The green colour of the emerald is darkest in those specimens which funiish to 
analysis most organic matter : it is completely destroyed by heat, becoming white 
and opaque. 

EMETINE. A base constituting the emetic principle in ipecacuanha. — O. G. W, 


EMPTHEUMA, means the ofFenaWe smell produced by fire applied to organic 
matters, chiefly vegetable, in close yessels. Thus, empyrenmatic vinegar is obtained 
by distilling wood at a red heat, and empyreumatlc oil from many animal substances 
in the same way. 

ENAMELS (j^maiur, Fr. ; Schmelzghs, Germ.) are varieties of glass, generally 
opaque or colovred, always formed by file combination of different metallic oxides, 
to which certMn fixed fusible salts are added, such as the borates, fluates, and phos- 

The simplest enamel, and the one which serves as a basis to most of the others, is 
obtained by caldning first of all a mixture of lead and tin, in proportions varying 
from 15 to 50 parts of tin for 100 of lead. The middle term appears to be the most 
suitable for the greater number of enamels ; and this alloy has such an affinity for 
oxygen, that it may be calcined with the greatest ease in a fiat cast-iron pot, and at a 
temperature not above a cherry red, provided the dose of tin is not too great. The 
oxide is drawn off to the sides of the melted metal, according as it is generated, new 
pieces of the alloy being thrown in from time to time, till enough of the powder be 
obtained. Great care ought to be taken that no metallic particles be left in the oxide, 
and that the calcining heat be as low as is barely sufficient ; for a strong fire frits the 
powder, and obstructs its subsequent comminution. The powder when cold is ground 
in a proper mill, levigated with water, and elutriated. In this state of fineness and 
purity, it is called calcine or fiux, and it is mixed with silicious sand and some alka- 
line matter or sea-salt The most ordinary proportions are, 4 of sand, 1 of sea- 
salt, and 4 of cakme. Chaptal states, that he has obtained a very fine product 
from 100 parts of calcine, made by calcining equal parts of lead and tin, 100 parts 
of ground flint, and 200 parts of pure sub-carbonate of potash. In either case, 
the mixture is put into a crucible, or laid simply on a stratum of sand, quicklime 
spontaneously slacked, or wood-ashes, placed under a pottery or porcelain kiln. This 
mass undergoes a semivitrification, or even a complete fusion on its surfiice. It is 
this kind of frit which serves as a radical to almost every enamel ; and by varying the 
proportions of the ingredient, more fusible, more opaque, or whiter enamels are ob- 
tained. The first of these qufdities depends on the quantity of sand or flux, and the 
other two on that of the tin. 

The sea-salt employed as a flux may be replaced either by salt of tartar, by pure 
potash, or by soda ; but each of these fluxes gives peculiar qualities to the enameL 

Most authors who have written on the preparation of enamels, insist a great deal on 
the necessity of selecting carefully the particular sand that should enter into the com- 
position of the frit, and they even affirm that the purest is not the most suitable. 
Clouet states, in the 34th volume of the Annales de Chimie, that the sand ought to con- 
tain at least 1 part of talc for 8 of silicious matter, otherwise the enamel obtained is 
never very glaray, and that some wrinkled spots from imperfect fusion are seen on its 
sarfiice ; and yet we find it prescribed in some old treatises, to make use of ground flints, 
fritted by means of salt of tartar or some other flux. It would thence api>ear that the 
presence of talc is of no use'towards the fusibility of the silica, and that its absence 
may be supplied by increasing the dose of the flux. In all cases, however, we ought 
to beware iS metallic oxides in the sand, particularly those of iron and manganese, 
which most frequently occur, and always injure the whiteness of the frit 

The ancients carried the art of enamelling to a very high perfection, and we occa- 
sionally find beautiful specimens of their work. Then, as at present, each artist made 
a mystery of the means that succeeded best with him, and thus a multitude of curious 
processes have been buried with their authors. 

The Venetians are still in possession of the best enamel processes, and they sup- 
ply the French and other nations with the best kinds of enamel, of every coloured 

Enamels are distinguished into transparent and opaque ; in the former all the ele- 
ments have experien^ an equal degree of liquefaction, and are thus run into crystal 
glass, whilst in the others, some of their elements have resisted the action of heat, so 
that their particles prevent the transmission of light This effect is produced par- 
ticularly by the oxide of tin. 

The frits for enamels that are to be applied to metallic surfaces require greater fhsi- 
bili^, and should therefore contain more fiux ; and the sand used for these should be 
calcined beforehand with one-fourth its weight of sea-salt ; sometimes, indeed, metallic 
flaxes are added, as minium or litharge. For some metallic colours, the oxides of lead 
are very injurious, and in this case recourse must be had to other fiuxes. Clouet states 
tbat he has derived advantage from the following mixtures, as bases for purples, blues, 
and some other delicate colours : — 

Three parts of silicious sand, one of chalk, and three of calcined borax ; or, three of 
glass (of broken crystal goblets), one of calcined borax, one-fourth of a part of nitre, 


and one part of weU-vashed-diaphoretic antimony. These oompositions affioidftTerx 
white enamel, which accordfl perfectly well with blue. 

It is obTious that the composition of this primary matter may be greatly Tarted : 
but we should never lose sight of the essential quality of a good enamel ; which is, 
to acquire, at a moderate heat, sufficient fluidity to take a shining sarbee, withoat 
running too thin. It is not complete fhsion wluch is wanted ; but a pasty state, of 
such a degree as may give it, after cooling, the aspect of having suffered complele 

Dead'whiU EnameL — This requires greater nicety in the choioe of its materials 
than any other enamel, as it must be free from every species of tint, and be perfectly 
white ; hence the frit employed in this case should be itself composed of perfectly 
pure ingredients. But a fi'it should not be rejected hastily because it may be some- 
what discoloured, since this may depend on two causes ; either on some metallic 
oxides, or on fuliginous particles proceeding from vegetable or animal sabstanees. 
Now the latter impurities may be easily removed by means of a small qnantity of 
peroxide of manganese, which has the property of readily parting with a portion of 
Its oxygen, and of thus facilitating the combustion, that is to say, the destractimi of 
the colouring carbonaceous matter. Manganese indeed possesses a colouring power 
itself on glass, but only in its highest state of oxidisement, and when reduced to the 
lower state, as is done by combustible matters, it no longer communicates ctdour to the 
enamel combinations. Hence the proportion of manganese shoald never be in excess; 
for the surplus would cause colour. Sometimes, indeed, it becomes necessary to give 
a little manganese-colour, (1. e. a pink tint) in order to obtain a more agreeable shade 
of white; as a little asure blue is added to linens, to brighten or counteract the dnlness 
of their yellow tint 

A white enamel may be conveniently prepared also with a calcine composed of 
two parts of tin and one of lead calcined together ; of this combined oxide, <Mie part 
is melted with two parts of fine crystal and a very little manganese, all previously 
ground together. When the fusion is complete, the vitreous matter is to be poared 
into clear water, and the frit is then dried, and melted anew. The pouring into 
water and fusion are sometimes repeated four times, in order to secure a very uniform 
combination. The crucible must be carefhlly screened from smoke and flame. The 
smallest portions of oxide of iron or copper admitted into this enamel will destroy its 

Some practitioners recommend the use of washed diaphoretic uttimony (anti- 
moniate of potash, f^om metallic antimony, and nitre deflagrated together) for white 
enamel; but this product cannot be added to any preparation of lead or other 
metallic oxides ; for it would tend rather to tarnish the colour than to clear ft up ; 
and it can be used therefore only with ordinary glass, or with saline fluxes. For 
three parts of white glass (without lead) one part of washed diaphoretic antimony 
is to be taken ; the substances are well ground together, and fused in the conunon 

Blue EnameL — This fine colour is almost always obtained from the oxide of cobalt 
or some of its combinations, and it produces it with such intensity tiiat only a very 
little can be used, lest the shade should pass into black. The cobalt blue b so rich 
and lively that it predominates in some measure over every other colour, and masks 
many so that they can hardly be perceived ; it is also most easily obtained. To bring 
it out, however, in all its beauty, the other colours must be removed as much as pos- 
sible, and the cobalt itself should be tolerably pure. This metal is associated in the 
best known ores with a considerable number of foreign substances, as iron, arsenic, cop- 
per, nickel, and sulphur, and it is difficult to separate them completely; but for enamel 
blues, the oxide of cobalt does not require to he perfectly free fh)m all foreign metals; 
the iron, nickel, and copper being most pr^udicial, should be carefully eliminated. 
This object may be most easily attained by dissolving the ore in nitric acid, evaporating 
this solution to a syrupy consistence, to expel the excess of acid, and separate a portion 
of arsenic. It is now diluted with water, and solution of carbonate of soda is dropped 
slowly into it with brisk agitation, till the precipitate, which is at first of a whitish 
gray, begins to turn of a rose-red. Whenever this colour appears, the whole most be 
thrown on a filter, and the liquid which passes through must be treated with more of 
the carbonate of soda, in order to obtain the arseniate of cobalt, which is nearly pure. 
Since arsenic acid and its derivatives are not capable of communicating colour them- 
selves, and as they moreover are volatile, they cannot impair the beauty of the blue, and 
hence this preparation affords it in great perfection. 

Metallic fluxes are not the most suitable for this colour ; because they always com- 
municate a tint of greater or less force, which never fails to injure the purity of the 
blue. Nitre is a useful addition, as it keeps the oxide at the maximum of oxidation, 
in which state it produces the richest colour. 


YMim £iiaaM21— There are many proceeses for making this colour in enamel ; bat 
it is aomeirhat difficult to fix, and it is rarely obtained of an uniform and fine tint It 
may be produced directly with some preparations of silver, as the phosphate or snlphate ; 
bat this method does not always succeed, for too strong a heat or powerful fluxes readily 
destroy it, and nitre is particularly prejudicial. This uncertainty of success with the 
salts of siWer causes them to be seldom employed ; and oxides of lead and antimony are 
therefore preferred, which afford a fine yellow when oombined with some oxides that 
are refractory enough to prcTcnt their complete Titriflcation. One part of white oxide 
of antimony may be taken with fh>m one to three parts of white lead, one of alum, 
and one of sal-ammooiae. Each of these substances is to be puWerised, and then all 
are to be exactly mixed, and exposed to a heat adequate to decompose the sal-ammoniac. 
This operation is jndged to be finished when the yellow colour is well brought out 
There is produced here a combination quite analogous to that known under the name 
of Naples ydlow. 

CMmt siisdcs of yellow may be procured either with the oxide of lead alone, or by 
adding to it a little red oxide of iron; the tints varying with the proportion of the 

Ciouet says, in his Memoir on Enamels, that a fine yellow is obtained with pure 
oxide of silTer, snd that it is merely necessary to spread a thin coat of it on the spot 
to be eoloored. The piece is then exposed to a moderate heat, and withdrawn as soon 
as this has reached the proper point The thin film of metallic silver revived on the 
surface bcinff removed, the place under it will be found tinged of a fino yellow, of 
hardly an^ ukickness. As the pellicle of silver has to be removed which covers the 
cfdonr, it is requisite to avoid fixing this film with floxes : and it ought therefore to 
be applied after the fusion of the rest The yellows require in genmd but little 
sdkaline flux, as they answer better with one of a metallic nature. 

€^rt€n JSntmeL — It is known that a green colour may be produced by a mixture of 
yellow and blue; but recourse is sddom had to this practice for enamels, as they can 
be obtained almost always directly with the oxide of copper; or, still better, with the 
oxide of chrome, which has the advantage of resisting a strong heat 

Chemists describe two oxides of copper, the protoxide of an orange colour, which 
oommnnieates its colour to enamels, but it is difficult to fix ; the deutoxide is blue in 
the state of hydrate, but blackish •brown when dry, and it colours green all the yitreous 
comlnnations into which it enters. This oxide requires, at most one or two proportions 
of flux, either saline or metallic, to enter into complete fusion ; but a much onaller 
dose is commonly taken, and a little oxide of iron is introduced. To 4 pounds of frit 
for instance 2 ounces of oxide of copper and 48 grains of red oxide of iron are used ; 
and the ordinary measures are pursued for making very homogeneous enamel. 

The green produced by oxide of chrome is much more solid ; it is not affected by a 
powerful fire, but it is not always of a fine shade It generally inclines too much to 
the dead'ieaf yellow, which depends on the degree of oxygenation of the chrome. 

Red Eiutmd, — We have just stated, that protoxide of copper afforded a fine colour 
when it could be fixed, a result difficult to obtain on accoant of the fugitive nature of 
this oxide ; slight variations of temperature enabling it to absorb more oxygen. The 
proper point of fusion must be seized for taking it from the fire whenever the desired 
odour is brought out. Indeed, when a high temperature has produced peroxidisement, 
this may be corrected by adding some combostible matter, as charcoal, tallow, tartar, 
&c The copper then retnms to its minimum of oxidisement and the red colour which 
had vanished, reappears. It is possible, in this way, and by pushing tiie heat a little, 
to accomplish the complete reduction of a part of the oxide ; and the particles of metallic 
copper thereby disseminated in a reddish ground, give this enamel the aspect of the 
stone called avenHaine, The snrest and easiest method of procnring protoxide of 
copper is to boil a solution of equal parts of sugar, and sulphate or noher acetate of 
copper, in four parts of water. The sugar takes possession of a portion of the oxygen 
of the cupreous oxide, and reduces it to protoxide ; when it may be precipitated in 
the form of a granular powder of a brilliant red. After about two hours moderate 
ebullition, the liquid is set aside to settle, decanted off the precipitate, which is washed 
and dried. 

The protoxide properly employed by itself, fbmishes a red which vies with the 
finest carmine, and by its means every tint may be obtained fVom red to orange, by 
adding a greater or smaller quantity of peroxide of iron. 

The preparations of gold, and particularly the oxide and purple of Cassius, are like- 
wise employed with advantage to colour enamel red, and this composition resists a 
powerful fire tolerably weUL For some time back, solutions of gold, silyer, and platinum 
have been used with success instead of their oxides ; and in Uiis way, a more intimate 
mixturo may be procured, and, consequently, more homogeneoos tints. 

Black EnameL — Black enamels are made with peroxide of manganese or protoxide 


of iron ; to which more depth of colour is ^yen with a little cobalt CUy alone, 
melted with about a third of its weight of protoxide of iron, gives, according to Cloiiet, 
a fine black enamel. 

Violet Enamel — The peroxide of manganese in small quantity by itself fiimishes, 
with saline or alkaline fluxes, an enamel of a Tery fine violet hne ; and variatiottt of 
shade are easily had, by modify'ing the proportions of the elements of the coloored 
frit. The great point is to mamtain the manganese in a state of peroxidation, and, 
consequently, to beware of placing the enamel in contact with any substance attractive 
of oxygen. 

Such are the principal coloured enamels hitherto obtained by means of metallic 
oxides ; but since the number of these oxides is increasing every day, it is to be wished 
the new trials be made with such as have not yet been employed. From such researches 
some interesting results would unquestionably be derived. 

Of painting on EneaneL — Enamelling is only done on gold and copper ; for silver 
swells up, and causes blisters and holes in the coat of enameL All enamel psdntings 
are, in &ct, done on either copper or gold. 

If on gold, the goldsmith prepares the plate that is to be painted upon. The gold 
should be 22 carats fine: if purer, it would not be sufficiently stiff; if coarser, it would 
be subject to melt ; and its alloy should be half white and half red, that is, half silver 
and half copper ; whereby the enamel with which it is covered will be less disposed 
to turn green, than if the alloy were entirely copper. 

The workman must reserve for the edge of the plate a small fillet, which he calls the 
border. This ledge serves to retain the enamel, and hinders it from falling off when 
applied and pressed on with a spatula. When the plate is not to be counter-enamelled, 
it should be charged with less enamel, as, when exposed to heat, the enamel draws up 
the gold to itself, and makes the piece convex. When the enamel is not to cover the 
whole plate, it becomes necessary to prepare a lodgment for it With this view, all 
the outlines of the figure are traced on the plate with a black-lead pencil, after which 
recourse is had to the graver. 

The whole space enclosed by the ontlines must be hollowed ont in bas-reliefs of a 
depth equal to the height of the fillet had the plate been entirely enamelled. This 
sinking of the sur&ce must be done with a fiat graver as equally as possible ; for if 
there he an eminence, the enamel would be weaker at that point and the green would 
appear. Some artists hatch the bottom of the hollow with close lines, which cross each 
other in all directions ; and others make lines or scratches with the edges of a file broken 
off square. The hatchings or scratches lay hold of the enamel which might otherwise 
separate from the plate. After this operation, the plate is cleansed by boiling it in 
an alkaline lye, and it is washed first with a little weak vinegar, and then wi£ dear 

The plate thus prepared is to be covered with a coat of white enamel, which is done 
by bruising a piece of enamel in an agate or porcelain mortar to a coarse powder like 
eand, washing it well with water, and applying it in the hollow part in its moist state. 
The plate may meanwhile be held in an ordinary forceps. The enamel powder is 
spread with a spatula. For condensing the enamel powder, the edges of the plate are 
struck upon with a spatula. 

Whenever the piece is dry, it is placed on a slip of sheet iron perforated with 
several small holes, see Jig, 720, which is laid on hot cinders ; and it is left there 
until it ceases to steam. It must be kept hot till it goes to the fire ; for were it 
allowed to cool it would become necessary to heat it again very gradually at the 
mouth of the furnace of fusion, to prevent the enamel from decrepitating and 
flying off. 

Before describing the manner of exposing the piece to the fire, we must explain 
the construction of the furnace. It is square, and is shown in front elevation in fig, 72 1. 
It consists of two pieces, the lower part a, or the body of the ftimace, and the upper 
part B, or the capital, which is laid on the lower part as is shown in^. 722, where 
these two parts are separately represented. The furnace is made of good fire-clay, 
moderately baked, and resembles very closely the assay or cnpellation furnace. Its 
inside dimensions are 9 inches in width, 13 inches in height in the body, and 9 in 
the capital Its general thickness is 2 inches. 

The capital has an aperture or door, c, fig, 721, which is closed by a fire-brick 
stopper m, when the fire is to be made active. By this door fuel is supplied. 

The body of the furnace has likewise a door d, which reaches down to the pro- 
jecting shelf B, called the bib (mentonniire)^ whose prominence is seen at ^fig, 721. 
This shelf is supported and secured by the two brackets, F, f ; the whole being 
earthenware. The height of the door d, is abridged by a peculiar fire brick o, which 
not only covers the whole projection of the shelf E, but enters within the opening of 
the door d, filling its breadth, and advancing into the same plane with the inner sur&oe 



of the foHMce. This plate is called the hearth ; its purpose will appear presently ; it 
may be taken oat and replaced i^t pleasure, by laying hold of the handle in its front. 

Belov the shelf b, a square hole, h, is seen, which senres for admitting air, and for 
extractiog the asbet. Similar holes are left upon each side of the surface, as is shown 
in the ground plan of the baK,yi^. 722, at h. 

On a level with the shelf, in the interior of the furnace, a thin fire-tile t rests, per* 
forated with numerous small holes. This is the grate represented in a ground view 
in>!^. 72a Figt. 723, 724, 725, represent, under different aspects, the muffle. Fig, 722 
shows the eleyation cX its further end ; fig, 724 its sides ; and^. 725 its front part 
At i^f4» 722, the muffle is seen in its place in the furnace, resting on two bars of 
iron, or, stfll better, on ledges of fire-clay, supported on brackets attached to the 
lateral sides of the furnace. The muffle is made of earthenware, and as thin as 
possible. The fuel consists of dr^ beech- wood, or oaken branches, about an inch in 
diameter, cut to the length of nme inches, in order to be laid in horizontal strata 
within the furnace, one row only being placed above the muffle. When the muffle 
has attuned to a white red heat, the sheet iron tray, bearing its enamel plate, 
is to be introduced with a pair of pincers into the front of the muffle, and gradually 
adTaneed towards its further end. The mouth of the muffle is to be then closed with 
two pieces of charcoal only, between which the artist nSay see the progress of the 
operation. WhencTcr the enamel begins to flow, the tray must be turned round on its 
base to insure equality of temperature ; and as soon as die whole surface is melted, the 
tray must be withdrawn with its plate, but slowly, lest the yitreous matter be cracked 
by sudden refrigeration. 

The enamel plate, when cold, is to be washed in very dilute nitric acid, and after- 
wards in cold water, and a second coat of granular enamel paste is to be applied, with 
the requisite precautions. This being passed through the fire, is to be treated in the 
same way a third time, when the process will be found complete. Should any chinks 
happen to the enamel coat, they must be widened with a graver, and the space being 
filled with ground enamel, is to be repaired in the muffle. The plate, covered with a 
pure white enamel, requires always to be polished and smoothed with sandstone and 
water, particularly if the article have a plane surface ; and it is then finally glazed at 
the fire; 

The painting operation now follows. The artist prepares his enamel colours by 
pounding them in an agate mortar, with a pestle of agate, and grinding them on an 
agate slab, with oil of larender, rendered vificid by eJLposure to the sun in a shallow 
vessel, loosely covered with gauze or glass. The grinding of two drachms of enamel 
pigment into an impalpable powder will Occupy a labourer a whole day. The 
painter should have alongside of him a stove in which a moderate fire is kept up, for 
drying his work whenever the figures arC finished. It is then passed through the 

The following was the process adopted by Henry Bone, R. A., and his son, the late 
Henry Pierce Bone, Who have produced the largest enamels ever painted ; and 
beyond the time and consequent expense there appears no practical limit to the size 
of enamel paintings. 

Preparing the jSate, — For small plates (up to two inches long) ptare gold is the best 
material. Silver (quite pure) is also useo, but is apt to get a disagreeable yellow 
edonr at the edges by repeated firings. For larger sizes, copper is used. The copper 

Vol- IL K 




shoald be annealed antil quite free ftom spring, and then cleaned irith dilute ■olphinie 
acid (one part acid, fonr water , and shaped in a wooden moald, afterwards used in 
making the plate so as to produce a conirex surface varying according to the siae of 
the plate, taking care that the shaping does not reproduce the spring in the copper, 
in which case the process must be repeated. If the plate is not raised in the centre, 
in the course of repeated firings the comers will rise irregularly, producing nndnUuions 
over the plate, perfect flatness being next to impossible for large pictures. The 
copper is then laid face downwards on the convex wooden mould used for shaping, 
and enamel ground fine with water is spread over it with a small bone spoon ; when 
covered, a fine cloth doubled is pressed gently on it to absorb the water, and then it is 
fimoothed with a steel spatula. This forms the back of the plate, and when fired this 
part is finished. The copper is now reversed on a convex board the exact counter- 
part of the other, and covered with white enamel ground fine in the same way as 
above. The plate is now ready for firing, and after it has been fired and cooled the 
surface must be ground smooth with a flat piece of flint or other hard substance, with 
silver sand and water. It must next be corcred with a softer and more transparent 
kind of enamel called flux, ground and spread on in the same way as the first enameU 
but this time only on the face of the plate. This is fired as before, and when cool the 
surface must be again ground smooth, and when glazed in the furnace the plate is 
finished. For the first coat a white solid enamel is used to prevent the green colonr 
from the oxidised copper showing through ; the second coat is a softer enamel, to 
enable the colours used to melt with less heat 

Firing. — The plate is placed on a planche of firestone, or well baked Stourbridge 
clay, supported on a bed of whiting, thoroughly dried in the furnace, the exact shape 
of the plate as originally made, which must be used in all subsequent firings. After 
the whiting is formed in the shape of the plate it should be notched with a flat knife 

diagonally across, as in the accompanying diagram. 
The use of this is to produce an effect of diagonal 
bracing while the plate cools, and experience has 
shown that it tends considerably to keep the plate in 
its original shape. When the plate is small (up to 
three inches in length) it may be annealed for passing 
into the hot muffle as follows : — The planche bearing 
the plate may be placed on another planche heated in 
the muffle and placed in the front of the muffle for a few 
minutes, until the steam of the plate or the oil of the 
picture shall have evaporated ; it may then be put in 
the mouth of the muffle and gradually inserted to 
the hottest part After firing it should l>e placed on 
another hot planche and allowed to cool gradually. Largo pictures require a differf nt 
arrangement of the fiirnace. Over the muffle there should be a fixed iron annealhig 
box, with an iron shelf and door. The bottom should be of cast iron about one inch 
thick. This should be so arranged that when the muffle attains a white heat the 
bottom of the annealing box should be of a brightish red at the back, and a dull 
blood red in front Large pictures should be placed on the bottom of the box before 
the furnace is lit, and the larger the size of the picture the slower should the furnace 
be brought to its full heat, so as to allow five or six hours for the largest siae, and two or 
three for smaller plates. When fired the picture should be returned to the shelf of the 
annealing box, and left there till quite cold, for which purpose large plates require at 
least twelve hours. The colours used are mostly the same as those prepared for 
jewellers and glass painters. 

Enamelling at the Lamp. — The art of the lamp enameller is one of the moat agree- 
able and amusing that we know. There is hardly a subject in enamel which may 
not be executed by the lamp-flame in very little time, and more or less perfectly, 
according to the dexterity of the artist, and his acquaintance with the principles 
of modelling. 

In working at the lamp, tubes and rods of glass and enamel must be provided, of 
all sizes and colours. 

The enamelling table is represented in fig. 727, round which several workmen, 
with their lamps, may be phwed, while the large double bellows d below is set a-blowmg 
by a treadle moved with the foot The flame of the lamp, when thus unpelled by a 
powerful jet of air, acquires surprising intensity. The bent nozzles or tubes a, a, jl, 
A, are made of glass, and aredrawn to points modified to the purpose of the enameller. 

Fig, 728 shows, in perspective, the lamp a of the enameller standing in ics cistern 
B ; the blowpipe c is seen projecting its flame obliquely upwards. The blowpipe is 
acijustable in an elastic cork d, which fills up exactly the hole of the table into 
which it enters. When only one person is to work at a table provided with several 

a Planche. 

b Bed of whiting. 



lamps, he sits down at the same side with the pedal of the bellows ; he takes oat the 
other blowpipes, and plugs the holes in the table with solid corks. 

The lamp is made of copper or tin plate, the wick of cotton threads, and either 
tallow or oil may be used. Between the lamp and the workman a small board or 



sheet of white iron b, called the screen, is interposed to protect his eyes from the 
glare of light. The screen is ^tened to the table by a wooden stem, and it throws 
ita shadow on his face. 

The enamelling workshop ought to admit little or no daylight, otherwise the artist, 
not perceiving his flame distinctly, would be apt tocommit mistakes. 

It is impossible to describe all the manipalations of this ingenious art, over which 
taste and dexterity so entirely preside. Bat we may give an example. Suppose the 
enameller wishes to make a swan. He takes a tube of white enamel, seals one of its 
ends hermetically at his lamp, and while the matter is sufficiently hot, he blows on 
it a minikin flask, resembling the body of the bird ; he draws out, and gracefully 
bends the neck; he shapes the head, the beak, and the tail; then, with slender 
enamel rods of a proper colour, he makes the eyes ; he next opens up the beak with 
pointed scissors ; he forms the wings and the legs ; finally attaching the toes, the 
bird stands complete. 

The enameller also makes artificial eyes for human beings, imitating so perfectly 
the colours of the sound eye of any indiyidual as to render it difiicult to discover 
that he has a blind and a seeing one. 

It is dtfiB.caIt to make large articles at the blowpipe ; those which surpass 5 or 6 
inches become nearly unmanageable by the most expert workmen. 

EMAMELLnfo or Cast Iron and other Hollow Ware for Saucepans, &c. In 
December, 1799, a patent was obtained for this process by Dr. Samuel Sandy Hickling. 
His specification is subdiyided mto two parts -. — 

1. The coating or lining of iron yessels, &c., by fusion with a yitrifiable mixture, 
composed of 6 parts of calcined flints, 2 parts of composition or Cornish stone, 9 parts of 
litharge, 6 parts of borax, 1 part of argillaceous earth, 1 part of nitre, 6 parts of calx of 
tin, and 1 part of purified potash. Or, 2ndly, 

8 parts of calcined flints, 8 red lead, 6 borax, 5 calx of tin, and 1 of nitre. Or, Srdly, 

12 of potter's composition, 8 borax, 10 white lead, 2 nitre, 1 white marble calcined, 
1 argillaeeoos earth, 2 purified potash, and 5 of calx of tin. Or, 4thly, 

4 parts calcined flint, 1 potter's composition, 2 nitre, 8 borax, 1 white marble cal« 
cined, ^ argifiaeeous earth, and 2 calx of tin. 

Whieheyerof the above compositions is taken, must be finely powdered, mixed, fused, 
the yitreons mass is to be ground when cold, sifted, and levigated with water. It is then 
made into a pap with water or g^m water. This pap is smeared or brushed over the 
interior of the vessel, dried and fused with a proper heat in a muffle. 

Calcined bones are also proposed as an ingredient of the flux. 

The fusibility of the vitreous compounds is to vary according to the heat to be 
applied to the vessel, by using various proportions of the silicious and fluxing 
materials. Colours may be given, and also gilding. 

The second part or process in his specification describes certain alloys of iron and 
nickel, which he casts into vessels, and lines or coats them with copper precipitated 
&om its saline solutions. It also describes a mode of giving the precipitated copper an 
enamel sor&ce by acting upon it with bone ashes and zinc with the aid of heat. 

A &etory of such enamelled hollow wares was carried on for some time, but it was 
given np for want of due encouragement 

A patent was granted to Thomas and Charles Clarke on the 25th of May, 1839, for 
a method of enamelling or coating the internal surfaces of iron pots and saucepans, in 

K 2 


sach a way as shall preyent the enamel from cracking or gplltting oif from the etkcts 
of fire. This specification prescribes the vessel to be first cleaned by exposing it to the 
action of dilute sulphuric acid (sensibly sour to the taste) for three or four hoorii 
then boiling thcTessel in pure water for a short time, and next applying the eompontinii. 
This consists of 100 lbs. of calcined ground flints; 50 lbs. of borax, calcined, and finely 
ground with the above. That mixture is to be fused and gradually cooled. 

40 lbs. weight of the above product is to be taken with 5 lbs. weight of potter's day; 
to be ground together in water until the mixture forms a pasty consistent mass, 
which will leave or form a coat on the inner surface of the vessel about one-sixth of an 
inch thick. When this coat is set, by placing the vessel in a wann room, tlie second 
composition is to be applied. This consists of 125 lbs. of white glass (without lead), 
25 lbs. of borax, 20 lbs. of soda (crystals), all pulverised together and vitrified by 
fusion, then groand, cooled in water, and dried. To 45 lbs. of that mixture, 1 lb. of 
soda is to be added, the whole mixed together in hot water, and when dry pounded ; 
then sifted finely and evenly over the internal surface of the vessel previously covered 
with the first coating or composition whilst this is still moist This is the glaaing. 
The vessel thus prepared is to be put into a stove, and dried at the temperature of 
212^ Fahr. It is then heated in a kiln or muffle like that used for glazing china. The 
kiln being broaght to its full heat, the vessel is placed first at its mouth to heat it grt- 
dually, and then put into the interior for fusion of the glaze. In practice it has been 
found advantageous also to dust the glas^ powder over the fused glaze, and apply a 
second fluxing heat in the oven. The enamel, by this double application, bcooiDcs 
much smoother and sounder. 

Messrs. Kenrick, of West Bromwich, having produced in their fiictory and sent into 
the market some excellent specimens of enamelled saucepans of cast iron, were sued 
by Messrs. Clarke for the invasion of their patent rights ; but after a long litigation 
in Chancery the patentees were nonsuited in the Court of Exchequer. The previoiis 
process of cleansing with dilute sulphuric acid appeared by the evidence on the trial to 
have been ^ven up by the patentees, and it was also shown by their own principal 
scientific witness that a good enamelled iron saucepan could be made by Hickling't 
specification. In fact, the formulsB by which a good enamel may be compounded are 
almost innumerable ; so that a patent for such a purpose seems to be untenable, or at 
least most easily evaded. Dr. Ure exposed the finely enamelled saucepans of Messrs. 
Kenrick to very severe trials, having fused even chloride of calcium in them, aiMl 
found them to stand the fire very perfectly without chipping or cracking. Such a 
manufacture is one of the greatest improvements recently introduced into domestic 
economy ; such vessels being remarkably clean, salubrious, and adapted to the most 
delicate culinary operations of boiling, stewing, making of jellies, preserves, &c. 
They are also admirably fitted for preparing pharmaceutical decoctions, and ordinary 

The enamel of these saucepans is quite free fVom lead, in consequence of the glass 
which enters into its composition being quite f^ee fVom that metal In several of the 
saucepans wiiich were at first sent into the market, the enamel was found on analysis 
to contain a notable proportion of oxide of lead. In consequence of the quantity of 
borax and soda in the glaze, this oxide was so readily acted upon by acids that sugar 
of lead was formed by digesting vinegar in them with a gentle heat 

Enamelled iron saucepans had been many years ago imported from Geimany, 
and sold in London. Dr. Ure had occasion to analyse their enamel, and found that 
it contained abundance of litharge or oxide of lead. The Prussian government has 
issued an edict prohibiting the use of lead in the enamelling of saucepans, which are so 
extensively manufactured in Peiz, Gleiwitz, &c. Probably the German ware sent to 
England was fabricated for exportation, with an enamel made to flux easily by a dose 
of litharge. 

A suitable oven or mnfile for lining or coating metals with enamel may have the 
following dimensions : — 

The outside, 8 feet square, with M^inch walls; the interior muffle, 4 fieet square at 
bottom, rising 6 inches at the sides, and then arched over ; the crown may be 18 inches 
high from the floor ; the muffle should be built of fire-brick, 2^ inches thick. Another 
arch is turned over the first one, which second arch is 7 inches wider at the bottom, 
and 4 inches higher at the top. A 9-inch wall under the bottom of the muffle 
at its centre divides the fire-place into two, of 16 inches width each, and 3 feet 
3 inches long. The flame of the fire plays between the two arches and up through 
a 3-inch flue in front, and issues f^om the top of the arch through three holt's, 
about 4 inches square. These open into a* flue, 10x9 inches, which runs into the 

The materials for the enamel body (ground flint potter s clay, and borax) arc first 
mixed together, and then put into a rcverberatory furnace, 6 feet 7 inches long, by 


3 feci 4 inches wide, and 12 inches high. The flame from an 18-inch fire-place passes 
over the bearth. The materials are spread over the floor of the oven, about 6 inches 
thick, and ignited or fritted for 4 or 5 honrs, nntil they begin to heaTC and work like 
yeast, when another coating is pat on the top, also 6 inches thick, and fired again, and 
so on the whole day. If it be fired too mnch it becomes hard and too refractory to 
work in the ma£9es. The glaze is worked in an OTen similar to the above. It may 
be composed of about one-half borax and one-half of Cornish stone (partially decom- 
poeed granite) in a yellowish powder procured from the potteries. This is fritted for 
10 hours, and then fused into a glass which is ground up for the glase. 

ENAMELLED LEATHER. Leather glazed upon one surface, the so-called 
enamelling composition being in all respects analogous to the ordinary varnishes. In- 
stead of enamelling the grain sarfeu^e^ as is usually done, Mr. Nossiter removes that 
surface by splitting or buffing, and then produces what is called ** a finish *' upon the 
surface thus formal, by means of a roller, or glass instrument The flesh side of the 
skin may be thus prepared for enamelling; and it is less liable to crack, and the 
enamel to become cloudy on it than the grain side. See Leatheb, 

ENCAUSTIC PAINTING. A mode of painting with heated or burnt wax, 
which was practised by the ancients. The wax, when melted, was mixed with as 
mocJi colour, finely powdered, as it could imbibe, and then the mass was spread on 
the wall with a hot spatula. When it became cold the designer cut the lines with a 
cold pointed tool, and other colours were applied and melted into the former. Many 
modifications of the process have been employed. Amongst the moderns, the term 
has been improperly given to some cements, which have nothing of an encaustic 
chamcter about them. 

ENCAUSTIC TILES. See Ttleb and Tesssilb. 
BNDOGEN0U& See EzuOEZvbus. 

ENGRAVING, a word derived from cy, m, and y^duptt, to grave or write, is the 
art of executing designs or devices, upon metal, stones, and other hard substances. In 
the common acceptation of the woid in the present day, it means the execution of 
soch works on plates of copper or steel, for the purpose of obtaining from them im- 
pTKsions in ink or some other coloured fluid. Engraving, in the widest sense of the 
term, is the oldest of the fine arts ; at least, the Scriptures mention it before any 
reference is made either to painting or sculpture. In the Book of Exodus, ch. xxviii. 
V. 29, we read that " Aaron shall bear the names of the children of Israel in the 
breast-plate of judgment upon his heart ; " and again, in the same chapter, Moses is 
commanded to ^ make a plate of pure gold, and grave upon it, like the engravings of 
a signet. Holiness to the Lord." Further on, in the 35th chapter of the same book, 
Moses speaks of Bezaleel, the son of Uri, as a man " filled with the spirit of God, in 
visdom, in understanding, and in knowledge, and in all manner of workmanship ; 
and to devise curious works, to work in gold, and in silver, and in brass, and in the 
catting of stones," &c Of him and of Aholiab it is said, — ** Them hath he filled with 
wisdom of heart, to work all manner of work of the en^ver," &c. &c. These 
extracts will suffice to show the antiquity of the art of mcising, or cutting hard 
substances; whether or not it had its origin at a period anterior to the time of Moses 
there is no record, but it is not improbable that the Israelites acquired some knowledge 
ot the art from the Egyptians during their lengthened captivity, an assumption 
strengthened by the fact that numerous specimens of hieroglyphic engraving, on metal 
plates and on stone, have been discovered in Egypt and brought to this country t 
their dates, however, have not, in all cases, been ascertained with certainty. 

It is unnecessary to trace back all that might be written respecting the state of this 
art among the nations of antiquity in its various applications ; but as an example of 
its adoption for a purpose altogether practical, a passage from Herodotus may be 
adduced. This historian, referring to a period about 500 years before the Christian era, 
says : — " Aristagoras exhibited to the king of Sparta a tablet, or plate, of brass, on 
which was inscribed every part of the habitable world, the seas, and the rivers ; " or, 
in other words, Aristagoras, who was a native of Cuma, had in his possession a 
metallic map. Moreover, as it is intended to limit this notice to the art of en- 
graving on steel or copper for printing purposes, we pass over those branches or 
departments of the art Uiat relate to die-sinking, seal-engraving, and engraving on 
coins, the latter a common process with the ancient Britons and Saxons, who also, 
according to the opinion of many modem antiquarians, used to ornament their 
weapons of war with designs cut by the graving-tool. 

The transition from all previous methods of engraving, to that which in some degree 
assimilates to what is now practised as the result of the discovery of printing, has been 
thus described by the late Mr. Landseer, who quotes an earlier writer, Mr. Strutt : — 
** Soon after the conquest (though, from other information, X think it must have been 
at the least 250 years from that memorable era) a new species of engraving, entirely 


134 ENGBAVme. 

different flrom the mingled work of the engrayer, goldsmith, and chaser, vbich had 
preceded it, was introduced into, or invented in, England, of which there is icareelj 
an old country church of any consequence, but affords some curious specimens, aad 
England more than any other nation in Europe. The brass plates on oar dd 
sepulchral monuments are executed entirely with the grayer, the shadows beiii^ 
expressed by lines or strokes, strengthened in proportion to the required depth of 
shade, and occasionally crossed with other lines a second and, in some instanoo, a 
third time, precisely in the same manner as a copper plate is engrayen thst is is* 
tended for producing impressions. These engraved efSgies are commonly foinid on 
those horizontal tombstones which form parted the pavement within the chnrehes;aod 
the feet of the congregation, which kept the lights bright by friction, filled the in- 
cisions with dust, and thus darkened the shades : very neat or exquisite workmanship 
is not therefore expected ; yet some of them bear no small evidence of the abilities 
of the monks, or other workmen, by whom they were performed." Impressioss, 
technically called ** rubbings," are taken from these monumental brasses by antiqaa- 
rians, for the purpose of ulustrating works in archseology. The process is simple 
enough ; a sheet, or sheets, as may be required, of white paper, sufficiently large to 
cover the brass tablet, are laid upon it ; these are then rubbed over with a lump of 
*» shoemaker's heel -ball," a composition of wax and lamp-black, which leaves on the 
paper an impression of the raised portions of the metal. 

The fifteenth century, which must always be considered as the dawn of anirenal 
light and knowledge, gave to the world the art of printing, and from this ioTentios 
arose a new era in the art of engravins;: the earliest method of printing, both boob 
and illustrations, was, as is described under the article Wood Engraving ^ from engraTed 
blocks or tablets. It seems singular that, though engraving on various metals had 
been practised long before that on wood, no attempt had ever been made to obtain 
impressions fh>m the plates ; like many other important discoveries, this is said to be 
the result of accident Vasari, the historian of Italian art, says that, in the year 1460, 
Maso, or Thomaso Finiguerra, a Florentine goldsmith, chanced to let flail a small 
engraved plate, on which, as was customary with engravers, he had rnbbed a little 
charcoal and oil, that he might the better see the state of his work, into some melted 
sulphur, and observing that the exact impression of his engraving was left on the 
sulphur, he repeated the experiment, by passing a roller gently over it It was suc- 
cessful, and Finiguerra imparted his discovery to Baldini, also a goldsmith of Florence, 
by whom it was communicated to others. But the most probable origin of the art of 
printing from metallic plates, is that which is attributed to the early Italian workers 
m ni«//o, or inlaid modeling work, an art used for ornamenting table utensils, swords, 
armour, fitc : this art consisted in cutting or engraving the required design on silver, 
and filling up the incisions with a black composition, said to be made of silver and lead, 
which, from its dark colour, was called by the ancients nigellum, abbreviated by the 
Italians into niello; this mixture, when run into the engraved lines, produced a regular 
effect of chiar-oscuro in the entire work. From these engraved pUtes or objects, the 
artists in ntW/o, who were the goldsmiths and silversmiths of that perod, were accns* 
tomed to take impressions, by smoking the metal, and then, after cleaning the smoo^ 
surface with oil, impressing upon it a piece of damp paper. From such an origiui or 
from some other very similar to it, undoubtedly, came the art of chalcography, or 
plate-printing, and it is equally certain, that the art of engraving with the bmn, or 
as it is now called, " line engraving," arose in the workshops of the gold and 8ilve^ 

The practice of making paper from rags, without which the former art would hare 
proved comparatively useless, had been adopted generally throughout Europe towards 
the end of the fourteenth century, whereby the chief obstacle to printing was remored. 

Not very long after the discovery of plate-printing, the engravers, separating them- 
selves from the manufacturing goldsmiths and chasers, formed thenselves into a dis- 
tinct body, opened schools for pupils, and took up their rightful position among the 
artists of the time. 

Italy and Germany have each contended for the hononr of being the first discoverers 
of the art of printing from engraved plates, but the best authorities give to the former 
country the priority of claim, though the Germans, to whom the printing prew J^ 
earliest known, soon surpassed their rivals, both in that art and in engraving : buttney 
have not always maintained the superiority. 

The principal Italian engravers, contemporary with, or immediately following ^^^J 
guerra, were Baldini, Botticelli, and Andrew Mantegna ; in Germany, the names oi 
Martin Schon, who began his career about the year 1460, and engraved his own com- 
positions, Israel Van Mecheln, Leydenwurf, and Wolgemup, stand prominently forwaw; 
but it was not till the commencement of the sixteenth century, that engraving occupie** 
a high position among the arts of either country. Singularly enough, Italyt GcrmaoT* 


and HoUand, produced each an engraver, whose -works to this day are held in the 
highest estimation ; while Marc Antonio Raimondi (bom at Bologna, in 1488), and 
Albert Dnrcr (bom at Nuremberg, in 1471), were respectively practising the art in 
Italy and Germany, Lucas Van Leyden (bom at Leyden, in 1494) disputed in the 
Low Countries the palm with these distinguished competitors. As these artists have 
ever been considered the patriarchs of engraving, a few words respecting the merits of 
each may not inappropriately be introduced here. 

Travelling to Venice for improvement. Marc Antonio saw there some prints, by 
Albert Durer, of Uie life of the Virgin ; these he copied with tolerable fidelity ; he soon, 
however, quitted Venice, and went to Rome, where he made the acquaintance of 
Raffaelle, a large number of whose works he engraved. ** The purity of his outlines," 
says Bryan, ** the beautiftil character and expression of his heads, and the correct 
drawing of the extremities, establish his merits as a perfect master of design.*' His 
works fi'equently exhibit a deficiency in reflex light and harmonv of chiar-otcuro^ and 
he appears to have been ignorant of the principles of rendering local colour, or tints, 
in the abstract ; neither did he attempt, or else was unable, to express the various 
textures of substances : these are, however, minor defects by comparison, and may 
easily be excused when the state of art generally at that period is taken into account. 
** Raffaelle," says Landseer, ** was Marc Antonio's object ; and the blandishments, the 
splendour, and the variety which would have been indispensably necessary to the 
translation of Gorreggio or Titian, were not called for here." 

Albert Durer, the head of the German school of engraving, laboured under disad- 
vantages with which the artists of Italy had not to contend : the latter had frequently, 
if not constantly, the graceful forms and flowing outlines of antique sculpture made 
fi&miliar to them : and hence their works exhibit, even from the earliest time, much 
greater elegance of manner, and refinement in execution, than those of Germany. 
The engravings by Durer, whom Landseer supposes to be the first who corroded his 
plates with aqua'fortis^ partake largely of the stiff, dry, and gothic manner, peculiar 
to the country and the period, and which to this day is more or less discernible in 
German art If Durer had been so fortunate as to have had the pictures of Raffaelle 
to engrave, he would doubtless have left the world prints of a very different character 
than those we now see : we should have had more grace of expression, and freedom 
of lines, but less originality in the style of execution, and, probably, less vigour. 
Durer engraved only his own designs, and his faults or defects were those of his 
time : but, notwithstanding his Gothic bondage, nothing that has ever appeared in 
more recent periods, surpasses, in executive excellence, his '* St Jerome seated in a 
Room;*' here all the objects are rendered with a fidelity, that only the camera could 
emulate. That very remarkable and mysterious composition known as ** The Death's 
Head,** is also a masterly example of execution : the helmet, with all its pomp of 
heraldic appendage, and the actual and reflex lights on its polished surface, are 
characteristically, though minutely, expressed : the skull is accurately drawn, and 
its bony substance unmistakably described. The head of the Satyr, with its beard 
and wild redundance of snaky tangled hair, has considerable and well-managed 
breadth of light and shade : the drapery of the female, quaiDt as it is in style, is not, 
as we see it in Durer's other works, hard, stiff, and formal, but relaxes into freedom 
and simplicity, and has quite a silky texture ; in fact, it approaches very nearly to 
what we now call " picturesque composition of forms, and light and shade." Dcrer's 
etching appears to have been bitten in, or corroded with the acid, at once. He seems 
either not to have known, or did not care to practise, the process now adopted, of 
" stopping out," for the purpose of producing gradation of shade. The admirable 
wood engravings by this artist are referred to in their proper place. 

The works of Van Leyden, the Dutchman, are even more gothic in taste and style 
than those of Durer, with whom he is said to have been intimately acquainted : they 
exhibit the same amount or degree of stiff, angular drapery; as much, perhaps 
even more, inattention to grace and dignity of form, without his fertile imaginatioa, 
his occasional vigour, and his truthfiil observation of individual nature. His execution 
is neat and clearly defined, but his plates are deficient in firmness and harmonious 
effect, and his lines are without variation in substance ; those that represent near 
objects, and those that express objects at a distance, aro equally fine and delicate ; hence 
the monotony apparent in his prints. They are almost entirely sacred or legendary 
subjects, from his own designs; among the finest are ** The Temptation of St Anthony, 
engraved in 1509, when he was only thirteen years of age; ** The Crucifixion," and 
the ** Adoration of the Magi." 

It would be beyond the province of this notice to record the progress of the art 
through the continental schools till it took root in England; yet a short history of its 
introduction and growth on our soil, may not be considered out of place. 

Until the mid<Ue of the last centtuy, neither painting nor engraving had attained 



any eminence in this coantiy ; the latter art, especially, was practised chiefly by 
foreigners, as Hollar, Simon, Vaillant, Blooteling, &c. ; previously to whom ve had, 
of our own countrymen, Faithorne, an admirable engraver of portraits, Payne, White, 
and one or two others of inferior merit ; but, with the exception of Faithorne, none 
whose works are now held in much esteem. The enconragement afforded by George 
III., almost as soon as he ascended the throne, to the fine arts generally, and the 
establishment of the Royal Academy, which offered to artists a position in the coontrj 
they had never before neld, gave an impulse to every section, or branch, of art pro- 
fessors. Hogarth's name had, however, become widely known many years before : 
his numerous plates, all of them from his own designs, are to this day much sought 
after, not so much, perhaps, for any especial excellence as examples of fine engrav- 
iiigs, as for the talent and genius which the subjects display. ** Hogarth composed 
comedies as much as Moliere," was the remark of Walpole : he died just as art was 
beginning to be recognised and patronised in England. Francis Vivares, a French- 
man by birth, but long settled in England, where he studied the art under Chatelain, 
carried landscape-engraving to a high point of excellence ; some of his prints after 
pictures by Claude and Gaspar Poussin, exhibit remarkable freedom in the foliage 
of the trees, and truth in the texture of the various objects introduced in the 
landscape. WooUett, bom at Maidstone, in Kent, who died in 1785; and Sir 
Robert Strange, a native of one of the Orkney islands, who died in 1792, ad- 
vanced the art still further; indeed, it is a question whether engraving has ever 
found more able exponents than these two disting^hed men : the latter engnrtd 
several portraits, which have rarely been surpass^ at any period in the history of 
art The works of both these engravers are characterised bv bold and Tigorons 
execution, produced by the combined use of the etching-needle and the gimver. 
Cotemporary with these, or their immediate successors, were Browne, who some- 
times worked with WooUett, Bartolozzi, Hall, Booker, Green, Ryland, Watts* Sharp, 
Mc Ardell, Smith, Earlom, &c. ; all aided, by their proficiency, to uphold the booonr 
of the art ; while John Landseer, father of uie living painters, Baimbach, Eng-leheart, 
Pye, and John Burnet, — the last two yet with us, — may be regarded as the chief 
connecting links between the past generation and the present 

Engraving on metal plates may be classed under the following heads: — J^tcAia^, 
line, mezzotintOt chalkt stipple, and aquatint Before describing the processes of work- 
ing these respective kinds, a notice of the instruments used by the engraver is neces- 
sary. These, with some modifications, are employed in all the styles. 

The etching^point, or needle, is a stout piece of steel- wire inserted into a handle ; two 
or three, varying in thickness, are requisite, and they should be frequently and care- 
fully sharpened. This is best done by turning the needle round in the fingers while 
rubbing it on a hone, and afterwards on a leather strop prepared with putty powder, 
or on an ordinary razor-strop, to take off any roughness, and to make it perfectly 

The dry-point is a similar instrument, used for delicate lines: it must be sharpened 
on the hone till a fine conical point is obtained. 

The graver, or burin, is the principal instrument employed in engraving : several 
are required, differing from each other in form, from, the extreme lozenge shape to the 
sqmire; the former being used for cutting fine lines, the latter for broad: the grsTer 
fits into a handle about five inches and a half long, and it should be well-tempered 
before using, an operation requiring great care. The angle at the meeting of the two 
lower sides is called the belly, and the breadth of the end, the face. To sharpen the 
former, lay one of the flat sides of the graver on the oilstone, keeping the right arm 
tolerably close to the side, and rub it firmly; next rub the other in the same way: 
the face is sharpened by holding it firmly in the hand, with the belly upwards, in a 
slanting direction ; rub the end rather gently on the stone, at an angle of about forty- 
five degrees, taking care to carry it evenly along until it acquires a very sharp pciint: 
this being done, hold the engraver a little more upright to square the point, which a 
Tery few rubbings will effect The graver for line work must be slightly turned up, 
to enable the engraver to run it along the plate ; otherwise the first indentation be 
makes on the metal would cause his instrument to become fixed : the graver for 
stipple should be slightly turned down, to make dots only. 

The scraper, which should have three fluted sides, is used for taking off the fricrr 
left by the action of the needles on the metal. 

The burnisher is employed to soften lines that have been bitten in, or engraved too 
dark, and to polish the plate, or get rid of any scratches it may accidentally have 

The dabber used to lay the etching -ground evenly, is made by enclosing a small 
quantity of fine cotton wool very tightly in a piece of silk, the threads of which 
should be, as much as possible, of uniform thickness. 


There are a few other materials which an engraver should have at hand, bat they 
are not of sufficient importance to be mentioned here ; ire may, however, point out 
what is technically called a bridge, which is nothing more than a thin board for the 
hand to rest on ; it should be smoothly planed, and of a length and breadth in pro- 
porti<m to the sise of the plate; at each end a small piece of wood should be fastened 
to raise it above the plate when covered with wax. A blind, made of tissue-paper 
stretched upon a frame, ought to be placed between the plate and the light, to enable 
the engraver to see his work on the metal with greater facility and clearness. 

In describing the processes of engraving the various styles enumerated above, little 
more tiian a general outline of each method can be given, yet sufficient, it may be 
presmned, to show the nature of the operation : to narrate all the details that might 
be included in the subject would supply matter enough for a small volume. 

EicluRg may be claned under two heads ; that which is made the initiatory process 
in line-engraving, and that which is known as painUr^a-eteking ; the latter was prac- 
tised to some extent by very many of the old painters, particularly those of the 
Dutch school ; and it has also recently come into fashion with many of the artists of 
our own day, but more for amusement, however, than for any other purpose ; in 
both cases the method of proceeding is alike. Etching is the result of a chemical 
process resulting in corrosion of the metal on which the design has been laid down, 
or transferred, in the following manner. The plate must first be covered with a sub- 
stance already spoken of as etching- ground, which may be purchased of most of the 
inincipal artists' oolourmen, but many engravers niake their own : the annexed 
receipt has been handed to us by Mr. C. W. Sharpe, who has engraved some (^ the 
largest steel-plates published recently, as that which he always uses : — 

Black pitch 1 

White wax 1 

Burgundy pitch --------f 

Asphaltum ---------i 

Gum mastic ---------i 

Melt the first three ingredients over a slow fire in a pipkin, then add the other two 
finely powdered, stirring the whole together all the time ; when well mixed, pour it 
into warm water, and nuike it up, while warm, into balls ; if too soft, a little less wax 
should be used. Care must be ta^en not to let the mixture bum during the process 
of making. 

The etching-ground resists the action of the aqua-fortis. It should be tied up in a 
piece of strong silk, and applied thus, which is called laying the ground : — Take the 
plate firmly in a small hand vice ; hold it, with the polished face upwards, over a 
eharooal fire that it may not get smoked, till it is well, but not too much, heated : rub 
the etching-ground, in the silk, over the plate till it is evenly covered ; the wax, 
melting with the heat, oozes through the silk. To effect a more equal distribution 
of the ground, take the dabber and £eib the plate gently all over, till it appears of an 
uniform colour ; continue the dabbing till the plate begins to cool, but not longer. 
The ground is Uien blackened by being held over the smoke of a candle, or two or 
three tied together, — wax is fbr preferable to tallow ; keep the plate in motion, so 
that every part be made equally dark, and also to avoid ii^ury, by burning, to the 
composition ; when cold the plate is ready to receive the design. To transfer this, a 
very correct ontline of the subject is made with a black-lead pencil on a piece of thin 
hard paper: ihsten the tracing, or drawing, at the top edge, with its face downwards, 
on to the etching-ground, with a piece of banking-wax, described hereafter, and by 
passing it through a printing-press — such as is used by plate printers, to whom it 
should be taken — the drawing is transferred to the ground. The bridge being laid 
over the plate, the process of etching may now be commenced ; the points, or needles, 
which are used to complete the design, remove the ground from the metal wherever 
they pass, and expose Uie latter to the action of the acid during the process of what 
is termed biting m. The needles with the most tapering points should be used for the 
skies and distances, changing them for others for the foreground, which generally re- 
qaires broader and deeper lines. Any error that has been made may be remedied by 
covering the part evenly with the etching-ground mollified by spirits of turpentine, 
using a camel's-hidr pencil for the purpose ; and, when dry, the lines may be re- 
etched through it 

The next operation is that of biting in, performed thus : — A wall or border of bank- 
ing' weue is put round the edge of the plate : this wax, called sometimes bordering wax, 
is made by melting over a slow fire, in a glazed pot, two parts of Burgundy pitch, and 
one of bees- wax, to which is added when melted, a gill of sweet oil ; when cold it is 
quite hard, but by immersion in warm water it becomes soft and ductile, and must be 


applied in kids state ; it will adhere to the metal hj being firmlj- prened down with 
the hand : the object in thus banking up the plate is to prevent the escape of the 
acid which is to be applied ; but a spout or gutter must be left at one comer to poor 
off the liquid when necessary. Mr. Fielding, — to whose work on the art of engraTing 
we are indebted for some of the practical hints here adduced, availing ourselves, 
however, of the improvements introduced into modem practice, — recommends the 
following mixture as the best :^ " Procure some strong nitrous acid, and then mix, in 
a wide mouthed bottle one part of the acid, with five parts of water, adding to it a 
small quantity of sal ammoniac, in the proportion of the size of a hazel-nut to one 
pint of acid, when mixed for biting. The advantage of using the sal ammoniac is, 
that it has the peculiar property of causing the aqua fortistobite more directly down- 
wards, and less laterally, by which means lines laid very closely together are less 
liable to run into each other, nor does the ground so readily break up.** When the 
mixture is cool — for the acid becomes warm when first mixed with water — poar it 
on the plate, and let it continue there till the more delicate lines are presumed to be 
corroded to a sufficient depth ; this will probably be in about a quarter of an hour ; 
sweep off the bubbles as they appear on the plate with a camel's-hair pencil, or a 
feather ; then pour off the acid through the gutter at the comer, wash the plate with 
warm water, and leave it to dry. Next, cover those parts which are sufficiently 
bitten in with Brunswick black, applying it with a camelVhair pencil, and leave it to 
dry ; again put on the acid, and let it remain twenty minutes or half an hoar, to give 
the next degree of depth required ; and repeat this process of stopping out and Inting 
«n, until the requisite depths are all attained : three bitings are generally enough for a 
painters etching. The work is now complete, unless the graver is to be used upon it, 
and the banking- wax may be removed, by slightly warming the margin of the plate ; 
and, finally, wash the latter with a soft rag dipped in spirits of turpentine, and 
rubbing it with olive oiL If, when the plate is cleaned, the engraver finds that the 
acid has acted as he wishes, he has secured what is technically termed ** a good 

Steel plates require another method of biting-in, on account of their extreme hard- 
ness, and liability to rust ; the mode just described is applicable only to copper, 
the metal generally used by painters for their etchings. For steel plates mix 

Pyroligneous acid -------i 

Nitric acid ---------i 

Water 3 

This mixture should not be allowed to remain on above a minute ; let it be washed 
off at once, and never use the same water twice ; the plate must be set up on its edge, 
and dried as quickly as possible to avoid mst : the acid may be strengthened where 
a stronger tint is required. 

debiting, a process frequently adopted to increase the depth of tint where it is re- 
quired, or to repair any portion of a plate that has been worn by printing or acci- 
dentally injured, is thus performed. The plate must be thoroughly cleaned, all traces 
of grease removed, by washing it with spirits of turpentine and potass, and polished 
with whitening; it is then, when warmed over a charcoal fire or with lighted 
paper, ready for receiving the ground; this is laid by using a dabber charged with 
etching-ground, and carefully dabbing the surface ; by this means the surface of the 
plate only is covered, and the lines already engraved are left clear ; any part of the 
plate that it may not be necessary to rebite, must be stopped out with Brunswick black, 
and then the acid may be poured over the whole, as in the first process. 

Etching on soft ground is a style of engraving formerly much practised in imitation 
of chalk or pencil drawings ; since the introduction of lithography, however, it has 
been entirely abandoned. The soft ground is made by adding one part of hog^s lard 
to three parts of common, or hard, etching-ground, unless the weather be very warm, 
when a smaller quantity of lard will suffice ; it should be laid on and smoked in the 
manner already described. Mr. Fielding gives the following method for working on 
it. ** Draw the outline of your subject faintly on a piece of smooth thin writing 
paper, which must be at least an inch larger every way than the plate ; then damp it, 
and spread it cautiously on the ground, and turning the edges over, paste down to the 
back of the plate ; in a few hours the paper will ^ dry, and stretched quite smooth. 
Kesting your hand on the bridge, take an H or HB pencil, and draw your subject on 
the paper exactly as you wish it to be, pressing strongly for the darker touches, and 
more lightly for the delicate parts, and, accordingly as you find the ground more or 
less soft, which depends on the heat of the weather or the room you work in, use a 
softer or harder pencil, remembering always that the softer the ground the softer the 


pencil " (should be), ** When the drawing is finished, lift up the paper earefoU j fh>m 
the pbte, and wherever yon have touched with the pencil, the ground will stick to 
the paper, leaving the copper more or less exposed. A wail is then put round the 
margin, the plate hit in, and if too feehle, rebit in the same way as a common etching, 
using Aorc/ etchmg-ground for the rebite." 

jMe emgraving unquestionably occupies the highest place in the category of the art \ 
and, taking it as a whole, it is the most suitable for representing the various objects 
that constitute a picture. The soft, pulpy, and luminous character of flesh ; the rigid, 
hard, and metallic character of armour ; the graceful folds and undulations of draperies, 
the twittering, unsteady, and luxuriant foliage of trees, with the bright yet deep-toned 
colour of skies, have by this mode, when practised by the best engravers, been more 
suoceasfhlly rendered than by any other. The process of line-engraving is, first, to 
etch the plate in the manner already described, and ^^rwards to finish it with the 
graver and dry point. An emfraver'a etching differs from a painter*$ etching in that 
erery part of Uie work has an unfinished appearance, though many engravers, espe- 
cially of landscapes, carry their etchings so fbr as to make them very effective : 
engravers ot historical and other figure subjects, generally, do little more than etch 
the outlines, and the broad shadowed masses, or colours, of the draperies ; the flesh 
being entirely woi^cd in with the burin, or graver : no definite rules can be laid 
down as to the extent to which the etching should be advanced ere the work of the 
tool conunences, as scarcely two engravers adopt the same plan precisely: much 
must always depend on the nature of the subject Neither would it be possible to 
point out in what particular way the graver should be used in the representation of 
any pardcular object : this can only be learned in the studio of the master, or by 
Btuidying the works of the best engravers : as a rule it may be simply stated, that in 
making the incision, or line, the graver is pushed forward in the direction required, 
and should be heU by the handle, at an angle very slightly inclined to the plane of the 
steel or copper plate : the action of the graver is to cut the metal clean out. 

Within the last few years an instrument, called a ruling nuichine, has been brought 
into nse for laying in flat tints in skies, buildings, and objects requiring straight, or 
slightly curved lines : considerable time is saved to the artist by its use, and more 
even tmts are produced than the most skilful hand-work, generally, is able to effect ; 
bat to counterbalance these advantages, freedom is frequently sacrificed, and in 
printing a large number of impressions, the machine>work, unless very skilfully 
ruled in, is apt to wear, or to become clogged with ink, sooner than that which is 

Mezzotinta engroiring is generally supposed to owe its origin to Colonel Ludwig von 
Siegen, an officer in the service of the Landgrave of Hesse; there is extant a portrait 
by him, in this style, of Amelia, princess of Hesse, dated 1643. Yon Siegen is said 
to have communicated his invention to Prince Rupert, to whom many writers have 
assigned the credit of originating it : there are several plates executed by the Prince 
still in existence. It differs from every other style o( engraving, both in execution 
and in the appearance of the impression which the plate yields : a mezzotint engraving 
resembles a drawing done in washes of colour, by means of a camelVhair pencil, 
rather than a work executed with any sharp pointed instrument : but a pure mezzo- 
tint engraving is rarely produced in the present day, even for portraits ; the advan- 
tages derived from combining line and stipple, of which we shall speak presently, 
with it, to express the different kinds of texture in objects, have been rendered so 
obvious as almost to make them necessary : this combination is termed the mixed 
styU. The distinguishing excellences of mezzotint are the rich depth of its shadows, 
an exquisite softness, and the harmonious blending of light and shade : on the other 
hand, its great defect is the extreme coldness of the high lights, especially where they 
oeeur in broad masses. 

The instruments used for this kind of work are, Inamishers, scrapers, shading too/s^ 
roulettes, and a cradle, or rocking tool. The burnisher and scraper differ in form from 
those already described : the roulette is used to darken any part which may have been 
scraped away too much ; it ought to be of different sizes : the cradle is of the same 
form as the shading tool, and is used for the purpose of laying grounds. 

The operation of engraving in mezzotint is precisely the opposite of that adopted 
in all other styles : the processes in the latter are from light to dark, in the former 
ftom dark to light, and is thus effected. A plate of steel or copper is indented all over 
its face by the cradle, an iostrument which somewhat resembles a chisel with a toothed 
or serrated edge, by which a burr is raised on every part in such quantities that if 
filled in with ink, and printed, the impression would exhibit a uniform mass of deep 
bbkck : this operation is called laging the ground; it is performed by rocking the cradle 
to and fro, and the directions, or ways, as the engravers call them, are determined by 
a plan, or scale, that enables the engraver to pass over the plate in almost any number 


of direcUons without repeating any one ef them. When an outline of the sulgect 
has been first etched in the ordinary way before the ground is laid, the engraver pro- 
ceeds to scrape away, and then burnish the highest lights, after which the next lightest 
parts are similarly treated, and the process is repeated after this manner till the work 
is finished ; the deepest shades are produced from the ground that is left untouched. 
There is, however, no style of engraving for the execution of which it is so diffiealt 
to lay down any definite rules, for almost every engraver has his own method of 

Chalk or gtipple engraving, for the terms are synonymous, is extremely simple. 
The plate has first to be covered with the etching ground, and the subject transferred 
to it in the ordinary way : the outline is then laid in by means of small dots made 
with the stipple graver ; all the darker parts are afterwards etched in dots lai^er and 
laid closer together. The work is then bitten in vrith the acid; and the ground being 
taken off, the stipple graver must again be taken up to complete the operation ; the 
light parts and the dark are respectively produced by small and large dots laid id 
more or less closely together. Stipple is well adapted for, and is often used in, the 
representation of flesh, when all the other parts of the subject are executed in line: 
hence it is very frequently employed in portraiture, and in engravings from sculpture. 
Chalk engraving is simply the imitation of drawings in chalk, and is executed like stipple, 
only that the dots are made with less regularity, and less uniformity of size ; in the 
present day, the two terms are generally considered as expressing the same kind of 

Aquatint engraving^ which represents a drawing in Indian-ink or bistre even more 
than does mezzotint, has been almost entirely superseded by lithography, and still 
more recently by chromo-lithography ; and there seems little probability that it will 
ever come into fashion again. This being the case, and as any detailed description 
of the mode of working would, to be of any service, occupy a very considerable space, 
it will, doubtless, be deemed sufficient to give only a brief outline of its character and 
of the mode of operation ; this we abbreviate from the notice of Mr. Fielding, for- 
merly one of our most able engravers in aquatint. The process consists in pouring 
over a highly polished copper plate a liquid composed of resinous gum, dissolved in 
spirits of wine, which latter, evaporating, leaves the resin spread all over the plate in 
minute grains that resist the action of the aquafortis, which, however, corrodes the bare 
surface of the copper that is left between them : this granulated surface is called a gromd. 
The ground having been obtained, the margin of the plate should be varnished over, 
or stopped out, and, when dry, the subject to be aquatinted must be transferred to the 
plate, either by tracing or drawing with a soft black4ead pencil, which may be used 
on the ffround with nearly the same facility as paper; if the former method be adopted 
the tracmg must be carefully fastened down to the copper by bits of wax along the 
upper edge. A piece of thin paper, covered on one side with lamp-black and sweet 
oil, is placed between the tracing and the ground, with the coloured side downwards, 
and every line of the subject must be passed over with the tracing point, using a 
moderate pressure. The tracing being finished and the paper removed, a wall of 
prepared wax, about three quarters of an inch high, must be put round the plate, 
with a large spout at one comer, to allow of the acid running off. 

The plate is now ready for use ; and the completion of the design is commenced by 
stopping out the highest lights on the edges of clouds, water, &c., with a mixture of 
oxide of bismuth and turpentine varnish, diluting it with spirits of turpentine till of a 
proper consistence to work freely. Next pour on the acid, composed of one part of 
strong nitrous acid and five parts of water ; let it remain, according to its strength, 
from half a minute to a minute, then let it run off, wash the plate two or three times 
with clean water, and dry it carefully with a linen cloth. This process of stopping 
out and biting in is continued till the work is complete ; each time the aquafortis is 
applied a fresh tint is produced, and as each part successively becomes dark enough 
it is stopped out; in this manner a plate is often finished with one ground bitten in 
ten or twelve times. We would recommend those who may desire to become thoroughly 
acquainted with this very interesting yet difficult mode of engraving to consult Field- 
ing's Art of Engraving, 

A few remarks explanatory of the method of printing steel or copper plates seem to be 
inseparable from the subject. The press used for the purpose consists of two cylinders 
or rollers of wood, supported in a strong wooden fhune, and movable at their axes. 
One of these rollers is placed just above, and the other immediately below, the plane 
or table upon which the plate to be printed is laid. The upper roller is turned round by 
means of cogged wheels fixed to its axis. The plate being inked by a printer^s inking- 
roller, an operation requiring great care, the paper which is intended to receive the 
impression is placed upon it, and covered with two or three folds of soft woollen stnff 


like blanketing. These are moved along the table to the spot where the two rollers 
meet ; and the npper one being turned by the handle fixed to the fiy-wbeel, the plate 
passes throagh it, conTeying die impression as it moves ; the print is then taken off 
the plate, which has to undergo the same process of inking for the next and every 
sDCceeding impression. The jfrcoft of an engraved plate are always taken by the 
most skilfal workmen in a printing establishment ; in the principal houses there are 
generally employed from two to six men, according to the amount of bnsiness trans- 
acted, whose duty it is to print proof impressions only; they are called prooers* A care- 
ful, steady workman is not able to print more than Arom 180 to 300 good ordinary 
impresnonsirom a plate, the subject of which occupies about seven inches by ten inches, 
even in what is considered a long day's work, that is, about fourteen hours ; the prover^ 
from the extreme care required in inking the plate, and from the extra time occupied in 
wiping it, and preparing the India-paper, will do from thirty to forty, according as the 
subject of the plate is light or heavy. This difference in the cost of production, taking 
also Into account that &e proofs are worked off before the plate has become worn, 
even in the least degree, and that very few proofs, compared with the ordinary prints, 
are generally struck off, is the reason why they are sold at a price so much greater than 
the latter. 

Notwithstanding the vast multiplication of engravings within the last few years, it 
is generally admitted, by those best acquainted with the present state of the art, that 
it is not in a healthy condition. The highest class of pictorial subjects — ^history, and 
the highest style of engraving — line, have given place to subjects of less exalted cha- 
racter, and to a mixed style of work, which, however effective for its especial purpose, 
is not pure art. The pictures by Sir R Landseer have gained for engravings of such 
subjects a popularity that has driven almost everything else out of the field, and have 
created a taste in the public which is scarcely a matter of national congratulation. We 
have engravers in the country capable of executing works equal to whatever has been 
piYNinced elsewhere at any time, but their talents are not called into requisition in such a 
way as to exhibit the art of engraving in its highest qualities. Publishers are not 
willing to risk their capital on works which the public cannot appreciate, and hence 
their windows are filled with prints, the subjects of which, however pleasing and 
popular, are not of a kind to elevate the taste ; while the conditions under which en- 
gravers generally are compelled to work, offer but little inducement for the exercise 
of the powers at their command. Engraving on copper is in the present day but rarely 
attempted ; formerly nothing else was thought of ; now the demand for engraving is 
so great that copper, even aided by the electrotype, is insufficient to meet its require- 
ments. In consequence of the comparatively small number of impressions which it 
yields, a copper-plate will seldom produce more than .liOO or 600 good prints ; we have 
known a steel, with occasionally retouching, produce more than 30,000, when well 
engraved, and carefully printed ; very much depends on the printer, both with regard 
to the excellence of the impression and the durability of the plate. The public demand 
18 for prints both large and cheap, and to obtain this result, the engraver is too often 
obliged to sacrifice those qualities of his art which under other circumstances his work 
would exhibit Such is the state of engraving with us now. There are few, even of 
the best artists we have, who by their utmost efforts can earn an income equal to 
that of a tradesman in a small but respectable way of business. This is an evil to be 
deplored, for it assists to deteriorate the art by forcing the engraver to labour hard for 
a maintenance, instead of placing him in a position that would enable him to exalt the 
art and his own reputation at the same time. 

A process of depositing steel upon an engraved copper-plate has recently been brought 
over to this country from France. M. Joubert, a French engraver long settled in 
England, has introduced it here ; he has informed us that a copper-plate iSbus covered 
may be made to yield almost any number of impressions, for as the steel coating be- 
comes worn it can be entirely taken off, and a new deposit laid on without injury to the 
engraving, and this ma^ be done several times; M. Joubert has repeated the experi- 
ment with the most satisfactory results. He thus describes his process in a commu- 
nication made to the Society of Arts, and printed in their journal : — 

**' If the two wires of a galvanic battery be plunged separately into a solution of 
iron, having ammonia for its basis, the wire of the positive pole is immediately acted 
upon, while that of the negative pole receives a deposit of the metal of the solution — 
this is the principle of the process which we have named '* acierage.'* 

** The operation takes place in this way : — By placing at the positive pole a plate or 
sheet of iron, and immersing it in a proper iron solution, the metal will be dissolved 
under the action of the battery, and will form an hydrochlorate of iron, which, being 
combined wilh the hydrochlorate of ammonia of the solution, will become a bichlo- 
ride of ammonia and iron; on a copper plate being placed at the opposite pole and 


likewise immersed, if the solatioD be properly satarated, a deposit ot iron, bright and 
perfectly smooth, is thrown upon the copper^plate, from this principle : — 

" Water being composed of hydrogen and oxygen : 

" Sal ammoniac being composed of : — 

" 1st. Hydrochloric acid containing chlorine and hydrogen ; 

** 2nd. Ammonia, containing hydrogen, nitrogen, and oxygen : 

" The water is decomposed under the galvanic action, and the oxygen fixes itself 
on the iron plate, forming an oxide of iron ; the acid hydrochloric of the soliition 
acting upon this oxide becomes a hydrochlorate of iron, whilst the hydrogen preci- 
pitates itself upon the plate of the negative pole, and, unable to combine with it, comes 
up to the surface of the solution in bubbles. 

** My invention has for its object certain means of preparing printing sorfaees, 
whether for intaglio or surface printing, so as to give them the property of yielding 
a considerably greater number of impressions than they are capable of doing in their 
ordinary or natural state. And the invention consists in covering the printing sur- 
faces, whether intaglio or relief, and whether of copper or other soft metal, with a 
very thin and uniform coating of iron, by means of electro-metallurgical processes 
And the invention is applicable whether the device to be printed from be produced by 
engraving by hand, or by machinery, or by chemical means, and whether the snr^ 
face printed fh>ra be the original, or an electrotype surface produced therefrom. I 
would remark that I am aware that it has been before proposed to coat type and 
stereotypics with a coating of copper, to enable their surfaces to print a larger number 
of impressions than they otherwise would do ; I therefore lay no claim to the general 
application of a coating of harder metal on to the surface of a softer one, but my 
claim to invention is confined to the application of a coating of iron by means of 
electricity on to copper and other metallic printing surfaces. 

" In carrying out the invention I prefer to use that modification of Grove's battery 
known as Bunsen*s, and I do so because it is desirable to have what is called an in- 
tensity arrangement The trough I use for containing the solution of iron in which 
the engraved printing surface is to be immersed in order to be coated is, lined with 
gutta percha, and it is 45 inches long, 22 inches wide, and 32 inches deep. In pro- 
ceeding to prepare for work, the trough, whether of the size above mentioned or 
otherwise, is filled with water in combination with hydrochlorate of ammonia (sal 
ammoniac) in the proportion of one thousand lbs. by weight of water to one hundred 
lbs. of hydrochlorate of ammonia. A plate of sheet iron, nearly as long and as deep 
as the trough, is attached to the positive pole of the battery and immersed in the sola- 
tion. Another plate of sheet iron, about half the size of the other, is attached to the 
negative pole of the battery, and immersed in the solution, and when the solution has 
arrived at the proper condition, which will require several days, the plate of iron 
attached to the negative pole is removed, and the printing surface to be coated is at* 
tached to such pole, and then immersed in the bath till the required coating of iron is 
obtained thereto. If, on immersing the copper plate in the solution, it be not im- 
mediately coated with a bright coating of iron all over, the bath is not in a proper 
condition, and the copper plate is to be removed and the iron plate attached and 
returned into the solution. The time occupied in obtaining a proper coating of iron 
to a printing surface varies from a variety of causes, but a workman after some ex- 
perience and by careful attention will readily know when to remove the plate from 
the solution ; and it is desirable to state that a copper plate should not be allowed to 
remain in the bath and attached to the negative pole of the battery after the bright 
coating of iron begins to show a blackish appearance at the edges. Immediately on 
taking a copper plate from the bath ^eat care is to be observed in washing off the 
solution from all parts, and this I beheve may be most conveniently done by causing 
jets of water forcibly to strike against all parts of the surface. The plate is then 
dried and washed with spirits of turpentine, when it is ready for being printed fh»m 
in the ordinary manner. 

** If an engraved copper plate be prepared by this process, instead of a comparatively 
limited number of impressions being obtained and the plate wearing out gradually, a 
very large number can be printed off without any sign of wear in £e plate, the iron 
coating protecting it effectually ; the operation of coating can be repeated as many 
times as required, so that almost an unlimited number of impressions can be obtained 
ft'om one plate, and that a copper one. 

*' This process will be found extremely valuable with regard to electrotype plates 
and also for photogalvanic plates, since they can be so protected as to acquire the 
durability of steel, and more so, for a steel plate will require repairing from time to 
time, these will not, but simply recoating them whenever it is found necessary ; by 
these means one electro copper plate has yielded more than 12,000 impressions, and 
was found quite unimpaired when examined minutely." — J, D. 


ENGRAVING ON WOOD. The art of wood engraving is so intimately con- 
nected with that of book-printing, that it is impossible to disseTer the one from the other, 
inasmuch as the earliest books were printed from large woodcuts, the entire page, 
text, and illustrations being engrared in one solid block. Hence the term " block- 
books " given to these ancient works. The impression flrom these engraved pages is 
generally taken in a thin ink, sometimes of a brown hue, which occasionally spreads 
or blots on the lines or letters ; and the printing is generally supposed to have been 
effected by friction on the back of the damped paper laid on the inked lines ; the 
sheets so printed were afterwards pasted back to back, and thus formed consecutive 
pages of the volume. Such books originated from the large wood-cuts of a devotional 
cUus, which, in the early part of the 1 5th century, were spread by the clergy among 
the common people, perhaps to counteract the evil produced by the use of playing 
cards, which were also printed in large sheets of cuts, and severed afterwards; but on 
this point typographical antiquaries are not agreed, ss dates and other evidence are 
wanting to enable us to fix either time, or place, to these early productions. The 
earliest wood-cut bearing a date is that belonging to Earl Spencer, and representing 
Su Christopher carrying the Saviour across an arm of the sea; it has two lines of 
text beneath it, and the date 1423 thus expressed *'millesimo cccc^ xx° tercio."* 
The British Museum is possessed of some very early single-leaf wood- cuts: one repre* 
senting Christ brought before Pilate, is executed in bold coarse outline, the figures 
are very large, and retain the characteristic features of the drawings seen in manu- 
scripts of the 14th century. Another undated cut is one of those fanciful inventions 
-which the scholastic men of that early day delighted in constructing; it is termed 
TurriM Sapiencit, every stone of which is inscribed with the name of some moral 
virtue, the foundation buttresses being prudence, fortitude, justice, and temperance; 
the windows which give it internal light being discretion, religion, devotion, and con- 
templation. Another representing the seven nges of man, is supposed to be a work 
of the middle of the 15th century. It was found pasted inside the covers of an old 
book, a practice which has preserved many specimens of old engraving which would 
else have been lost. On the opposite cover is a fragment of another large cut, repre- 
senting the Virgin with St. Joachim and St. Anne. The St Christopher above named 
was ducovered in the cover of a volume in the conventual library at Buxheim, in 
Suabia. All these old wood-cuts, as well as the block books, are generally daubed 
with flat tints of coarse colour, supposed to have been done with stencil plates, such 
as the card painters used on some occasions; but evidently rudely executed by hand 
in others. They are all precisely of the kind to attract the uneducated eye ; and to 
this day similar coarse prints are used by the clergy to aid the devotions of the 
peasants of the Germanic nations. 

The most celebrated of the block books is that termed the BihUa Pauperum. Each 
page is divided by architectural compartments into three subjects, from the Old and 
New Testament, selected to form ** parallel passages " of sacred writ ; above and below 
are other compartments with heads of the prophets, and in the intervening spaces, 
or upon scrolls, are explanatory inscriptions. The page measures 10 inches by 7^, 
and IS one of the most elaborate works of its class ; but it exhibits very small claims 
to attention as a specimen of art, certainly less than the Cantica Canticorum, each page 
of which is divided horizontally into two pictures, with slight descriptive lines on 
scrolls ; or the Apoccth/psis SancU Johannes, which is similarly arranged, and in both 
of which we occasionally find much power of drawing and ability of grouping. The 
dates of these books can only be conjecturally given, but they are probably contem- 
porary with the St Christopher, or but a few years later. Judging from general 
characteristics the Apocalypte seems to be the earliest The figures are executed 
entirely in outline, with no attempt at shadows, which appear sparingly on the St 
Christopher, and are very freely introduced in the Canticles^ and still more abundantly 
in the Biblia Pauperum, These effects are always produced by a series of short lines 
laid parallel to each other, nor is any attempt made to enrich the meagre character of 
the work by crossing the lines, as in more modem engraving. The debate, which has 
excited so many historians as to the place where printing first had birth, hss included 
many doubts concerning the country where these old block-books were fabricated ; 
but from the armorial bearings which appear on the shields of some figures in the 
Cantidesj Germany seems to be the country where that series was designed f; probably 

* Voeh interest was excited some few years ago by the diacotery of a cut in the llbrniy at Brusseli ap- 
parently tiearing ao earlier date ; but strict InvestigRtion has since proved that one of the C's In the date 
nas been omitted ; this mali^ just one hundred years difTerence in its age. But the date thus altered is 
quite in accordance with the general character of the design and execution of the cut, which, on the 
contrary, do not at ali jwreo with the earlier date originally as&lRned to it. 

t Among them is the doable.headed eagle of Austria, the blade eagle of GermanT, the three crowns 
of Cologne, the cross-keys of Eatisl)on, the arms of Wurtemberg, Nymphenburg, and Alsace. 


Flanders or Holland may daim the BibliaPawpenm^ which does not bear equal traces of 
refinement in art. The Speculum Humana Salvationu has been claimed for Laurence 
Coster of Haarlem. Tbis book was a combination of block-book and movable type, 
liaying long cuts across the top of each page, divided by columns into two sabje^ 
with moveable types beneath. It is not unosaal to meet with woodcut pages of type 
alone at this period; and books with such pages, or with the addition of wood cats, 
were produced by the old engravers after the invention of movable types ; bat, as 
metal-cast letters speedily usurped the place of the wooden ones, the wood engravexs 
seem to have soon confined themselves to the pictorial branch of the art 

The love of pictured illustrations of narrative history gave a permanence to the 
art of wood engraving, and the works printed in Italy, as well as those introdnoed 
into Eneland by Caxton, were adorned with cuts. They are* however, of the 
rudest kmd, with broad heayy lines, and were most probably produced from coarse 
pen drawings made on the surface of the wood, and mechanically cut by the engraver. 
Toward the close of the fifteenth century ** cross hatching " (as lines of shadow cross- 
ing each other are technically termed) is first seen, and in the Nurembnrg Chronicle, 
1493, they are freely used. The designers and engravers of these outs, perceiving 
the effect, which may be so readily obtained in wood engraving, by leaving the wood 
untouched with the graver for solid masses of shadow, have availed themselves of it, 
and given stronger effect to their cuts thereby. Michael Wohlgemuth and William 
Pleydenwurff were the designers employed; the former artist was the master of 
Albert Durer, who ultimately raised wood engraving to the highest point of ex- 

Durer's first great work was a series of sixteen large cuts illustrative of the 
Apocalypse. They were published in 1498, and attracted great attention from the 
vigour and strange originality of their design, and the artistic character of their treat- 
ment In 1511 another series of cuts was published at Nuremberg by Durer, 
illustrative of the Apocryphal Life of the Virgin. They evidence the great improve- 
ment which the artist had made during the interval, and are certainly the finest wood 
cuts which had ever been executed up to that period ; but they are eclipsed by the 
series of eleven large cuts published soon after, representing scenes in the Passion of 
Christ ; and which may be fairly considered triumphs of the art of wood-engraving, 
unsurpassed in design and execution by any successors. The art had now become 
appreciated wherever it was known, and a host of wood engravers found employ in 
Nuremberg, cutting the designs of Darer, Hans Burgmair, Hans Schanfelein, and 
other artists ; who found no lack of patronage in the old imperial city, for the EUnpe- 
ror Maximilian I., extensively employed them in various works illustrative of his real 
or fancied exploits.* 

So important was this royal patronage, that the engravers set no bounds to the sise 
of the works they attempted, and hit upon the plan of joining one block of wood to 
another, until in the engraving representing the triumphal arch in honour of this 
emperor, a wood-cut was completed in this way, measuring ten feet hj nine. The 
size is, however, not its only claim to attention, for it is throughout designed and en- 
graved with the utmost care and beauty. 

In all these cuts of the great masters of the art of wood-engraving, we only find the 
name of the designer recorded ; thus, Durer, and others of his era, whose names 
occur on cuts, were the designers and draughtsmen on the wood ; but the engraver 
was considered in the light of a mechanician, and, except in a very few instances, his 
name was not displayed. To fully understand this, it is necessary here to explain the 
whole process of wood engraving at this time. A block of wood being prepared 
from a perpendicular catting of pear-tree* upon the surface was made a drawing, in 
which every line was delineated with pencil or reed-pen, exactly as the cat was 
ultimately to appear ; the intervening spaces of plain wood between every line were 
then cut away ; and in this manual dexterity consisted the whole merit of the engraver. 
The abundance of cross-hatching so constantly found in old wood cuts, is explained 
by the fact of this being the easiest and best mode for the draughtsman to employ in 
getting his effects of light and shade ; the extreme labour it involves to the engraver 
not bemg considered ; but when it is understood that each minute space has to be cut 
down from each angle of the lines, and the centre entirely cleared out, some idea may 
be formed of the labour required, when thousands of such squares occur on some of 
Durer*s large cuts, independent of other work. The backs of some of these old blocks, 
particularly those in the Triumphs of Maximilian, are marked with the names of the 
engravers, and there is proof that women practised the art ; but it is not at all likely 

* Such were the Adventures of the Knight Thuerdank, under which form the emperor was figured ; 
** The Wtoe King," an equally flatt(>rinR picture of hit early education and actlont ; and the magnifiocot 
•eriea of cuta, known m ** The Triumphs of Maximilian." 


that the artists who designed* and drew upon the wood these de8ig:ns, went through 
the merely mechanical labour of engraving them. 

The great impetus thus given to wood engraving*, kept it prominently before the 
world during the whole of the sixteenth century, when the presses of the continent 
continually brought forth a series of volumes remarkable for the beauty of the cuts 
by which they were illustrated. This practice of the book-trade gave rise to a 
series of artists known as " the little masters " of the German school, fh>m the small 
size of their works; among whom the principal who connected themselves with 
engrsTing on wood were Virgil Solis, Henry Aldegraver, the two Bebaims, Lucas 
Cranach, Urse Graff, Albert Altdorffer, Jost Ammon, and Solomon Bernard. 

In Italy, Ugo da Carpi practised with success, from the year 1518, the art of en- 
graving on wood imitations of tinted drawings ; an art which originated with the 
Germans, but which he much enlarged and improved. It consisted in a series of blocks 
cut to imita^ patches of colour, and made to print over each other in gradations of 
tint, until the chiaroscuro of a drawing was secured ; then the coarser and bolder 
lines defining the whole design were printed oyer all, and a capital imitaUon effected 
of the bold cartoons, consisting of vivid outline and broad washes of tint, used as first 
sketches for their pictures and frescoes by the artists of that enL 

A perfect rage for book illustration seems to have beset the printers soon after the 
death of Durer. The most prolific artists who supplied their wants, were Jost Ammon 
and Solomon Bernard : the foi mer executed a multitude of designs on every imagina- 
ble subject ; the latter, equally prolific, devoted himself chiefiy to the illustration of 
sacred or clasnc literature. The greatest publishers of such books were Sigismond 
Feyeraband, of Frankfort-pn-the- Maine; Jean de Toumes, and Trechsel, of Lyons ; 
and Plantyn, of Antwerp. From their presses issued a series of small yolumes, which 
can only come under the generic title of ** picture books ; " for they were got up for 
the sake of exhibiting the favourite art of wood-engraving, and only contain a few 
descripCiTe lines of type beneath each cut. The cuts executed by Ammon are all 
remarkable for correctness of drawing and vigorous effect ; those of Bernard are 
less schoIasticaUy correct, but contain more evidence of grace and faincy. The de- 
signs of these artists abound in books published between 1550 and 1580; but the 
most admirable series were executed in a little volume published at Lyons, in 1538, 
without the name of draughtsman or engraver, the Simtdackres de la Mcrt^ known 
among bibliographers as the ** Lyon's Dance of Death" a collection of cuts which, 
for minute beauty and perfection of design and execution, are completely unrivalled, 
and have not been equalled by any modem copyistf This was the Augustan age of 
book'illustration, which flourished in popular favour until the close of the sixteenth 
century, when a minute tamenesSf in contradistinction to the vigour of the earlier en- 
gravers, began to appear, and reached its culmination in such cuts as were given in 
Nicolay's " Travels in Turkey ** (Antwerp, 1576). 

Titian is said to have furnished designs for various woodcuts, particularly the 
series of Costumes published at Venice in 1590; and a very large coarse cut of the 
Destruction of Pharaoh and his host, more than four feet long, is said to have been 
one among many of uncommon size executed from his designs, they were printed on 
separate blocks, and then pasted together in the manner of wall-papers. One repre- 
senting the sacrifice of Abraham is remarkable for the variously tinted inks in which 
it is printed to exhibit gradations of distance. 

Wood-engraving, in the early part of the seventeenth century, had sunk from its 
high estate. The last great artist who had employed himself in connection with the 
art was Hans Holbein, and we do not find a great name again conjoined with it until 
the middle of that century, when Rubens employed Jeghers, of Antwerp, to engrave 
some of his drawings on wood. The generality of woodcuts in books of this era, 
rival in coarseness the older block-books; the wood-engravers seem to have sunk into 
mechanical unassisted by good artists to furnish them with drawings. The art had 
become vulgarised, its profession a trade, and the demand and supply scarcely better 
than the requirements of the ballad printer desired. They weje ancillary to the 
commonest uses of the press, and all art speedily vanished f^om the cuts manu- 
factured probably at a very cheap rate for temporary use. Of this kind are the 

* Durer's engraTlngs v^re to exceedingly popular, that they found their war all over Europe. 
Raphael admhred them in Rome, and was induced to perpetuate his own designs by employing Marc 
Antonio Raimondi to engrave them on metal under his own super intendeuce. So originated the 
modem print trade. Durer's designs were so much in request, that Lucas van Leyden imiuted them 
on copper, for sale to such persons as could not perceive the great difference between the vigorous ori- 
ginals, aud his tame and disagreeable copies. Durer was ultimately obliged to apply for legal restrictions 
against these pimcle*. 

f The designs have been popularly ascribed to Holbein, and, apparently, with reason. An artist 
named Hans Lutzelburgher, of Basle, has been coiyectured to have been the engraver, from the 
initials H. L. on one of them. By this time it Lad become usual to append the initials of engravers to 
woodcuts, as well as those of the designers. 
Vot.IL L 


cuts sprinkled tlirongh the English books of the time of James and Charles L It if 
possible that the printers vere supplied with them from Germany and Flanders. It wis 
customary to use woodcuts repeatedly, particularly if merely ornamental ; in this 
way initial letters were reproduced as the stock in trade of the printing-office? * ; and 
even scenes of adventure^ adopted unscrupulously for other events* to which there 
was the slightest general resemblance. f The names of these ** wood-cutters" have 
not descended to our time ; their works are widely scattered over general literature, 
and it is not until the middle of the century that we meet with any instance of an 
attempt to arrest the downward progress of the art Then, as we have previoudy 
noted, Rubens, probably anxious to rival Durer, engaged Christopher Jeglier, of 
Antwerp, to execute, under his own superintendence and at his expense, a series of 
large drawings made by himself upon the wood. They differ from the style of the 
earlier masters, and frequently have a confused blotted look in the lines, which pro- 
duce deep shadows ; they possess, however, all that boldness and vigour of treatment 
for which the great Flemish painter was so deservedly celebrated ; but the engraviDg 
is coarse and mechanical. Rubens appears to have felt this, and sometimes a tinted 
block is added over all, with high lights cut upon it, to give softness and brightness 
to the whole ; an idea he may have adopted from the engravers of Italy who suc- 
ceeded Ugo da Carpi (among whom may be honourably mentioned Andreas Andreani, 
of Mantua, born 1540, died 1620), or from the designs of Lalleman engraved by Bu- 
sinck, which were nearly contemporaneous in France. 

Though " fallen from its high estate," the art never sank into complete decay, 
either in England or upon the continent; there were always a few who followed the 
profession, and aided the printer with such cuts and diagrams as he might require. 
The family of the Jeghers practised in Antwerp until the end of the century; a clever 
series of woodcuts illustrative of the service of the Mass was published at Ghent, 
and executed by Kraaft in 1732. In France, the family of Le Sueur were employed 
through three generations by booksellers ; the last, Nicholas, died in 1764; while 
Papillon, the author of a Traits de la Gravure en BoU, had practised the art from the 
commencement of the century until 1770, and had been patronised so extensively by 
the booksellers of France and Holland that he counts his cuts by the thousand. In 
England, E. Kirkhall executed cuts for books, and from 1722 to 1724 a series of 12 
block- prints, in imitation of Ugo da Carpi's work already alluded to ; in this latter style 
he produced a greater pupil in J. Jackson, who very successfully copied some of the 
great works of Titian, Paul Veronese, and others, during the years 1738 to 1742 ; at this 
time he resided in Venice, after a short sojourn in Paris, where he was occasionally 
employed as a wood-engraver. Many cuts scattered through English books about 
the same period bear the initials of F. H. for Francis Hoffman, whose name is en- 
graved in fiill on a tail-pipce, representing cupids surrounding a lighted altar, to be 
seen in the first edition of Gulliver'a Travels, 1726, vol. ii. p. 47. An engraver named 
Lister executed some cuts of a much better character than usual about 1760, particularly 
those in the Oxford Sausage; and in Sir John Hawkins's History of Music are some of 
the largest and most ambitious cuts at that time attempted anywhere. They were 
engraved by T. Hodgson. Three other persons named respectively, W. Pennock, 
S. Watts, and H. Cole, occasionally devoted themselves to wood-engraving, which 
seems to have been practised by such copper-plate engravers as devoted themselves 
to *• general work " for the printing trade or the public, and who varied their labours 
by occasionally engraving shop-bills or door-plates. 

There is one great change in the cuts produced during this period, the result of a 
different style of drawing made for the wood-engravers, and which discarded cross- 
hatching and its consequent tedious labour, for a tinted or vrashed drawing which 
could be cut into a series of lines by the tool, expressing the varied tints more simply 
and readily. The art of ** lowering *' or scraping down to a lower level various parts 
of a cut that should appear light, and so assist the press in its labours, was «lso prac- 
tised, and the harder wood of the box tree used. Such was the state of the art when 
a Northumbrian peasant boy was destined to appear, again draw universal attention 
to the neglected profession, and found the modem school of wood engraving. 

Thomas Bewick was the son of parents engaged in a colliery, who lived at Cherry- 
bum twelve miles west of Newcastle-on-Tyne ; he was bom in 1763 and passed his 

• In the old printing oflBce of Plantyn at Antwerp, !• still prescrred a large quantity of voodrntt, ori- 
ginallj engraved for the boolis be issued at the end of the 16th century, particularly the embleina of 
Alciatl and Sambaco. 

t The number of impressions a woodcut will yield has never yet been esUbllshed. The elasticity of 
wood gives it a great advantage over metal in press-printing; and while copper and steel wear out, 
wood shows little sign of wear ; many thousands of impressions may be taken by a carefully moderate 
printer without injuring a woodcut. As an instance with what impunity a bad printer may use a coarse 
woodcut, may be mentioned the fact, that the ballad printers of the middle of the last century occaaloa- 
ally used cuts that had been engraved in the reign of Charles L, and had headed popular ballads for 
more than 100 yeart. 


early jesn helping his fkther's labour. His leisure hoars -were earnestly devoted to 
the small amount of knowledge a village school could impart ; but as a strong love 
for nature, and for its imitation, soon developed itself in the boy, his father determined 
to apprentice him to an engraver of Newcastle, Mr. R. Bcilby, whose work was of that 
" general " kind undertaken in a busy country town. There he occasionally engraved 
initials on tea-spoons or names ou door plates, until, in the second year of his ap- 
prenticeship, his master received an application from Dr. Hutton for wood-cut 
diagrams, such as were then executed in London, to illustrate his treatise on 
mensuration. Beilby knew that young Bewick had been making some attempts in 
this style and he encouraged him to persevere; he did so, and Hutton's book was 
published in 1770 with Bewickls cuts. The young engraver had many difficulties to 
contend against, and had even to construct his own tools ; among the rest, a double- 
pointed graver to enable him to cut both sides of a line at once, and so ensure its 
equal thickness throughout In 1775, he executed a cut and sent it to the Society of 
jljts, in London, who awarded him a medal ; and in the following year he visited 
London, and was employed by Hodgson, whom we have already noted as the engraver 
of the cuts in Hawkins's History of Music; as well as by H. Cole. There need be 
Uttle doubt that this visit to the London wood- engravers was useful to Bewick, for he 
must have become by that means acquainted with the usual mode of practising the art, 
the proper kinds of tools used, and the various things which make the mechanical part of 
the profession ; but he had fortunately formed a style of his own, so very original, and 
based so finnly on the study of nature, that wood-engraving in his hands became an art 
presenting many novel and attractive features never visible before. The wood-engravers 
ftom the days of Durer, or from the first invention of the art, depended slavishly on the 
drawings made upon the wood, and did little more than cut away the interstices; but 
Bewick cut out of the wood a vast deal of that which no draughtsman could so draw ; 
for with the aid of a slightly tinted drawing, he would cut Uie foliage of trees, the 
plumage of birds, the texture of animals, or small figures and birds, by the graving 
tool alone. His dextrous hand was guided by a perfect knowledge of nature, and 
every line be cut expressed drawing ; in this was his great distinction over all other 
wood engravers ; he cut his pictures out of the wood, the others cut the wood out of 
the pictures. 

Bewick disliked London, and speedily returned to his native place. His first work 
was an illustrated edition of Qay*8 Fables, published in 1779 by T. Saint, a printer of 
Newcastle, much engaged in the publication of children's books, and such as the 
travelling chapmen carried in their packs for the edification of the villagers. These 
cots bear the earliest traces of that accurate delineation of nature, and minute truth- 
fulness of expression, which ultimately gave his works universal renown. The wild 
plants and grasses, however minute they are cut, can always be distinguished by the 
naturalist ; the proper foliage of every tree is truthfully cut by his graver ; the birds 
and insects, however minute, are perfect in drawing ; and the general effect of his 
wood-cuts artistically powerful As he fnll^ felt the value of leaving the wood itself 
to express solid shadow, he had not the timidity which imagines labour to be neces- 
sary to success. The little cut of the Fox and the Bramble in this volume is a good 
illustration of Bewick's mode. Every leaf of the bramble is cut out, white upon 
black, with the most truthful power of drawing ; the spines on the stem of the bramble 
are visible to the eye ; the fern beside it is similarly expressed by cutting the form 
of its foliage with the most perfect freedom upon the solid block of wood. Each 
bush has its distinctive leaf. The dogs in tbe distance arc similarly cut out by the 
graver on a tinted ground ; and the few lines which cover the body of the fox 
entangled in the bramble, express its texture with a spirit which no mere cutting of a 
drawing placed on wood by a professional draughtsman could ever give. Bewick's 
cuts are sometimes termed coarse^ but no elaboration of labour will elevate the costliest 
woodcut above these works, for which Bewick obtained but nine shillings each; 
unless drawing can be expressed by the engraver as perfectly as Bewick could 
express it. 

Assisted by his brother John, the Newcastle engraver issued a series of works 
devoted to natural history ; the best being the History of British Birds, Here 
Bewick's knowledge of nature, and power of expression by means of his graver 
shone forth conspicuously. His books became equally celebrated for tbe hum6rou8 
tail-pieces he occasionally introduced redolent of whim and original genius. He labcmred 
stead&stly at his art to a good old age. His brother John \tefi Newcastle to reside in 
I>ondon, where he was much employed, but a pulmonary complaint killed him at the 
early age of thirty-five. He died in 1795. Thomas Bewick lived to the advanced 
age of seventy-five. He died in 1828, having worked upon a large woodcut only 
a few days before his death. 

The pupils educated by Bewick were few. The best were Charlton Nesbit, Luke 

L 8 


Clennell, William Hanrey, and John Jackson. Nesbit settled in London, and 
extensively employed during a long life. Clennell after a while, devoted himself to 
pa'mting. Harvey turned bis attention to drawing on vood, and bis designa for book 
illustration may be numbered by the thousand ; his best are in Lane's edition of the 
Arabian NiyhU Entertainments. Jackson was greatly employed by the publiaher of 
the latter work, Mr. Charles Knight, particularly on the best cuts in the once-fiuned 
Penny Magazine, 

At the early part of the present century, Mr. Robert Branston founded a London 
school of wood-engravers, of which he was the head. His style was peculiar, imlike 
Bewick's, though like him he was self-taught His cuts have more refinement, bat 
less knowledge of nature ; his best pupil was John Thompson, who combines in his 
best cuts, the refined knowledge of light and shade, with much of Bewick's power of 
expressing drawing. Samuel Williams was one of the few modem engravers, who 
made his own drawings upon the wood, and he produced very brilliant effects by 
frequently leaving the wood in solid masses of bkick. Drawings for wood engnven 
were at this time chiefly supplied by artists who devoted themselves to that particular 
branch of the art ; and knew how to design their compositions so that they should 
best display th( peculiarities of wood-eugraved e£ESects. Thurston, Craig, and Harvey 
were the principal artists so engaged. 

A large number of wood-engravers, the pupils of the Newcastle and London aidiert^ 
helped to supply the booksellers at home and abroad for a considerable number of 
years. It was the custom, some twenty years ago, for the foreign booksellers, parti- 
cularly in Paris, to send the blocks across the channel to English engravers to execute ; 
this led ultimately to several settling on the continent, particularly in France and 
Germany. The French publishers always sent the wood block with the drawing 
carefully executed on its surface, by a native artist These drawings were always 
elaborately executed in pencil, greatly resembling etchings ; little was consequently 
left for the engraver to do, but follow the lines and cut away the spaces ; patience 
hence became the chief virtue of the wood engraver ; and it was ultimately found 
that its exercise produced so certain an effect, that apprentices knowing nothing of 
art might aid in thus working out good engravings ; and the old style of tinted draw- 
ing on wood was discarded for this *'fiic-simile" work ; the best draughtsmen among 
the French and German artists having willingly furnished these drawings, English 
artists of a higher grade were induced to draw on wood, but they occasionally iaikd 
from not clearly understanding the peculiar effects their work should produce, and 
the characteristics of the art. Generally speaking, wood engravers prefer cutting 
ft'om the drawings of professional draughtsmen on wood ; who generally execute their 
work with such elaborate precision, that the engraver has nothing more to do than 
follow their lines ; this, however, has made mere mechanism of much modem wood- 
engraving ; and many expensive cuts exhibiting pencilling in crossed and re-crossed 
lines, occupying wearisome labour, and costing many ill-bestowed sovereigns, caa 
only be classed with such '* art '* as is devoted to engraving the Lord's Prayer in the 
compass of a silver penny ; and merely produces the same general effect that Bewick 
would have obtained in a few bold lines. 

The great difference between ancient and modern wood engraving consists in this 
very boldness ; and the practice of the art was essentially different in the sixteenth and 
eighteenth centuries. The old wood engravers cut on large blocks of soft womi, 
such as pear-tree, the way of the grain ; the modems, on small blocks of the hardest 
wood they can obtain — the turkey box, and across the grain. The old engravers 
cut the work downwards with small knives or gouges ; the moderns use gravers of 
various widths to cut out the spaces between fine lines, and broader chisels or gouges 
to clear away the broad spaces of white. Wood engraving is the exact opposite to 
copper-plate engraving in the mode by which the lines of engraving are produced. 
The copper-plate engraver produces his lines by cutting into the metal at once, the 
wood engraver produces his lines in relief cut out of the block of wood ; every line 
he engraves has to be cut by a double operation, by slicing away the wood on each 
side of it ; for though it is recorded that Ikwick invented a double cutting fork-shaped 
graver to cut away both sides of a line at once, no such tool has ever since been 
used in the profession. 

In order to luake the whole process of wood engraving clear to the reader, 
we will now simply describe the production of a wood cut from the time it leaves 
the timber-merchant, until it is fit for the hands of the printer. The log of box is cut 
into transverse slices, I of an inch in depth, in order that the face of the cut may be on 
a level with the surface of the printer's type, a d receive the same aniount of 
pressure ; the block is then allowed to remain some time to dry, and Uie longer it is 
allowed to do so the better, as it prevents accidents by warping and splitting, which 
sometimes happen after the cut is executed if the wood is too green. The slice is 
ultimately trinuned into a square block, and if the cut be large, it is made in various 


pieoes strongly clamped and screwed together ; and this enables engravers to get 
large cuts done in an incredibly short space of time, by patting the various pieces 
into different engravers' hands, and then screwing the whole together. The upper 
surface of the wood is carefully prepared so that no inequalities may appear upon 
tt» and it is then consigned to ihe draughtsman to receive the drawing. He covers 
the surface with a light coat of flake white mixed with weak gum- water, and the 
thinner this coat the better for the engraver. The French draughtsmen use an 
abundance of flake white, but this is liable to make the drawing rub out under the 
engraver's hands, or deceive him as to the depth of the line he is cutting in the wood. 
The old drawings of the era of Durer seem to have been carefully drawn with pen 
and ink on the wood ; but the modem drawing being very finely drawn with the 
pencil or silver point is obliterated easily, and there is no mode of *' setting '* or 
securing it To obviate this danger the wood-engraver covers the block with paper, 
and tears out a small piece the size of a shilling to work through, occasionally re- 
moving the paper to study the general effect, in damp and wintry weather he some- 
times wears a shade over the mouth to hinder the breath from settling on the block. 
It is now his business to produce in relief the whole of the drawing ; with a great 
variety of tools he cuts away the spaces, however minute, between each of the pencil 
lines ; and should there be tints washed on the drawing to represent sky and water, 
he cuts such parts of the block into a series of close lines, which will, as near as he 
can judge, print the same gradation of tint. Should he find he has not done so com- 
pletely, be can re-enter each line with a broader tool, cutting away a small shaving, 
thus reducing their width and consequently their colour. Should he make some fatal 
error that cannot be otherwise rectified, he can cut out the part in the wood, and 
wedge a plug of fresh wood in the place, when that part of the block can be re- 
engraved. An error of this sort in a wood-cut is a very troublesome thing ; in copper 
engraving it is scarcely any trouble ; a blow with a hammer on the back will obliterate 
the error on the fiice, and produce a new surface ; but in wood, the surface is cut 
entirely away except where the lines occur, and it is necessary to cut it deep enough 
not to touch the paper as it is squeezed through the press upon the lines in printing. 
To aid the general effect of a cut, it is sometimes usual to lower the surface of the 
block before the engraving is executed in such parts as should appear light and delicate ; 
they thus receive a mere touch of the paper in the press, the darker parts receiving 
the whole pressure and coming out with double brilliancy. When careful printing 
is bestowed on euts, it is sometimes usual to ensure this good effect, by laying thin 
pieces of card or paper upon the tympan, of the shape needed to secure pressure on 
dark parts only. 

Wood engraving, as a most useful adjunct to the author, must always command a 
certain amount of patronage. In works like the present, the author is greatly aided 
by a diagram, which can more clearly explain his meaning than a page of letter- 
press ; and it can be set up and printed with the type, a mode which no other style 
of art can rival in simplicity and cheapness. The taste for elaborately executed 
wood engravings may again decrease, as we find it did for nearly two centuries ; but 
it was never a lost art, and never will be, owing to the practical advantages we speak 
of, unless it be superseded by some simpler mode of doing the same thing hitherto 
undiscovered. The number of persons who practise wood engraving in London 
alone, at present is more than 200, and when we consider the quantity done in the 
great cities of the continent, and the large amount of book illustration in constant 
demand ; the creative power of one single genius — Thomas Bewick — shines forth 
in greater vigour than ever. — F. W. F. 

ENTRESOL. A floor between other floors ; a low set of apartments placed above 
the first floor. The Quadrant, Regent Street, has a good example of the entresol. 
In Italy the term Mazzanino, or little middle floor, is used to indicate the same 

ENVELOPES. The manufacture of envelopes has so largely increased, that the 
old method of folding them by means of a **bone/oldinQ stick,** although a good workman 
could thus produce 3000 a day, was not capable of meeting the demand ; hence the 
attention of several was turned to the construction of machines for folding them. 
Amongst the most successful are the following. 

Envelope folding, — In the envelope folding machine of Messrs. De la Rue & Co., each 
piece of paper, previously cut by a fly press into the proper form for making an envelope 
(and baring the emblematical stamp or wafer upon it), is laid by the attendant on a square 
or rectangular metal frame or box, formed with a short projecting piece at each corner, 
to serves as guides to the paper, and furnished with a movable bottom, which rests on 
helical springs. A presser at the end of a curved compound arm (which moves in a 
vertical plane, then descends, and presses the paper down into the box, — - the bottom 
thereof yieldmg to the pressure ; and thereby the four ends or flaps of the piece of paper 

L 3 


are caused to fly ap ; the presser may be said to consist of a rectangular metal frame, tbe 
ends of which are attached to the outer part of the carved arm, and the sides thereof to 
the inner portion of the arm ; so that the ends and sides of the presser can move inde- 
pendently of each other. The ends of the presser then rise, leaving the two sides of it still 
holding down the paper ; two little lappet pieces next fold over the two side flaps of tlie 
envelope ; and immediately a horizontal arm advances, carrying a V-shaped pieceebarged 
with adhesive matter or cement (from a saturated endless band), and applies the eme 
to the two flaps. A third lappet presses down the third flap of the envelope upon the 
two cemented flaps, and thereby causes it to adhere thereto ; and then a pressing-piece, 
of the same size as the finished envelope, folds over the last flap and presses the whole 
flat. The final operation is to remove the envelope, and this is effected by a pair d 
metal fingers, with indiarubber ends, which descend upon the envelope, and, momt: 
sideways, draw the envelope off the bottom of the box (the pressing piece having mored 
away and the bottom of the box risen to the level of the platform of the machine) on to 
a slowly moving endless band, which gradually carries the finished envelopei away. A 
fresh piece of paper is laid upon the box or frame, and the above operations are repeated. 
This machine makes at the rate of 2700 envelopes per hour. 

Another machine for the same object, was invented by Mr. A. Remond, of Binniag- 
ham, and is that employed by Messrs. Dickinson & Co. The distingaishing feature 
of this arrangement is the employment of atmospheric pressure to feed in the paper 
which is to form the envelope, and to deflect the flaps of the envelope into iodiiKd 
positions, to facilitate the action of a pinnger, which descends to complete the folding. 
The pieces of paper, cut to the proper form, are laid on a platform, which is furnished 
with a pin at each corner, to enter the notches in the pieces of paper, and retain tieo 
in their proper position, and such platform is caused alternately to rise and bring the 
upper piece of paper in contact with the instrument that feeds the folding part of the 
machine, and then to descend until a fresh piece is to be removed. The feeding in- 
strument consists of a horizontal hollow arm, with two holes in the under side, and 
having a reciprocating movement. When it moves over the upper piece of paper 
on the platform, a partial vacuum is produced within it, by a suitable exhausting ap* 
paratus, and the paper is thereby caused to adhere to it at the holes in its nnder sur- 
face by the pressure of the atmosphere. The instrument carries the paper o«r » 
rectangular recess or box ; and then, the vacnum within it being destroyed, it depositi 
the paper between four pins, fixed at the angles of the box, and returns for another piece 
of paper. As the paper lies on the top of the box, the flap which will be nndennott 
in the finished envelope, is pressed by a small bar or presser on to the upper edge « 
two angular feeders, communicating with a reservoir of cement or adhesive matter, and 
thereby becomes coated with cement ; and at the same time, the outermost or seal flap 
may be stamped with any required device, by dies, on the other side of the machine. 
A rectangular fhime or plunger now descendis and carries the paper down into the box; 
the plunger rises, leaving the flaps of the envelope upright ; streams of air, issuing from 
a slot in each side of the box, then cause the flaps to incline inwards : and theibldm^ 
is completed by the plunger again descending ; the interior and under surfiwe of suca 
plunger being formed with projecting parts, suitable for causing the several ^P* *J 
fold in proper superposition. The bottom of the box (which is hinged) opens, and 
discharges the envelope down a shoot on to a table below ; the feeding instrument 
then brings forward another piece of paper ; and a repetition of the above movements 
takes place. 

EPSOM SALTS. A sulphate of magnesia, consisting of magnesia 16-26, snlphane 
acid 32-52, water 51 '22. It derives its name fh)m a mineral spring contaimng tne 
salt at Epsom. It is largely manufactured. See DoLoifiTE. ^^ 

EQUISETUM. Horsetails. A family and genus of acotyledonons plants, wc 
Dutch Rush. 

EQUIVALENTS. CHEMICAL. By this term is understood the proportioni » 
which substances combine with each other to form definite compounds. These ^ 
portions are referred to the common standard, hydrogen, which is taken as umtf- 
The limits of this work preclude the possibility of entering into the history » 
the steps by which the doctrine of equivalents was gradually developed ; ^"* '^ ^ 
proper that we should indicate some of the methods by which the equivalents of ele- 
ments and compounds are ascertained and demonstrated to be correct Bnt befo^ 
proceeding it is necessary to define the term equivalent This is not easy to <», 
because tibe theoretical ideas of all chemists are not the same. Suppose, for y 
ample, the constitution of water were to be taken as the starting point On ^'^^f^^^j^J 
it to the action of the pile, it is immediately observed that the ratio of the ^ 
gases evolved is as 1 to 2. One chemist will at once assume that water is a si^iP 
binary compound of one equivalent of each of its constituents. But this involves 
assumption that the gaseous volume of the equivalent of hydrogen is twice that 


oxygen. The other chemist assDining that one yolnme of a gas represents an eqaiva- 
lent, considers water to be a ternary compoond having the formula H^O. It is plain 
that the atom of hydrogen will have only half the value on the second hypothesis that 
it will on the first, or, what comes to the same thing, the atom of oxygen will be 
twice as great If, with some chemists, we consider the volumes of the gases to repre- 
sent atoms or eqairalents, then, water consisting of two volumes of hydrogen and one 
volume of oxygen, and as by weight water contains 8 parts of oxygen to 1 part of 
hydrogen, it is plidn that 8 parts of oxygen by weight will represent one equivalent, 
and 1 part by weight of hydrogen will represent 2 equivalents. Consequently 1 
equivalent of hydrogen will weigh '5. But to avoid fractional numbers it will (on these 
a^umption8)be more convenient to write the equivalent of hydrogen -i 1, and oxygen 
1 6. In this country it is usual to consider the atom of hydrogen as occupying twice the 
space in the gaseous state of that of oxygen. The atomic weights being, therefore, 
oxygen 8 and hydrogen 1. 

We have said that it is b^ no means easy to define an equivalent The difficulty 
arises not merely from the different aspects under which theoretical chemists regard 
the elements and their compounds, but also from the practical difficulties attending 
the determination of the true constitution of some substances. Thus the equivalent 
of bismuth is assumed by some to be 71 and by others 213 ; the oxide in the one 
case becomes BiO, in the other BiO\ The first equivalent being only one-third as 
great as the second. But, it is to be observed, the variations in the theoretical views 
of chemists are of no consequence, so long as we clearly comprehend the nature of 
those variations. The r^ative values or proportions are the same in all cases. It is, 
in fact, somewhat the same as if one class regarded the avoirdupois pound as made up 
of sixteen ounces, each ounce weighing 437 '5 grains, and the other considered it as 
consisting of eight ounces, each ounce containing 875 '0 grains. 

In order to clearly understand the nature of the equivalents as received in this 
country, it is necessary to remember that there are three relations of volume amongst 
gases, namely, one, two, and four volumes. The first relation applies solely to ele- 
mentary gases, file two others apply to elements and compounds. [It is true that 
the vapour densities of pentachloride of phosphorus, chloride of ammonium, and, 
perhaps, one or two other substances, appear to diflPer from this rule, but it is probable 
that like sulphur, the vapourdensities require to be determined under special conditions 
of temperature or pressure.] In the table of equivalents the density of the vapours 
of those substances which are capable of assuming the gaseous states are so placed 
that the number obtained by experiment may be compared with that deduced from 
theoretical considerations. In the following table the vapour volumes or combining 
measures of some of the more important elements are given. We shall see presently 
the practical value of the information contained in it 











two volumes. 

Oxygen - 




one volume. 

Chlorine - 





Salphur - 





Bromine - 





Selenium - 















Fluorine (fiypotheUcal) 



Arsenic - 





Nitrogen * 










It must be remembered that all volatile compounds possess four volume formulse, 
except a few, which in this country are always written as if possessing a condensation 
to two volumes ; such are carbonic acid, carbonic oxide, sulphurous acid, &c With 
the above information it will be easy for any person to calculate the density of any 
vapour or gas by the aid of the following directions. 

To obtain the density of any vapour or gas hamng a condensation to four volumes, 
such as most organic or inorganic compounds, — Multiply half the density of hydrogen 
by the atomic weight of the vapour or gas. Example : — Find the density of the 
vapour of hydrobromic acid. The atomic weight of bydrobromic acid is 81. The 
density of hydrogen is 0692, half of which is 0346. Then 00346 x 81 « 2*8026. 
Experiment gave 2*73. 

To obtain the density of any vapour or gas having a condensation to two vohanes, 
— Multiply the density of hydrogen by the atomic weight of the gas or vapour. 
Example : — Find the density of chlorine gas. The atomic weight of chlorine being 
35*d, and the density of hydrogen -0692, we have by the rule, 0*0692 x 35 '5 » 2 4566. 
The density by experiment is 2*44. 

To obtain the density of any vapour , or gas^ having a condensation to one «o/t<me.— > 
Multiply twice the density of hydrogen by the atomic weight of the gas or vapour. 
Example : — Find the density of Sie vapour of oxygen. The atomic weight of 

L 4 


oxygen being 8, and twice the density of hydrogen being 0*1384, we hATe 
0*1384 X 8 e 1*1072. Experiment has yielded I -1056. 

The above methods of calculating the densities of vapours and gases are those always 
employed by the writer of this article, and will be found incomparably shorter' and 
more convenient than any other. 

It is perfectly plain that, by a simple inversion of the above rol^ it is eqnaJly easy 
from the known density of a gas or vapour to calculate its atomic weight. Never- 
theless, for the sake of those who are unaccustomed to calculations of this kind, we 
append the following rules. 

To calculate the atomic weight o/ any gas or vapour having a condentation to fonr 
volumes. — Divide the density of the gas by half the density of hydrogen. Ezavple : 
— Find the atomic weight of hydrobromic acid gas, the density of which is 2-8026 ; 
2*8026 ^, ^^ 


To calculate the atomic weight of any gas or vapour having a condensatiom to two vo- 
lumes, — Divide the density of the gas by the density of hydrogen. 

To calculate the atomic weight of any gas or vapour having a condensation to cne vo- 
lume. — Divide the density of the gas by twice the density of hydrogen. 

It is plain then that if we are in possession of the atomic weight and vapour volume of 
any substance, it is easy to determine the density of its vapour or gas. Alaoi, that 
having the density of the vapour and the vapour volume, it is easy to calculate the 
atomic weight If we consider for an instant what is meant by the term density of a 
vapour or gas, it will appear equally easy to find, from the density of the gas, the 
weight of 100 cubic inches at the standard temperature and pressure. By the density 
of a gas is meant the number expressing how much it is heavier or lighter, balk for 
bulk, than air. If, therefore, we multiply the density of a gas by the wei^t of 100 
cubic inches of air, at the standard temperature and pressure (» 30*00 grainsX ve 
immediately find the number required. Example : — The density of hydrogen is 
0*0692 and 0*0692 x 30 « 2*0760, or the weight of 100 cubic inches of hydrogeo, at a 
temperature of 60^ Fahr., and 30 inches of the barometer. 

From what has been said, it is evident that no difficulty exists in determining the 
equivalents of bodies which can be obtained in a gaseous state. Where the equi- 
valent of a fixed body is to be ascertained, or where it is desired to proceed in a 
different manner, the method employed must depend upon the nature of the substance. 
We shall consider three of the most simple and general cases, namely, an acid, an 
alkali, and a neutral body. 

1. Mode of determining the equivalent of an acid. — For this purpose it is neces- 
sary to analyse a salt, the constitution of which is known. If the base or metallic 
oxide in the salt is one of which the atomic weight is well established, it is very easy 
to determine the combining proportion of the aoid. We say, as the peroenta^ of 
oxide is to the percentage of acid, so is the atomic weight of the oxide to the atomic 
weight of the acid. Example : — Butyrate of silver has the following composition :-* 

Oxide of silver .------ 59*487 

Butjric acid -------- 40*513 

We therefore say : — 


59-487 : 40-513 :: 116 : 79-000 

Percentage of oxide Percentage of acid. Equivalent of oxide Equivaient of the 
ofailver. of silver. add. 

It must be remembered that the atomic weight so obtained is that of the anhydrous 
acid, so that one equivalent of water must be added to find the atomic weight of the 
acid in its ordinary condition. If the equivalent desired be that of a hydrogen acid, 
the method of proceeding must be slightly modified, but the details need not be given 
as they are self-evident 

2. Mode of determining the equivalent of an alkali. — Several methods present them- 
selves, each possessing certain advantages. Most alkalies, organic and inorganic, 
form salts well adapted for enabling their atomic weight to be ascertained by analysis. 
We shall select as an example ammonia, and the salt employed to settle the atomic 
weight will be the sulphate, which contains : — 

Oxide of ammonium - - - - - - 39*40 

Sulphuric acid . - . . ... 60*60 

In the same way that an oxide of known composition is the datum employed to 



deteimine the equiyalent of an acid, so, on the other hand, an add, the formula of 
which is irell established, serves to enable the formula of an alkali to be deduced. We 
therefore say : — 

60*60 : 39*40 :: 40*00 : 2600 

V V ■ ' 

PerceoUge of acid. PercenUge of alkali. 

Equivalent of the 

Equivalent of the 

Most alkalies, especially those derived from the organic kingdom, form well defined 
and easily crystallisable compounds with some of the metallic chlorides, especially 
those of gold, platinum, and palladium. These salts are well adapted for enabling 
atomic weights to be fixed. 

3. Mode of deiermining the equivalent of a neutral substance. — Neutral bodies are 
formed upon so many models or types that no general method can be given for the 
required purpose. If volatile at moderate temperatures, the density of the vapour can 
be ascertained, and this is generally sufficient Salts have their equivalents found 
by determining the percentage composition, and proceeding as in examples 1 and 2. 
"The equivalent of a metal is found by forming a compound with some substance, the 
atomic weight of which is well known, such as oxygen or sulphur. The compound is 
then carefully analysed. Exakple : — It has been found that 100 parts of oxide of 
copper contain 

Copper --------- 80*00 

Oxygen- ------- -20*00 

We therefore say:— . 






Percentage of Percentage of Equivalent of Equivalent of 

oxygen. copper. oxygen. copper. 

A precisely analogous mode of proceeding may be adopted with chlorides, iodides, &e. 

A careful study of the numbers in the following tables will enable us to observe 
nnmerous and highly iq^resting relations subsisting between them. It has been 
shown by M. Dumas that certain families or groups of elements fall into natural triads, 
owing to the relations between their atomic weights. With bodies of this kind, it is 
found that, if the sums of the atomic weights of the extremes of the series be divided 
by two, we obtain the atomic weight of the middle body ; thus : — 




Sulphur 16*00 
Tellurium 64*00 





s 40*00 





« 23*00 

2 2 2 

The triads here are i. chlorine, bromine, and iodine; n. sulphur, selenium, and 
tellurium ; in. lithium, sodium, and potassium. Space will not allow of the subject 
being developed at greater length in this work. The student, interested in this branch 
of chemistry, will find much information in the papers of Dr. Odling, recently pub- 
lished in the Journal of the Chemical Society. 

Table of the Equivalents^ ^c, of the Non-metaUic Elements. 


Bromine - 
Chlorine - 
Fluorine - 
Hydrogen - 
Nitrogen - 
Selenium - 


Equivalent Density as Var 


pour or Gas. 
























[Note. — The densities of the vapours of carbon, selenium, and fluorine are 
hypotheticaL That of sulphur is usually represented by a number three times as 



great as the above, bat this is owing to the experiment not haying been performed at 
a sufficiently high temperature.] 

Table of the Equivalents of the Metallic Elements. 



Cadmium - 
Didymium - 
Glucinum • 
Gold - 
Ilraenium - 
Iron - 
Lead - 
Mercury - 
Niobium - 
Palladium - 
Platinum - 
Potassium - 
Rhodium - 
Strontium - 
Tantalum - 
Tellurium - 
Terbium - 
Thorium - 
Tin - 
Titanium - 
Tungsten - 
Uranium - 
Vanadium - 
Zinc - 
Zirconium • 




















11 00 


























19-4 to 19-6 










104 00 





Mg . 



Mn • 


































108 OO 























17-2 to 17-6 












It will be seen, from the above table, that a very considerable number of the equiva- 
lents are entire multiples of that of hydrogen. M. Dumas and others have, however, 
shown by elaborate and conclusive experiments, that the doctrine of the equivalents 
of all elements being multiples of that of hydrogen is not a law of nature, as, in 
addition to chlorine, there are several undoubted exceptions. — C. G. W. 

EREMACAUSIS, — 9/010 combustion. This term has been applied to that constant 
combination of oxygen with carbon and hydrogen, to form carbonic acid and water, 
which is anceasingly going on in nature, as in the decay of timber, or the '* heating " 


of hay or grain pat toother in a moist state. Perfect dryness, and a temperature 
below freezing, stops this eremacausis, or slow combustion. 

ERYTHRIC ACID. Colorific principle of Angola and Madagascar Orcbilla 
-weeds (See Orchuxa.) By macerating the lichen m milk of lime, Stenhoose ob- 
tained 12 per cent, of crude erythric acid. It yields red coloured compounds with 
ammonia, and also in its reaction with hypochlorite of lime. See Lichen. 

ERMINE. See Fur. 

ERRATIC BLOCKS. Rounded and weather-worn fragments of the harder 
rocks, which are found very widely scattered, at great distances trota the places from 
-which they are supposed to have been deriyed. They are generally supposed to have 
been removed by the transporting power of icebergs and fields of ice. 

ESPARTO. A species of rush — the Stipa tenacwtima — found in the southern 
provinces of Spain. It is used for making cordage, shoes, matting, baskets, nets, 
mattresses, sacks, &c. Cables made of esparto are said to be excellent *, being light, 
they float on the surface of the water, and are not therefore so liable as hempen cubles 
to be cut or injured by a foul bottom. — M^CuUocfu 

ESSENCE OF SPRUCE is prepared by boiling the young tops of the Abies nigra, or 
black spruce, in water, and concentrating the decoction by evaporation in a water bath. 

ESSENCES. See Psbfumebt. 

ESSENTIAL OILS. See Oils, fixed and essential, and Otto. 

ESSENCE D'ORIENT, the name of a pearly looking matter procured from the 
blay or bleak, a fish of the genus cyprinus. This substance, which is found princi- 
pally at Uie base of the scales, is used in the manufacture of artificial pearls. A large 
quantity of the scales being scraped into water in a tub, are there rubbed between the 
hands to separate the shining stuff, which subsides on repose. The first water being 
decanted, more is added with agitation till the essence is thoroughly washed from aU 
impurities, when the whole is thrown upon a sieve ; the substance passes through, but 
the scales are retained. The water being decanted ofi^ the essence is procured in a 
▼iscid state, of a bluish-white colour, and a pearly aspect. The intestines of the 
same fish are also covered with this beautiful glistening matter. Seyeral other fish 
yield it, but in smaller proportion. When well prepared, it presents exactly the ap- 
pearance and reflections of the real pearl, or the finest mother of pearl ; properties 
which are probably owing to the interposition of some portions of this same substance 
between the laminsB of these shelly concretions. Its chemical nature has not been 
investigated ; it putrefies readily when kept moist, an accident which may however 
be counteracted by water of ammonia. See Pbahls. 

ETCHING VARNISH. {Aetzgrynd-DeckfimiM, Germ.) Though the practice 
of this elegant art does not come within the scope of our Dictionary, the preparation of 
the Tarnishes, and of the biting menstrua which it employs, legitimately belongs to it. 

The varnish of Mr. Lawrence, an English artist resident in Paris, is made as 
follows : Take of virgin wax and asphaltum, each two ounces, of black pitch and 
burgundy- pitch, each half an ounce. Melt the wax and pitch in a new earthenware 
glazed pot, and add to them, by degrees, the asphaltum, finely powden'd. Let the 
whole boil till such time as that, taking a drop upon a plate, it will break when it is 
cold, on bending it double two or three times betwixt the fingers. The varnish, 
being then enough boiled, must be taken off the fire, and after it cools a little, must be 
poured into warm water, that it may work the more easily with the hands, so as to be 
formed into balls, which must be kneaded, and put into a piece of taffety for use. 

Care must be taken, first, that the fire be not too violent, for fear of burning the in- 
gredienta, a slight simmering being sufficient ; secondly, diat whilst the asphaltum is 
putting in, and even after it is mixed with the ingredients, they should be stirred con- 
tinually with the spatula ; and, thirdly, that the water into which this composition is 
thrown should be nearly of the same degree of warmth with it, in order to prevent a 
kind of cracking that happens when the water is too cold. 

Preparation ^the hard varnish used by Caliot, commonly eaUed the Florence Var- 

nish Take four ounces of fat oil very clear, and made of good linseed oil, like that 

used by painters; heat it in a clean pot of glazed earthenware, and afterwards put to it 
four ounces of mastick well powdered, and stir the mixture briskly till the whole be well 
melted, then pass the mass through a piece of fine linen into a glass bottle with a long neck, 
that can be stopped very securely; and keep it for the use that will be explained below. 

Method of applying the soft varnish to the plate, and of blackening it — The plate 
being well polished and burnished, as also cleansed from all greasiness by chalk or 
Spanish white, fix a hand-vice on the edge of the plate where no work is intended to 
be, to serve as a handle for managing it when warm ; then put it upon a chafing-dish, 
in which there is a moderate fire, and cover the whole plate equally with a thin coat 
of the varnish ; and whilst the plate is warm, and the varnish upon it in a fluid state, 
beat every part of the varnish gently with a small ball or dauber made of cotton 

156 ETHER. 

tied up in taffety, which operation smooths and distribates the yarnish eqoall oTer 

the plate. . . 

When the plate is thus uniformly and thinly covered -with the varnish, it must he 
blackened by apiece of flambeau, or of a large candle which affords a copioas smoke; 
sometimes two or even four such candles are used together for the sake of despatch, 
that the varnish may not grow cold, which if it does during the operation, the plate 
must be heated again, that it may be in a melted state when that operation is performed; 
but great care must be obtained not to burn it, which when it happens may be easily 
perceived by the varnish appearing burnt and losing its gloss. 

The menstruum used and recommended by Tnrrell, an eminent London artist, for 
etching upon steel, was prepared as follows : — 

Take Pyroligneous acid 4 parts by measure. 
Alcohol 1 part, mix, and add 

l^itric acid I part. 

This mixed liquor is to be applied from I to 15 minutes, according to the depth 
desired. The nitric acid was employed of the strength of 1-28— the double aquafortis 
of the shops. 

The eau forte or menstruum for copper, used by Callot, as also by Piranesi, with a 
Blight modification, is prepared, with 8 parts of strong French vinegar, 

4 parts of verdigris, 
4 ditto sea salt, 
4 ditto sal ammoniac, 
* I ditto alum, 

16 ditto water. 

The solid substances are to be well ground, dissolved in the vinegar, and diluted 
with the water ; the mixture is now to be boiled for a moment, and then set aside to 
cool. This method is applied to the washed, dried, and varnished plate, after it has 
suffered the ordinary action of aquafortis, in order to deepen and finish the delicate 
touches. It is at present called the eau forte a passer, 

ETHER, C*H*0. (Or, for four volumes of vapour, OH'K)'. For the nature of fowr^ 
vdume formtd<B^ see the articles Equivalents, Chemical, and Formoub.) S^ 
Sulphuric ether. Oxide ofethyle, Ethylic or Vinic etiier, &c. &c. By this term is known 
the very volatile fluid produced by the action on alcohol of substances having a power- 
ful affinity for water. 

Preparation on small scale. — A capacious retort with a moderate sized tubulature is 
connected with an efficient condensing arrangement Through the tubulature passes 
a tube connected with a vessel full of spirit, sp. gr. 0'83. The tube must have a stop- 
cock to regulate the flow. A mixture being made of five parts of alcohol of the density 
given above, and nine parts of oil of vitriol, it is to be introduced into the retort, and 
a lamp flame is to be so adjusted as to keep the whole gently boiling. As soon as the 
ether begins to come over, the stopcock connected with the spirit reservoir is to be 
turned sufficiently to keep the fluid in the retort at its original level. 

Preparation on large scale. — The apparatus is to be arranged on the same principle, 
but, for fear of fracture, may be constructed of cast iron, lined with sheet lead in the 
part containing the mixture. The chief disadvantage of this arrangement is its 
opacity, whereby it becomes impossible to see the contents of the retort, and there- 
fore not BO easy to keep the liquid at its original level. In this case the quantity dis- 
tilling over must be noted and the flow of spirit into the retort regulated accordingly. 
The most convenient mode of proceeding is to have a large stone bottle with a tubu- 
lature at the side near the bottom (like a water filter) to hold the spirit A tube passes 
from the bottle to the retort It has at the end, near the retort or still, a bend downwards 
leading into the tubulature. If a glass still be used it must for ss^fety be placed in a 
sand bath. The distillate obtained, either on the large or small scale, is never pure 
ether, but contains sulphurous and acetic acids, besides water and alcohoL To 
remove these, the distillate is introduced, along with a little cream of lime, into a large 
separating globe, such as that mentioned under Bromine. The whole is to be well 
agitated, and the lime solution then run off by means of the stopcock. The purified 
ether still contains alcohol and water, to remove which it should be rectified in a 
vater bath. The fluid will then constitute the ether of commerce. If the second 
distillation be pushed too far the ether will, if evaporated on the hand, leave an un- 
pleasant after smell, characteristic of impure ether. If wished exceedingly pure, it 
must be shaken up in the separating globe, with pure water. This will dissolve 
the alcohol and leave the ether, contaminated only by a little water, which may be 
removed by digestion with quicklime and redistillation at a very low temperature on 
a hot water bath. 


Pare ether is a colourless mobile liquid, sp. gr. 0*71. It boils at 95° F. The 
density g^ its vapour is 2*56 (calculated)! Gay-Lussac found it 2 '586. 

The word ether, like that of alcohol, aldehyde, &c., is now used as a generic term 
to express a body derived Arom an alcohol by the elimination of water. Many chemists 
write the formula C^ilK), and call it oxide of ethyl in the same manner as they regard 
alcohol as the hydrated oxide of the same radical. But there is no just reason for 
departiog from the law we have laid down with reference to the formules of organic 
compounds. (See Equivalents, Chemical.) We shall therefore write ether CU'^C. 
This view has many advantages. We regard, with Gerhardt and Williamson, ether 
and alcohol as derived from the type water. Alcohol is two atoms of water in which 
one equlTalent of hydrogen is replaced by ethyle; ether is two atoms of water in 
which both atoms of hydrogen are replaced by that radicaL But there are a large 
class of compound ethers procurable by a variety of processes. These ethers were 
long regarded as salts in which oxide of ethyle acted the part of a base. Thus, when 
butyrate of soda was distilled with alcohol and sulphuric acid, the resulting product 
was regarded as butyrate of oxide of ethyle The compound ethers are regarded as 
two atoms of water in which one equivalent of hydrogen is replaced by the radical of 
an alcohol, and the other by the radical of an acid. In addition to those there are 
othen more closely resembling the simple ethers. They are founded also on the 
water type, both atoms of hydrogen being replaced bv alcohol radicals, but by 
different individuals. They are called mixed ethers. The following formulas show 
the chemical constitution of all these yarieties placed for comparison in juxtaposition 
with their type : — 

Hj"^ CH'i"^ C'Hm" C'H'O'S*^ 

Water (3 eqs.) Common etber. Methylo-ethjrlic ethrr. Butjric ether. 

In the above formula the first represents the type water. The second common ether, 
the two equivalents of ethyle replacing the two of hydrogen. In the third, we have a 
mixed ether, one of the equivalents of hydrogen being replaced by ethyle and the other 
by methyle. The fourth illustration is that of a compound ether : one of the hydro- 
gens is there replaced by ethyle, and the other by the oxidised radical of butyric acid. 

Ether is largely used in medicine and chemistry. In small doses it acts as a power- 
ful stimulant Inhaled in quantity it is an ansesthetic. It is a most invaluable solvent 
in organic chemistry for resinous, £itty, and numerous other bodies. — C. G. W. 

ETHER, ACETIC, is used to flavour silent com spirits in making imitation 
brandy, it requires therefore some additional notice beyond the other ethers. It may 
be prepared by mixing 20 parts of acetate of lead, 10 parts of alcohol, and ll| of 
concentrated sulphuric acid ; or 16 of the anhydrous acetate, 5 of the acid, and 4} of 
absolute alcohol; distilling the mixture in a glass retort into a very cold receiver, 
aigitating along with weak potash lye the liquor which comes over, decanting the 
supernatant ether, and rectifying it by re-distillation over magnesia and ground 

Acetic ether is a colourless liquid of a fragrant smell and pungent taste, of spec. 
grav. 0-866 at 45° F., boiling at 166° F., burning with a yellowish flame, and disen- 
gaging fumes of acetic acid. It is soluble in 8 parts of water. 

Acetic ether may be economically made with 3 parts of acetate of potash, 3 of very 
strong alcohol, and 2 of the strongest sulphuric acid, distilled together. The first pro- 
duct must be re-distilled along with one-fifth of its weight of sulphuric acid ; as much 
ether will be obtained as there was alcohol employed. 

ETHIOPS was the name given by the alchemists to certain black metallic prepara- 
tions. Martial ethiops was the black oxide of iron ; mineral ethiops, the black sul- 
phuret of mercury ; and ethiops per se, the black oxide of mercury. 

ETHYLAMINE, C^H'N. An exceedingly volatile base, discovered by Wurtz. 
It is produced in a great number of reactions. Several alkaloids existing in the 
animal and vegetable kingdoms afford ethylamine on distillation with potash. Its 
density at 476°, is 0*964. It boils at 66° F. It is regarded as ammonia in which 
an equivalent of hydrogen is replaced by ethyle. — C. G. W. 

ETIOLATION. Deprived of colour by being kept in the dark. Celery, sea-kale, 
and some other plants are purposely blanched or etiolated by excluding the light, 
this exclusion preventing the formation of chioropkyll, the green colouring matter of 

EUCALYPTUS. The gum tree of the New Hollanders. Mr. Backhouse (Com- 
panion to (he Botanical Magazine) says, " We often find large cavities between the 
annual concentric circles of the trunk filled with a most beautiful red or rich ver- 
milion coloured liquid gum, which flows out as soon as the saw has afforded it an 
openmg. The gum yielded by the Eucalyptus resinifera is considered by druggists 


as not in the least inferior to the kind which the pterocarpos or red saonden 
wood of India prodaces. 

EUDIOMETER, is the name of any apparatus suhservient to the chemical exami- 
nation of the atmospheric ur. It means a measure ofpurityj but it is employed merelj 
to determine the proportion of oxygen which it may contain. The explosive eudio- 
meter, in which about two measures of hydrogen are introduced into a graduated glass 
tube, containing five measures of atmospheric air, and an electric spark is pused 
across the mixtare, is the best of all eudiometers ; and of these, the siphon form pro- 
posed by Dr. Ure in a paper published by the Royal Society of Edinburgh in 1819 is 
the most convenient. 

EUGENIA. A genus of plants of the order Myrtacese, called after Prince Eagene 
of Savoy. 

The most remarkable species of this genus is the allspice, or pimento tree. See 

EUKAIRITE. An ore of silver found in a copper mine in Sweden. According to 
Berzelius it consists of, 

Selenium ------- -26" 

Silver 38*93 

Copper ------.- 23-05 

Earthy matter ----... 890 

Carbonic acid, &c. - - ♦ - - - -3*12 

EUPIONE. A fluid first discovered by Reichenbach in wood tar. All the 
properties of eupione agree with the indifferent hydrocarbons found in Boghead 
naphtha. (See Naphtha, Boghead.) Eupione is so indifferent to the action of 
acids, that it may be repeatedly treated with concentrated oil of vitriol, or fuming 
nitric acid, without any action taking place. Its density varies with the boiling 
point, from 0*633 to 0-740. It is said to be contained among the products of the 
distillation of rape oil. There is no doubt that these hydrocarbons will, eventoallf, 
be of great value in the arts. — C. G. W. 

EURITR A granulous compound of feldspar and quartz, with sometimes garnet 
" It generally occurs as veins, or as local masses in other gpranites, and rarely, I be- 
lieve, as veins traversing other rocks at a distance from granite. These, therefore 
are probably veins of segregation, or of injection during consolidation, and not of sub- 
sequent formation." — Jukes's Student''^ Manual of GeMogy. 

EVAPORATION (Eng. and Fr. ; Abdampfen; Abdunsten, Germ.) is the process 
by which any substance is converted into, and carried off, in vapour. Though ice, 
camphor, and many other solids evaporate readily in dry air, we shall consider, at 
present, merely the vaporisation of water by heat artificially applied. 

The vapour of water is an elastic fluid, whose tension and density depend upon the 
temperature of the water with which it is in contact Thus the vapour rising frcMn 
water heated to 165° F. possesses an elastic force capable of supporting a colomn w 
mercury 10*8 high ; and its density is such that 80 cubic feet of such vapoor codUid 
one pound weight of water ; whereas S2 J cubic feet of steam of the density corre- 
sponding to a temperature of 212° and a pressure of 30 inches of mercury, weigh one 
pound. When the temperature of the water is given, the elasticity and specific grt^^J 
of the vapour emitted by it, may be found. 

Since the yapour rises from the water only in virtue of the elasticity due to itsgsscooi 
nature, it is obvious that no more can be produced, unless what is already incnmbeQt 
upon the liquid have its tension abated, or be withdrawn by some means. Suppose |^' 
temperature of the water to be midway between freezing and boiling, viz. 122°ranr., 
as also that of the air in contact with it to be the same, but replete with moistnre. so 
that its interstitial spaces are filled with vapour of corresponding elasticity audspecitic 
gravity with that given off by the water, it is certain that no fresh formation of vsp^^ 
can take place in Uiese circumstances. But the moment a portion of vapour is sljowea 
to escape, or is drawn off by condensation to another vessel, an equivalent portion oi 
vapour will be immediately exhaled from the water. , 

The pressure of the air and of other vapours upon the surface of water in an open vessel, 
does not preyent evaporation of the liquid ; it merely retards its progress. Expcn*°J® 
shows that the space filled with an elastic fluid, as air or other gaseous body, is ^^^P^r^ 
of receiving as much aqueous vapour as if it were vacuous, only the repletion of *"■ 
space with the vapour proceeds more slowly in the former predicament than in tn 
latter, but in both cases it arrives eventually at the same pitch. Dr. Dalton very 
ingeniously proved, that the particles of aeriform bodies present no permanent o^^. 
to the introduction of a gaseous atmosphere of another kind among them, but ^^^J^ 
obstruct its diffusion momentarily, as if by a species of friction. Uence, exhalation 
atmospheric temperatures is promoted by the mechanical diffusion of the vapoQ^ 


througli the air with Tentilating fans or chimney draughts ; though under hrisk ebul- 
lition, the force of the steam readily overcomes that mechanical obstruction. 

The quantities of water eTaporated under different temperatures in like times, are 
proportional to the elasticities of the steam corresponding to these temperatures. A 
Teasel of boiling water exposing a square foot of surface to the fire, eyaporates about 
725 graiDS in the minute; the elasticity of the yaponr is. equiyalent to 30 inches of 
merenry. To find the quantity that would he eTaporated from the same surface per 
minute at a heat of 88^ F. : — At this temperature the steam incumbent upon water is 
capable of supporting 1*28 inch of mercury ; whence the rule of proportion is 30 : 
1*^8 :: 725 : 30*93 ; showing that about 31 grains of water would be eTaporated in 
the minute. If the ur contains already some aqueous vapour, as it commonly does, 
then the quantity of CTaporation will be proportional to the difference between the 
elastic force of that Tapour, and what rises from the water. 

Suppose the air to be in the hygrometric state denoted by 0-38 ut an inch of 
mercury, then the aboTC formula will become 30 : 1-28 — 0*38 : : 720 ; 2 1 '41 ; show- 
ing that not more than 21^ grains would be evaporated per minute under these 

The elastic tension of the atmospheric Tapour is readily ascertained by the old ex- 
periment of Le Roi, which consists in filling a glass cylinder (a narrow tumbler for 
example) with cold spring water, and noting its temperature at the instant it be- 
comes so warm that dew ceases to be deposited upon it This temperature is that 
which corresponds to the elastic tension of the atmospheric Tapour. See Vapouh, 
Table ot 

TV'heneTCT the elasticity of the Tapour, corresponding to the temperature of the 
water, is greater than the atmospheric pressure, the evaporation will take place not 
only from its surface, but fh>m CTery point in its interior ; the liquid particles 
throughout the mass assuming the gaseous form, as rapidly as they are actuated by 
the caloric, which subTcrts the hydrostatic equilibrium among them, to constitute the 
phenomena of ebullition. This turbulent vaporisation takes place at any temperature, 
CTen down to the freezing point, provided the pneumatic pressure be remoTed from 
the liquid by the air pump, or any other means. Ebullition always accelerates eva- 
poration, as it serves to carry off the aqueous particles not simply from the surface, 
but from the whole body of the water. 

The Tapours exhaled from a liquid at any temperature contain more heat than the 
fluid fh>m which they spring ; and they cease to form whenever the supply of heat 
into the liquid is stopped. Any volume of water requires for its conversion into 
Tapour about y?o« iimu as much heat as is sufficient to heat it from the freezing to the 
boiling temperature. The heat, in the former case, seems to be absorbed, being inap- 
preciable by the thermometer; for steam is no hotter than the boiling water from 
which it rises. It has been therefore called by Dr. Black, latent heat; in contradis- 
tinction to that perceived by the touch and measured by the thermometer, which is 
called setuiMe heat The quantity of heat absorbed by one Tolume of water in its con- 
Tersion into steam, is about 1000^ Fahr. ; it would be adequate to heat 1000 volumes 
of water, one degree of the same scale. Were the vessel charged with water so 
heated, opened, it would be instantaneously emptied by vaporisation, since the whole 
caloric, equiTalent to its constitution as steam, is present When upon the other hand, 
steam is condensed by contact with cold substances, so much heat is set free as is 
capable of heating about fiTC times its weight of water fW>m 32^ to 212^ F. 

Bqual weights of vapour of any temperature contain equal quantities of heat ; for 
example, the vapour exhaled fVom one pound of water, at 77® F., absorbs during its 
formation, and will give out in its condensation, as much heat as the steam produced by 
one pound of water at 212® F. The first portion of vapour with a tension » 30 inches, 
occupies a space of 27*31 cubic feet ; the second, with a tension of 0-92 inch, occupies 
a space of 890 cubic feet* Suppose that these 890 volumes were to be compressed 
into 27*31 in a cylinder capable of confining the heat, the temperature of the vapour 
would rise from 77® to 212®, in Tirtne of the condensation, as air becomes so hot by 
compression in a syringe, as to ignite amadou. The latent heat of steam at 21 2® F. is 
1180^ — 180 » 1000; that of Tapour, at 77®, is 1183— 45»1135 ; so that, in fact, 
the lower the temperature at which the Tapour is exhaled, the greater is its latent heat, 
as Joseph Black and James Watt long ago proved by experiments upon distillation 
and the steam engine. 

From the preceding researches it follows, that evaporation may be effected upon 
two different plans : — 

I. Under the ordinary pressure of the atmosphere; and that either, 

* One pound avoirdupolf of water conUina 27 72 cubic Inches ; one cubic inch of water Tormi 1696 
cubic inches of steam at 212P F. : therefore one pound of water will form 27'31 cubic feet of such steam ; 
atidOi» : 30 :: 27*31 : S90 cubic iieet. 


A, by exteraal application of heat to boilers, with a, an open fire ; b, Bteam; c, hot 
liquid media, 

B, by evaporation with air ; a, at the ordinary temperature of the atmosphere ; i, 
by carrentB of warm air. 

2. Under progressively lower degrees of pressure than the atmospheric, dovn to 
evaporation in as perfect a Tacuum as can be made. 

It is generally iiffinned, that a thick metallic boiler obstmcts the passage of the 
heat through it so much more than a thin one* as to make a considerable di£ferencein 
their relatlre powers of evaporating liquids. Dr. Ure states that he made a series of 
experiments upon this subject. Two cylindrical copper pans, of equal dimensions, 
were provided ; but the metal of the one was twelve times thicker than that of the 
other. Each being charged with an equal volume of water, and placed either apoD 
the same hot plate of iron, or immersed, to a certain depth, in a hot solution of muriate 
of lime, he found that the ebullition was greatly more vigorous in the thick than 
in the thin vessel, which he ascribed to the conducting substance up the sides, above 
the contact of the source of heat, being 12 times greater in the former case than in the 

If the bottom of a pan, and the portions of the sides, immersed in a hot fluid mediam, 
solution of caustic potash or muriate of lime, for example, be corrugated, so as to con- 
tain a double expanse of metallic surface, that pan will evaporate exactly doable the 
quantity of water, in a given time, which a like pan, with smooth bottom and aides, 
will do immersed equally deep in the same bath. If the corrugations contain three 
times the quantity of metallic surface, the evaporation will be threefold in the above 
circumstances. But if the pan, with the same corrugated bottom and sides, be set 
over a fire, or in an oblong flue, so that the current of flame may sweep along the cor- 
rugations, it will evaporate no more water from its interior than a smooth pan of lilie 
shape and dimensions placed alongside in the same flue, or over the same fire. This 
curious fact Dr. Ure states he has verified upon models constructed with many modi- 
fications. Among others, he caused a cylindrical pan, 10 inches diameter, and 6 
inches deep, to be made of tin-plate, with a vertical plate soldered across its diameter; 
dividing it into two equal semi-cylindrical compartments. One of these was smooth 
at the bottom, the other corrugated ; the former afiPorded as rapid an evaporation over 
the naked fire as the Utter, but it was far outstripped by its neighbour when ploogcd 
into the heated liquid medium. . 

If a shallow pan of extensive surface be heated by a subjacent fire, by a liqtud 
medium, or a series of steam pipes upon its bottom •, it will give off less vapour in the 
same time when it b left open, than when partially covered. In the former case, the 
cool incumbent air precipitates by condensation a portion of the steam, and also op* 
poses considerable mechanical resistance to the diffusion of the vaporous partiel^ 
In the latter case, as the steam issues with concentrated force and velocity from tbe 
contracted orifice, the air must offer less proportional resistance, upon the kno^ 
hydrostatic principle of the pressure being as the areas of the respective bases of tne 
communicatmg vessels. , . , 

In evaporating by surfaces heated with ordinary steam, it must be borne in mino 
that a surface of 10 square feet will evaporate fully one pound of water per minote, or 
725 X 10 a- 7250 gr., the same as over a naked fire ; consequently the condensing ajf* 
face must be equally extensive. Suppose that the vessel is to receive of water 2500 lt*i 
which corresponds to a boiler 5 feet long, 4 broad, and 2 deep, being 40 cubic feet d) 
measure, and let there be laid over the bottom of this vessel 8 connected tubes, eac 
4 inches in diameter and 5 feet long, possessing therefore a surface of 4'8 feet sqoare. 
If charged with steam, they will cause the evaporation of half a pound of ^'^'-^^^ 
minute. The boiler to supply the steam for this purpose must expose a surface of 4 
square feet to the fire. It has been proved experimentally that 10 square feet sorfac^ 
of thin copper can condense 3 lbs. of steam per minute, with a difference of ^^^^jjf^^ 
ture of 90 degrees Fahr, In the above example, 10 square feet evaporate 1 »b. o^ 
water per minute; the temperature of the evaporating fluid being 212° F, codsR' 
quently 3:1 : : 90 : ^. During this evaporation the difference of the ^^V^^}^.^ 
therefore ■» 80°. Consequently the heat of the steam placed in connection *'^'' f^ 
interior of the boiler, to produce the calculated evaporation, should be, 212 + 80* 
242°, corresponding to an elastic force of 536 inches of mercury. Were the tempe- 
rature of the steam only 224, the same boiler in the same time would ?^^^^. 
minished quantity of steam, in the proportion of 12 to 80 ; or to produce the sam 
quantity the boiler or tubular surface should be enlarged in the proportion of 30 
12. In general, however, steam boilers employed for this mode of evaporation are 
such capacity as to give an unfailing supply of steam. f 

We shall now illustrate by some peculiar fonns of apparatus, different systems 
evaporation. Fig. 729 explains the principles of evaporating in vacua A B rep ' 



sent* a pan or kettle eharged with the Uqaor to be evaporated. The aomewhat wide 
oriiloe c, aeeored with a iorew-plog, serves to admit the hand for the purpose of 


deanini^ it thoroughly out when the operatioo is finished ; A is the pipe of commnni-* 
cation wi^ the steam boiler; 6 is a tube prolonged and then bent down with its end 
plnnged into the liquor to be evaporated, contained in the charging back (not shown 
in the figure). H is a glass tube communicating with the vacuum pan at the top and 
bottom, to show by the height of the column the quantity of liquid within. The 
eduction evaporating pipe c is provided with a stop-cock to cut off the communication 
when required, t is a tube for the discharge of the air and the water from the steam- 
case or jacket ; the refrigerator b is best formed of thin copper tubes about I inch in 
diameter, arranged aig-zag or spirally like the worm of a still in a cylinder. The 
small air-tight condenser f, connected with the efflux pipe/ of the refrigerator, is 
famished bdow with a discharge cock y, and surrounded by a cooling case, for the 
collection of the water condensed by the refrigerator. In its upper part there is a 
tube k, also furnished with a cock, which communicates with the steam boiler, and 
through which the pan a b is heated. 

The operation of this apparatus is as follows: after opening the cocks c,/, g, and- 
before admitting the cold water into the condenser e, the cock of the pipe k is opened, 
in order that by injeeting steam it may expel the included air ; after which the cocks 
k and ^ are to be shut The water must now be introduced into the condenser, and 
the cock b opened, whereon the liquid to be eyaporated rises from the charging back, 
through the tube b, and replenishes the vacuum pan to the proper height, as shown by 
the register glass tube h. Whenever the desired eyaporation or concentration is 
^ectcd, the cock c must be closed, the pipe A opened, so as to fill •the pan with steam, 
and then the efflux cock a is opened to discharge the residuary liquor. By shutting 
the cocks a and k, and opening the cock 6, the pan will charge itself afresh with liquor, 
and the operation will be begun anew, after b has been shut and c opened. 

The contents of the close water cistern r, may be drawn off during each operation. 
For this purpose, the cock /must first be shut, the cold water is to li^ then run out of 
the condenser a, and k and g are to be opened. The steam entering by k makes the 
water flow, but whenever the steam itself issues from the cock g, this orifice must be 
immediately shut, the cocky opened, and the cold water again introduced, where- 
upon the condensed water that had meanwhile collected in the under part of the 
refrigerator, flows off into the condenser vessel f. Since some air always enters with 
the liquor sucked into the pan, it must be removed at die time of drawing off the 
water from the two condensers, by driving steam through the apparatus. This 
necessity will be less urgent if the liquor be made to boil before being introduced into 
the vaenumpan. 

Such an apparatus may be modified in sise and arrangement to snit the peculiar 

You IL M 


object in Tiew, vhen it will be perfectly adapted Ka the eoneentraltoii of eitrMi df 
tvery kind, aa well oa taliiw lolation* containiDg vegetable acidt or alkBlia. TW 
interior vessel x b should be made of tinned or plated copper. For an ucoDiil li 
Howard's vacnom pan, made upon the same principte, tee Sdgab. 

When B boiler is eel over a fire, its bottom should not be placed too near Hu ptx. 
lest il refrigerate the Same, and prevent that virid combustloo of the fuel esseuSil u 
the maximum production of heat bj its means. The evil iofluence of leninp us 
lillle room beloeea the grate and the copper maj' be illustrated bj a veij liniple 
ciperimeot. If a small copper or porcelain capsule containing water be held oiir 
tbe flame of a candle a lillle way abuve its apex, the flame will suffer no sbslesml if 
brightaessor siic, but will continue to keep the water briskly boiling. If tlic opiiie 
be now lowered into the middle of the flame, this will immediately lose its bngblwa, 
becoming doll and smoky covering the bottom of tbe capsule with soot ; and. ovin; 
to the imperfect combustion, though the water is now surronnded by the Bu», in 

burned. For coal, the grale should be set higher and be somewbat smaller. >> i* i^l 
door for feedinglhe flroi rf, an arch of flre-bricka over the hearth; e, a grste tin™?' 
which the ashes fall Into the pit beneath, capable of beiog closed in front wl 
extent by a sliding door b, a and c are two coppera encased in brickworks /l" 
flue. At tbe end of the hearth near m, where the fire plays first upon the n^fi 
the sole it made si mewhat lower and wider, tu promote the apreading of the nn 
imder the vessel The second copper c, receives the benefit of the waste ^'^ 
nay be placed upon a higher level, ao as to discharge its concentrated liqaol 'V * 
■top-cock or siphon into the first 

Fig. 731 represents a pan for evapora^ag Uquids, which are apt, daring coaw'"'* 
tion, to let fall crystals or other sediment. . 

Tbeao woold be Injured either bf IM '" 
playing upon the bottom of Ike pafr "'^ 
adhesion to it, they would allow ike a'^,'^ 
get red hot, and in that stale ran every r« 
of being burnt or rent on the suddaa B"^ 
of a little liqoor through the i"'™'*''^ 
When Urge coppers have their «*'<"' 
planted in loam, so that the flame "l^jj 
in flues round their sidea, they are said » 
cM-tet, , , 

A is a pear-shaped pan, charged wi» " 
liquid 10 be eraporatod ; it i« fBrnuheii ™ 
a dome cover, in which there is sa op""! 
with a flange/, fur attaching a tube, <■" ™' 
duct the steam wherever it may be ■^"IT 
a is tbe fire-place; i, the ash-p"- '" 
conical part lerminatea below in ihem"'' 
furnished with a stop-cock al i" oofilt 
Through the tobe cdrf. fVimished il»« *?: 
below with the stop-cooks c and e\ "^j^ 

During the operation, ttw upper cock i 


it crmpontM ; bat the nnder cock c' ii Rhat. Tlie flame fron tlM fire-place pU;a 
Tonnd the keole in tbe ipkoe (, and the emoke eecftpea downvardB thnnigh ihe floe i 
into the chimnej. The lower cylindrieal part g Tcmaini thoa compara^Tety cool, 
mud coUecta the crjatalline or other aoJid inatler. Alter acme time, the imder atop- 
cock c', npco the aapply-iupe, ia la be opened to admit aome of the cold liquor into 
the cylindrical neck. That cock being agaia shut, the a«dimeiit aettled, and the 
large atop-coek (a hoTiaontal side valve would be prefetuble) h opened, tbe cryitala 
are (uSeiied Ui descend intothe mbjaeent reoeivcr; after which the stop-cock Aiaihnt 
and the opeiatinn ia cootinned. A conitraction upon thia principle ii well adapted 
for beating dyeing coppers, in which the sediment should not be dutarbed.or eipoaed 
to tbe action of the Bre. The fire-place should be built la for the brewing copper. 

Fig. TSfi representa an obkmg evaporatiag pan, in vhicb the flamey ^r beUiag 
alimg ita bottom, tama 
Dp at ila flirther end, 
plays back along iu 
8Dl&x,aTid paaaeaoff 
iDlo tbe chimney. A. 
ia a rectangtUarreaari, 
from 10 to 15 feet 
long, 4 to 6 feel brood, 
and I or 1} feet deep. 
The fire bricka, Dpon - 
Tbiehthe put retcs.are so arranged as to distribvte the flame eqoBlly along its bottom. 
Leidenfroat in 175fl ('liuu^ ^ C%Miie)obaervedsome remarkable facta connected 
with cTaporatioD, which have tinee received aome striking illBBtratioa ftvm the 
experiments of M. Boaligny. 

When water is thrown on a plate heated considerably above the boiling point of 
water, the liqoid aatomea a spheroidal form,and thia condition liaa hence received the 
name of the "ipbercndml atate." Thia water rolla aboat like melted crystal wilhoat 
any ai^oa of ebollitioa, and K ia dissipated bat very alowly. The explanation nsnally 
pven IB M ftdlows : — >* Tbe canse of the phenomena appears to be this, water eibibiU 
anattractian for the eorfaM ofalmostallaolids, and well them; flnid mercary eibibits 
the oppoeite property, or repulsion for moat snrfaces. Tbe attraction of water fbr 
nrfoces brings it into the closest contact with them, and greatly promote! the com- 
monieatiMi of heat by a heated vessel to the water contained in it. But heat appean 
to develope a repnlaive power fat bodies, and it is probable that, above * pecnliar tem- 
peratoie, (he healed metal no longer poeeessel this attraction for water. The water 
not being attracted to the snrftce of the hot metal, and induced to spread over it, ii 
not rapidly heated, and therefore Ixnls off slowly." — Oraiam. 

The explanation given by this excellent aalhority on all melteia connected with 
phyaico-chenical acience has been selected as representing feirly tbe prevailing 
view. It is not, however, quite satisfkctory. The water is swd to be at a sensible 
distance from the hot plate, and a layer of aqneons vaponr of very high temperature 
is known to sarronnd tbe water, and yet the spheroidal Irater does not acquire the 
boiling temperature. Here ia evidence of some peealiar, and as yet □nexplaioed 
cooditKM, beloDginR, difaer to heat of a certain kind or degree, or to the molecules of 
tbe bod^ onder ib mfloence. 

Boat^ny obaerred that water may pas* into the spheroidal slate at any temperature 
■bore S*<fiV^ and remain in that state imtil the temperatore falls to 388° F., when 
evaporation rapidly eamei. Ether and alcohol pas* into the spheroidal atate at I ia° F. 
■nd 373° F. A thermometer being plunged in liquid* while in the spheroidal stale, 
indi cale d tbe following temperatures j — 

Water BOS-TOf. 

Absolute alcobol 1G79 

Ether • 936 

HfdrooUorie ether 60-9 

SolphnroDS acid ----.. 13-1 

All these bring some degrees below the boiling tempenitBre of thoae fluids. 

BoDligny has shown that the vapoor escaping &Dm water in the spheroidal stale, 
■Ithongh it liBB a very elevated temperature, does not possess the usual eltuticity of 
steam ; it does not exert an expansive power. But if the vessel ftnm which tbe 
'Vapour is forming is allowed to cool, to a certain point, a degree of elaslieitj equal to 
the elevated temperature of the vapour Is suddenly exerted. This is supposed by 
Boatigny to explain many steam boiler eiploeions. 

Whenever evaporation takes place, it should be remembered. It produces cold 
— that is, it lowers the temperature of the body &om which the evapontion is taking 



•place. Leslie, hj the eraporation of ether in Taciio» teaxe merciiTy. Thilorier 8o& 
dified carbonic acid by the intense cold produced by its own eYaporatiom. Bontigny 
froze water in a red hot vessel, by the evaporation of sulphoroos acid from the heated 
vessel in which the water is in the spheroidal state. 

Further remarks on these points, will be found under the heads respectively of 
Coal, Steam Boii^eiis, Vapoub. 

EXOSMOSE and ENDOSMOSE. As some manafactnring processes involT« the 
phenomena expressed by these two words, it appears necessary briefly to explain tbem. 

When two liquids are separated by a porous sheet of animal membrane, mglaced 
earthenware, porous stone, or clay, these liquids gradually diffuse themselves; and 
supposing salt and water to be on one side of the division, and water only on the 
other, the saline solution passes in one direction, while the water, tiiiough with less 
intensity, passes in another. 

Instead of the two words introduced by Dutrochet, Professor Graham proposes the 
use of the single term Osmose (from ^/<o;, impulsion). 

It was supposed that there was, at the same time, an impulsive force acting from without 
and another acting from within ; that there was indeed a current^otoin^ in, and another 
flowing out It however appears to be proved that the osmose between water and saline 
solutions, consists not in the passage of two liquid currents, but in the passage of particles 
of the salt in one direction, and of pure water in the other. Professor Graham has 
observed, that common salt diffuses into water, through a thin membrane of ox-bladder 
deprived of its outer muscular coating, at the same rate as when no membrane is 
interposed. This force plays an important part in the functions of life, and it will be 
found to explain many of the phenomena associated with Dyeing, Tanning, &e. 

EXOGENOUS. A botanical term, signifying growing by addition to the enter parts 
of the stem. 

The stem varies in structure in four principal ways. It is either formed by succes- 
sive additions to the outside of the wood, when it is called exogenous, or by sncceasive 
additions to its centre, when it is called endogenous^ or by the union of the bases of leav^ 
and the extension of the point of the axis, which is called acrogenous, or by simple 
elongation or dilatation where no leaves or buds exist, as among Thalhgens, — JJndUg, 

EXPANSION (Eng. and Fr.; Ausdehnungy Germ.) is the increase of bulk ex- 
perienced by all bodies when heated, unless a change in molecular arrangement takes 
place, as in the case of clays in the potter's kiln. 

Table I. exhibits the linear expansion of several solids by an increase of temperature 
from Z^ to 212<> Fahr.; Table II. exhibits the expansion in bulk of certain liquids. 

TABLE I.— Ztneor Dilatation of SoUds hy Heat. 
Dimensions which a bar takes at 212^ whose length at 32^ is l-OOOOOa 





in Volgv 



Glass tube - 


m m 











Deluc*s mean 

1 •00062800 




m m 

Dulone and Petit 






Lavoisier and Laplace 



Plate gUus 



da do. 



do. crown glass 


do. do. 

1 -00087572 


do. do. 



do. do. 



do. do. 



do. do. 

1 •00091751 

do. red 


m m 

Roy- - 




m m 

Roy, as glass 


Platina . 





do. - 



Dulong and Petit - 






Tfoughton • 


do. and glass 



' Berthoud 


Palladium - 



Wollaston - 


Antimony - 





Cast-iron prism 



Roy - 


Cast-iron - 



Lavoisier, by Dr. Young 





Trougbton - 


Steel rod - 





Blistered steel 



Phil. Trans. 1795, 428 




m m 










in Vulgar 

Steel not tempered - 


LsToiuer and Laplace 

1 00107875 


do. do. - 


da da 

1 -0010795^ 


do. tempered yellow 


da do. 

lOOl 36900 

do. dOb do. 


da da 


dow da da at a higher heat 

do. da 



Steel ... 


Trooghton - 


Hard ited . . - 



1 -00122500 

Amiealed steel 



1 -001 22000 

Tempered steel 


do. . - 


Iron . • - 




da - - - 




Soft iron, forged - 


LaToisier and Laplace 


Round iroo» wire drawn 


do. da 


Iron wire • - - 


Trottghton * •• 


Iron • - - 


Dulong and Petit 



Bismnth . . - 




Annealed gold 




Gold - - - 


Ellicot, by comparison 


do. procured by parting - 


Lavoisier and Laplace 



da Paris stan&rd, unannealed 


do. do. 


do. da annealed 


do. do. 



Copper - . - 




a • 

do. - . - 


LsToisier and Laplace 



da - - - 


da do. 



da - - - 


Troughton - 


d<\ * • . 


DuIoDg and Petit 



Brass ... 




da • - • 


LsToisier and Laplace 


do. - • - 


do. da 


Brass seale, supposed from Hambmrg 

Roy - . - 


Cast brass . . - 


Smeaton * * 


English plate-brass, in rod - 




do. da in a troagh form 

do. - 


Brass ... 


Troughton • 


Brass wire - - . - 



1 -00193000 





Copper 8; tin 1 




SUver ... 




da - - - 


Ellicot, by comparison 


da - - - 




do. ofeapel 


Lavoisier and Laplace 

1 •00190974 


da Paris standard 


do. do. 



SilTer - - . - 


Troughton • 


Brass 16, tin 1 




Speculum metal 




Spolter solder; brass 2, sine 1 




Malacca tin • * 


LaToisier and Laplace 



Tin from Falmouth 


da do. 



Fine pewter - • 




Grain tin - 




Tin - - - 



1 -00284000 

Soft solder; lead S, tm 1 - 




Zioc 8, tin 1, a little hammered 



1 -00269200 

Lead ... 


Lavoisier and Laplace 

1 -00284836 


do. . • • 


1 -00286700 

Zinc ... 



1 -00294200 

Zinc, hammered out \ inch per foot- 



Glass, from S20 to 21 S^ - 

Dulong and Petit • 



do. from212«>to392« - 


do. da 

1 00091827 

do. from 392«> to 572° - 


do. da 


Tlie last two measurements by an air thermometer. 

H 3 



TABLE IL^Expansion of certain Liqmdi hy being heated from, 32° to 21S<>« 




In Vulgar 


Mercary - - - - - 

Da]ong and Petit. - 



da in glass - - - 

da do. 



Water ftrom itt maximam density 

Kirwan - • - 



Muriatic acid (sp. gr. 1*137) 

Dalton - - - 



Nitric acid (sp. gr. 1-4Q) - 

da - - - 



Sulphuric acid (sp. gr. 1'85 ) 

da - - - 



Alcohol (to its boiling point) ? - 

do. - 




da - - - 



Water, saturated -with common salt 

da . . - 



Sulphuric ether (to its boiling point ) ? 

do. - 



'Fixed oils - - - - - 

da - - - 



Oil of turpentine - - - - 

da - - - 




1-04734 ; 

If the density of water at 39° be called 

at 212° it becomes - - - - 
and its volume has increased to - • 
at 77° it becomes - - - - - 
and its Tolnme has increased to only 
which, though one fourth of the whole range of temperature, is only ^ of the tots! 
expansion. Water at 60° F. has a specific gravity of - 0-9991253, 

and has increased in volume firom 39° to 1*00008, 

which is only about ^ of the total expansion to 212°, with qJ, of the total range of 

All gases expand the same quantity by the same increase of temperature, which 
fW>m 32° to 212*=^ Fahr.eii{° »}, or 100 volumes become 1'375. For each degree of 
Fahr. the expansion is ^y. 

When dry air is saturated with moisture, its bulk increases, and its specific gravity 
diminishes, because aqueous vapour is less dense than air, at like temperatures. 

The following Table gives the multipliers to be employed for converting one vdnme 
of moist gas at the several temperatures, into a volume of dry gas. 





63* F. 











































l^voisier and Laplace arrived, after an extenshre series of experiments, at the two 
important conclusions following : — 

Ist. All solid bodies whatever, being graduaHy heated fh>m the temperature of 
meltin|^ ice to that of boiling water, and Uien gradually cooled from the temperature 
of boilmg water to that of melting ice, will be found to have exactly the same dimen- 
sions at the same temperature during the process of heating and cooling; the gradual 
diminution of bulk in cooling corresponding exactly wil£ the gradiud increase of 
bulk in heating. 

2nd. Glass and metallic bodies gradually heated from the temperature of melting 
ice to that of boiling water, undergo degrees of expansion proportional to those <^ 
mercury at the same temperature ; that is to say, between die limits just men^ooed, 
the expansion of the solid corresponding to two degrees of the thermometer, is twice 
the expansion which corresponds to one degree, the expansion which corresponds to 



tbree degrees is three times the expansion which correspondfl to one degree, and so 
on ; the quantity of expansion being multiplied in the same proportion as the number 
of degrees through which the thermometer has risen is multiplied. See Heat, 
Lanbur^M Cj/dopeduu 

Experiments bj Fresnel, Forbes, Powell, Treyelyan, and Tyndal have a tendency 
to prove that heat occasions a repulsion between the particles of matter at small dis- 
tances. If a heated poker is laid slantingly on a block of lead at the ordinary tempe- 
rature, it will commence to vibrate, first slowlv, and will increase with such rapidity 
as to produce a musical note, which continues for some time, usually changing to an 
octave at the termination. These results would appear to prove a movement amongst 
the particles constituting the bar. 

Some remarkable examples of expansion are fdmished by the influence of sunshine 
on the Britannia Tubular Bridge. 

The most interesting effect is that produced by the sun shining on one side of the 
tube, or on the top, while the opposite side and bottom remain shaded and compara- 
tively cool ; the heated portions of the tube expand, and thereby warp or bend the tube 
towards the heated side, the motion being sometimes as much as 2^ inches vertically 
and 2^ inches laterally. 

While the tubes were supported on the temporary piers on the beach, these motions 
were easily observed. An arm carrying a pencil was fixed on the south side of the 
tabe, at the centre, and a board was fixed on a post independent of the tube, and at right 
angles to it; the pencil was pressed against the board by a spring, and the rise and fall, 
and the lateral motions of the tube, were consequently placed on the board. In this way 
a very interesting diagram was taken daily. The lowest part of each figure is the 
starting point, or normal position of the tube, to which the pencil always accurately 
returns during the night. As soon as the sun rises in the morning it starts towards 
the ri^t hand, rising obliquely, the top and one side of the tube being warmed, and 
the bottom and opposite side remaining unaffected. It continues thus till one o'clock, 
when the sun, having ceased to shine on the southern side, begins to warm the 
northern side, the top still retaining its high temperature, the tube thus acquires a 
nearly horisontal motion towards the left hand, the slight descent in the line indicating 
the diminished effects of the sun on the top as it gradually sinks. The greatest deflec- 
tion to the left hand is not attained until sunset, after which the tabe rapidly descends 
in a uniformly curved line to its resting point In the summer time this point is hardly 
attained before the rising sun compels it to commence its journey anew. When the 
sun is frequently obseured by passing clouds, very curious disigniins Are obtained. 
During the absence of the sun the tube begins to cool rapidly, and to return to its 
normal position, every passing cloud is thus beautifully recorded. 

The middle of the centre arch of Southwark Iron Bridge rises one inch in the 
height of summer. Wfaflta great lengths of iron pipe are laid down for the convey- 
ance of steam or hot water, sliding joints are necessary to prevent destruction either 
of the apparatus or of the building in which it is placed. 

The practical applications made of the expansion and contraction of metals by heat 
are many. The tire of a wheel is put on hot, and by its contraction on cooling, 
firmly binds the other parts of the wheel together ; boiler plates are riveted wiUi 
red-hot rivets ; collars of metal are driven on while hot, and the like. 

MoUard drew together the walls of a building that had bulged, by screwing up 
ban of iron tight to the walls while they were hot, and a similar process was adopted 
in the Cathedral of Armagh. 

Playfair and Joule (Chemictd Society's Memoiri) have made a valuable series of re- 
searches on the expansion of bodies by heat, principally salts ; these have not how- 
ever any soflicient practical bearing to occupy our space. 


EXTRACTS. (Extraitg, Fr; Extracten, Germ.) The older apothecaries used 
this term to designate the product of Uie evaporation of any vegetable juice or in- 
fusion, or decoction ; whether the latter two were made with water, alcohol, or ether ; 
whence arose the distinction of aqueous, alcoholic, and etherous extracts. 

Foarcroy made many researches upon these preparations, and supposed that they 
had all a common basis, which he called the extractive principle. But Chevreul and 
other chemists have since proved that this pretended principle is a heterogeneous and 
very vmriable compound. By the term extract therefore is now meant merely the 
whole of the soluble matters obtained from vegetables, reduced by careful evaporation 
to either a pasty or solid consistence. The watery extracts, which are those most com- 
monly made, are as various as the vegetables which yield them ; some containing 
chiefiy sogar or gum in great abundance, and are therefore innocent or inert ; while 
others contain very energetic impregnations. The conduct of the evaporating heat is 
the capital point in the preparation of extracts. They should be always prepared if 

M 4 


possible, from the jaice 6f the fresh plant, by sabjectiag its leflves <nr other snccnient 
part, to the action of a powerful screw, or hydraulic press ; and the CTaporation shoold 
be effected by the warmth of a water bath, heated not beyond 100° or 120 F. Steam 
heat is now applied advantageously in some cases, where it is not likely to decom* 
pose any of the principles of the plant But by far the best process for makbg 
extracts is in vacao, upon the principles explained in the article Etaporation. It is 
much easier to fit up a proper apparatus of this kind, than most practical men imagine. 
The vacuum may either be made through the agency of steam, as there pointed oot, 
or by means of an air-pump. One powerful air-pump may form and maintain a good 
vacuum under several receivers, placed upon the flat ground flanges of so many bssios, 
each provided with a stop-cock at its side for exhaustion. The air-less basin con- 
taining the juice being set on the shelf of a water-bath, and exposed to a proper tem- 
perature, will furnish in a short time a large quantity of medicinal extract, posscssiiig 
the properties of the plant unimpaired. 

For exceedingly delicate purposes, the concentration may be performed in the eold, 
by placing saucers filled with the expressed juice over a basin containing snlphorie 
acid, putting a glass receiver over them, and exhausting its air. 

The use of the air-pump for evaporating such chemical substances as are retdilj 
injured by heat, has been very coumion since Professor Leslie's discovery of the 
efficacy of the combined influence of rarefied air and an absorbing surface of sulphone 
acid in evaporating water at low temperatures. It has been supposed that the virtna 
of narcotic plants in particular might be better obtained and preserved by evaporttioa 
in vacuo than otherwise, as the decomposing agency of heat and atmospheric oxygen 
would be thereby excluded. There is no doubt that extracts thus made from the 
expressed juices of fresh vegetables possess for some time at least, the green aspect 
and odour of the plants in far greater perfection than those usually made in the air, 
with the aid of artificial heat. Dr. Meurer, in the Arckiv, der PHarmade for April, 
1843, has endeavoured to show that the colour and odour are of no use in determioiog 
the value of extracts of narcotics, that the albumen left unchanged in the extracts 
made in vacuo, tends to cause their spontaneovs decomposition, and that the extracts 
made with the aid of alcohol, as is the practice in Grermany, are more efficacious at 
first, and much less apt to be injured by keeping. M. Baldenius has, in the same 
number of the Archiv^ detailed experiments to prove that the juices of recent plants 
mixed with alcohol, in the homcsopathic fashion, are very liable to spontaxieoos 
decomposition. To the above expressed juicC) the Germans add the alcoholic tincture 
of the residuary vegetable matter, and evaporating both together, prepare very powerfol 


FACETTING. The process of cutting faces upon ornamental articles. Steel 
jewellerv, such as beads, studs, buttons, — the ornaments on the hilts of dress-swords 
and similar objects, are ground on horizontal laps with fine emery. Facets on gold 
and silver are cut and polished on revolving wheels, after the same general metiiod 
as that pursued by the lapidary for cutting facets on stones. 

FACTORY. In the sense in which this term is introduced here, it is contracted 
from manufactory ; meaning the place where workmen are employed in fabricathig 
goods. To describe all the various fiictories, would be to describe all the diffJereDt 
manufactures, or, at leasts the arrangements of the machines by which the raw material 
is converted into marketable goods. There is but one kind of factory which will be 
described in this place. The arrangements of a cotton factory fairly represent all the 
arrangements for other branches of textile manufactures, and here this is specially 
described. Under Silk, Wool, &c., will be found particulars of the machines used and 
their general arrangements in these factories respectively. 

Factory, Cotton (General Construction of). There is no textile substaoce 
whose filaments are so susceptible of being spun into fine threads of uniform tvist, 
strength, and diameter, as cotton wool. It derives this property from the smoothness, 
tenacity, flexibility, elasticity, peculiar length, and spiral form of the filaments ; hence, 
when a few of them are pulled from a heap with the fingers and thumb, they lay hold 
of and draw out many others. Were they much longer they could not be so readilj 
attenuated into a fine thread, and were they much shorter the thread would be deficient 
in cohesion. Even the differences in the lengths of the cotton staple are of advantage 
in adapting them to difierent styles of spinning and different textures of doth. 

If we take a tuft of cotton wool in the left hand, and seizing the projecting fibres 
with the right, slowly draw them out, we shall perceive with what remarkable &cUity 


they gUde past each other, and yet retain their mntual connection, while they are 
extended and arranged in parallel lines, so as to form a little riband susceptible of 
considerable elongation. This demonstration of the dactility, so to speak, of cotton 
irooU auoceeds still better upon the carded fleece in which the filaments have acquired 
a oertain parallelism ; for in this case the tiny riband, in being drawn out by the fingers 
to a moderate length, may at the same time receire a gentle twist to preserve its co- 
hesion till it becomes a fine thread. 

Hence we may imagine the steps to be taken or the mechanical processes to be 
pursued in cotton spinning. After freeing the wool of the plant from all foreign 
substances of a lighter or a heavier nature, the next thing is to arrange the filaments in 
lines as parallel as possible, then to extend them into regular ribands, to elongate these 
ribands by many successive draughts, doubling, quadrupling, or even octupling them 
meanwhile, so as to give them perfect equality of sixe, consistence and texture, and at 
the same time to complete the parallelism of the fibres by undoing the natural convo- 
lotions they possess in the pod. When the rectilinear extension has been thus carried 
to the fineness required by the spinner, or to that compatible with the staple, a slight 
degree of torsion must accompany the further attenuation; which torsion may be either 
momentary, as in the tube roving machine, or permanent, as in the bobbin and fly 
frame. Finally, the now greatly attenuated soft thread, called tkfihe roving, is drawn 
oot and twisted into finished cotton yam, either by continuous indefinite gradations 
of drawing and twisting, as in the throstle, or by successive stretches and torsions of 
considerable lengths at a time, as in the mule. 

Mechanical spinning consists in the suitable execution of these different processes 
hy a series of different machines. After the carding operation, these are made to act 
simnltaneoosly upon a multitude of ribands and spongy cords or threads by a multitude 
of mechanical hands and fingers. However simple and natural the above described 
course of manu&ctnre may appear to be, innumerable difficulties stood for ages in the 
way of its accomplishment; and so formidable were they as to render their entire 
removal of late years in the cotton fiictories of England one of the greatest and most 
lionourable achievements of human genius. 

The various operations may be thus classified for fine spinning :— 

1. The mixing and opening up or loosening the flocks of cotton wool, as imported in 
the bags, so as to separate at once the coarser and heavier impurities as well as those 
of a lighter and finer kind. 

2. The wiUcmng, aeutcking or blowing, and lapping, to remove seeds and dirt, and 
prepare the material in the form of a continuous lap or sheet for the next opera- 
tion of 

3. The carding, which is intended to disentangle every tuft or knot, to remove every 
remaining impurity which might have eluded the previous operation, and finally to 
prepare for arranging the fibres in parallel lines, by laying the cotton first in a fleecy 
▼eb^ and then in a nband form. 

4. The doubUng and drawing out of the card-ends or ribands, in order to complete 
the parallelism of the filaments, and to equalise their quality and texture. 

5. The rimng operation, whereby the drawings made in the preceding process are 
greatly attenuated, with no more twist than is indispensable to preserve the uniform 
contioaity of the spongy cords. 

6. The fine roving and stretching come next ; the former operation being effected by 
the fine bobbin and fly frame» the latter by the stretcher mule. 

7. The gpinning operation finishes the extension and twist of the yam, and is done 
either in a continuous manner by the throstle, or discontinuously by the mule : in the 
ibrmer, the yam is progressively drawn, twisted, and wound upon the bobbins ; in the 
latter, it is drawn out and twisted in lengths of from 56 to 67 inches, which are then 
wonnd all at once upon the spindles. 

8. The eighth operation is the winding, doubling, and singeing of the yams, to fit them 
for the muslin, the stocking, or the bobbin net lace manufacture. 

9. The packing press, for making up the yam into bundles for the market, concludes 
this series. 

iVb£e: — Yams spun for weaving into cloth, as named in the 8th operation, after 
being wound, are at once warped, and after being sized, or dressed, are ready for the 

10. To the above may be added the operations of the dressing machines, for fine 
waips ; the tape leg machine, for medium counts of warps, say 2As. to 50s., and sizing 
tronghs for warps of coarser counts. 

11. The power looms. 

12. The plaiting, or folding and measuring machine. 

13. The presft for compretoing the bundles of cloth ready for delivery. 

The site of the fiutory ought to be carefully selected in reference to the health of the 


operatives, the cheapness of proTisions, the fiusilities of transport for the rawnuiieriab; 
and the convenience of a market for the manufactured articles. An abundant supply 
of labour, as well as fuel and water for mechanical power, ought to be primary con- 
siderations in setting down a ikctory. It should therefore be placed, if possible, in a 
populous Tillage, near a river or canal, but in a situation Aree from marsh malaria, 
and with such a slope to the voider stream as may ensure the ready discharge of all 
liquid impurities. These circumstances happily conspire in the Astricts of Stock- 
port, Hyde, Staleybridge, Dukenfield, Bury, Blackburn, &c, and have eminently 
fiivoured the rapid extension of the cotton manufiustures for which these places aie 

The better to illustrate the above-named requisites for cotton spinning and manu- 
facturing, we proceed to a description of a mill at Stockport, Lancashire, containing the 
large number of 61,400 throstle and mule spindles, and 18S0 power looms. 

Sfr. E. M*Chtre*a Cotton. Factoiy. — The mill consists of a main body with two 
lateral wings, projecting'forwurds, the latter being appropriated to store-rooms, a count- 
ing-house, rooms for winding the yam on bobbins, and other miscellaneous purpoeea, 
The building has six floors besides the attic story. The ground-plan comprehends a 
plot of gpround 280 feet long by 200 broad, exclusive of Uie boiler sheds. 

The right-hand end, a (^Jig. 733) of the principal building, is separated frxMn the 
main body by a strong wall, and serves in the three lower stories for accommodating 
two ninety -horse steam engines, which are supplied with steam from a range of hoilen 
contained in a low shed exterior to the mill. 

The three upper stories over the steam engine gallery are used for unpacking, sorting, 
picking, cleanmg, willowing, and lapping Uie cotton wooL Here are the willow, the 
blowing, and the lap machines, in a descending order, so that the lap machine occapies 
the lowest of the three floors, bein^ thus most judiciously placed on the same level with 
the preparation room of the buildmg. On the fourth main floor of the factory there 
are, in the first place, a line of carding engines arranged, near and parallel to the 
windows, as shown at B b, in the ground plan (Jig, 733), and, in the second place, 
two rows of drawing frames, and two of bobbin and fly fhmies, in alternate lines, 
parallel to each other, as indicated by d, c, d, c, for the drawing frames, and e, b, s, e, 
loT the bobbin and fly frames in the ground plan. The latter naaohines are close to 
the centre of the apartment 

The two stories next under the preparation room are occupied with throstle frames, 
distributed as shown at f f, in the ground plan. They stand in pairs alongside of 
each other, whereby two may be tended by one person. These principal rooms are 
280 feet long, and nearly 50 feet wide. The two stories, over the preparation room, tiz., 
the fifth and sixth floors from the ground, are appropriated to the mule Jennies, which 
are placed in pairs fronting each other, so that each pair may be worked by one man. 
Their mode of distribution is shown at a o, in the ground plan. The last single 
mule is seen standing against the end wall, with its head-stock projecting in the 

The ground floor of the main building, as well as the extensive shed abutting behind 
it, marked by n, h, h, in the plan, is devoted to the power looms, the mode d placing 
which in plainly seen at h, h, h. 

The attic story accommodates the winding fhunes, and warping mills, and the warp 
sizing machines, subservient to power weaving. 

Some extra mules (self-actors), are placed in the wings. 

We shall briefly sum up the references in the ground plan as follows : — 

A, the ground apartment for the steam engines. 

B, the distribution of the carding engines, the moving shaft or axis running in a 
straight line through them, with its pulleys, for receiving the driving bands. 

c c, the drawing frames. 
D D, the jack, or coarse bobbin and fly frames. 
E E, the fine roving, or bobbin and fly frames. 

F, the arrangement of the throstle frames, standing in pairs athwart the gallery, in 
the 2nd and 3rd flats. 

0, the mules are here represented by their roller beams, and the outlines of their 
head-stocks, as placed in the 5th and 6th stories. 

B, the looms, with their driving pulleys projecting from the ends of their main axeiL 
Sometimes the looms are placed m parallel straight lines, with the rigger pulleys of the 
one alternately projected more than the other» to permit the free play of the driving- 
belts I sometimes tiie looms are placed, as generally in this engraving, alternately to 
the right and left, by a small space, when the pulleys may all project equally. The 
former plan is the one adopted m Mr. Orrell*s milL 

1, represents the cast-iron girders which support the floors of this fire-proof 



K, K, are closets placed in each floor, in the recesses of a kind of pilasters bailt 
against the outside of the edifice. These hollow shafts are Joined at top by horizontal 
pipes, which all terminate in a chest connected with the suction axes of a fan, whereby 
a coDstant draught of air circulates up the shafts, ventilates the apartments, and pre- 
Tents the reflux of offensive effluvia from the water-closets, howcTer careless the work- 
people may be. The closets towards the one end of the building are destined for the 
men ; towards the other for the women. 

i^ L, are the staircases, of a horse-shoe form, the interior space or shaft in the middle 
being used for the teagle or hoist In the posterior part of the shaft a niche or groove 
is left for the counter- weight to slide in, out of the way of the ascending and descending 

M, M, are the two porters* lodges, connected to the corner of each wing by a handsome 
iron balustrade. They are joined by an iron gate. 

It will be observed that the back loom-shed has only one story, as shown in section 
(^fig, 735). In the ground plan of the shed, n represents the roofing, of wood-woik. 
The raiters of the floors rest at their ends upon an iron plate, or shoe with edges (as 
it is caUed), for the girders to bear upon. 

Two steam engines, of fully 100 horse-power each, and two of 50 horse-power each, 
operate by cranks, which stand at right angles upon the shaft marked a both in the 
plan and section. In the centre, between the bearings, is a large cog-wheel, driving a 
smaller one upon the shaft marked h in both figures, to which the fly-wheel e belonga 
That prime motion wheel is magnificent, and possesses a strength equal to a strain of 
300 horses. From this shaft motion is giren to the main or upright shaft d^ in the 
section, by two bevel wheels, visible at the side and on the top of the great block of 
stone, about 5 toos weight (fig. 733), which gives a solid basis to the whole moTiog 

The velocity of the piston in these steam engines is 240 ft per minute. 

The first shaft makes 44'3 revolutions per minute ; the main upright shaft 58^ 
per minute. The steam engine makes 16 strokes per minute ; and the length of thrir 
stroke is 7 ft 6 in. 

As the one engine exerts its maximum force when the other has no force at all, and 
as the one increases as the other diminishes in the course of each pair of strokes, the 
two thus co-operate in imparting an equable the great gearing and ahaits, 
which, being truly made, highly polished, and placed in smooth bearmgs of hard bran, 
revoLre most silently and without those yibrations which so regularly recurred in the 
old factories, and proved so detrimental to the accurate performance of delicate spinniitg 

The steam for these four engines is supplied by four high pressure horixontal engines, 
made by B. Goodfelluw of Hyde, the exhausted steam from which has still power 
enough to drive the low pressure condensing engines. By an ingenious arrangement 
the condensing water from these engines, while on its return to the river is made to 
turn an 8 horse water-wheeL 

A 12-horse auxiliary engine for driving the warping mills, sising and drying fVamea, 
and mechanic's shop at night (in the event of br^ikages to the machinery), com- 
pletes the power of this great mill, equalling over 1000 indicated horse-power, all the 
steam being supplied by 5 boilers carrying 70 lbs. pressure. 

Note. — Prior to the application of the principle of compounding or unitinffhigh and 
low-pressure engines, the above-named four low pressure engines required nme boilers, 
carrying 14 lbs. pressure, to supply them with sufficient steam; now, as we have shown, 
boilers of smaller dimensions, carrying 70lbs. pressure, supply a sufficient quantity of 
steam, for increased power, at a reduction of fifty per cent on the consumption of 

The power for driving the machinery is conveyed from the engine rooms by shafting 
in the usual manner. 

^ To the horizontal ramifications from the upright shaft any desired Telocity of rota- 
tion WAj^ be given by duly proportioning the diameters of the bevelled wheels of 
communication between them ; thus, if the wheel on the end of the horizontal shaft 
have one-half or one-third the diameter of the other, it will gire it a double or a triple 

In the lowest floor, the second bevel wheel above the stone block drives the hori- 
xontal shaft e, seen in the ground plan ; and thereby the horizontal shaft f, at right 
angles to the former, which runs throughout the length of the building, as the other 
did thirough its breadth, backwards. The shaft/ lies alonnide of the back window 
wall, near the ceiling ; and from it the transverse slender uiafts proceed to the right 
and left in the main building, and to the shed behind it, each of them serving to drive 
two lines of looms. These slender or branch shafts are mounted with pulleys, each of 
which drives four looms by four separate bands. 


ttzi ini !□ [□ o n 
in [a [pi la [a !□ 
[□ [□ [a [□ [□ !□ 
tainin !□[□!□ 
a [a ra !□ tn tarn 



In tlie second and third floors, where the throstles are placed, the shaft d is seen in 
the section to driTC the following shafts : •— 

Upon the main apright shaft d (Jig. 735), there are in each of these stories two 
horizontal berel wheels, with their fkces fronting each other (shown plainly OTer </</), 
hy which are moved two smaller rertical berel wheels, on whose respectire axes are 
two parallel shafts, one over each other, a g, which traverse the whole length of the 
building. These two shafts move therefore with equal velocities, and in opposite 
directions. They run along the middle space of each apartment ; and wherever they 
pass the rectangular line of two throstle f^mes (as shown at f in the groond plan) they 
are each provided with a pulley ; while the steam pulleys on the axes of two conti- 
guous throsUes in one line are placed as fkr apart as the two diameters of the said shaft- 
pulleys. An endless strap goes from the pulley of the uppermost horizontal shaft 
round the steam or driTlng-pulley of one throsUe frame ; then up over the pulley 5, 
the second or lower shaft, g ; next up over the steam pulley of a second throstle ; and, 
lastly, up to the pulley of tiie top shaft, g. See gg in the throstle floors of the cro0 

In the preparation room, three horizontal shafts are led pretty dose to the oeOing 
through the whole length of the building. The middle one, h (see the plan,^!^. 733), 
is driven immediately by bevel wheels from the niain upright shaft d (fig, 734). The 
two side ones i, t, which run near the window walls, are driven by two horizontal shafts, 
which lead to these side shafts. The latter are mounted with puUeys, in correspondence 
with the steam pulleys of the two lines of carding engines, as seen between the cards in 
the plan. The middle shaft A, drives the two lines of bobbin and fly frames, b, b, b, s 
(see cross section), and short shafts t, t^ seen in the cross section of this floor, mo^ 
from the middle shaft A, turning the gallows fixed to the ceiling, over the drawing 
and jack frames, give motion to the latter two sets of machines. See c d in the cross 

To drive the mules in the uppermost story, a horizontal shaft k (see longitudinal and 
cross sections, as well as ground plan) runs through the middle line of the bnildiug, 
and receives motion flrom bevel wheels placed on the nudn upright shaft, </, immediately 
beneath the ceiling of the uppermost storr. From that horizontal shaft, h^ at every 
second mule, a slender upright shaft, /, passmg through both stories, is driven (see both 
sections), llpon these upright branch shafts are pidleys in each story, one of which 
serves for two mules, standing back to back against each other. To the single mules 
at the ends of the rooms, the motions are given by still slenderer upright shafts, which 
stand upon the head stocks, and drive them by wheel-work, the steps (top bearings) 
of the shafts being fixed to brackets in the ceilmg. 

In the attic, a horizontal shaft m m, runs lengthwise near the middle of the roof, and 
is driven by wheel- work from the upright shaft This shaft, si, gives motion to the 
warping mills and dressing machines. 

This cotton mill having been erected according to plans devised and executed by 
that very eminent engineer, Mr. Fairbaim, of Manchester, may be Justly reckoned a 
model.of fkctory architecture. It is mounted with 1320 power-looms, of which e«<eh 
100 require steam power equivalent to 25 horses to impel them, inclusive of the prepara- 
tion and spinning operations competent to supply the looms with yam. 

Ten looms, with the requisite dressing, without spinning, are considered to be equi- 
valent to 1 horse power in a steam engine. Steam power equivalent to 1 horse vill 

500 mule spindles, 
300 self-actor spindles, 

ISO throstle spindles of the common construction ; in which estimate the requisite 
preparation processes are included. 
In Mr. M'Clure^B mill there are in the throstle-fhime 

floors ........ 27,200 spindles 

And in the mule floors ..•-•- 34,200 „ 

Total yam spindles • 61,400 

To which add, power-looms 1820, producing the product of the spindles, in the shape 
of 300,000 yards of cloth in every week of 60 hours. 

One of the most compact and best regulated modem fkctories, on the small scale, 
which we visited in Lancashire, consisted of the following system of machines : — 

1 willow, 1 blowmg machine, 1 lap machine, capable, together, of cleansing and 
lapping 9000 pocmds of cotton per week, if required, 
21 cards, breakers, and flnishers, which carded 5000 lbs. of cotton every week of 

60 hours' work, being about 240 lbs. per card. 
S drawing-frames, of 8 heads each. 


8 coarse bobbin and fly frames. 
7 fine bobbin and fly fhunes. No stretcher mole. 
12 self-actor males, of Sharp and Boberts's eonstnietion, of 404 spindles each 

-^4848 mule spindles. 
10 throstle frames, of 236 spindlea each »2360 spindles. 
7 dressing machines. 
236 power-looms. 

* 2 warping mills. 
300 winding spindles for winding the warp. 

The roTings have 4 hanks in the poond, and are spun into jam No. 38 on the 
liinMtle, as well as the mule. 

One bobbin of the roviog (compressed) lasts 5 days on the self-actors, and 6 days on 
the throstles. 

According to the estimate of Peel and Williams, of Manchester, 66 horses power of 
a steam engme are cqaivalent to 396 power-looms, inclnding 16 dressing machines; 
the cloth being 36 inches wide npon the arerage, and the yam varying in fineness from 
12*6 to 40*8, the mean being 26*s. Here, the spinning and preparation not being 
inclnded, the allowance of power will appear to be high. The estimate giren abore 
assigns 10 looms, with the requisite dressing, to 1 horse ; but the latter assigns no more 
than 6. 

For the following experimental results, carefully made with an improved steam 
engine Huftcator, npon the principle of Mr. Watt's construction, we are indebted 
to Mr. Bennet, an engineer in Manchester. His mode of proceeding was to deter- 
mine, first of all, the power exerted by the fitu^tory steam engme when all the machines 
of the various floors were in action ; then to detach, or throw oat of gear, each system 
of machines, and to note the diminution of force now exercised. Finally, when all the 
machines were disengaged, he determined the power requisite to move the engine itself 
aa well as the great gearing-wheels and shafts of the factory. 

He found at the factory of J. A. Beaver, Esq., in Manchester, that 500 calico looms 
(without dressing) took the power of 33 horses, which assigns 15 looms to 1 horse 

At Messrs. Birley's &ctory, in Bfanchester, he found that 1080 spindles in 3 self- 
actor mules took 2*59 horses, being 417 spindles for 1 horse power ; that 3960 spindles 
in 11 self-actors took 8*33 horses, being 475 spindles per horse power ; 1,080 spindles 
in 3 self-factors took 2 horses, being 540 spindles per horse. 

At Messrs. Clarke and Sons, in Manchester, that 585 looms in weaving fustians of 
yarious breadths took 54 horses power, exclusive of dressing machines, being 1 1 looms 
to I horse. 

At J. A. Beaver's, on another occasion, he found that 1200 spindles, of Danforth*s 
construction, took 21 horses, beiug 57 spindles per horse power ; and that io a second 
trial the power of 22 horses was reqmred for the same effect, being 54 Danforth's 
spindles per horse power. 

An excellent engine of Messrs. Boulton and Watt, being tried by the indicator, 
affi>rded the following results in a factory : — 

A 60 horse boat-engine (made as for a steam boat) took 

14^ horses power to drive the engine with the shafts 14*5 
8^ blowing machines, with their 3 fans - - - 21*55 
10 dressing machines •••... 10*25 
12 self-actor mules of 360 spindles each (720 spindles 

per horse power) ------ 6*00 

6 Danforth*s throstle frames, containing 570 spindles (96 

in each), being 93 spindles to 1 horse power - 6*20 

At Bollington, in a worsted mill, he found that 106} spindles, inclnding preparation, 
took 1 horse power upon throstles. N. B. There is no carding in the loug wool or 
-worsted mannliicture for merinos. 

At Bradford, in Yorkshire, he found that a 40 horse power boat-engine, of Boulton 
and Watt*8» drove 598 calico looms, 6 dressing machines (equivalent to dress warp for 
180 of the said looms), and I mechanics' workshop, which took 2 horses power. Other 
engineers estimate 200 common throstle Spindles, by themselves, to be equivalent to 
the power of 1 horse. 

The shafts which drive the cards revolve about 120 times per minute, with a driving 
polley of from 15 to 17 inches in diameter. 

The shafts of the drawing and the bobbin and fly frames revolve from 160 to 200 
tint s per minute, with pulleys ft'om 18 to 24 inches in diameter. 

The shafts of throstle frames in general turn at the rate of ftx>m 220 to 240 times per 


minnte, with driving pulleys 18 inches in diameter, when they are spinning yam 
of from No. 35 to 40. The shafts of mules revoWe about 130 times per minute, with 
pulley 16 inches in diameter. 

The shafts of power looms reyolye from 110 to 120 times per minute, with pulleys 
15 inches in diameter. 

The shafts of dressing machines reyolve 60 times per minute, with pulleys 14 inches 
in diameter. 

Before quitting the generalities of the cotton manu&cture we may state the folloving 
facts communicated also by Mr. Bennet : — 

A waggon-shaped boiler, well set, will eyaporate 12 cubic ft of water with 1 cwt. of 
coals ; and a steam-boiler with winding flues will eyaporate 17 cubic ft. with the same 
weight of fuel : 7-f^ lbs. of coals of the former boiler are equivalent to 1 horse power 
exerted for an hour, estimating that a horse can raise 33,000 lbs. 1 foot high in a 

The first cotton mill upon the fire-proof plan was erected by the Messrs. Stmtt, 
at Helper, in Uie year 1797 ; that of Messrs. Phillips and Lee, at Manchester, in ISOl ; 
that of H. Houldsworth, Esq., of Glasgow, in 1802 ; and that of James Kennedy, at 
Manchester, in 1805 ; since which time many good fiutorles have been built fire-proo^ 
like Mr. M*Clure*s. 

The heating of the apartments of cotton factories is e£fected by a due distribution of 
cast-iron pipes, of about 7 or 8 inches diameter, which are usually suspended a little 
way below the ceilings, traverse the rooms in their whole length, and are filled with 
steam from boilers exterior to the building. It has been ascertained that one cubic 
foot of boiler will heat folly more than 2,000 cubic ft of space in a cotton milt nnd 
maintain it at the temperature of about 75^ Fahr. If we reckon 25 cubic ft contents 
of water in a waggon-shaped steam boiler as equivalent to I horse power, such a 
boiler would be capable of warming 50,000 cubic ft of space ; and therefore a 10 
horse steam boiler will be able to heat 500,000 cubic fr. of air frt>m the average 
temperature, 50°, of our climate, up to 75°, or perhaps even 80° Fahr. 

It has been also ascertained that in a well-built cotton mill, one superficial foot of 
exterior surface of cast-iron steam pipe will warm 200 cubic ft of air. In common 
cases for heating churches and public rooms, we believe that one-half of the above 
heating surface will be found adequate to produce a sufficiently genial temperature 
in the air. The temperature of the steam is supposed to be the same with that 
in Mr. Watt's low-pressure engines, only a few degrees above 212° — ^the boiling point 
of water. 

The pipes must be freely slung, and left at liberty to expand and contract under 
the changes of temperature, having one end at least connected with a flexible pipe of 
copper or wrought iron, of a swan-neck shape. Through this pipe the water of 
condensation is allowed to run ofif. The pipes should not be laid in a horizontal 
direction, but have a sufficient slope to discharge the water. The pipes are cast from 
half an inch to three-quarters thick in the metaL In practice the expansion of steam 
pipes of cast-iron may be taken at about one-tenth of an inch in a length of 10 fieeC, 
when they are heated from a little above the freezing to the boiling point of water. 
The upper surface of a horizontal steam pipe is apt to become hotter than the bottom, 
of the water be allowed to stagnate in it $ the difference being occasionally so great as 
to cause a pipe 60 feet long to be bent up two inches in the middle. 

In arranging the steam pipes provision ought to be made not only for the discharge 
of the water of condensation, as above stated, but for the ready escape of the air; other- 
wise the steam will not enter freely. Even after the pipes are filled with steam, a 
little of it should be allowed to escape at some ext.'^me orifice, to prevent the re- 
accumulation of air discharged from the water of the steam boiler. Li consequence 
of water being left in the pipes serious accidents may happen ; for the next time 
the steam is admitted into them, the regularity of heating and expansion is im- 
peded, some part of the pipe may crack, or a violent explosion may take place, and 
the joints may be racked to a very considerable distance, every way, from the place 
of ruptuI^e, by the alternate expansions and condensations. The pipes should there- 
fore he laid, so as to have the least possible declivity, in the direction of the motion of 
the steam. 

Formerly, when drying rooms in calico printing works were heated by iron stoves, 
or cockles, their inmates were very unhealthy, and became emaciated ; since they have 
been heated by steam pipes the health of the people has become remarkably good, and 
their appearance frequently blooming. 

Factobt is also a place where factors meet to dispose of goods, as Tea fkctories, 
&c. &C. 

FAHLERZ. Grey copper-ore, called also Panabase, from the many oxides it 
contains, and TetrahedriU from its form. 



Tke aitaljsis of a eiTstalited specimen from Hoel Protper, in Cornwall, gave 

Copper - 

- 3018 

Antimony - 

- 23-66 

SUver - 

- traces 


- 4-40 


- 6-99 


- 25-04 



Specimens from Baden and Freiberg haye been found to contain as much as from 
IS to 31 per cent, of silver. The fbllowing analysis by M. Rose, of grey copper ore, 
or Fahlers» will show the variation in composition of this interesting mineral : — 




1. St. Marie Auxillines, in Alsace 




2. Gersdorf, Freiburg - - - 




3. Kapnik, Hungary ... 




4. Dillenburg, in Nassau - - - 




5. Mine Zidda, at Clansthal 


28 24 


6. Mine Wenzel, near Wolfnach, 





7. Mine Kabacht, near Freiburg 




Besides Arsenic, Iron, Zinc, and Silver. 

FAINTS is the name of the impure spirit which comes over first and last in the 
distillation of whiskey; the former beuig called the strong, and the latter, which is 
mnch more abundant, the weak faints. This crude spirit is much impregnated with 
fcetid essential oil (fusel oil), it is therefore yery unwholesome, and must be purified 
by rectification. 

FALSE TOPAZ. A light yellow pellucid yariety of quartz crystal. It may be dis- 
tinguished from yellow topaz, for which when cut it b frequently substituted, by its 
difference of crystalline form, the absence of cleavage, inferior hardness, and lower 
specific grayity. Found in the Brazils, &c. 

FAN {JEvtntaU, Fr.; Fdcher. Germ.) is usually a semi-circular piece of silk or 
paper, pasted double, enclosing slender slips of wood, ivory, tortoise-shell, whale-bone, 
&c., arranged like the tail of a peacock in a radiating form, and susceptible of being 
folded together, and expanded at pleasure. This well-known hand ornament is used by 
ladies to cool their faces by agitating the air. Fans made of feathers, like the wing of a 
bird, hs^ve been employed from time immemorial by the natives of tropical countries. 

Ftm. is also the name of the apparatus for winnowing com, for urging the fires of 
furnaces, and for purposes of ventilation. For an account of the powerful blowing 
and ventilating fan machines, see Foundry and Venttlator. 

FANG, a mining term, A niche cut in the side of an adit or shaft, to serve as an 
air course. Sometimes the term afanging is applied to a main of wood pipes. 

FARINA {Fcainej Fr. ; MehL, Germ.) is the flower of any species of com, or 
starchy root, such as potato, arrow- root* &c See Bread and Starch. 

FATS {GraisseSf Fr. ; Fette, Germ.) occur in a great number of the animal 
tissues, being abundant under the skin in what is called the cellular membrane, round 
the kidneys, in the folds of the omentum, at the base of the heart, in the mediastinum, 
the mesenteric web, as well as upon the surface of the intestines, and among many of 
the muscles. Fats yary in consistence, colour, and smell, according to the animals 
from which they are obtained ; thus, they are generally fluid in the cetaceous tribes, 
soft and rank-flayoured in the camiyorous, solid and nearly scentless in the ruminants, 
usually white and copious in well-fed young animals ; yellowish and more scanty in the 
old. Their consistence yaries also according to the organ of their production ; being 
firmer under the skin and in the neighbourhood of the kidneys than ameng the 
movable viscera. Fat forms about one-twentieth of the weight of a healthy animal. 
But as taken out by the butcher it is not pure; for being of a vesicular structure it is 
always enclosed in membranes, mixed with blood, blood-vessels, lymphatics, &c. These 
foreign matters must first be separated in some measure mechanically, after the fat is 
minced small, and then more completely by melting it with hot water, passing it through 
a sieve, and letting the whole cool very slowly. By this means a cake of cleansed fkt 
will be obtained. 

Braconnot and Raspail have shown that solid animal fats are composed of very small 
microscopic, partly polygonal, partly reniform particles, which are connected together 
by very thin membranes. These may be ruptured by mechanical means, then sepa- 
rated by triturating the fresh fats with cold water, and passing the unctuous matter 
through a sieve. The particles float in the water, but eventually collect in a white 

Vol. IL N 



granular crystalline appearance, like starch. Each of them consists of a Tetteolar in- 
tegument, of the nature of stearioe, and an interior floid like elalne, vhich afterwards 
exudes. The granules float in the water, but subside in spirits of irine. When 
digested in strong alcohol, the liquid part dissolves, but the solid remaini. Tbeie 
particles differ in shape and size, as obtained from different animals; those of the 
calf, ox, sheep, are polygonal, and from j^ to ^ of an inch in diameter ; those of the 
sow are kidney-shaped, and from 50 to <^ ; those of man are polygonal, aad from ^ to 
^ ; those of insects are spherical, and at most ^ of an inch. 

Fats all melt at a temperature much under 212^ F. When strongly beatei vitb 
contact of air, they diffuse white pungent fumes, then blacken, and take fire. When 
subjected to distillation they afford a changed fluid oil, carburetted hydrogen, sod ihe 
other products of oily bodies. Exposed for a certain time to the atmosphere, tber 
become rancid, and generate the same fiit acid as they do by sap o niAoati o B.^ In tbeir 
fresh state they are all composed principally of stearine, margarine, and oleine,vithi 
little colouring and odorous matter ; and in some species, hircine, from the goat ; 
phocenine, from the dolphin ; and butyrine from butter. By snbjectmg them to a 
great degree of cold, and compressing them between the folda of blotting psper, a resi- 
duum is obtained, consisting chiefly of stearine and margarine ; the latter of whidi 
may be dissolved out by oil of turpentine. 

Beef and Mutton Suet.— When fresh, this is an insipid, nearly inodorous fiit, of ft firm 
consistence, almost insoluble in alcohol, entirely so, if taken from the kidDe^s ud 
mesenteric web of the ox, the sheep, the goat, and Oie stag. It varies in ita vlutenea 
consistence, and combustibility, with the species and health of the animals.^ Thej nur 
all be purified in the manner above described. Strong sulphuric acid derelop^ 
readil;^ the acid fats by stirring it through melted suet Alkalies, by saponifieitioo, 
give rise to one of the three acids, — the stearic, margaric, or oleic. Beef soet coossts 
of stearine, margarine, and dieine ; mutton and goat suet contain a little hirdoe. the 
specific gravity of the tallow of which common candles are made is, by Ure*s experi- 
ments, 0-936. The melting point of suet is from 98<> to 104<» F. The proportion 
of solid and fluid fat in it is somewhat variable, but the former is in mat^ kr]ger 
proponion. Mutton suet is soluble in 44 parts of boiling alcohot, of 0*620 ; beef 
suet in 44 parts. Marrow fat cansists of 76 of stearine, and 24 of oleine ; it meUs it 
1150 F. 

Hog*t lard is soft, fusible at SI*' F., Convertible, by an alkaline solotioa, iotoi 
stearate, margarate, oleate, and glycerine. Its sp. grav, is 0*936, at 50^ F. It consists 
of 62 of oleine, and 88 of stearine, in 100 parts. 

Goo$e-fat consists of 68 oleine and 32 stearine. . 

Butter^ in summer consists of 60 of oleine and 40 of stearine ; in winter, 0^ ^ ^| 
oleine, and 65 of stearine ; the former substance being yellow and the other white. i( 
differs, however, as produced from the milk of different cows, and also sccordmg to 
their pasture. 

The ultimate constituents of stearine, according to Chevreni, are, 79 csrhon; H • 
hydrogen ; and 9*8 oxygen in 100 parts. 

See Maboabinb, Oleinb, Soap, Stearins. 

The following statement is given on the authority of Braconnot : — 

Fresh butter in summer 

^— ^— in winter 

Hog*s lard 

Ox marrow 

Goose fat - - 

Duck fat 

Ox tallow 

Mutton suet 

Dr. Robert Dondas Thomson has given the following list of animal fhts and their 
melting points; — 

Badger fat 
Beef tallow • 
Calf - 
Camel - 
Cochineal fat 
Cow*8 butter 


Duck's fat 






Hare - 


Hog's lard 


Horse grease 



Hunan iki • 


Steariae (duek) - 



Cetine - 



Chloreftine • 

Stearine (hamaa) - 


CBntharides ht - 

» (•be€p) - 


Margarine (batter) 

„ (oxen) - 


Palimtine • 

(hog) - 




M. Dumas nyi that batter contains no stearine. The pnriflcation and deeoloration 
of fills has been the object of many patents. One of the best is to mix two per 
cent, of strong salphorie aoid with a qoantity of water, in which the tallow is heated 
for some time with mooh stirring ; to allow the materiab to cool, to take off the 
SDpenatant &t, and to re-melt it with abundance of hot water. More tallow will 
thus be obtained, and that considerably whiter and harder than is nsoally procnred by 
tlie aselters. 

Dr. Ure states that be has found that chlorine and chloride of lime do not improre, 
but rather deteri(»ate, the appearances of oils and other ihtty bodies. According to 
Appert, minced suet subjected to the action of high-pressure steam in a digester, 
at 250^ or seo^ F., becomes so hard as to be sonorous when struck, whiter, and 
capable when made into candles, of giTing a superior light. A convenient mode 
of rtmdtrntg minced tallow, or melting it, is to put it in a tub, and driTe steam 
through it from numerous orifices in ramifying pipes placed near the bottom. 
Mr. Watt's plan of purifying fiits, patented in March, 1836, has been successful. 
He employs dilate sulphuric acid, to which he adds a little nitric acid, with a very 
small quantity of bichromate of potash, to " supply oxygen,** and some oxalic acid. 
These are mixed with the fat in the steaming tub. When the lumps of it are nearlv 
diasolTed, he takes for every ton of fat, one pound of strong nitric acid, dilated with 
one quart of water ; to which he adds two ounces of alcohol, naphtha, sulphuric ether, 
or spirits of tuipentiae; and after introducing this mixture, he continues the boiling 
for half an hour. Hie fot is finally washed. 

Others have proposed to use vegetable or animal charcoal first, especially for rancid 
oils, then to heat them with a solution of sulphate of copper and oonunon salt, which 
is supposed to preeipitate the fetid albuminous matter. 

Mr. Prynne obtawed a patent in March, 1840, for purifjriag tallow for the candle- 
maker, by heating it along with a solution of carbonate of potash or soda for 8 hours, 
letting the whole cool, removing the tallow to another vesael, heating it by means of 
steam np to 206<^ F., along with dry carbonate of potash (pearlasb) : letting this mix- 
tore cool very slowly; and finally removinff the tallow to a vessel inclosed in steam, 
so as to expel any subsidiary moisture. — NewUnCs Journal^ xxl 858. 

A patent for a like purpose was obtained in June, 1842, by Mr. H. H. Watson. He 
avails himsdf of the blanching power of oxygen, as evolved Arom permanganate of 
potash (chameleon mineral), in the act of its decomposition by acids, while in contact 
with the melted fiU. He prescribes a leaden vessel (a well joined wooden tub will 
also serve) for operating upon the melted tallow with one-twentieth of its weight of 
the manganate dissolved in water, and acidulated to the taste. The whole are to be 
well mixed, and grsdoaliy heated firom 150° up to 212° F., and maintained at that 
temperature for an hour. On account of the tendency of the dissolved man- 
ganate to spontaneous decomposition, it should be added to the dilute acid, mixed 
with the fot previously melted at the lowest temperature consistent with its fluidity. 

Mr. Wilson, of Vauxhall, has applied centrifugal action to the separation of the 
liquid from the more solid parts of fatty matters, employing in preference the hydro- 
exiraetars used by Seyrig and Co. for drying textile fabrics. Mr. Wilson applies a 
stoot cotton twill in addition to the wire-grating; and in order to avoid the necessity 
of di|Eging the concrete parts, and to prevent them fhmi dogging the interstices for 
the dischaj]ge of the oily matter, he pbuses the whole in a bag 8 inches in diameter, 
and of such length thst when hud on the rotating machine against the grating the 
two ends will nwet The speed of the machine must be kept below that at which 
stearic add or stearine would pass ; which is known by the limpidity of the expressed 
fluid. To take advantage of the liquefying influence of heat, he keeps the tempera- 
tare of his own room about 2^ F. above that of the substances under treatment 

The chemistfy of fot will be foond in Urt^t JHcHtmary of Ckemutry. For Imports, 
&C., see TajLLOw. 

FAULTS iFaiUet, Fr.), in mining, are disturbances of the strata which interrupt 
the miner's operations, and put him at a loss to discover where the vein of ore or bed of 
ooal has been ** ikroum " by the convulsion of nature. 

A mineral vein, may be regarded as a fissure formed by the consolidation of the 
rocks in which it exists, or bv some movement of the entire mass, produdng these 
cracks at right angles to theline of greatest mechanical force ; these have been even- 

N 2 

180 FAULTS. 

tDtllT filled in vilh the mlaenl or metaltifeioos mftlter wluch ve God la Ihm. Alta 
Ihii bM taken plice. there faai som«Ciiiie« bMii a movemeDl of n portion of ihr gnKiiid, 
BDd the mineral vein, or Iod*,tiu been TrBctared. A simpie illustration of tbii it ik bl- 
lowmg,^. 736, wbere we have the minerHl lein dlalocated, and Bubwqoentl} to [fae dii- 
locatioD tben has been ft fonnationof a string of spalhose iron, following die brndiip 
of a crack formed by the moTemen't, which, in this case, has been less iW Iht widtb 
of the lode. In thelarge majorilj of eiamples tb» " heaTe"or "throw"of iheWeii! 
heenverj considerable. It is usual to apeak of s/aaJt as if the fissure bad adudljiumd 
thelode. It should be understood that an actud movement of great matMt of llutdid 
earth is implied, and consequently, the 2oiJe having been formed befbreUieiiMrTtli>Bit,il 
is moved with tbe rock in which il is enclosed. Fig. 738 is the plan o(Teinsl,S,S.t, 
and an Elvan course a a, which have been dislocated along the line &, c. ud tU lie 
lodes nod the Elvao course moved. Id this case the moTement has probablj takm pin 
iTom the North towards the South. This disturbance will be continned (o s pni 
depth, and in /$, 137isBaectionahowiiig the dislocation of a lode into tbne[anL Ed 
T3S 737 

this case the marenient has probably been the mbsidence of that portion "C" f[^ 
containing the lode 5, and the further subsidence of that portion contsimng w ^ 
a i the condition of the surftce being subsequently altered bv denudalion. l« ^^ 
clinalionof alodeisfreqneiitly chang^ by these movements, An» A- ^''."^'tt* 
to represent the original condition of the lode by a coovulaioo, tiie pordw ^ ^ 
ftlien away leaving a chasm between, and the " dip " or incliostion of ""^ v, 
therefore materiaUy changed. The direction of the lode is frequently i"^ ^jj 
these movements. Many lodes b Cornwall have a direction from the N. rft- ^ 
& of W, up to a fenit, on the other side of which the direction is changed ff™"j. 
of E. to the N. of W. Where these distnrhances are of fn^uent occurrenee, ik 
cutties of mining are greatly increased. t fg 

The dislocations and obstructions found in coal-flelds, which render the W^ 
coal so difficult, and their mining so laborious and uncertain, are the toUo^'^f' 
1. Di'Aei. S. Slipi or Faulu. 3. Hitcha. 4. Trouhla. ^ j^^ 

The first three, uifer dislocation of the strau ; the fourth, changes hi the bn 




1. A duke is a wall of extraneoiu matter, which diTidet all the beds in a coal-field* 
Dikes extend not only in one line of bearing through coal-fields for many miles, but 

ran sometimes in different directions, and have often irregular bendings, but no sharp 
angular turns. When ftom a few feet to a few fiithoms in thickness, they occur some- 
times in numbers within a small area of a coal basin, running in various directions, 
and even crossing each other. Fig. 740, represents a ground plan of a coal-field, 
intersected wih greenstone dikes. A B 
and c i> are two dikes standing parallel 
to each other ; b f and o h are cross 
or oblique dikes, which diyido both 
the coal strata and the primary dikes 
A B and c D. 

2. SUps or fatdts run in straight 
lines through coal-measures, and at 
every angle of incidence to each other. 
Ftg, 741 represents a ground plan of 
a coal-field, with two slips A B and c d, 
the line of bearing of the planes of the 
strata, which throw them down to the 
outcrop. This is the simplest form of 
a slipk jPi^. 742, exhibits i>art of a 1^ 
coal-field intersected with sups, like a 
cracked sheet of ice. Here A B is a '^ 
dike; while the narrow lines show 
faults of every kind, producing dislo- 
cations Tarying in amount of shp from 
a few to a great many fi&thoms. The fkults at the points a, a, a vanish ; and the 
lines at o denote four small partial slips called hitches. 

The effects of slips and dikes on the coal strata appear more prominently when 
viewed in a vertical section, than in a ground plan, where they seem to be merely 
walisy Teins, or lines of demarcation. Fig. 743 is a vertical section of a coal-fieldt 




from dip to rise, showing three strata of coal a^b,e, a b represents a dike at right 
angles to the plane of the coal-beds. This rectangular wall merely separates the coal- 
measnresi, affecting their line of rise ; but farther to the rise, the oblique dike c d in- 
terrupts ihe coals a, b, c, and not oxdy disjoins them, but has produced a movement 
which has thrown them and their cpncomitant strata greatly lower down ; but still, 
with, this depression, the strata retain their paraUelism and general slope. Nearer to 
the outcrop, another dike, b f, interrupts the coals a, ft, c, not merely breaking the 
oontinaity of the planes, but throwing tiiem moderately up, so as to produce a steeper 
inclination, as shown in the figure. It sometimes happens that the coals in the com- 
partment H, betwixt the dikes c and e, may lie nearly horizontal, and the effect of the 
dike s, F, is then to throw 
ont the coals altogether, 
leaving no vestige of them 
in the compartment k* 

The effect of slips on 
the strata is also repre- 
sented in the vertical sec- 
tion,^. 744, where OjbfC 
are coeds with their asso- 
ciated strata, A b is an 
interaecting slip, which 
throws all the coals of the 
first compartment much lower, as' is observable in the second, Na 2; and from 
the amount of the slip, it brings in other coal-seams, marked 1, 2, 3, not iq the 




compartment No* 1. c &, is a slip prodnoing a similar ranlt, but not of the ame 
magnitade i x 7 repreients a slip across the strata, rererse in direction to the former ; 
the effect of which is to throw up the coals, as shown in the area Na 4. Sock 
a slip occasionallj brings into play seams seated onder those marked ct, b^ e, n 
Eeeo at 4, ft, 6 } and it may hi^pen that the coal marked 4 lies in the proloog- 
ation of a well-known seam, as r, in the compartment Ka 3, when the case be- 
comes pu2zling to the miner. In addition to the abore varieties, a number of slips or 
hitches are often seen near one another, as in the area marked No. 5, where the indi- 
vidual displacements are inconsiderable, but the aggregate dislocation may be great, 
in reference to the seams of the 6th compartment 

y^5 The resnlts of dikes and slips on a 

horizontal portion of a field are exem- 
plified in fy. 745. .Where the eoal- 
measures are horiaontal, and the faohs 
ran at a greater angle than 45^ to the 
line of bearing, tfaej are termed "dip " 
and **ri8e" fwolts, as ▲ b, c i^ k f. Tbi 
MlomingJIg. 746, which ti an aceoiale 
section of the Mostyn coal'^fieid, Flint- 
shire, will show the amoont to which 
those disturbances are experienced. 
The letters mark with sufficient dis* 

a. Worked oat. 

b. DHto. 

c. 5 jd. ooal worked eot. 
tf. 3 7d. ditto. 


Inferior coal. 

Yard coal woriced oat. 
4 ft. coal (tolerable). 

i. Main coal, 6ft. C^rciy 1 
J. 5 ft. coaL 
k, fltone ooal. 
A 3ft.coaL 

tinctness the beds on either side of die 

Coal viewers or engineers re^aitl the 
dislocations now described as bemg sob- 
Ject in one respect to a general law, 
which may be thus explained:— Let 
Jig, 747 be a portion of a coal-measure ; 
A, being the pavement and b the roof 
of the coal-seam. If, in pursuing the 
stratum at c, a dike d ooeurs, standing at 
right angles with the pavement, they 
conclude that the dike is merely a partttion-wdl between the beds by its own thick- 
ness, leaving the ooal-seam undisturbed on either side ) but if a dike f fonns> «b at b» 



sa obtnttt Mgb vidi the paicment, tbay coneloda tliit the dike ii not ■ limple 
paititioD between the KnO, bat bat dirovD np tha Mrenl leami Into the predica- 
ment iliovti U a. Finall;, ihoold ■ dika a mika U i in leaie angla wltb th« pare* 
tneot, the; coodode that the dike hat ihrairQ down the eoal measnrM into the poai- 

Diltea and balls are denominated npthnnr or downthTOw, according to the powtion 
tbcT are net vitta in working the mine. Thai in fig. 7U, if [he miner it adTuicing 
to ihe rise, the dike a b obiioiulr doe* not change the direetioa ; bat c n is a down- 
tbrow dike of a certain nomber of &thoms tovardj the rise of the buln, and e f is an 
upthrow dike likewise towards the rise. On tha other hand, when the dikes are met 
with by the miner in «oAiii|; ttam the rise to the dip, the name* of the aboTe dikes 
would be reTencd ; for what u «□ upthrow la the first ease, becomes « downthrow in 
the second, relatiTe to the mining operationa. 

S. We haye seen that AiCclu are small and partial slips, where the disloeatton does 
not cxeeed the thickuev of tha c«sl-seam; and the; are correetlyeMMgfa called s(^ 
bj Ihe miner. Fig. 71S reprs- 
•ents the operstim of Ihe AilcAes 
a, B, c. D, a. r, a, h, on the coal- C 
Ineasnrct. Tbongh obserTcd in | 
one (K two seams Of a field, tfaev 
maj not appear in the rest, as w 
the case whh dikes and ftnltt. 

Id the abova deaeriptioo die 
langnage of the mine has been 
retained, bat in the esse of tha 

dike, as of the /aJt-pntpa; it is DOt diat the dike has lifted the coal bed op or 
down, bat daring Ihe conTnlsiTe moTements of the eartli, when those trap dikes were 
being fened from below, great moremcDts were prodaoed on either side of the fisinres, 
throDgh which the mtdlen matter tseended, and hence the alteration inthepoaitioii of 
the beds, which were preriously, perhaps, nearly in a horisontal plane, 

FEATHERS. (Pfoo, Fr. ; Fakni, Oerra.) "The most beaatlfU, the most com- 
plex, and the moat highly eUbonied of all the eorerings of B»ii»infis, dne to the d«- 
velopBent of the epidermal lyslem, is the plumage of hird*.' — Obsh. 

A ftaihar consists ot the " q<^" the " Aa/t," and Ihe " now." The *«ne consists 
of " barbs * and " borbales." 

The f«t& is pierced by a lower and an o^er orifloe, and eoctaint a series of light, 
dry, conical eapmlea, fitted one apon another, and nnited together by a central pedicle. 
The diajl it slightly bent, the coocaire side is dirided into two snr&ces by a middle 
loDgitn^nal line continaedfrom theupperorificeof cheqnill,dieoonTex side is smooth. 
Both sides are oorercd with a homy material similar to that of the qoill, and they 
enckae a pecnliHr white, soft, dastic sobstaace, called the ** pifA." Tha barU tie 
aiuched to the tides of the ilian. The bari>iUt are giren at ftom eldier tide of the 
tnrbe, and are somdimea limilarlj barbed tbemselres, as maybe seen in thebarbulea 
of the long feathers of the peacock's taiL 

The barbules are commonly short and close set, tOd earred in contrary dbetrtiooa, 
so that two adjoining series of barboles interlock together and fana the mechaniEm 
b; which the barbs are oompacted into the close and resisting Tana of the qnill, or 
" feslher," properly to called. Whoi the barbolea are long and loose, they characterise 
that fotnt of the feather which is properly called a " jMme," and snch are the most 
Til liable products of the plumage of birds in a commercial point of view, litt-g. Ihe 
piames of the ostrich. 

The Dowm. — The lower faarbs in every kind of fMher are nsoslly tooae, fbrming 
the down, which is increased in moat birds by what is called the ** Kceesory plune. 
This it ntoally a soft downy tnft, but Tsriet in different species, and eiea in tha 
restfaersofdifferent parts of the body of the ssme bird. The Tslneoffestbersfor bed 
■taffing depends apon the proportion of kwae soA down that enten into their composi- 
tion ) and as the " scctttory plame " in tha t>ody leathers of the swans, geese, and 
ducks, is almost as bog as tlie feather fi-om whidi it springs, hence arises the com- 
mercial Taloe of tbe feathers of tbose aqaatio birds. — Omn. 

The first eoTering of the young bird is a down. In tnoct birds a eerlain portion of 
the down leathen is retained with the tme ftethers, and this pn^rtion is nsoally 
greatest in the aquatia birds. 

It is most remarkable in the eider dnek (Amai wullitima). "The down of (he 
eider combines, with its pecaliar softnasa, fineness, and lightness, to great a degree of 
elasticily (hat the quantity of this beantifol material which might be compressed and 
concealed between tha two hands of a man, will serre to staff the evrerlet of a bed." 


Featben oonstitate the subject of the manafactare of the Piumassier, a name given 
to the artisan who prepares the feathers of certain birds as ornaments for ladles and 
for military men, and to him also who combines the feathers in yarions forma. We 
shall content ourselves ^ith describing the method of preparing ostrich feathers, as mist 
others are prepared in the same way. 

Several qualities are distinguished in the feathers of the ostrich ; those of the male, 
in particular, are whiter and more beautiful. . Those upon the hack and above the 
wings are preferred ; next those of the wings, and lastly, of the tail. The down is 
merely the feathers of the other parts of the body, which vary in length from 4 to 14 
inches. This down is black in the males, and grey in the females. The finest white 
feathers of the female have always their ends a little greyish, which lessens their 
lustre, and lowers their price. These feathers are imported from Algiers, Tunis, 
Alexandria, Madagascar, and Senegal; this being the order of their value. 

The scouring process is thus performed : — 4 ounces of white soap, cut small, are 
dissolved in 4 pounds of water, moderately hot, in a large basin ; and the solution is 
made into a lather by beating with rods. Two bundles of the feathers, tied with 
packthread, are then introduc^, and are rubbed well with the hands for five or six 
minutes. After this soaping they are washed in clear water, as hot as the hand 
can bear. 

The whitening or bleaching is performed by three successive operations. 

1. They are immersed in hot water mixed with Spanish white, and well agitated 
in it ; after which they are washed in three waters in succession. 

2. The feathers are azured in cold water containing a little indigo tied np in a fine 
cloth. They should be passed quickly through this bath. 

3. They are sulphured in the same way as straw hats are (see Sulfhubino) ; they 
are then dried by hanging upon cords, when they must be well shaken from time to 
time to open the fibres. 

The ribs are scraped with a bit of glass cut circularly, in order to render them very 
pliant By drawing the edge of a blunt knife over the filaments they assume the 
curly form so much admired. 

Those feathers which are of a dingy colour are dyed black. For 20 pounds of 
feathers, a strong decoction is made of 25 pounds of logwood in a proper quantity of 
water. After boiling it for 6 hours, the logwood is taken out, 8 pounds of copperas 
are thrown in ; and, after continuing the ebullition for 15 or 20 minutes, the copper 
is taken from the fire. The feathers are then immersed by handfiils, thoroughly 
soaked, and worked about ; and left in two or three days. They are next cleansed in 
'a very weak alkaline lye, and soaped three several times. When they feel very' soft 
to the touch, they must be rinsed in cold water, and afterwards dried. White feathers 
are very difficult to dye a fine black. 

For dyeing other colours, the feathers should be previously well bleached by the 
action of the sun and the dew ; the end of the tube being cut sharp like a toothpick, 
and the feathers being planted singly in the grass. After fifteen days* exposure, tliey 
are cleared with soap as above described. 

Hose colour or pink, is given by safflower and lemon juice. 

Deep red, by a boiling hot bath of Brazil wood, after aluming. 

Crimson. The above deep red feathers are passed through a bath of cudbear. 

Prune de Monsieur, The deep red is passed through an alkaline bath. 

Blues of every shade,, are dyed with the indigo vat 

Yellow ; after aluming, with a bath of turmeric or weld. 

Other tints may be obtained by a mixture of the above dyes. 

Feathers supply us with a soft elastic down on which we can repose onr wearied 
frames, and enjoy sweet slumbers. Such are called bed feathers. 

Ooose feathers are most esteemed. There is a prejudice that they are best when 
plucked from the living bird, which is done thrice a year, in spring, midsummer, and 
the beginning of harvest The qualities sought for in bed teaSiers are softness, 
elasticity, lightness, and warmth. Their only preparation when cleanly gathered are 
a slight beating to clear away the loose matter, but for this purpose they must be first 
well dried either by the sun or stove. Stoving or hot air being also necessary to 
remove any animal matter liable to putrefy. 

The feathers of the eider duck, Ancu moUissima, called eider down, -possesa in a 
superior degree all the good qualities of goose down. It is used only as a covering to 
beds, and never should be slept upon, as it thereby loses its elasticity. 

Quills for writing. These consist usually of the feathers plucked out of the wings 
of geese. Dutch quills have been highly esteemed, as the Dutch were the first who 
hit upon the art of preparing them well, by clearing them both inside and outside from 
a fatty humour with which they are naturally impregnated, and which prevents the 
ink firom flowing freely along the pens made with them. The Dutch for a long time 


employed hot cinders or ashes to attain this end ; and their secret was preserved very 
carefully, bat it at length tranipired, and the process was then improved. A bath of 
very fine sand must be kept constantly at a suitable temperatnre, which is about 140^ 
F. i into this the quill end of the feather most be plnnged, and left in it a few instants. 
On taking the feathers out they must be strongly rubbed with a piece of flannel, after 
which they are found to be white and transparent. Both carbonate of potash in solution 
and dilate solphnric acid hare been tried to effect the same end, but without success. 
The yellow tint which gives quills the air of age, is produced by dipping them for a 
short time in dilute muriatic acid, and then making them perfectly dry. But this 
process most be preceded by the sand-bath operation. 

Quills are dresKd by the London dealers in two ways ; by the one, they remain of 
their natural colour ; by the other, they acquire a yellow tint. The former is called 
the Dutch method, and the principal workman is called a Dutcher. He sits before a 
small stove fire, into which he thrusts the barrel- of the quill for about a second, then 
lays its root quickly below his blunt-edged knife, called a hook, and, pressing this 
firmly with the left hand, draws the quill briskly through with his right. The l^d on 
-which the quill is laid to receive this pressure is called the plate. A skilful workman 
can pass 2000 quills through his hands in a day often hours. They are next cleansed 
by being scrubbed by a woman with a piece of rough dog-fish skin, and then tied up 
in bundles. 

In the goose's wing, the five exterior feathers only are valuable for writing; the 
first is the hardest and roundest of all, but the shortest ; the next two are the best of 
the five. The heaviest quills are generally the best. 

FECULA {Fecule, Fr. ; StdrkemefU, Germ.) sometimes signifies com flour, some- 
times starch, from whatever source obtained ; and it is also applied to chlorophyll, 
the green matter of plants. The term is applied to any pulverulent matter obtained 
from plants by simply breaking down the texture, washing with water, and sub- 

FEEDER, a mining term, A small lateral lode falling into the main lode or 
mineral vein. 

FELL. The hide of an animal. 

FELL-MONGER. The business of the fellmonger is to separate the wool fVom 
the akin. The wool is sold to the woolstapler, and the stripped skins sent to the leather 
dressers or parchment makers. 

FELSPAR (OftftoM, Fr. ; FeUlspath, Germ.) is a mineral crystallising in oblique 
rhomboidal prisms, susceptible of two cleavages ; lustre more pearly thtui vitreous ; 
spec grav. 2*39 to 2*58 ; scratches ^lass, but is softer than quartz ; yields no water 
when calcined ; fusible at the blowpipe into a white enamel ; not affected by acids. 
The liquid left from its analytical treatment with nitrate of baryta, nitric acid, and 
carbonate of ammonia affords on evaporation an alkaline residuum which precipitates 
platina from its chloride, and appears from this, as well as other tests, to be potash. 
Felspar consists of silica, €6*75; alumina, 17*50; potash, 12 ; lime, 1*25 ; oxide of 
iron, 0-7 5. — {Rote,) This mineral is a leading constituent of ffranite ; some varieties 
of which, by the decomposition of the included felspar, furnish tiie petuntze or Cornish 
stone, so much used in the porcelain and best pottery manufiictnres. 

The Felspars may be divided into four groups : — 

I. Potash felspar (which often contains some soda) ; common feUpar, or ortkoclase; 
and kuciie, 

II. Soda felspar (or soda and potash) ; (Ubite, nfacoiite^ oiUgoclase, and nepkeline. 
II L Soda and lime felspar (containing some potash), andesint^ vosgiU, 

IV. Lime felspar ; anorthite, labmdorite^ tkiortaurite. 

y» Lithia felspar, or peialite. 

I. Orthoclasb, the common constituent of granite, of which it ordinarily composes 
from 40 to 45 per cent, consists of silica, 65*85, alumina, 18*06, potash, 16'59 » 100*00. 
It is colourless, or pale flesh-coloured, or yellow. The name is generally restricted 
to the snbtranslucent varieties, there being many sub-varieties founded on variations 
of Instre, colour, &c., to which other names have been given. Amongst the varieties 
so comprehended under the general name of orthoclaro, the principal are adularia* 
transparent or translucent felspars found in large crystals in granitic rocks. Moonstone 
and snnstone are varieties of adnluia, which are described under their proper 
letters. In addition to potash, some specimens of adnlaria contain more than four 
per cent of soda. 

GuLSflT 7SL8PAB (Sanidinj ice^spar in part), occurs crystallised in the form of a 
clear transparent glass in trachytic and volcanic rocks. 

MuBCHisoNiTE, named after the distinguished geologist and fonnder of the Silurian 
system, is a yellowish-grey or flesh-red felspar from Dawlish, and from Heavitree, 
near Exeter. It is remarkable for its opalescence. 


Ertthbitb is a flesh-coloured felspar, occurring in amygdaloid near Kilpatriek. It 
contains 3 per cent of magnesia. 

Leucitb is not so hard as orthodase, is transparent and tnfhsibie. It ooenrs in 
detached trapesohedral crystals of a white coloar, which, from the similarity of their 
forms to the common yariety of garnet, have obtained the name of ** white gameL** 
It is found abundantly in trachyte on the Rhine, between Lake Laaeh and Andemach, 
and also in the older lavas of VesuTiua, some of which appear to be ahnoat entirely 
composed of it " The leucitic lavas, of the neig^boniiiood of Rome, have beoi used, 
for the last 8000 years at least, in the formation of millstonea." — Dana, 

It is composed of silica, 55*1 ; alumina, 23'4 ; potash, 21*5»10OO. 

II. Albitb, or CUaodandiU is frequently a constituent of granite, and, more 
frequently than common felspar, of syenite and greenstone; bnt it often oceon 
associated with the latter in the same granite, when it ma^ be distinguished by its 
greater whiteness and translucency. It is composed of sihca, 68*7; alumina, 19*5; 
soda, 11 '8 a 100*0. 

Rtacoijte is supposed by Rose to be a mixture of felspar and nephelinc. It 
resembles glassy febpar, and occurs in doubly oblique riiombic prisms. It consists of 
silica, 51*86; alumina, 28*66 ; lime, 1*30; soda, 11*60; potash, 6*58 a 100-Oa 

It is found in the trachytes of Bohemia and Hungary, in the lavas of Vesavioi; 
and in pitchstone in the islands of Arran and Rum. 

Oliooclass, or toda spodument, consists of silica, 62*3 ; alumina, 23*5 ; ioda, 14*2 = 
lOO'O. It occurs in porphyry, granite, syenite, serpentine, and basalt At Tenerifle 
it is met with in trachyte. 

Nephbline, or Ehombaidaifekpart occurs in six-sided prisms, and is composed of 
silica, 44*4; alumina, 83*6 ; soda, 16*9; potash, 5*1 « 100*0. 

The name nepheline includes the crystallised Tarieties f^om VesuTins, while, mider 
the name ElsBolite, are comprised the coarser massive Tarieties with a greasy lustre. 
It is found in the older lavas of Vesuvius, and in the lava of Capo di Bove, near Rome. 

III. Andesine occurs in a whitish syenite in the Andes, in the Vosges, and else- 
where. It consists of silica, 60*16 ; alumina, 23*86 ; peroxide of iron, 1*65 ; magnena, 
0*84; lime, 5*91 ; soda, 6*58; potash, 1*00; « 100*00. 

Vosgite is Labradorite rendered hydrous by partial alteration. It is of a whitish 
colour, sometimes with a shade of green or blue, and has a pearly or greasy lustre. 
It consists of silica, 49*32; alumina, 30*07; peroxide of iron, 0*70; protoxide of naa- 
ganese, 0*60; lime, 4*25; magnesia, 1*96; soda, 4*85; potash, 4*45; water, 3*15 « 
99'35.--(i>e/eMe.) Found in the porphyry of Temuay in the Vosges. 

IV. Akorthits occurs in white translucent or transparent crystals, with a Titreoas 
lustre, inclining to pearly on the planes of cleavage. It consists of silica, 43-2 ; 
alumina, 36*8 ; lime, 20*0. Occurs among the old lavas of Vesuvius in the ravines 
of Monte Somma, and in the island of Procida, in the bay of Naples. It has also 
lately been found by Professor Haughton, in syenitic dykes traversing limestooe 
(forming 85 per cent of the rock), near Oarlingford in Ireland. 

Thiobsauritb is an Icelandic variety of anorthite, and consists of nlica, 48*36; 
alumina, 30*59 ; peroxide of iron, 1 -37 ; magnesia, 0*97 ; protoxide of mangaiieae, a 
trace; lime, 17*16 ; soda, 1*13 ; potash, 0*62 » 100*20.-^G^tA. 

Labradorite, or Labrador feUpar, consists of silica, 53*69 ; alumina, 29*66 ; lime^ 
12*13 ; soda, 4*50 « 100*00. 

It occurs principally as a constituent of other rocks, in the lavas of Etna and Vesu- 
vius, in the oriental verde antique of Oreece and other porphyries, as well as in certain 
homblendic rocks, granites, and syenites. On the coast of labrador, whence it was 
origindly brought, it is associated with hornblende, hypersthene, and magnetic iron 
ore. Labradorite receives a fine polish, and on account of its beautiful chatoyant 
reflections, it is valued for ornamental purposes and sometimes used in Jewellery. The 
parts exhibiting the varied play of colours are disposed in irregular ^lots and psttchcs, 
and the same spot, if held in differeut positions, displays various tints, of which violet 
and red are the most rare. 

The pla^ of colours is supposed to be produced by microscopic crystals of quarts 
imbedded m the stone. (?) 

It is manufactured into brooches, bracelets, snuff-boxes, &e. It looks best when 
cut in plain, very flat cabochon, and a great deal of skill is required to divide the 
stone in such a manner that the iridescent portions (on which its beauty depends) 
may be displayed to the utmost advantage. 

V. Petaute is remarkable as being the mineral in which Arfvedson first dis- 
covered lithia. It is white, iVequently with a reddish tinge, and possesses a glistening 
lustre and a lamellar structure. Translucent Not affected by acids. Emits a blue 
phosphorescent light when gently heated. 

It consists of silica, 77*9; alumina, 17*7; lithia, 3*1 ; soda, 1*3 » 100-0. The only 


known European locality is the iron mine of Uton, an islattd 35 milct S. £. of Stockholm, 
It is fonnd in the United States, and in Upper Canada, near York, on JLake Ontario. 

FELSPATHIC. Of or belong'mg to felspar. 

FELTINQ iFeuiraffe, Fr. ; FUtem, Qerm.) is the process hy which loose flocks 
of wool, and hairs of varions animals, as the heaver, rabbit, hare, &c., are mutuallj 
interlaced into a compact textile fabric The first step towards making felt is to mix, 
in the proper proportions, the different kinds of fibres intended to form the stuff; and 
then, by Uie yibratory strokes of the bowstring, to toss them ap in the air, and to 
cause them to £U1 as irregdlarly as possible, opon the table, opened, spread, and 
scattered. The workman covers this layer of loose flocks with a piece of thick 
blanket stuff slightly moistened; he presses it with his hands, moving the hairs 
backwards and forwards in all directions. Thns the different fibres ^ interlaced, by 
their ends pnrsaing ever tortnons paths ; their vermicnlar motion bemg always, how- 
ever, root foremost. As the matting gets denser, the hand pressure should be in- 
creased in order to overcome the increasing resistance to the decussation. 

A first thin sheet of soft spongy felt being now formed, a second is condensed upon 
it in like manner, and then a third, till the requisite strength and thickness be ob- 
tained. These different pieces are successively brought together, disposed in a way 
suitable to the wished-for article, and united by continued dextrous pressure. The 
stuff must be next subjected to the falling nulL See Hat Manujactubb, under 
which hcaA the process of felting is described. 

FERMENT (Eng. and Fr. ; Hefr Germ.) is the substance which, when added 
in a small quantity to vegetaUe or animal fiuids, tends to excite those intestine motions, 
and changes, which accompany fermentation. It seems to be the result of an alteration 
which vegetable albumen and gluten undergo with contact of air amidst a fermenting 
mass. The precipitates or lees which fall down, when fermentation is finished, consist 
of a mixture of the fermenting principle with the insoluble matters contained in the 
fermented liquor, some of whiehy like hordeine^ existed in the worts, and others are 
probably generated at the time. 

To prepare a pure fennent, or at least a compound rich in that principle, the pre- 
cipitate separated during the fimnentation of a clear infusion of malt, commonly called 
yeast or barm, is made use of. This pasty matter must be washed in cold distilled 
water, drained and squeezed between the folds of blotting paper. By this treatment 
it becomes a pulvemlent mass, composed of small transparent grains, yellowish grey 
when viewed in the compound microscope. It contains much water, and is therefore 
soft, like moist gluten and albumen. When dried it becomes, like these bodies, 
translucid, yeUowish brown, homy, hard, and brittle. In the soft humid state it is 
insipid, inodorous, insoluble in water and aleohoL If in this state the ferment be 
left to itieU^ at a temperature of from 60^ to 70^ F., but not in too dry a situation, it 
putrefies with the same phenomena as vegetable gluten and albumen, and leaves, like 
them, a residuum resembling old cheese. See FEUMENTATioif and Ysast. 

FERMENTATION. (/^srstea/olMm, Fr. ; GSbnmg, GensL) A <^nge which takes 
place, under the influences of air and moisture at a certain temperature, in the con- 
stituent particles of either vegetable or animal substances. This change is indi- 
cated by a sensible internal motion — the development of heat — the evolution of 
gaaeoos products. Fermentation may be divided into several kinds, as — 

Saccharine, Bntyric, 

Acetic, Glyceric, 

Alcoholic or Vinous, Lactic, 

Putrefiictive, Mucous. 

Of the latter examples but a brief notice is required. Mucoue fermentoHtm is esta- 
blished when the juice of the beetroot or carrot is kept at a temperature of 100^ for 
some time, when a tumultuous decomposition takes place. All the sugar disappears, and 
the liquor is found to contain a large quantity of gum, and of mannite with lactic acid. 
jMcHe FermaUaium, — If a scdution of one part of sugar in five parts of water be 
made to ferment, by the addition of a small quantity of cheese or animal membrane, 
at a temperature <k 9(fi or 100^, lactic acid is formed, which may be separated by 
adding a little chalk, the lactate of lime depositing in crystalline grains. In lactic 
fermentation mannite invariably is produced as a secondary product, the formation of 
which is not explained. It has been suggested that the formation of mannite is con- 
nected with the production of succinic acid, which Schmidt, in a letter to Liebig, states 
that he has fbund in fermenting liquids containing sugar. He suggests the following 
formula : — 

C»HW + C*H"0* = C'E^O" 

Mannite^ Succioic acid. prap« lugar. 


. Glyceric Fermentation, — When glycerine is mixed with yeast, and kept in avam 
place for some weeks, it is decomposed and conyerted into metacetonic acid. ThU 
fermentation resembles the last named. The glycerine, C*H'0*, forming metaeetonie 
acid, C«H*0\ as sugar, CH'O", does lactic acid, OH^O*, by loss of the elements of 
water. — Kane, 

Butyric Fermentation. -^ If the lactic fermentation is allowed to proceed beyond the 
point indicated for the formation of lactate of lime, the precipitate in part rc^issolves 
with a Ycry copious evolution of hydrogen gas, and carbonic acid, and the liqaor 
contains butyrate of lime. In this action two atoms of lactic acid, C^H'H)", 
produce butyric acid, C'H'O', carbonic acid, and hydrogen gas. 

Putrefactive Fermentation. See Putrefaction. 

The three first named kinds of fermentation demand a more especial attention from 
their importance as processes of manufacture. Under the heads respectivelj— Acetio 
Acn>, Beer, Brewing, Distillation, Malt, and Wine, will be found eTeiythiDg 
connected with the practical part of the subject ; we have therefore onJy now to deal 
with the chemical and physical phenomena which are involved in the remarkable 
changes which take place. When vegetable substances are in contact with air asd 
moisture, they undergo a peculiar change (decomposition). Oxygen is absorbed aad 
carbonic acid and water are given ofi^ while there is a considerable development 
of heat This may take place with greater or less rapidity, and thus eremaeausk 
fermentation, or combustion may be the result ; the spontaneous ignition of hay (as 
an example) being the final action of this absorption of oxygen. 

Saccharine Fermentation, — If starch, C"H»(y + 2HO, be moistened vith an infusion 
of pale malt, it is rapidly converted into dextrine, C"H>*0", and hence into grape 
sugar, C^'H^O"; this is especially called the saccharine fermentation, since sagaris 
the result. 

Acetic and Alcoholic Fermentation, — If sngar is dissolved in water, it will renan 
perfectly unaltered if the air is excluded ; but if exposed to the air, a gradoal decom- 
position is brought about, and the solution becomes brown and sour. Oxygen has \m 
absorbed, and acetic acid produced. If, however,' the sugar is brought into contact vith 
any organic body which is in this state of change, the particles of the sngar participate 
in the process, carbonic acid is evolved, and alcohol produced. There are some sab- 
stances which are more actiye than others in producing this change. Yeast is the moat 
remarkable ; but blood, white of egg, glue, and flesh, if they have begun to potrefy. ve 
capable of exciting fermentation ; yegetable albnmen and gluten being, however, more 
active. Vegetable albumen, gluten, and legumin d iffer from most yegetable bodi^ in the 
large quantity of nitrogen which they contain. These substances exist in all frnits, and 
hence, when fruit is crushed, the sugar of the Juices in contact with the albnm^o^ 
gluten being then exposed to Uie air, oxygen is rapidly absorbed, the nitrogenooa body 
begins to putrefy, and the sugar passes into fermentative activity. The necessity w 
oxygen is at the commencement of the decomposition ; when the putrefaction of toe 
albumen or gluten has once begun, it extends throughout the mass withoat in- 
quiring any farther action of the air. These may he regarded as '^^'^^.rj' 
ments. Yeast is an artificial one. This body will be more particularly descnoed. 
See Teast. 

To produce a vmous liquid, it is necessary that there shall be present sngar* or 
some body, as starch or gum capable of conversion into sngar, a certain portion o 
water, and some ferment— for all practical purposes ^(u^* and the tem|>erature mooi 
be steadily maintained at about 80" F. Both cane and grape sugar yield alcohol Dy 
fermentation, but Liebig considers that cane sugar, before it undergoes vinous '^'"^* 
tation, is converted into grape sugar by contact with the ferment; and that, conse- 
quently, it is grape sugar alone which yields alcohol and carbonic acid. / 

Grape sugar, as dried at 212^, contains exactly the elements of two at^ 
alcohol and ifour of carbonic acid. As 2(C*HH)») and 400* arise from C'*H"0 . 

Cane sugar takes an atom of water to form grape sugar. It follows therefore tw 
cane sugar should in fermenting yield more than its own weight of carbonic api 
and alcohol ; and it has been ascertained by experiment that 100 parts ^^^X^^^a 
104, whilst by theory 105 should be produced, consisting of 5 1 -3 of carbonic acid, m 
53-7 of alcohol — (JTane.) Dr. Pereira has given the following very inteUig^oie 
arrangement to exhibit these changes : — 


1 equivalent of *| T ^ ^* 

crystallised cane I I eq. of I 8 „ 
lugar ... 171 }• grape -{ 8 „ 

1 equivalent of I sugar 160 I 4 „ 

water . . 9j Cl2 „ 

carbon 94 _--^4 eq. carbouit 

carbon 48«,,..^ ' acid . • •'^ 

oxygen 64-^*<^v.,.^^ 

oxygen 32- -Z!>~-^ . .. , oj 

bydrog.lS — -^>* . eq.alcoho' 'J^ 

180 180: lio *" 


These ftcts will sufficiently prove tliat yinooi or alcoholic fermentation is but a 
metamorphosis of sagar into alcohol and carbonic acid. 

Soch are the generally received yiews. We find, however, some other views pro* 
mulcted which it is important to notice. 

Ldebig calls pvire/aeHve/ermeiUaUomj^-'eyeary process of decomposition which, caused 
by extmal inflnences in any part of an organic compound, proceeds through the 
entire mass without the fhrther co-operation of the originsl cause. Fermentatum, 
according to Liebig's definition, is the decomposition exhibited in the presence of 
putrefying substances or ferments, by compounds nitrogenous or non-nitrogenous, 
which alone are not capable of putrefaction. He distingoishes, in both putrefaction 
and fennentation, processes in which the oxygen of the atmosphere continually co- 
operates, from such as are accomplished without fbrther access of atmospheric air. 

Lielug opposes the view which considers pntre&ction and fermentation as the 
result of vital processes, Uie development of vegetable formations or of microscopic 
animals. He adduces that no trace of vege^ formations are perceptible in milk 
which is left for some time in vessels carefhlly tied over with blotting paper, not 
even after fermentation has regularly set in, a large quantity of lactic acid having 
been formed. He fhrther remarks o( fermentative processes, that alcoholic fermen- 
tation having been observed too exclusively, the phenomena have been generalised, 
while the explanation of this process ought to be derived rather ttom the study of 
fermentative phenomena of a more general character. 

Blondean propounds the view t£tt every kind of fermentation is caused by the 
development of fimgi. Blondean states that alcoholic fermentation is due to a fungus 
which he designates Tormtla eerevituB ; whilst another, PeniciUiwn glaucttm^ gives rise to 
lactic fiermentatioD. The latter fermentation follows the former in a mixture of 
30 grm. of sugar, 10 gnn. of yeast, and 200 c. c. of water, which has undergone 
alcoholic fermentation at a temperature of about 20°, being terminated in about two 
days. Beer yeast, when left in contact with water in a dark and moist place, contains, 
according to Blondean, germs both of Torvula eertvUia^ and of PenicUIium glaucwn ; 
the former can be separated by a filter, and will induce alcoholic fermentations in 
sugar water, whilst the latter are extremely minute, and pass through the filter ; the 
filtrate, mixed with sugar water, gives rise to lactic fermentation. Acetic fermen- 
tation is due to the development of Torvula aceti ; sugar is converted into acetic acid, 
without evolution of gas, if 500 grm. dissolved in a litre of water, be mixed with 
£00 grm. of casein, and confined in contact for a month at a temperature of about 20^. 
Tbe conversion of nitrogenous substances into &t (for instance, of casein, in the 
mann&cture of Roquefort cheese ; of fibrin under similar circumstances), which 
Blondean designated by the term fatty fermentation (fermentation adipeiue), is caused 
by PenicUUum glaucvan or Torvula viridia ; and the former fungus is stated to act 
likewise in butyric and in urea-fermentation (conversion of the urea into a car- 
bonate of ammonia). 

Opposed to this view Schubert has published an investigation upon yeast In 
order to prove that the action of yeast is due merely to its porosity, he founds his 
investigation upon some experiments of Brendecke (particularly in reference to the 
statement that fermentation taking place in a solution of sugar in contact with porous 
bodies is due to an impurity of sngar) ; according to which various porous bodies, 
such as charcoal, paper, flowers of sulphur, &;c., to which some bitartrate of ammonia 
is added, are capable of inducing fermentation in a solation of raw sugar. His ob- 
servations are also based upon some experiments of his own, which seem to indicate 
that porous bodies, even without the addition of a salt, are capable of exciting fermen- 
tation in a solution of (pure ?) cane sugar. Whatever may be the means whereby 
alcohoiie fermentation is induced, he states it to be indispensable that the body in 
question should be exposed for some time to the inflaence of air, and that oxygen and 
carbonic acid are absorbed by tiie ferment Both oxygen and carbonic acid, being 
electro-negative substances, stand in opposition to the electro-positive alcohol, and 
therefore predispose its formation, but only when they are highly condensed by the 
powerful surface attraction of the yeast, or of any porous body. The electrical 
tension, he states, may be increased by many salts, provided that the latter do not at 
the same time chemically affect either tiie sugar or the ferment 

C. Schmidt has commanicated the results of his experiments to the Annale 
Chem, Pharm. After stating numerous experiments, he continues : " Nor are fungi 
the primum movent of saccharic fermentation ; the clear filtrate obtained by throwing 
almonds crashed in water upon a moist filter, soon induces fermentation in a solution 
of urea and of grape sagar ; in the latter case, no trace of ferment cells can be dis- 
covered under the microscope, not even after fermentation is fully developed. If the 
solation, still containing sugar, is allowed to stand eight days or a fortnight after 
fermentation has ceased, an exuberant development of cellular aggregations is ob- 


served, bat no putrefaction ensaes; the fungi, well washed and introdaeed iato a 
fresh solution of grape sugar, continue to grow luxuriantly, indneing, howeTer, if it 
all, but Tery weak fermentation, which rapidly ceases ; henoe the growth of fungi 
during fermentative processes is but a secondary phenomenon. The incresseof & 
residuary ferment, which occurs after yeast has been in contact with sagar, ariiei 
from a development of ferment cellulose, which probably takes place at tl^ ezpeoM 
of the sugar. If muscle, gelatine, yeast, &c., in a very advanced state of pabid de- 
composition be introduced into a solution of i sugar in 4 water, all phenanena of 
putrefaction disappear ; after a few hours, active fermentation sets in, ferment edk 
being formed, and the liquid contuns alcohol, but no mannite. The insdirity of 
crushed yeast is due, not to the destruction of the fungi, but to the chemicsl ehao^ 
which are induced in yeast during the considerable time necessary for complete eoo- 
minutioD. The crashed cells, introduced into sugar water, give rise to the prodsc- 
tioo of lactic acid, without evolution of gas.*' Schmidt is of opinion that fermcntatioa 
is a process analogous to the formation of ether. He believes that one of the con- 
stituents of yeast, together with the elements of grape sugar, gives rise to the fonniF 
tion of one or several compounds, which are decomposed in statu naaetHii (like 
sulpho-vinio acid), splitting into alcohol and carbonic acid. 

We believe that the preceding paragraphs fidrlv represent the views which have been 
promulgated upon the phenomena of change, which are in many respects 8nsl(>goBi 
to those of combustion and of vitality, presented in the fermentative prooene^ 
Much has been done, but there are still some points which demand the esreiol it- 
tention of the chemist 

In a practical point 'of view, the question which arises from the alteratioD io tlie 
specific gravity of the fluid by fermentation is a very important one, a kaowledge 
of the original gravity of beer being required to fix the drawback allowed npon 
beer when exported, according to the terms of 10 Vict c 5. By this set a dnwbick 
is granted of 5s. per barrel of thirty -six gallons, upon beer exported, of which "the 
worts used before fermentation were not of less specific gravity than 1*054, sod not 
greater specific gravity than 1*081,** and a drawback of 7s. 6dL per barrel upon beer 
of which ** the worts used before fermentatkn were not of less specific gravitj thu 
1*081.** The brewer observes the original gravity of his worts by means of some 
form of the hydrometer, and preserves a record of his observation. The re^eoae 
officer has only the beer, fVom which he has to infer the original grsTity. Fron 
the great uncertainty which appeared to attend this question, Profeaeon Gn* 
ham, Hofmann, and Redwood were employed by the Board of Inkuid Reveooe to 
discover how the original gravity of the beer m^t be ascertained most accoratelf 
from the properties of the beer itselfl When worts are fermented, the sugar pa«ei 
into alcohol, and they lose in density, and assume as beer a dififerent specific grantj 
The gravity of the wort is called the original gravity — that of the beer, iter grav^ 
The report of Graham, Hofknann, and Redwood, upon •* original gravities," ^^ 
supposed to be in thje hands of every brewer ; but as some of the points examined 
materially explain many of the phenomena of vinous fermentation, we have tiaof- 
ferred a few paragraphs to our pages : — 

*' As the alcohol of the beer is derived from the decomposition of asecbanne 
matter only, and represents approximately double its weight of stareh ^P'^'^ 
speculative original gravity might be obtained by simply increasing the exuwn 
gravity of the beer by that of the quantity of starch sugar known to be decomiw*" 
in the fermentation. The inquiry would tiien reduce itself to the best mesns ^^^^^ 
tatning the two experimental data, namely, the extract gravity and the P'^P^'^'j^l 
alcohol in the beer, particularly of the latter. It would be required to decide ▼D<<r 
the alcohol should be determined from the gravity of the spirits distilled fron tK 
beer ; by the increased gravity of the beer when its alcohol is evaporated off; hyt ^ 
boiling point of the b«Br, which is lower the larger the proportion of *J^^ 
present ; or by the refracting power of the beer upon li^^t — > various methodi ^ 
commended for the valuation of the spirits in beer. 

** Original gravities so deduced, however, are found to be useless, being in ^'^ 
and always under the truth, to an extent which has not hitherto been at all *^^\^ 
for. The theory of brewing, upon a close examination <rf the processi provei w ^ 
less simple than is implied in the preceding assumption; and other changes *PP^^ 
occur in worts, simultaneously with the formation of alcohol, which woi^d ^^^J^ 
be allowed for before original gravities could be rightly estimated. It ^ '^ 
necessary to study the gravity in solution of each by itself, of the principal c^^!^ 
substances which are fbund in fermented liquids. These individual gravitiea den 
the possible range of variation in original gravity, and they brought oat clesny 
the first time the nature of the agencies which chiefly itfect the result ^^ 

•« The nse of cane sugar is now permitted in breweries, and the solution of s°P 



may be ttndied fint as the wort of simplest composition. The tables of the specific 
gravity <k sugar solutions, constructed by Mr. Bate, have been verified, and are con- 
sidered entirely trustworthy. The numbers in the first and third columns of Table I., 
which follows, are however, from new observations. It is to be remarked that these 
numbers have all reference to weights, and not to measures. A solution of cane 
sugar, which contains 25 grains of sugar in 1000 grains of the fluid, has a specific 
gravity of 1010*1, referred to the gravity of pure water taken as 1000 ; a solution of 
50 grains of eane sugar in 1000 grains of the fluid, a specific gravity of 1020*2, and 
so on. The proportion of carbon contained in the sugar is expressed in the second 
eolmnn ; the numbers being obtained tnm the calculation that 171 parts by weight 
of cane sncar (C**H**0**) consist of 72 parts of carbon, It parts of hydrogen, and 
88 parts en ozy^gen ; or of 72 parts of carbon combined with 99 parts of the elements 
of water. It is useftil to keep thus in view the proportion of carbon in sugar so- 
lutions, as that element is not mvolved in several of the changes which precede or 
aecompany the principal change which sugar undergoes during fermentation, and 
which changes only affect the proportion of the oxygen and hydrogen, or elements of 
water, eomlmied with the earbon. The proportion of oxygen and hydrogen in the 
altered sugar increases or diminishes during the changes referred to ; but the carbon 
remains constant, and affords, therefore, a fixed term in the comparison of different 

Tabls L — Specific gravity oftolutions of CoM-mgar in waUr» 

Ome SusBT, In 1000 ptrU 
bf woight. 

Carbon In 1000 parti 
\xr weight. 

Specific GraTltj. 































** When yeast is added to the solution of cane sugar in water, or to any other sac- 
charine solution, and fermentation commenced, the specific gravity is observed to 
fall, owing to the escape of carbonic acid gas, and the fonnation of alcohol, which 
is specifically lighter than water; 171 grains of sugar, together with 9 grains of 
water, being converted into 92 grains of alcohol and 88 grains of carbonic acid 
(CH^ iO^> + HO - 2C«H«0* + 4C03). But if the process of fermentation be closely 
watched, the fall of gravity in cane sugar will be found to be preceded by a decided 
increase of gravity. Solutions were observed to rise from 1055 to 1058, or 3 degrees 
of gravity, within an hour after the addition of the yeast, the last being in the usual 
proportion for fermentation. When the yeast was mixed in minute quantity only, 
such as Jv of the weight of the sugar, the gravity of the sugar solution rose gradually 
in four dajrs from 1055 to 1057*91, or also nearly 3 degrees ; with no appearance, at 
the same time, of fermentation or of any other change in the solution. This remark- 
able increase of density is owing to an alteration which takes place in the constitution 
of the cane sugar, which combines with the dements of water and becomes starch 
sugar, a change which had been already proved by H. Rose and by I>uhrunihut, to 
precede the vinoos fermentation of cane sugar. The same conversion of cane sugar 
into starch sugar, with increase of specific gravity, may be shown by means of acids 
as well as of yeast. A solution of 1000 ports of cane sugar in water, having the specific 
gravity 1054*64, became with 1 part of crystallised oxalic acid added to it 1054*7 ; 
and being afterwards heated for twenty-tibree hours to a temperature not exceeding 
128^ Fahr., it was found (when cooled) to have attained a gravity of 1057*63 — an 
increase again of nearly 3^ of gravity.*' 

The di&rence between the gravities of solutions of cane sugar and starch sugar 
are of great practical value, but these must be studied in the original ; the result how- 
ever being ** that the original gravity of a fermented liquid or l^r must be different, 
according as it was derived from a wort of cane su^ or of starch sugar." 

The gravity of malt wort was determined to be mtermediate between that of pure 
eane sqgar and starch sugar, and solutions containing an equal quantity of carbon ex* 
hibited the following gravities: — 

Cane sugar - 1072*9 Pale malt - 1074-2 Starch sugar - 1076*0 


Two other substances vere found to infinence the original graTity of die wortr 
dextrin, or the gam of starch, and caramel Tables are given of the specific 
gravities of these, from which the following results have been deduced -. — 

Starch sugar - - - 1076 

Dextrin - - - - 1066-9 

Caramel - - - - 1062-3 

Caramel is stated to interfere more than dextrin in giving lightness or apparent 
attenuation to fermented worts, without a corresponding production of alcohoL 

** Another constituent of malt wort, which should not be omitted, b the soluble 
azotised or albuminous principle derived from the grain. The nitrogen was deter- 
mined in a strong wort of pale malt with hops, of the specific gravity 1088, and con- 
taining about 21 per cent of solid matter. It amounted to 0-217 per cent of the 
wort, and may be considered as representing 8*43 per cent of albumen. In the sane 
wort, after being fully fermented, the nitrogen was found to amount to 0*134 percent, 
equivalent to 2*11 per cent of albumen. The loss observed of nitrogen and albumen 
may be considered as principally due to the production and growth of yeast, which is 
an insoluble matter, at the cost of the soluble albuminous matter. Solutions of egg- 
albumen in water, containing 3*43 and 2-1 1 per cent respectively of that substance, 
were found to have the specific gravities of 1004*2 and 1003*1. Hence a loss of 
density has occurred during fermentation of ri degree on a wort of 1088 origiasl 
gravity, which can be referred to a change in the proportion of albuminous matter. 
It will be observed that the possible influence of this substance and of the greater or 
less production of yeast during fermentation, upon the gravity of beer, are restricted 
within narrow limits." 

The reporters' proceed : — 

" The process required for the determination of the original gravity of beer, most 
be easy of execution, and occupy little time. It is not proposed, in Uie examination 
of a sample, to separate by chemical analysis the several constituents which have 
been enumerated. In fact, we are practically limited to two experimental observa- 
tions on the beer, in addition to the determination of its specific gravity. 

** One of these is the observation of the amount of solid or extractive matter still 
remaining after fermentation, which is always more considerable in beer than in the 
completely fermented wash of spirits. A known measure of the beer might be evapo- 
rated to dryness, and the solid residue weighed, but this would be a troublesome 
operation, and could not indeed be executed with great accuracy. The same object 
may be attained with even a more serviceable expression for the result, by measoring 
exactly a certain quantity of the beer, such as four fluid ounces, and boiling it dovn 
to somewhat less than half its bulk in an open vessel, such as a glass flask, so as to 
drive off the whole alcohol. The liquid when cool is made up to four fluid ounees, 
or the original measure of the beer, and the specific gravity of this liquid is observed. 
It has already been referred to as to the extract gravity of the beer, and represents a 
portion of the original gravity. Of a beer of which the history was known, the original 
gravity of the malt wort was 1121, or 121^ ; the specific gravity of the beer itself 
before evaporation, 1043 ; and the extract gravity of the beer 1056*7, or 56-7^. 

'* The second observation which can be made with sufficient facility upon the beer, 
is the determination of the quantity of alcohol contained in it This information may 
be obtained most directly by submitting a known measure of the beer to distilfaitioa, 
continuing the ebullition till all the alcohol is brought over, and taking care to con- 
dense the latter without loss. It is found in practice that four ounce-measures of the 
beer form a convenient quantity for the purpose. This quantity is aocnrately 
measured in a small glass flask, holding 1750 grains of water when filled up to a maik 
in the neck. The mouth of the small retort containing the beer is adapted to one end 
of a glass tube-condenser, the other end being bent and drawn out for the purpose of 
delivering the condensed liquid into the small flask previously used for measuring the 
beer. The spirituous distillate should then be made up with pure water to the 
original bulk of the beer, and the specific gravity of the last liquid be observed by the 
weighing bottle, or by a delicate hydrometer, at the temperatnre of SO^ Fahr. The 
lower the gravity the larger will be the proportion of alcohol, the exact amount of 
which may be learned by reference to the proper tables of the gravity of spirits. The 
spirit gravity of the beer already referred to proved to be 985*25 ; or it was 14-05® 
of gravity less than 1000, or water. The * spirit indication ' of the beer was there- 
fore 14*05^ ; and the extract gravity of the same beer 56-7^. 

^ The spirit indication and extract gravity of any beer being given, do we possess 
data sufficient to enable us to determine with certainty the original gravity ? It 
has already been made evident that these data do not supply all the factors necessary 
for reaching the required number by calculation. 



** The fonnation of the extractive matter, vhich chiefly distarbe the original 
gnr^tj, increaBes with the progresa of the fermentatioo ; that is, with the proportion 
of alcohol in the fermenting liqaor. Bat we cannot predicate from theory anj 
relation which the formation of one of these snhstancet should bear to the formation 
of tlie other, and are nnable, therefore, to say beforehand that becanse so much 
sugar has been oonyerted into alcohol in the fermentation, therefore so much sugar 
has also been converted into the extractive substance. That a uniform, or nearly 
nnifonn relation, however, is preserved in the formation of the spirits and extractive 
sabfltanoe in beer brewing, appears to be established by the observations which 
follonr. Such an uniformity in the results of the vinous fermentation is an essential 
condition for the success of any method whatever of determining original gravities, at 
least within the range of circumstances which affect beer brewing. Otherwise two 
fermented liquids of this class, which agree in giving both the same spirit indication 
and the same extractive gravity, may have had different original gravities, and the 
aolutiou of our problem becomes impossible.** 

The following table, one of several of equal value, gives the results of a particular 
fermentation of cane sugar. " Fifteen and a half pounds of refined sugar were dis- 
solved in 10 gallons of water, making 10} gallons of solution, of which the specific 
gravity was 1055*3 at 60^ ; and after adding three fluid pounds of firesh porter yeast, 
Uie specific gravity was 1055*95. The onginal gravity may be taken as 1055*3 

Table II. — Fermentaikn of Sugar* Wort of original gramtjf 1055*3. 


KiimtMr of 



Period of 




Degrees of Extrsct 

Degrees of Extract 
Gravity U$i. 


Days. Hours. 
























1 5 





1 12 





1 19 





2 11 





8 11 





5 12 





6 12 




** Colomns m. and t. respectively exhibit the spirit which has been produced, and 
the solid matter which has disappeared ; the first in the form of the gravity of the 
spirit, expressed by the number of degrees it is lighter than water, or under 1000, 
and the second by the iUl in gravityof the solution of the solid matter remaining 
below the original gravity 1055*8. This last value will be spoken of as ' degrees of 
gravity lost ; ' it is always obtained by subtracting the extract gravity (column iv.) 
from Uie known original gravity. To discover whether the progress of fermentation 
has the regularity ascrib^ to it, it was necessary to observe whether the same re* 
lation always holds between the columns of * degrees of spirit indication * and * de- 
grees of gravity lost.' It was useful, with this view, to find what degrees lost 
corresponded to whole numbers of degrees of spirit indication. This can be done 
safely from the preceding table, by interpolation, where the numbers observed follow 
each other so closely. The corresponding degrees of spirit in4ication and of gravity 
lost, as they appear in this experiment upon the fermetitation of sugar, are ns follows: — 

Tablb III. — Fermentation, of Sugar^Wort of original gravity 1055*3. 

Decrees of Spirit 

Degrees of Extract 
Gravity lost. 

Degrees of Spirit 

Degrees of Extract 
Gravity lost. 















Vol* n. 




** In two other fermentations of cane sngar, the degrees of gravity lost, found to 
correspond to the degrees of spirit indication, nerer dMered from the numbers of tbe 
preceding experiment, or from one another, more than 0*9^ of gravity lost '^'" '" 
sufficiently close approximation. 

** The following table is of mnch importance : — 

This ill 

Table IV. — Stabch-Sdgab. 

Degrees of Spirit Indication, with corresponding degrees (^grtnitg lost 

Beiitles the dfgreei of graTitj lost corresponding to whole degrees of tfilrtt in<UcatioD, the degree* of 
gravity lost corresponding to tenths of a degree of spirit indication are added from alcoIaiMD. 

Degrees of 







































































































































'* It is seen from this table that for b^ of spirit indication, the correspoodiog d^ 
grees of gravity lost are 18-8®. For 5-9° of spirit indication, the corresponding d^ 
grees of gravity lost are 22*2^. 

" This table is capable of a yaloable application, for the sake of which it ^. f**" 
strncted. By means of it, the unknown original gravity of a fermented ^4°'^ 
beer from cane sngar may be discovered, provided the spirit indication and extiirt 
gravity of the beer are obiserved. Opposite to the spirit indication of the beer m t« 
table, we find the corresponding degrees of gravity lost, which last, added to tw 
extract gravity of the beer, gives its original gravity. . /^ 

" Suppose the sugar beer exhibited an extract gravity of 7-9® (1007-9), m.^'JJJ 
indication of 11®. The hitter marks, according to the table, 47-7° of gravity i» 
which added to the observed extract gravity, 7-9®, gives 55-6® of original grsTity w 
the beer (1055-6)." , 

Similar tables are constructed for starch sngar, and for various worts vitb v» 
without hops. - . ,^ 

After explaining many points connected with the problem, as it P***^ 
under varied conditions as it respected the original worts, the Report proceeds:— 

" The object is still to obtain the spirit indication of the beer. The specific gn^J 
of the beer is first observed by means of the hydrometer or weighing bottla- 
extract gravity of the beer is next observed as in the former meUiod ; but the 
for this purpose may be boiled in an open glass fiask till the spirits are S?"^*^. 
new process does not require the spirits to be collected. The spiritless liqwp '*°^' 
ing is then made up to the original volume of the beer as before. By losing tts ^P* ^^^ 
the beer of course always increases in gravity, and the more so the richer m a| 
the beer has been. The difference between the two gravities is the new 'P*^' -j- 
cation, and is obtained by subtracting the beer gravity from the extract g™^ J' 
which last is always the higher number. 

** The data in a particular beer were as follows : — 

Extract gravity 
Beer gravity . - 

- 1044-7 

- 1035 1 

Spirit indication - - . . . 9-6® 

" Now the same beer gave by distilhitiont or the former method, a spirit >"Jj^^ 
of 9*9°. The new spirit indication by evaporation is, therefore, less by OS ^^ 
the old indication by distillation. The means were obtained of c<>ii^P^"°^J|^L bf 
indications given by the same fermented wort or beer in several hundred caieB> 


adopting the practice of boiling the beer in a retort, instead of an open flask or 
basin, and collecting the alcohol at the same time. The evaporation nniformly indi- 
cated a quantity of spirits in the beer nearly the same as was obtained bv distillation, 
but always sensibly less, as in the preceding instance. These experiments being 
made upon fermented liquids of known original gravity, the relation coold always be 
observed between the new spirit indication and tibe degrees of specific gravity lost by 
the beer. Tables of the degrees of spirit indication, with their corresponding degrees 
of gravity lost, were thos constructed, exactly in the same manner as the tables which 
precede ; and these new tables may be applied in the same way to ascertain the 
original gravity of any specimen of beer. Having found the degrees of spirit indi- 
cation of the beer by evaporation, the corresponding degrees of gravity lost are taken 
from the table, and adding these degrees to the extract gravity of the beer, also ob* 
served, the original gravity is found. Thus the spirit indication (by the evaporation 
method) dT the beer lately referred to, was 9*6°, which mark 43^ of gravity lost in the 
new tables. Adding these to 1044*7, the extract gravity of the same beer, 1087*7 is 
obtained as the original gravity of the beer." 

The results of the extensive series of experiments made, were, that the problem 
could be solved in the two extreme conditions in which they have only to deal with 
the pare sogars entirely converted into alcohol. 

** The real difficulty is with the intermediate condition, which is also the most fre- 
quent one, where the solid matter of the beer is partly starch sugar and partly ex- 
tractive} for no accurate chemical means are known of separating these substances, 
and so determining the quantity of each in the mixture. 

** But a remedy presented itself. The fermentation of the beer was completed by 
the addition of yeast, and the constituents of the beer were thus reduced to alcohol 
and extractive only, from which the original gravity, as is seen, can be calculated. 

*' For this purpose a small but known measure of the beer, such aa four fluid 
ounces, was careAiUy deprived of spirits by distillation, in a glass retort To the 
fluid, when cooled, a charge of fresh yeast, amounting to 150 grains was added, and 
the mixture kept at 80^ for a period of sixteen hours. Care was taken to connect 
the retort, from the commencement, with a tube condenser, so that the alcoholic 
vapour which exhaled from the wash during fermentation should not be lost When 
the fermentation had entirely ceased, heat was applied to the retort to distil off the 
alcohol, which was collected in a cooled receiver. About three-flfths of the liquid 
were distilled over for this purpose ; and the volume of the distiUate was then made 
up with water to the original volume of the beer. The specific ^vity of the last 
sptritooos liquid was now taken by the weighing bottle. To obtam a correction for 
the small quantity of alcohol unavoidably introduced by the yeast, a parallel expe- 
riment was made with that substance. The same weight of yeast was mixed with 
water, and distilled in another similar retort The volume of this second distillate 
was also made up by water to the beer volume ; its specific gravity observed, and de- 
ducted from that of the preceding spirituous liquid. This ^cohol was added to that 
obtaiaed in the first distillation of the beer, and the weight of starch sugar cor- 
responding to the whole amount of alcohol was calculated. This was the first result 

** For the solid matter of the beer : the spiritless liquid remaining in the retort was 
made up with water to the beer volume, and the specific gravity observed. A 
eorrection was also required here for the yeast, which is obtained by making up the 
water and yeast distilled in the second retort, to the original volume of the fser, and 
deducting the gravity of this fluid from the other. The quantity of starch sugar cor- 
responding to this corrected gravity of the extractive matter was now furnished by 
the table. This was the second result 

** The two quantities of starch sugar thus obtained were added together. The 
specific gravity of the solution of the whole amount of starch sugar, as found in the 
table, represented the original gravity of the beer. 

** This method must give an original gravity slightly higher than the truth, owing 
to the circumstance that the dextnn, albumen, and salts,- which are found among the 
solid matters dissolved in beer, are treated as having the low gravity of extractive 
matter, and accordingly amplified by about one-sixth, like that substance, in allowing 
for them ultimately as starch sugar. The error from this source, however, is incon- 
sfderable. It is to be further observed, that the error from imperfect manipulation, 
of which there is most risk in the process, is leaving a little sugar in the extractive 
matter from incomplete fermentation. This accident also increases the original 
gravity deduced.- The process has given results which are remarkably uniform, and 
is valuable in the scientific investigation of the subject, although not of that ready and 
easy execution which is necessary for ordinary practice, and which recommends the 
former method." 




Table V. — To be used in ascertaining Original Gravities by the DistiUation 


Degrees of Spirit Indicai 

ion tpiih 

correnponding degrees c 

>f gravity lost in 

, Afalt WorU, 

Degree* of 

S iirit 
Ind cation. 





































































20 9 

































35 4 









39 7 








43 7 


44 2 
























































Table VL — To be used in ascertaining Original Gravities by the Evaporation 


Degrees of Spirit Indication with corresponding degrees of gravity lost in Malt Worts, 

Degrees of 


















































































































































































FERRIC ACID. (FeO*.) This new compound having been prescribed as a 
source of supplying oxygen to persons confined in diving-bells and in mines, bj 
M. Fay erne, claims notice in a practical work. M. Fremy is the discoverer of this 
acid, which he obtains in the state of ferrate of potash, by projecting 10 parts of dry 
nitre in powder upon 5 parts of iron filings, ignited in a crucible ; when a reddish 
mass, containing much ferrate of potash, is formed. The preparation succeeds best 
when a large crucible, capable of holding about a pint of water, is heated so strongly 
that the bottom and a couple of inches above it, appear faintly, but distinctly red, in 
which state the heat is still adequate to efiect due deflagration without decomposition. 
An intimate mixture of about 200 grains of dried nitre with about one>half its wei|rht 
of the finest iron filings, is to be thrown at once upon the side of the crucible. The 
mixture will soon swell and deflagrate. The crucible being taken flrom the fire, and 
the ignited mass being cooled, is to be taken out with an iron spoon, pounded, and 
immediately put into a bottle, and excluded from the air, from which it would speedily 


attract moisture, and be decompoied. It is resolved by the action of water, espe- 
dsJly with heat, into oxygen gts, peroxide, and nitrate 'of iron. This acid has not 
been obtained in a f^ state ; it appears indeed to be scarcely capable of existing alone, 
decomposing, as soon as liberated, into oxygen and ferric oxide. — Graham, 

Mr. J. D. Smith prepares the ferrate of potash by exposing to a full red heat a mix- 
tore of finely powdered peroxide of iron with four times its weight of dry nitre. It 
has an amethyst hue, but so deep as to appear black, except at the edges. Oxyg«n is 
rapidly evolved by the action of the sulphuric or nitric acid upon its solution. He 
considers the atom of iron to exist in this compound associated with 3 atoms of 
oxygen, or double the proportion of that in the red oxide. Hence 69 fprains of pure 
ferric acid should give off 12 grains of oxygen, equal to about 35 cubic inches; but 
how much of the ferrate of potash may be requisite to produce a like quantity of oxygen 
cannot be stated, from the uncertainty of the operation by which it is produced. 

FERROCYANIDE& The compounds of the radical ferrocyanogen. The latter 
radical is bibasic, when, therefore, it combines with hydrogen to form ferrocyanic 
acid, it takes up two atoms. These two atoms of hydrogen can be replaced by 
metals as in ferrocyanide of potassium or pnissiate of potash, as it is commonly called. 
See Prussiate of Potash. Ferrocyanogen consists of ON'Fe, which may also be 
written Cy^Fe, or, for brevity's sake, Cfy. 

The modes of preparing the ferrocyanides differ, according as the resulting sub- 
stance b soluble or insoluble in water. The soluble salts, such as those with alkalies, 
are prepared either by neutralising hydroferrocyanic acid with the proper metallic 
oxide, or by boiling pmssian blue with the oxide, the metal of which it is intended to 
combine with the ferrocyangen. Other methods may also be adopted in special cases. 
The processes for preparing the ferrocyanides of the alkali metals on the large scale 
will be described in the article Prussiate of Potash. 

When the ferrocyanide is insoluble in water, it may be prepared by precipitating 
a salt of the metal with ferrocyanide of potassium. Thus, m the preparation of the 
reddish or purple ferrocyanide of copper, 

2(CnO,SO*) + K*Cfy -CuKJfy + 2(K0,S0*> 

The above equation written in full becomes : — 

2(CttO,SO^ + K«C«N»Fe - CuK}«N»Fe + 2(KO,SO^. 

Ferrocyanide of potassium is much used as a test for various metals, in consequence 
of the characteristic colours of the precipitates formed with many of them. The prin- 
cipal ferrocyanides with their colours and modes of preparation will be found in the 
following list : — 

Ferrocyanide of aluminium j^—Kn instable compound formed by digesting hydrate of 
alumina with ferroprussio acid. 

Ferrocyanide* of antimony and areenic, — Neither of these salts are known in a state 
of purity. 

Ferrocyanide of barium, — This salt may be prepared by boiling pmssian blue in 
slight excess with baryta water and evaporating to crystalUsation. 

Ferrocyanide of bismuth. — When a solution of ferrocyanide of potassium is added 
to a solution of a salt of bismuth, a yellow precipitate is obtained. It becomes of a 
greenish tint on keeping for some time. 

Ferrocyanide of cadmium may be attained as a white precipitate on adding a solution 
of ferrocyanide of potassium to a soluble salt of cadmium. 

Ferrocyanide of calcium may be prepared in the same manner as that of barium, 
but, owing to the sparing solubility of lime in water, we must substitute cream of 
lime for baryta water. 

Ferrocyanide of cerium is a white salt only sligfaUy soluble in water. Its properties 
are very imperfectly known. 

Ferrocyanide of chrotHium. — The protochloride of chromium gives a yellow pre- 
cipitate with ferrocyanide of potassium. 

Ferrocyanide of cobalt. — Salts of cobalt give a pale blue precipitate with ferrocyanide 
of potassium. It appears to decompose on keeping, as its colour becomes altered. 

Ferrocyanide of copper, — When ferrocyanide of potassium is added to a solution of 
subchloride of copper, a white precipitate appears, which, on exposure, becomes con- 
verted into a purplish red substance, apparently identical with the ordinary ferro- 
cyanide of copper which falls down on the admixture of salts of the protoxide of 
copper with solutions of ferrocyanide of potassium. 

Ferrocyanide ofglueinum may be obtained, according to Berselius, under the form 
of an amorphous varnish, by decomposing ferrocyanide of lead with a solution of sub- 
sulphate of glucina. 

Ferrocyanide of hydrogen constitutes ferroprussic acid. 

Ferrocyanide of iron, orpruman blue, — This salt exists in several conditions, ac- 


. 198 FIBBES. 

cording to the mode of preparadon. The ordinary salt is formed h y addmg a Mlntioi 
of ferrocjanide of potassium to a solation of a persalt of iron. Hie following equa- 
tion explains the reaction that ensues with the sesqnichloride : — 

2(Fe«ClO + 3(CfyK»«3(CfyFe«) + 6KCL 

Fenoeyatdde of lead is procured as a white precipitate by adding a solnttoD of 
ferroeyanide of potassiam to a salt of lead. 

Ferroeyanide of magnesium is probably best prepared by neutralising ferroprusie 
acid with magnesia or its carbonate. It forms a pale yellow salt 

Ferroeyanide of memganeee ma^ be obtained as a white precipitate, on adding ferro- 
eyanide of potassiam to a solution of pure protochloride or protosolphate of nin- 

Ferroeyanide qf mercury. — This compound cannot be obtained in a state of poiitj 
by precipitation. It has not been sufficiently examined. 

Ferrocyanides of moiybdenunu — Molybdons salts give, with ferroeyanide of po- 
tassium, a dark brown precipitate soluble in excess of the precipitant If a salt of 
molybdic oxide be treated in the same manner, a precipitate is obtained, haTUg a 
similar appearance, but insoluble in excess. Molybdates in solation give precipiuta 
lighter in colour than the last. 

Ferroeyanide of nickel is obtained under the form of a pale apple green precipitate, 
on addition of prossiate of potash to a salt of nickel. 

Ferroeyanide ofeilver. — Ferroeyanide of potassium gives a white precipitate with 
silver salts. 

Ferroeyanide of aodium may be formed by the action of caustic soda on pmssian blue. 

Ferroeyanide ofetrontium can be procured precisely in the same manner as the cor- 
responding barium salt substituting solution of caustic strontia (obtained fron the 
nitrate by ignition) for baryta water. 

Ferroeyanide of tantalum has probably never been obtained pure. Wollaaton found 
that tantalic acid (dissolved in binoxolate of potash) gave a yellow precipitate with 
prussiate of potash. 

Ferroeyanide of thorium. — A white precipitate is produced by the action of solotioa 
of prussiate of potash on salts of thorium. 

Ferroeyanide of tin. — Pure salts of tin, whether of the per- or prot-oxide,giTe 
white precipitates with ferroeyanide of potassiam. 

Ferrocyanides of titanium, — Solutions of titanates give a golden brown precipitate 
when treated with solation of ferroeyanide of potassium. 

Ferrocyanides of uranium, — The protochloride gives a pale, and the perchlonde 
a dark reddish brown precipitate with ferroeyanide of potassium. 

Ferroeyanide of vanadium. — Salts of vanadic oxide gfive pale yellow, and ofvanamc 
acid, rich green precipitates with prussiate of potash. 

Ferroeyanide of yttrium. — Chloride of yttrium gives a white precipitate with ferro- 
eyanide of potassium. , . 

Ferroeyanide of^ zinc cannot be prepared by precipitation. It may be obtained n 
the form of a white powder by the action of oxide or carbonate of sine on ferro- 
prussic acid, — C. G. W. For Fbrro-Ctanooen, see Ure's Dictionary of CkesMtrf- 

FIBRES, or FIBROUS BODIE& From time to time numerous grasies, fibroof 
barks, and other substances of a similar character, have been introduced into com- 
merce; a few of these only have been foand available for mannfactare. It is, howerer, 
deemed of interest to describe briefly some of these. Some of the more inportaot 
vegetable fibres will be folly noticed under their respective heads. (See Coib, Fux. 
Hkmp, &c.) , 

China Grass. — This fibre is obtained from Urtica nivea, which grows »bundW 
in China, and in various parts of our Indian empire. The samples which have be^ 
imported are principally obtained from Canton and Hong-Kong. In 1B49, ^^\^ 
Wright and Co. obtuned a patent for the preparation of this fibre. Their pro^ 
consisted essentially of boiling the stems in an alkaline solution, liter they ^i*^ 
previously steeped for 24 hours in cold water, and for 24 hours in water at 9(r t^ 
The fibre is then thoroughly washed with pure water, and finally subjected to ^ 
action of a current of high pressure steam till nearly dry. . . 

CaUooee Hemp or Rhea. — This fibre is usually confounded with China 5J*** 1^- -J 
there is little doubt they are obtained fh>m two different kinds of urtica. ^^t • ^ 
grass from the Urtica nivea of Willdenhow ; the Callooee Hemp, Kabnoi, or ^***V 
Sumatra ; and the Bhea from the Urtica tenacissima of Roxburgh. The P^^^ 
ducing the Callooee hemp, was introduced from Bencoolen to Calcutta in ^^^^Z^i^ 
nnder the care of Dr. Roxburgh, it was for many years cultivated in the ^'J*" ^j 
Gardens. In 1814, a quantity of the Callooee hemp was imported into ^^^"J^iftg 
properly tested ; its practical value was thought so highly o^ that the Society ^^' 
awarded a silver medal to Capt. James Cotton, of the East India Company, ^^^ 



trodneed it '* The eluef obstacle which interfered, howerer, with its lue, wai the 
difficulty which was found to exist in the preparation of the fibre fh>m the stems of 
the plants ; none of the processes usually adopted with flax or hemp were Ibnnd to 
be at all suitable to them ; and the rude, wasteful, and imperfect means employed by 
the natlTes in preparing the fibre for the manufacture of twine, thread, and fishing 
nets, by the mere process of scraping, were wholly inapplicable on a large scale, 
and gave besides only a Tery inferior result. When macerated or retted in water, it 
was found that the fibre itself was more easily destroyed than the glutinous matter of 
the stem. During the last forty years, ▼arious attempts hare been made to devise a 
good and cheap process for preparing this fibre, but hitherto without mueh success ; 
and consequently, till quite recently, the cost of the fibre was such as to preclude its 
being broi^t into the market as a substitute for flax. But recent iuTestigations have 
shown that the Urtica tenacissima and the heterophyOa may be obtained in almost un- 
limited quantities in Tarious parts of India ; and a process which has been lately 
patented appears, to a very great extent, to have removed the practical difficulties 
which previously stood in the way of its employment by manuihcturers ; so that in a 
few years it is probable that the Callooee hemp will constitute an important addition to 
the fibrous materials employed in the arts." — Juno's BeporU Great Exhibition^ 1851. 

Neilgherry Nettle ( Urtiea heterophyUa), — This nettle appears to be remarkable beyond 
all others for its stinging properties. It is abundant in Mysore, flourishing in Alpine 
jungles. The Todawars prepare the fibre of this plant by boiling the stems In water, 
after which they readily separate it Arom the woody parts and then spin it into a 
coarse but very strong fibre. The Malays simply steep the stems in water fbr ten or 
twelve days, after wUch they are so much softened that the outer fibrous portion is 
easiW peeled off. 

yircum Nar, — This is the native name of the fibres of the CaJoiropis (^AscUpias) 
gigetnteoj a plant which grows wild, abundantly, in various parts of the Bengal and 
Madras presidencies, and is used by the natives in the manufacture of cord called 
" LamMore,** or '• T<mdee OnrP 

Aloe fibre^ or Nar^ the produce of the Agave vivipcura, and other allied species. 
This is often called the ** Silk grass fibre.'* 

Pine-apple fibre, sometimes called ** Ananas JIcuf," This has been prepared in Java, 
and at Travancore. Many fine specimens have been brought to this country. 

Plantain fibre. — In the Government establishments of Ceylon this is extensively 
employed. Canvass and ropes are made of it It is obtained fix>m the Musa textilis. 
It is calculated that 8 cwt per acre of this excellent fibre might be obtained. 

Mahant bark. — Employed at St Vincent's in the manufacture of fishing nets, 
common cord, and coarse lines for fishing. 

New Orleans moss {TtUandsia usneoides), a substitute for horse hair as a stuffing 
material for upholsterers. Sometimes the fibrous husk of the Indian com is used 
for the same purpose, but it is more brittle than the moss. 

Palm-tree fibre. These fibres are obtained from many varieties of the palm. 

Grass fibre. Many of the grasses are now being used in the manufacture of paper, 
and for other purposes. 

The following tables by Dr. Roxburgh and Dr. Wright, afibrd much information 
as to the relative strengths of different kinds of fibrous substances. The first table 
giTes experiments made by Dr. Roxburgh in 1804; some of the fibres were, however, 
probably imperfectly prepared. 

Commoii Name. 

Botanical Name. 

Breaking Weight. 

1. Hemp (English^ 

2. Murga (Sfmseviera) 

3. Aloe .... 

4. Ejoo .... 

5. Donsha • . . - 

6. Coir ... - 

7. Hemp (Indian) 

8. Wo<^et comal 

9. ? - . - - 

la Sunn .... 

11. Bunghi paat ... 

12. Ghtt nala paat - 

13. ?- 

14. Flax (Indian)- 

Cannabis sativa ... 
Alectris nervosa ... 
Agave Americana f - 
Saguerus HumpJm ... 
JEschynomone cannabina - 
Cocos nuci/era - - - 
Cannabis sativa ... 
Abroma Augusta ... 
Banhinia .... 
Crotoiaria juncea ... 
Corchorus olitorius ... 

„ capsularis 
Hibiscus mainhot ... 
Linum usitatissimum 




















In 1808, Dr. Roxburgh made another series of experiments, of which the foUowiog 
table gives the result : — 

Common Name. 

Botanical Name. 

Breaiing Wei|hL 

1. Bowstring hemp 

2. Callooee hemp 
8. ?- 

4. Sunn - - - - 

5. Hemp (Indian) 

6. Doncha .... 

7. ?- - - - 

8. Miista paat ... 

9. Bunghi paat ... 
10. Plantain- ... 

AtcUpiag Sp, .... 
Urtica tenacusima ... 
Corchonu eapsularia 
Crotolaria jvncea ... 
Catmabis aativa ... 
jEachynomone cannabina - 
Hibiscus sb-ictus ... 

„ canm^inus 
Corchorus olitorius ... 
Musa . . - « - 




Experiments were made not long since by Dr. Wright on several well known up- 
table fibres when made into ropes. The following were the results : — 

Common. Name. 

Botanical Name. 

BreakiBK Vfti^i 

1. Yercum nar ... 

Calotropis gigatUea ... 


2. Janapum ... 

Crotolaria juncea ... 


3. Cutthalay nar ... 

Agave Americana ... 


4. Cotton . - . - 

Gossypium herbaeeum 


5. Maroot .... 

Sanseviera zeykmica 


6. Pooley mungu 

HibiscuM cantuUfinus 


7. Coir .... 

Cocos nuci/era ... 


The defect of all these fibres is, as it regards their use in weaving, that they breik 

at the knot, and in all weaving processes the fibres require frequent joining. 

Of vegetable substances of the nature and quality of undressed hemp we ia^aied 

in 1857, from 

Cwt. Computed real taloflL 

Spain - - - . . . 7,250 . £ 8,997 

Mexico 12,301 - 14,753 

British East Indies .... 5,498 . 6,899 

Other parts 2,309 - 2,918 

27,358 £33,567 

The peculiarities of these fibres are not specified, but as they are not hemp, to 
tow, or jute, we may fairly infer that many of the fibres named above are included 
in these importations. 

FIBRE, VEGETABLE, called also Lignine (Liffneux, Fr. ; PJlanzenfeuentof, 
Germ.) ; is the most abundant and general ingredient of plants, existing in all their 
parts, the root, the leaves, the stem, the flowers, and the fruit ; amounting in the com* 
pact wood to 97 or 98 per cent. It is obtained in a pure state by treating saw-diut 
successively with hot alcohol, water, dilute muriatic acid, and weak potash lye, which, 
dissolve, first, the resinous ; second, the extractive and saline matters ; third, the ctr- 
bonate and phosphate of lime ; and, lastly, any residuary substances. Ligneous 
fibres, such as saw-dust, powdered barks, straw, hemp, fiax, Imen, and cotton cloth, are 
convertible by the action of strong sulphuric acid into a gummy substance analogous 
to dextrine, and a sugar resembling that of the grape. 

Much attention has, of late years, been directed to the conversion of vegetable fihre 
into paper. See Paper. 

FIBRINE (Eng. and Fr. ; Thierischer Faserstoff, Germ.) constitutes the princip 
part of animal muscle ; it exists in the chyle, the blood, and may be regarded tf toe 
most abundant constituent of animal bodies. It may be obtained in a pure state br 
agitating or beating new drawn blood with a bundle of twigs, when it will attach itwu 
to them in long reddish filaments, which may be deprived of colour by working them 
with the han£i under a streamlet of cold water, and aiterwards freed from any ad- 
hering grease by digestion in alcohol or ether. 

Fibrine, thus obtained, is solid, white, flexible, slightly elastic, insipid, inodoroos* 
dionser than water, but containing 4 fifths of its weight of it, and without action o& 

FILE. 201 

litmiu. When dried, it becomes semi-transparent, yelloirish, stiff, and brittle : water 
restores its softness and flexibilitj. 100 parts of fibrins consist of 53*36 carbon, 19*68 
oxygen, 7'OS hydrogen, and 1931 aiote. As the basis of fiesh, it is a rery nutritions 
snbstance, and is essential to the sustenance of camivorons animals. 


FILE (Xune, Fr.; FdU^ Germ.) is a well known steel instrument, haying teeth 
npon the surface for cutting and abrading metal, ivory, wood, &c. 

When the teeth of these instruments are formed by a straight sharp-edged chisel, 
extending across the sorfiK^e, they are properly caUed files ; but when by a sharp- 
pointed tool, in the form of a triangular pyramid, they are termed rasps. The former 
are need for all the metals, as well as ivory, bone, horn, and wood ; the latter for 
wood and horn. 

Files are divided into two varieties, ftom the form of their teeth. When the teeth 
are a series of sharp edges, raised by the flat chisel, appearing like parallel furrows, 
either at right angles to the length of the file, or in an oblique direction, they are 
termed aingle cut But when these teeth are crossed by a second series of similar 
teeth, they are said to be doubte cut. The first are fitted for brass and copper, and 
are found to answer better when the teeth run in an oblique direction. The latter 
are suited for the harder metals, such as cast and wrought iron and steel. Such teeth 
present sharp angles to the substance, which penetrate it, while single cut files would 
slip over the surface of these metals. The double cut file is less fit for filing brass 
and copper, because its teeth would be very liable to become clogged with the filings. 

Files are also called by different names according to their various degrees of 
fineness. Those of extreme roughness are called rough ; the next to this is the 
bastard cut ; the third is the second cut ; the fourth, the smooth ; and the finest 
of all, the dead smooth. The very heavy square files used for heavy smith- work 
arc sometimes a little coarser than the rough $ they are known by the name of 

Flies are also distinguished from their shape, as fiat, half-round, three-square, four- 
square, and round. The first are sometimes of uniform bresdth and thickness 
thronghont, and sometimes tapering. The cross section is a parallelogram. The 
half-round is generally tapering, one side bein^ flat, and the other rounded. The 
cross section is a segment of a circle varying a little for different purposes, but seldom 
equal to a semicircle. The three-square generally consist of three equal sides, being 
equilateral prisms, mostly tapering ; those which are not tapering are used for sharp- 
ening the teeth of saws. The four-square has four equsl sides, the section being a 
square. These files are generally thickest in the middle, as is the case with the 
smith's rubber. In the round file the section is a circle, and the file generally 

The heavier and coarser kinds of files are made ftom the inferior marks of blistered 
BteeL Those made Arom the Russian iron, known by the name of old sable, called 
from its mark CCND, are excellent The steel made from the best Swedish iron, 
called Hoop L or Dannemora, makes the finest Lancashire files for watch and clock 

The steel intended for files is more highly converted thsn for other purposes, to give 
them proper hardness. It should however be recollected, that if the hardness be not 
accompanied with a certain degree of tenacity, the teeth of the file break, and do but 
little senrioe. 

Small files are mostly made of cast steel, which would be the best for all others, if 
it were not for its higher price. It is much harder than the blistered steel, and fVom 
having been in the fluid state, is entirely free from those seams and loose parts so com- 
mon to blistered steel, which is no sounder than as it comes from the iron forge before 

The smith's rubbers are generally forged in the common smith*s forge, from 
the converted bars, which are, for convenience, made square in the iron before they 
come into this country. The files of lesser size are made from bars or rods, drawn 
down from the blistered bars, and the cast ingots, and known by the name of tilted 

The file-maker's forge consists of large bellows, with coke as fhel. The anvil- 
block, particularly at Sheffield, is one large mass of mill-stone grit The anvil is of 
considerable size, set into and wedged fast into the stone ; and has a projection at one 
end, with a hole to contain a sharp-edged tool for cutting the files from the rods. It 
also contains a deep groove for containing dies or bosses, for giving particular forms 
to the files. 

The flat and square files are formed entirely by the hammer. One man holds the 
hot bar, and strikes with a small hammer. Another stands before the snvil with a 
two-handed hammer. The latter is generally very heavy, with a broad face for the 

202 FILR 

large filei. Thsy loth ■triko with mch tmih u to make the lurhee mMl] nl 
flat, wilhoat what ii called hand-hsmmeriDg. Thii arise* frnm their gT«U eipcnns 
ID die lame kind of work. The eipeditioo aiiiiag from the laiiie cuiuIiiki(Ib 

The half-rooDd file* are made in a bou Ikftencd into the grooTe abcm maitaL 
The Meel beiog drawn ont, i> lud apon the rounded reced, and hammered till it Gli 
the die. 

The tbree-iided fl1« are formed limilarl; io a boo, the receu of which coana rf 
two sidei, with the angle downwanll. The iteel ii SiM drawn ont iqQut, anil l^ 
placed in a boas with an angle downwards, so that the hammer formi oae odt. ud 
the bofii two. The round files are formed bj a swage uinilar to ihow iwd tij 
common imitha, but a little conicoL 

The file cutter reqoirti an aDvii of a die greater or leas, proportioned to dw ait of 
hii files, with a face as ereu and fiat as possible. The hammers weigh (nm at u 
fire or iie ponods. The chisels are a little broader than the file, ghvpcHd lo a 
angle of about SO degrees. The length is jnat snffidcnt for them to be beldfiBlK- 
tween the finger and thamb, and so strong as not to bend with the strnkts of ili 
hammer, the inCeniitj of which may be best couceiTed by the depth of the iBi;nBii& 
The anVil is placed in the jhce of a Mnmg wooden post, to which a woodea ksI i> u- 
tached, at a small distance below the level of the anvil's &ce. The file ii &it lui 
upon the bare anvil, oae end prDjecting over the front, and the other over ibe tack 
edge of the same. A leather strap now goes over each end of the file, ud piwi 
down upon each side of the block to thevorkmsn's feet, which, being put intilbanp 
on each side, like a stirrap, holds the file firmly upon the anvil as it is cat. Wliili in 
point of the file is catting, the strap passes over oae part of the file only, tht pa 
resting upon the aovil, and the tang apon a prop on the other side of the Unp. "^^ 
one side of the file ia single cut, a fine file is run slightly over the teeth, to take lOf 
the roughness ; when Itaey are to be double cat, another set of teeth i< cat, amn 
the former nearly at right angles. The file is now finished upon one aide, anl il ■ 
evident that the cat side cannot be laid upon the hare anvil to cut the other, A da 
piece (rf'Bn alloy of lead and tin ia interpoied between the toothed sorfue udUi 
anvil, while the other side is cut, which completely preserves the side alrtadj Irrati 
Similar pieces of lead and tin, with angular and rounded grooves, are Bsed br miint 
triangular and half-round files. 

Rasps are cat precisely in the aame way, by using a triangalar paneb iosuao ■■ ■ 

flat chisel The great art in cutting a rasp is to pSue every new tooth as mntn » 

possible opposite to a vacancy. . 

File cutting machines have been from time to time invented, to '^'^^\^ 

Montigny re^ a memoir before the Committee of Commerce, in which he ^'^"^ 

the inventions for file-cutling in 1699 by Dnverger, in I7S.1 by Fordoort, la U" 

by Thiout, in 1756 by Brachat and Gamain, and in 17?8i since which, i" 1*"^ ^ 

invented a file-cottiug machine] and in 1836 Ericsson introduced another, '"j^ 

Bobison, juat before his death, invented a method for cutting curved file* I "^ " 

1B43, Messrs. Johnson, Cammell, and Co. received the medal of the Scottish SofidJ 

of Arts for perftctiug Sir J. Robison's acheme. The accompanying •""r.'^ 

which are representationa of the file-cntting machine of Mr. W. Shilton of Bumiiigl^ 

wiU ahow the general pM^ 

uponwhlch thoae machmea M* ""■ 


Ia order to render thiJ '"^"f 
better understood, two vie« <*«' 
appanitua for producing the '"^ 
cut or teeth of the file*. »" P],~^, 
Fig. 7*9 is an elevBdca « « 
upper part of the fil^"«^^ 
chine, as seen on one ude i J^ '" 
U a plan or horisontal vi(», " * 
machine appears on the tep. 

a, ia the head of the till twn" 
placed in the end of lb" '"f * 
which ia moonted on "n ^^ 
turning in proper bwrinP/j,^ 
frame work of the machio* ^ * " ^ 
tilt wheel mounted on MOtW" 
s. also lumiog in i^^P "1^ 
frame work of the machine, and having any required nimiber of prqjectiooi " "r 
pets upon it for depressing the tail <a ahoner end of the hammer st tilt I**" 

FILE. 203 

The tilt vheol J, lecriTw iu rotUorj iDotion from tli« tootbed wheel j^ noanted 
npoD the Hme utle, and it laket into guar with t, pimioD g, npoD the mtia iluft A, 
which ia (ctoated b; a band paued 

frotn any Srst mover to the tif^er "*° 

OD its eiid, or in any other codtc- 
nicDt maiuier. The bed upon which 
the blank piece of sleel bean ia E 
marked L Thii bed ii Bnnl; lap- 1 
ported Dpon matonrf placed apoa 
proper ileeperv - j, ia one of the 
bkank pieoea of Iteel mider opeta- 
tion, udisehowDiecnrediDthepair 
ofjawaoT holding clampa k, mounted 
cm ceolre pirn in the slide L,fig. 7S0, I 
which tlide ia held dowo by a iprioK 
and alide beneath, and ii moTed 
backward* and forward* \a the ma- 
chine opoD the (v) edges pi m, of 
the fraioe, bj mcana of the rack a 
and ita pinion; the latter being 
loonnted uponlbe axle of the ratchet 
wheel p, and which ratchet wheel 

ji made to tarn al iDlerrali by metuu of the pall g, npon the end of the lever r, 
fig. 750. Thiileier i« depresM>d, after every cut has been effected upon the blank bj 
meana of the teeth or tappets of the wheel *, comiajt in contact with Uie inclined plane 
t, upon the lever r. The tappet wheel t, ia mounted npon tbe end of the axle e, of 
the tilt wheel, and eonaeqaentlj revolvec with it, and by depreMiog the lever r, eiery 
time (hat a tooth paue* the inclined plane t, the click q, it made tn drive the ratchet 
wheel ^, and thereby the adTftncing morement of the blank is effected after each 
blow of the lilt hammer. 

There ii a itrong spring k, attached to the apper side of the till hammer, its end 
being confined nnder an adjostible inclined plane i>, moanled in the ftame lo. which 
inclined plane can be raised or lowered by iu adjusting screw* ni required, to pro- 
dooe more or leu teniion of the spring. 

A similar spring ia placed on the under side of the tilt hammer, to r«i*e and lastain 
ihe cntter or tool clear i^tbe bed aAer every blow, and in conjonclioD with lajety 
holdera or catchen, to counteract any vibration or tendency the spring h, may have 
to canse the hammer to reiterate the blow. 

Tbe end of the lower spring acts on an inclined plane, mounted in the frame », 
which hai an adjusting screw similar to u, to regulate the lenaion of the spring. 

In eaae the onder tpring shanld raise, that is, return the hammer, with sufficient 
force or velocity lo caose the top spring u, to reiterate the blow, the ends of the safety 
balden or catcben are made to move under and catch tbe tail of the lever b, immedi- 
ately on it* b«ing raised by the under springs, which i* effected by the following 
meaoi: — The holders are mounted upon a plate or carriage 1, Jig 749, which turn* 
npoa a small pin or axle mountrd in the ear* of a cross bar ; the upper end* of the 
hidden are kept inclined toward* tbe tail of (be tilt hammer by means of a spring 
fixed to theeroM bar, and which act* upon one end of the plate or carriage. 

In order that tbe holders may be removed out of the way of the tail of the hammer 
h, when the tilt wheel i* about to effect a blow, tbe tooth of tbe tilt wheel which 
last acted upon Ihe hammer comes in contact with an inclined plane fixed on 
tbe plate or carriage t, and by deprening that end of tbe plate, causes the upper 
ends of Ihe holders to be withdrawn from nnder the tail of the hammer h. The 
tilt wheel continuing lo revolve, the next tooth adviutces, and depresses the tail of tbe 
hammer, but before it leavei tbe tail of the hammer, tbe tooth last in operation will 
have quitted tbe inclined plane and aUowed the spring to return the holden into their 
Canncr pOBlion. After the tooth has escaped from the tail of i, the hammer will im- 
mediately descend and effect the blow or cut on the blank, and as the tul of the 
hammer riaea, it will come in contact with tbe inclined planes at the upper ends of the 
holders, and force them backward* ; and as soon a* tbe tail of the hammer hag passed 
tbe lop of the holders, Ihe spring will immediately force the holders forward under 
the tail of the hammer, aod prevent tbe bammer rising again until the next tooth 
of the tilt wheel i* aboot lo depress the end of tbe h^imer, when the ume move- 
ments of the parts will be repeated, and the machine will continue in operation until 
a anffleient length of the blank of sleel (progresuvcly advanced under tbe bi 
baa been operated npon, when it will be thrown ont of ge~ 

204 FILE. 

most end of the slide / Ufig. 750, Ot^mes in contact as it is moTed forward bj the nek 
n, and its pinion. The sliding bar 6, is connected at its left end to the bat lever 8, 
the other end of this lever being formed into a forked arm, which embraces t clmeh 
npon the main shaft, and as the slide / continues to advance, it will come in oootirt 
with a stop ; and when it has brought a sufficient length of the blank pieces of steel 
under the operation of the cutting tool, the slide /, in its progress, will hate mored 
that stop and the bar 6 forward* and that bar, by means of the bent lever 8,iri0 vitli- 
draw the clutch on the main shaft, from locking into the boss of the fly-vbeel, tod 
consequently stop the further progress of the machine ; the rigger and fl/'vhed 
turning loosely upon the main shaft. 

The cut file can now be removed from out of the clamps, and rerened toeottlK 
other side, or another blank piece put in its place ; and after throwing bsck the pill 
^ of the ratchet wheel p, the slide i, and with it the ft^sh blank, may be moTed bick 
into the machine by turning the winch handle, on the axle of the ratohet wheel ^ the 
reverse way, which will turn the pinion backwards, and draw back the rack n, vithoot 
affecting any other parts of the machine ; and on moving back the bar 6, bj the 
handle 11, placed on the stop, the clutches will be thrown into gear agsiSjUdtke 
machine proceed to cut the next blank. 

When the blanks have been thus cut on one side, and are reversed in tbe BuehiBe 
to form the teeth upon the other side, there should be a piece of lead placed betvecntbe 
blank and the bed to protect the fresh cut teeth. 

It will be seen that the position of the stop upon the bar 6, will detarmiiM tix 
length or extent of the blank piece of steel which shall be cut or operated npoa; ind 
in order that the progressive movement of the blanks under the cutting tool mtr be 
made to suit different degrees of fineness or coarseness of the teeth (that is thedtf- 
tance between the cuts), there is an a^josting screw upon the lever r, the heid d 
which screw stops against the under side of an ear projecting from, the fnofi-^oii 
and thereby determines the extent of the motion of the lever r, when depreoed by 
the tappets of the wheel «, acting upon the inclined plane t, consequently detennnuBg 
the number of teeth the ratchet wheel p shall be moved round by the pall f ; u» 
hence the extent of motion conmiunicated by the rack and pinion to the slide I vA 
the blank J, which regulates the distance that the teeth of the file are apart, and tbe 
lever r is forced upwards by a spring pressing against its nnder side. 

It will be perceived that the velocity of the descent of the hammer, and consh 
qnently the force of the blow, may be regulated by raising or lowering the i"^'"?^ 
plane v of the spring u ; and in order to accommodate the bed upon which thewBw 
rest to the different inclinations they may be placed at, the part of the bed is wnaA 
of a semi-globular piece of hardened steel, which fits loosely into a similar c^j'!^ 

similar shaped concavity. . 

There are guides 16, placed on the top of the bed i, for the purpose ^^^^^^^ 
blanks in their proper position towards the cutting tool, and these cos be ']^^t*v 
to suit blanks of any width, by turning the right and left handed screw 17. ."^"^ 
also another a^justible stop on the jaws or clamps k which serves as a gsi^' ^"^ 
placing the blanks within the jaws : and 19 is a handle or lever for raising the cUDp 
when required, which has a weight suspended ftx>m it for the purpose of heepingdo 
the blanks with sufficient pressure upon the bed. . ^ 

The cutting tool in the face of the hammer, can be placed at any required *^, 
inclination with the blank, it being secured in the head of the hammer by ^^P'^J 
screws. In cutting fine files a screw is employed in preference to the n^ 
pinion, for advancmg the slide /, and the blank piece of steel in the machine. 

Hardening the files, ^This is the last and most important part of file "Jr'j 
Whatever may be the quality of the steel, or however excellent the workio«n*"P' 
it is not well hardened all the labour is lost «. ^ 

Three things are strictly to be observed in hardening ; first, to prepare the nw 

the surface, so as to prevent it from being oxidated by the atmosphere *ben 
file is red hot, which effect would not only take off the sharpness of the ^^^^^ 
render the whole surface so rough that the file would, in a little time, bec^ 

clogged with the substance it had to work, Secondly, the heat ought ^^^ 
uniformly red throughout, and the water in which it is quenched, fresh «"° JJ^ 
for the purpose of giving it the proper degree of hardness. Lastly, ^^^.^^ 
immersion is of great importance, to prevent the files firom warping, ^^'^ " 
thin files is very difficult . i^ 

The first object is accomplished by laying a substance upon the fil^i ^^^iLTde 
it fuses, forms as it were, a ^Amish ii|H>n tiie surface, defending the metal from 

FILE. 205 

action of the oxygen of the air. Fonnerly the process cousisted in first coating the 
snrfaoe of the file with ale groonds, and then covering it over with pulverised common 
salt (mariate of soda). After this coating became dry, the files were heated red hot, 
and hardened ; after this, the surface was lightly brushed over with the dnst of cokes, 
when it appear white and metallic, as if it had not been heated. This process has 
lately been improved, at least so fkr as relates to the economy of the salt, which from 
the qoantity used, and the increased thickness, had become a serious object Those 
who nsed the improved method are now consuming about one fourth the quantity of 
salt used in the old method. The process consists in dissolving the salt in water 
to satnmtion, which is about three pounds to the gallon, and stiffening it with ale 
grounds, or with the cheapest kind of fionr, such as that of beans, to about the con- 
sistence of thick cream. The files required to be dipped only into this substance, and 
immediately heated and hardened. The grounds or the flour are of no other use, 
than to pve the mass consistence, and by that means to allow a larger quantity of 
salt to be laid upon the surface. In this method, the salt forms immediately a firm 
coating. As soon as the water is evaporated, the whole of it becomes fused upon the 
file. In the old method the dry salt was so loosely attached to the file, that the 
greatest part of it was nibbed off into the fire, and was sublimed up the chimney, 
withoat producing any effect. 

The carbonaceous matter of the ale grounds is supposed to have some effect in give 
ing hardness to the file, by combining with the steel, and rendering it more highly 
carbonated. It will be found, however, upon experiment, that vegetable carbon does 
not combine with iron, with suiBcient &cility to produce any effect, in the short space 
of time a file is heating for the purpose of hardening. Some file makers are in the 
habit of using the coal of burnt leather, which doubtless produces some effect ; but 
the carbon is generally so ill prepared for the purpose, and the time of its operation 
so short, as to render the result inconsiderable. Animal carbon, when properly pre* 
pared and mixed with the above hardening composition, is capable of giving hardness 
to the suirface even of an iron file. 

This carbonaceous matter may be readily obtained from any of the soft parts of 
animals, or from blood. For Uiis purpose, however, the refuse of shoemakers and 
curriers is the most convenient After the volatile parts have been distilled over, 
from ao iron still, a bright shining coal is left behind, which, when reduced to powder, 
is fit to mix with the salt Let about equal parts, by bulk, of this powder, and 
muriate of soda be ground together, and brought to the consistence of cream, by the 
addition of water. Or mix the powdered carbon with a saturated solution of the salt, 
till it become of the above consistence. Files which are intended to be very hard, 
should be covered with this composition, previous to hardening. All files intended 
to file iron or steel, parlicularly sa^ files, should be hardened with the aid of this 
mixture, in preference to that with the flour or grounds. Indeed, it is probable, that 
the carbonaceous powder might be used by itself, in point of economy, since the 
ammonia or hartshorn, obtained by distillation, would be of such value as to render 
the coal of no expense. By means of this method the files made of iron, which in it- 
self^ is unsusceptible of hardening, acquired a superficial hardness sufficient for any 
file whatever. Such fifes may, at the same time, be bent into any form ; and, in con- 
sequence, are particularly iwefkil for sculptors and die-sinkers. 

The next point to be considered is tbe best method of heating the file for hard- 
ening. For this pntpose a fire, similar to the common smith's fire, is generally 
employed. The file Is hold in a pair of tongues by the tang, and introduced into 
the fire, consisting of very small cokes, pushing it more or less into the fire for 
the purpose of heating it regularly. It must frequently be withdrawn with a view 
of observing that it is not too hot in any part When it is uniformly heated, from 
the tang to the point of a cherry red colour, it is fit to quench in the water. At 
present an oven, formed of fire-bricks, is used for the larger files, into which the 
blast of the bellows is directed, being open at one end, for the purpose of introduc- 
ing the files and the fuel Near to the top of the oven are placed two cross bars, 
on which a few files are placed, to be partially heating. In the hardening of heavy 
files, this contrivance affords a considerable saving, in point of time, while it permits 
them also to be more uniformly and thoroughly heated. 

After the file is properly heated for the purpose of hardening, in order to produce 
the greatest possible hardness, it should be cooled as soon as possible. The most 
common meUiod of effecting this is by quenching it in the coldest water. Some file- 
makers have been in the habit of putting different substances in their water, with a 
view to increase its hardening property. The addition of sulphuric flcid to the water 
was long held a great secret in the hardening of saw files. After all, however, it will 
be found, that clear spring water, free ttom animal and vegetable matter, and as cold 
as possible, is the best calculated for hardening files of every description. 



In qnenchiDg the files in vater, some caution most be observed. AU files, except the 
half-round, should be immersed perpendicularly, as quickly as possible, so that the 
upper part shall not cool. This management prevents the file from -warping. The 
half-round file must be quenched in the same steady manner ; but, at the same time 
that it is kept perpendicular to the surface of the water, it must be moved a Jittle 
horizontally, in the direction of the round side, otherwise it will become crooked 

After the files are hardened, they are brushed over with water, and powdered cokes^ 
when the surface becomes perfectly clean and metallic, They ought also to be washed 
well in two or three clean waters for the purpose of carrying off ^ the salt, whidi. if 
allowed to remain, will be liable to rust the file. They should moreoTcr be dipped 
into lime-water, and rapidly dried before the fire, after being oiled with olive oil, 
containing a little oil of tarpentine, while still warm. They are then finished. 

FILLIGREE {FiUgrane, Fr. ; Filigran, or Peine Drahtg^echt, Germ.) is, as tke 
last term justly expresses it, intertwisted fine wire, used for ornamenting gold and silver 
trinkets. The wire is seldom drawn round, but generally flat or angular ; and soU 
dered by gold or silver solder with borax and the blowpipe. Hie Italian word, 
filigranoy is compounded of filum and granum, or granular net*work ; becanse the 
Italians, who first introduced this style of work, placed small beads upon it. 

FILTRA.TION (Eng. and Fr.; Filtnren, Germ.) is a process purely mechaniei], 
for separating a liquid from the undissolved particles floating in it, which liquid may 
be either the usefiU part, as in vegetable infusions, or of no use, as the washings of 
mineral precipitates. The filtering substance may consist of any porous matter in a 
solid, foliated, or pulverulent form ; as porous earthenware, unsized paper, cloth of 
many kinds, or sand. The white blotting paper sold by the stationers answen ex- 
tremely well for filters in chemical experiments, provided it be previously washed with 
dilute muriatic acid, to remove some lime and iron that are generally present in it 
Filter papers are first cut square, and then folded twice diagonally into the sliape of a 
comet, having the angular parts rounded off. Or the piece of paper being cut into a 
circle, may be folded fan-like from the centre, with the folds placed exteriorly, aad 
turned out sharp bv the pressure of the finger and thumb, to keep intervals betwen 
the paper and the funnel into which it is fitted, to favour the percolation. The diameter 
of the fiinnel should be about three-fourths of its height, measured from the neck to 
the edge. If it be more divergent, the slope will be too small for the ready eflinx of 
the fiuid. A filter covered with the sediment is most conveniently washed by spootiag 
water upon it with a little syringe. A small camel's-hair paint brush is much employed 
for collecting and turning over the contents in their soft state. Agitation or vibration 
is of singular efficacy in quickening percolation, as it displaces Sie particles of the 
moistened powders, and opens up the pores which had become dosed. lostesid of a 
funnel, a cylindrical vessel may be employed, having its perforated bottom covered 
with a disc of filtering paper folded up at the edges, and made tight there by a wire 
ring. Linen or calico is used for weak alkaline liquors ; and fiannels, twilled woollen 
cloth, or felt- stuff for weak acid ones. These filter bags are often made conical like a 

fool's cap, and have their mouths supported by a wooden 
or metallic hoop. Cotton wool put loose into the neck d 
a funnel answers well for filtering oils upon the small 
scale. In the large way, oil is filtered in conical woollen 
bags, or in a cask with many conical tubes in its bottom, 
filled with tow or cotton wool. Stronger acid and alkaline 
liquors must be filtered through a layer of pounded glass, 
quartz, clean sand, or bruised charcoal. The alcarrhazas 
are a porous biscuit of stone ware nuule in Spain, which 
are convenient for filtering water, as also the poroos filtering 
stone of Teneriffe, largely imported into England at one 
time, but now superseded in a great measure by the arti- 
ficial filters patented under many forms, consisting e 
tially of strata of gravel, sand, and charcoal powder. 

It is convenient to render the filter self-acting, by 
modating the supply of liquid to the rate of percolation, so 
that the pressure upon the porous surface may be always 
equally great. Upon the small scale, the lamp-fountain or 
bird's-glass form so generally used for lamps, will be foond 
to answer. 

Fig, 751, represents a glass bottle A, partly filled with 

the fluid to be filtered, supported in the ring of a chemical 

stand, and having its mo th inverted into the same liquor in the filter funnel. It is 

obvious, that whenever this liquor by filtration falls below the lip of the bottle, air 



viU eDter into it, let down ■ tretii tapf[j to feed th« filter, and keep the (UddgI re- 
golaiij charged, [f larger qnaatilieB are to he operated apon, the foIJowiug appa- 
i>uu intLj he employed. Fig- T53, A k, ii a metallic -j^g 

*ei»el which nuj be made aii^tigbt ; c is the under 
pipe provided with a atopeock b, for letliDR doiro 
the liquor into the filter a b. Tbe upper pipe t, through 
which the flnid ia pooled \>j mean* of the fanuel k, 
has alMi a ttopcock which opeag or thata, at the ume 
time, the bhuU aide tulie h t, thr(iu);h which, during 
the entrance of the flaid, the air is let off tmrn the 
receiTcr. A glass tnbe g, shows the level of the 
liquor in the bod^ of the apparatus. In using it, the 
cock R most be first closed, and the cock a must be 
opened to fill the receiver. Then the filler ia set a 
going, by re-openlng tbe cock k, to as to keep the fluid 
in the filler upon a level with the opening of the lubeo. 
Both these piecea of apparatus are essentially the same. 
In man; msnnfiiclurei, self-acting filters are fed by 
tbe plumber's common contrivance of a ball-cock in 
which the sinking and riling of the ball, within certain 
limits, serves to open or ghat off the supply of liqaor 
aa it may be required or not l>umont hu adopted 
this expedient for his system of filtering sj-rup through 
& Btralum of granularly ground animal charcoal or i 
bone-black. F\g. 7 S3, ia a front view of this apparatns 
with 4 filters c ; and fig. 7S1 is a cross section. The 
fhuDcvork a supports the cistern A, in which the Sfrup 
is contained. Prom it the liquor flows through tbe 
■top-cock b, and the coonectioD-tQbe a, into the coninon 
pipe r, which communicates, by the abort branch tubes t, with each of the fonrfillera. 
The end of the branch tube, which ia inside of tbe filler tub, is provided with a stop- 

XK^ d/, whose opening, and thereby the efflux of the liquor from the cistern thraagh 
the UiIh- a, is regulated bj meana of the floating-baU g. Upon the brickwork D the 
filler tub stands, fttraished at A j^^ 

with a blse bottom of line or 
eopprr pierced with fine holes ; be- 
sides which, higher cp at i there is 
another such plate of metal fnr- 
Dubed wiih a strong handle A, by 
which it may be removed, when tbe 
bone-black needa to be changed. 
In the intervening spai^e I, the 
rrranolar coal is placed, o in tbe 
coTcr of the filter tnb, with a 
hanille also for lifting it One por- 
tion of it may be niacd by a hinge, 
when it la desired to inspect the 
pn^resa of ihe filtration within. 

■ M is a slender vertical tube, forming a commauication between the bottom part h, 
and the upper portion of the filter, to admit of the eiL^y escape of the air from that 
apace, and from among tbe bone-blacL as the sjrup descends ; otherwiac tbe filtration 


could Bot go on. p \s the stopcock through which the fioid collected in the 
space under k is let off from time to time into the common pipe 9, fig. 753. r b 
a trickling channel or groove lying parallel to the tube q, and in which, by means 
of a tube «, inserted at pleasure, the syrup is drawn off in case of its flowing in a 
turbid state, when it must be returned over the surface of the charcoaL 

The celerity with which any fluid passes through the filter depends, — 1, upon the 
porosity of the filtering substance ; 2, upon the pressure exercised upon it ; and 3, upon 
the extent of the filtering surface. Fine powders in a liquor somewhat glutinous, or 
closely compacted, admit of much slower filtration than those which are coarse and 
free ; and the former ought, therefore, to be spread in a thinner stratum and over a 
more extensive surface than the latter, for equal effect ; a principle well exemplified in 
the working of Dumont's apparatus, just described. 

In many cases filtration may be accelerated by the increase of hydrostatic or pneu- 
matic pressure. This happens when we close the top of a filtering cylinder, and con- 
nect it by a pipe with a cistern of fluid placed upon a higher level. The pressure of the 
air may be rendered operative also either by withdrawing it partially from a dose 
vessel, into which the bottom of the filter enters, or by increasing its density over the 
top of the liquor to be filtered. Either the air pump or steam may be employed to 
create a partial void in the receiver beneath the filter. In like manner, a forcing pump 
or steam may be employed to exert pressure upon the surface of the filtering liquor. A 
common siphon may, on the same principle, be made a good pressure filter, by making 
its upper leg trumpet-shaped, covering the orifice with filter paper or cloth, and filling 
the whole with liquor, the lower leg being of such length so as to create considenbte 
pressure by the difference of hydrostatic level. This apparatus is very convenient 
either on the small or great scale, for filtering off a clear fluid from a light muddy 
sediment The pressure of the atmosphere may be elegantly applied to commcm filtcn, 
by the apparatus represented in^. 755, which is merely a funnel enclosed within a 
^ gasometer. The case ▲ b bears an annular hollow vessel a h, 

*^^ failed with water, in which receiver the cylindrical gasometer, 

f d, e^f, I, is immersed. The filter funnel c is secured at its 

r II upper edge to the inner surface of the annular vessel a 6. In 

•'"I J" • consequence of the pressure of the gasometer regulated by the 

weight g, upon the air inclosed within it, the liquid is equallj 
pressed, and the water in the annular space rises to a corre- 
sponding height on the outer surface of the gasometer, as shown 
in the figure. Were the apparatus made of sheet iron, the an- 
nular space might be charged with mercury. 

In general, relatively to the application of pressure to filters, 
it may be remarked, that it cannot be pushed very far, without 
the chance of deranging the apparatus, or rendering the filtered 
liquor muddy. The enlargement of the surfiice is, generally 
speaking, the safest and most efficacious plan of increasing the 
rapidity of filtration, especially for liquids of a glutinous nature. This expedient is 
well illustrated in the creased bag filter now in use in most of the sugar refineries of 
London. See Sugar. 

In many cases it is convenient so to construct the filtering apparatus, as that the 
liquid shall not descend, but mount by hydrostatic pressure. This method has two 
advantages : 1. that without much expensive apparatus, any desired degree of hydro- 
static pressure may be given, as also that the liquid may be forced up through several 
filtering surfaces placed alongside of each other ; 2. that the object of filtering, which 
is to separate the particles floating in the fluid without disturbing the sediment, may 
be perfectly attained, and thus very foul liquids be cleared without greatly soiling the 
flltering surface. 

Such a construction is peculiarly applicable to the purification of water, either alone, 
or combined with the downwards plan of filtration. Of the former variety an example 
is shown in ^^. 756. The wooden or zinc conical vessel is provided with two per- 
forated bottoms or sieves e e, betwixt which the filtering substance is packed. Over 
this, for the formation of the space h A, there is a third shelf^ with a hole in its middle, 
through which the tube d b is passed, so as to be water tight. This places the upper 
open part of the apparatus in communication with the lowest space a. From the com- 
partment A A a small air tube / runs upwards. The filtering substance consists at bottom 
of pebbles in the middle of gravel, and at the top of fine sand, which may be mixed 
with coarsely ground bone-black, or covered with a layer of the same. The water to 
be filtered being poured into the cistern at top, fills through the tube b d the inferior 
compartment a, from which the hydrostatic pressure forces the water upward through 
the perforated shel^ and the filtering materi^s. The pure water collects in the space 
h A, while the air escapes by the small tube /, as the liquid enters. The stopcock t serves 


Id dra* off ihe filtered water. . 
tides nxpendcd in it have time 
orer the upper ihelf at d^ u 
veil as orer the nader one at 
a,sprecipilKte or deposit irhicb 
nuj be wished out of the latter 
caTity b/ meuu of the itop- 

As ui example of an apwards 
and dowDward* filter,^. ;S7 
maj be exhibited, a b c v i* 
a wooden or metallic ciateni, 
famished with tbe perforated 
>bclf e d aax its ander pan, 
upon wbich a Tertical partition 
is fixed tliroagb tbe axis of tbe 
TMsel. A iemiciTcnlar perfo- 
nted jhelf ii placed at a, and a 
second iimilar one at &. These 
horiiontBl sbelve* rest npon 
brackets in the sides of the cincnu, lo that the; may be readil; \iftrd onC. The space 
c is filled witb coarse sand, j with moderately fine, and H with very fine. The foul 
water is poured into the chamber E, and presses through o J H and into the Bpac«r, 
whence it maj be drawn bj the stopeock j^ 

Fig. TSS repreiails in section a filtering apparatoa eonsistiiig of two concentrio 
chambers ; the interior being destined for downwards GltratioD, and tbe exterior for 
upwards. Within the larger cistern ji, a amaller one b is placed conceDlricail}', witb 
its under part, aod is left open from distance to distance, to make a oommnnicatiun 
betwem the interior caTitj and tbe exterior annular space. These csTities are filled 
to the marked height with sand and graveL The inner cjlindrical space has En« 
sand below, then iharper sand with grannlsr charcoal, next coarse sand, aud lastly 
graiel. The annular space bai in like manner fioe sand below. The foul water i* 
introduced bj the pipe s, the ori&ce at whose end is acted upon h; a ball-coclc witb 

its IcTer a ; whereh; tbe water is kept always at the same level in 
Tbe water sinks through tbe sand strata of tbe middle leseel, pass< 

the inner Tessel. 
■,i through tbe sand strata of tbe middle leseel, passes oatwartts at its 
Mmom into the anaular space, tbence np Ibroagh the sand in it, and collecting aboie 
it, ia let off bj the stopcock on tbe pipe b. When a muddy deposit forms after some 
time, it maj be easily cleared out The cord e, running over the pulleys//, being 
drawD tight, the ball [ever will shot up tbe valre. Tbe stopcock d made fast to the 
eoDdneting tnbe ■ must then be opened, so that the water now overflows into the 
auDolar (pace at a ; the tube c, in communicatioii with Ihe inner space B, being opened 
bj taking oat tbe stopper h. The water thereby percolates through the sand strata in 
the reverse direction of its usual course, so as to clear away Ihe impurities in the 
space B, and to discharge them by the pipe c h. An apparatus of this kind of 
moderate size is capable of filtering a great body of water. It should be coo- 
Etmeted for thai purpose of masonry ; but upon a small acale it may be made of 

It apparalos for filtering oil upwards isrepreseuled in j!if. 799. ^isanoil 


cask, in which the impure parts of the oil hare accamalated over the hottom. hDne- 
diately above this, a pipe a is let in, which communicates with an elevated water ebteni 
n. /is the filter (placed on the lid of the cask), furnished with two perforated sbelvo, 
one at e and another at d; which divide the interior of the filter into three com- 
partments. Into the lower space immediately over the shelf e, the tube 6, faniibed 
with a stopcock enters, to establish a communication with the cask ; the middle esTitj 
e is filled with coarsely ground charcoal or other filtering materials ; and the upper 
one has an eduction pipe L When the stopcocks of the tubes a and h are opened, the 
water passes from the cistern into the oil cask, occupies firom its density always tbe 
lowest place, and presses the oil upwards, without mixing the two liquids ; wberebjfint 
the upper and purer portion of the oil is forced through the tube b into tbe fiher, od 
thence out through the pipe L When the fouler oil follows, it deposits its imporitiei 
in the space under the partition c, which may from time to time be drawn off throogh 
the stopcock k, while the purer oil is pressed upwards through the filter. Inthisvij* 
the different strata of oil in the cask may be filtered off in succession, and kept lepante, 
if found necessary for sale or use, without running any risk of mixing up the moddj 
matter with what is clear. According to the height of the water cistern a, will be tbe 
pressure, and of course the filtering force. When the filter gets choked irith dirt, it 
may be easily re-charged with fresh materials. 

it has been for many years the custom of the water companies to send the water taken 
from the river through filter beds, prepared usually of sand and gravel It was Iobj; 
thought that tbe effect of these filter beds was merely to separate the solid iofoIoNe 
matters suspended in the water. It has, however, b^n shown by the investigation of 
the late Mr. Henry M. Witt (a chemist of peculiar promise, lost too soon to science, 
and ere yet the world could recognise his powers), that these filter beds had tbe pover 
of separating many of the dissolved substances from tbe water ; that, in fiict, the lolabie 
salts of lime, and the like, were removed by some peculiar physico-mechanica] force, 
resident, as it appears, as a surfhce force, in all porous masses. There are many tctt 
remarkable examples in nature of the operation of this power in prodoeing bedi 
•barged with metsUliferous matter, some of which will be described under the bead of 


Mr. H. M. Witt communicated to the PhUoaophieai Magazine tor December, 1856, n 
account of some experiments on filtration, which ore of much value. Hanj of hif 
experiments were made at the Chelsea Water Works, and they appear of aucb interest 
that we quote the author's remarks to some extent 

** The system of purification adopted by the Chelsea Waterworks, at their works it 
Chelsea, consisted hitherto (for the supply has by this time commenced from Kiogs- 
ton) in pumping the water up out of tbe river into subsiding reservoirs, where it r^ 
mamed for six hours ; it was then allowed to run on to the filter-beds. These are 
large square beds of sand and gravel, each exposing a filtering surface of about S70 
square feet, and the water passes through them at the rate of about 6| gallons per 
square foot of filtering surface per hour, making a total quantity of 1687*5 gallons per 
hour through each filter. 

** The filters are composed of the following strata, in a descending order : — 

ft. in. 

1. Fine sand - - -26 

2. Coarser sand - - . - - . -10 

3. Shells - -06 

4. Fine gravel - -•- - - . -OS 

5. Coarse gravel - - - - - - -33 

These several layers of filtering materials are not placed perfectly flat, but are dis- 
posed in waves, and below the oonvex curve of each undulation is placed a poroas 
earthenware pipe, which conductB the filtered water into the mains for distributioa. 
The depth of water over the sand was 4 feet 6 inches. The upper layer of sand is 
renewed about every six months, but the body of the filter has been in use for aboot 
twenty years. 

«< Samples of water were taken and submitted to examination :-^ 

** 1st, fh>m the reservoir into which the water was at the time being pumped fVom 
the middle of the river. 

" 2nd, from the cistern, after subsidence and filtration." 

Experiments were made at different seasons of the year ; but one of Mr. Witt's 
tables will sufficiently show the results. 

1. Shows the quantities of the several substances originally present, represented io 
grains, in the imperial gallon (70,000 grains) of water. 

2. The amount present after filtration. 

3. The actual quantities separated in grains in the gallon of water. 



4. The per centage ntio wbich the amonnts separated bear to the qnantities 
origiimllj present. 




After mtraUoD. 




Per ceniJige ratio 

of leparated 


Total solid residue, includ- 
ing sospended matter 
Organic matter 
Total mineral matter 
Sospended matter - 
Total dissolTed 8alu 
lime .... 












" It has been assumed as a principle that sand filtration can only remore bodies 
mechanically suspended in irater, but I am not aware that this statement has been 
established by experiment ; in fact, I am not acquainted with any published analytical 
examination of the effects of sand filtration. 

*" These experiments supply the deficiency, and show, moreover, that these porous 
media are not only capable of removing suspended matter (80 to 92 per cent.)* but 
even of separating a certain appreciable quantity of the salts from solution in water, 
tIz. from 5 to 15 per cent of the amount originally present, 9 to 19 per cent of the 
common salt, 3 per cent, of the lime, and 5 of the sulphuric acid. 

'* Taking the purer water from Kingston, two experiments were made simultaneously 
with the same water, one filtration being through charcoal alone, and the other through 
sand alone, the sand filter having an area of 4 square feet, and consisting of the 
following materials : — 

ft. In. 

Fine sand • - - -- - . -19 

Shells n 

Gravel l} 

Coarse gravel -------- 9 

2 9 
Results of Sand Filiratiaiu 




After Y3 bourC action. 

AftOTlVOhovn'actkn. | 



Per ccntaRe 
of Quantity 




ratio or 



Total resMue 
Mineral lalu ... 
Organic matter 
Stttpmdeil matter - 
Chlorine - • . 
Chloride of Sodium 




• • 


' 0-846' 



m » 







Afts 840 taonn' acUon. 

After 376 hovn' action. 

Total rrddoe 
Hineral salra ^ . - 
Orfanlc matter 
Suspended matter - 
Chlorine ... 
Chloride of Sodium 























* Apart from its special interest, as compared with the following experiment, made 
simuHaneonsIy through charcoal, the following points are in themselves remarkable 
in the results obtained by this filtration through sand : — 

" Ist. That the filter continued increasing in efficacy even till the conclusion of the 
experiment >. e*> for 376 hours, not having lost any of its power when the experiment 
was terminated. 

** 2nd. That no weighable quantity of dissolved organic matter was removed by the 
sand in this experiment ; but it must be remembered that the quantity originally 
present was but small. 

p 2 



*' 3rd. Its power of removing soluble salts was considerable ; as a maxtmam, 21 per 
cent, of the common salt being separated. " 

Remits of Charcoal Filtration, 


After 7S boun' acdon. 










Total residue 
Mineral salti ... 
Organic matter 
Suspended matter - 
Chlorine ... 
Chloride of Sodium 








After MO hoonr KtioD. 

After 376 iMan'aettM. 

Total residue 
Mineral salts . - . 
Organic matter 
Suspended matter - 
Chlorine . . - 
Chloride of Sodium 


' 2-79 " 


• • 

' o-rw" 


"ao-48 " 






On comparing this experiment with the preceding, the following point comes «t 
as showing the difference between the effects of sand and charcoal as filtenog 

media. • ^ v iM 

By the charcoal, speaking generally, a considerably larger quantity of the tooi 
residue contained in the water was removed than by thejsand, their maximum resale 
being respectiyely as follows : — 

Amount originally 

24*578 grs. in! 
the gallon J 

Amount separated in Grains in the 

By Sand. 


By Charcoal. 


Amount separated in per eartsgerf 
the Quantity present. 

By Saad. 




Mr. Way has also shown that agricultnral soil possesses the power of •*!*„, ^^J 
the solnble salts and organic matter from water in a remarkaUe manner. ^^^ 
are without doubt many natural phenomena which are immediately ^P^j^ 
upon this power, posseted by porous bodies of all kinds, in a greater or 
degree. *^ 

FIRE ANNIHILATORS. This name is given to a portable machine m^'"^ 
by Mr. Phillips, which U adjusted to produce the immediate production orw»»j 
carbonic acid and other gases, which could be at once directed on the '^^ 
mass. The machine is cylindrical in form, and slightly conical. For use it "J^*^ 
with the following composition -. charcoal 20 parts, nitrate of potash 60 P^^.^^ 
gypsum 5 parts. These materials are boiled together in water, and *^®''^'lj, ^f $ 
in a stove at the temperature of 100°. The whole is moulded into the ^^^^^ 
brick, down the axis of which penetrates a hollow cavity for the reception ot ^ y^ 
which contains a mixture of chlorate of potash and sugar, surmounted by 4g 
of sulphuric acid. The charge so prepared is placed in a cylindrical v^^ 
forated in many places, which is itself within another cylindrical vessel, *V ^^ 
forated for the passage of the gases ; both these are contained in a double ^y^^ jj 
receiver, the lower part of which contains a quantity of water. The •PPrTjje n- 
closed by two covers, in the outer of which is an opening for the escape oi ^ 
pour. In the centre of the cover is placed a spike, for the purpose of J****. J^^a 
glass bottle deposited in the cavity of the charge. The spike being ^'"'P^^f the 
breaks the bottle, and the sulphuric acid causes the instantaneous ^^^^^^^{hnyogli 
chlorate of potash and sugar, which fires the charge. The gases now esc^p^ pjpaod, 
the perforations, and heating the air in the water chamber, and causing it ^^ ^^. 
forces the water up a tubular passage into the space between and around t ^.^^ 
drical vessels placed each within each, and being thus converted into ^^P^'\' ^\^ 
with the gases, and escapes by the discharge tube, forming a dense cioaoi 
rapidly extinguishes flame. 


FIRE ARMS, Manufacture of. This art u diyided into two branches, that of 
the metallic, and that of the wooden work. The first includes the barrel, the lock, and 
the mounting, with the bayonet and ramrod, for military arms. The second com- 
prises the stock, and in fbwling-pieces likewise the ramrod. 

71^ Barrd. — Its interior is called the bore ; itsd iameter, the calibre ; the back 
end, the breeeh ; the front end the mozzle ; and the closing of the back end, the breech 
pin or ping. The barrel is generally made of iron. Most military musquets and 
low-priced gnns were formerly fitshioned out of a long slip of sheet- iron folded to- 
gether edge-wise round a skewer into a cylinder ; they were then lapped over at the 
seam, and welded at a white heat The most ductile and tenacious sojft iron, free from 
all blemishes, must be selected for this slip. It is frequently welded at the common 
forge, bat a proper air-furnace answers better, not being so apt to bum the iron, 
which should be covered with ashes or cinders. The shape of the bore is given by 
hammering the cylinder upon a steel mandril, in a groove of the anvii Six mches of 
the barrel at either end are left open for forming the breech and the mnzxle by a sub- 
sequent welding operation ; the extremity put mto the fire being stopped with clay, 
to prevent the introduction of cinders. For every length of two inches, there are 
from two to three welding operations, divided into alternating high and low heats ; 
the latter being intended to correct the defects of the former. The breech and muzzle 
are not welded upon the mandril, but upon the horn of the anvil \ the breech being 
thicker in the metal, is more highly heated, and is made somewhat wider to save 
labour to the borer. The barrel is finally hammered in the groove of the anvil with- 
out the mandril, during which process it receives a heat every two minutes. In 
welding, the barrel extends about one-third in length ; and for musquets, is even- 
tually left from 3 to 3^ feet long ; but for cavalry pistols, only 9 inches. 

The best iron plates for gun-barrels are those made of stub iron, that is of old 
horse-shoe nails welded together, and forged into thin bars, or rather narrow ribands. 
At one time damaacus barrels were much in vogue ; they were fashioned either as above 
described, from plates made of bars of iron and steel laid parallel, and welded together, 
or from ribands of the same damascus stuff coiled into a cylinder at a red heat, and then 
welded together at the seams. The best modem barrels for fowling-pieces and the 
modem rifles are constructed of stub-nail iron in this manner. The slip or fillet is 
only half an inch broad, or sometimes less, and is left thicker at the end which is to 
form the breech, and thinner at the end which is to form the muzzle, than in the 
intermediate portion. This fillet being moderately heated to increase its pliancy, is 
then lapped round the mandril in a spiral direction till a proper length of cylinder is 
formed ; the edges being made to overlap a little in order to give them a better hold 
in the welding process. The coil being taken off the mandril and again heated, is 
struck down vertically with its muzzle end upon the anvil, whereby the spiral junc- 
tions are made closer and more uniform. It is now welded at several successive heats, 
hammered by horizontal strokes, called yum/>m^, and brought into proper shape on the 
mandriL The finer barrels are made of still narrower stub-iron slips, whence they 
get the name of wire twist On the continent, some barrels are made of steel wire, 
welded together lengthwise, then coiled spirally into a cylinder. Barrels that are 
to be rifl^, require to be made of thicker iron, and that of the very best quality, 
for they would be spoiled by the least portion of scale upon their inside. Soldiers* 
musquets are thickened a little at the muzzle, to give a stout holding to the bayonet 

The barrels thus made are annealed with a gentle heat in a proper furnace, and 
slowly cooled. They are now ready for the borer, which is an oblong square bit of 
steel, pressed in its rotation against the barrel by a lip of wood applied to one of its 
fiat sides and held in its place by a ring of metaL The boring bench works horizon- 
tally, and has a very shaky appearance, in respect at least of the bit In some cases, 
however, it has been attempted to work the barrels and bits at an inclination to the 
horizon of 30^, in order to mcilitate the discharge of the borings. The barrel is held in 
a slot by only one point, to allow it to humour the movements of the borer, which 
woold otherwise be infallibly 760 

broken.. The bit, as represented y rp - , . — p 

in Jig. 760, has merely its ^ 
square head inserted into a 
clamp-chuck of the lathe, and 
plays freely through the rest of 
its length. 

Fia. 761 represents in plan 
the boring bench for musquet 
barrels ; // is the sledge or 
carriage frame in which the barrel is supported ; a is the revolving chuck of the 
lathe, into which the square end of the hit, fig. 760, is inserted; 6 is the barrel, 

p 3 


olamped at its middle to the carriage, and capable of being presfed oowaidi agaiosi 
the tapering bit of the borer, by the bent lever c, worked by the left hand of tU 
operative against fulcrum knobs at d, which stand about two inches asonder. 
Whenever the barrel has been thereby advanced a certain space to the right, the bent 
end of the lever is shifted against another knob or pin. The borer appears to i 
stranger to be a very awkward and unsteady mechanism, but its perpetual yibrationi 
do not affect the accuracy of the bore. The opening broach may be of a sqoarv 
or pentagonal form ; and either gradually tapered from its thickest part, or of 
uniform diameter till within two inches of the end, whence it is suddenly tapered to 
a point 

A series of bits may be used for boring a barrel, beginning with the smallest lod 
ending with the largest. But this multiplication of tools becomes unnecessary, by 
laying against the cutting part of the bit, slips of wood, called spales, of gradoalljr 
increasing thickness, so that the edge is pressed by them progressively further from 
the axis. The bore is next polished. This is done by a bit with a very smooth edge, 
which is mounted as above, with a wedge of wood besmeared with a mixture of oilaod 
emery. The inside is finished by working a cylindrical steel file quickly backwards and 
forwards within it, while it is revolving slowly. 

In boring, the bit must be well oiled or greased, and the barrel must be kept eool 
by letting water trickle on it ; for the bit, revolving at the rate of 120 or 140 tiiiMSi 
minute, generates a great deal of heat If a flaw be detected in the barrel doriogtbe 
boring, that part is hammered in, and then the bit is employed to turn it oat 

Many sportsmen are of opinion that a barrel with a bore somewhat narrowed tovaidi 
the muzzle serves to keep shot better together ; and that roughening its inside with 
pounded glass has a good effect, with the same view. For this purpose, also, fine 
spiral lines have been made in their interior surface. The justness of the calibie of 
a fowling-piece or musket is tried by means of a truly turned cylinder of ateel, 3 
or 4 inches long, which ought to move without friction, but with uniform contact 
ft'om end to end of the barrel Whatever irregularities appear must be immediately 

The outer surfiice of the barrel is commonly polished upon a dry grindstone, hot it 
is better finished at a turning lathe with a slide rest 

Rifle barrels have parallel grooves of a square or angular form cut within them, each 
groove being drawn in succession. These grooves run spirally, and form each an 
aliquot part of a revolution from the chamber to the muzzle. Rifles should not be too 
deeply indented ; only so much as to prevent the ball turning round within the barrel, 
and the spires should be truly parallel, that the ball may glide along with a regular 

The Parisian gun-makers, who are reckoned very expert, draw out the iron for the 
barrels at hand forges, in fillets only one-ninth of an inch thick, one inch and a half 
broad, and four feet long. Twenty-five of these ribands are laid upon each other, be- 
tween two similar ones of double thickness, and the bundle, weighing 60 lbs., boood 
with wire at two places, serves to make two barrels. The thicker pliUes are intended 
to protect the thinner from the violence of the fire in the numerous succesave beats 
necessary to complete tibe welding, and to form the bundle into a bar two-thirds of an 
inch broad, by half an inch thick ; the direction of the individual pUtes relatively to 
the breadth being preserved. This bar folded flat upon itself, is again wrought at the 
forge, till it is oi3y half an inch broad, and a quarter of an indi thick, while the plates 
of the primitive ribands are now set perpendicular to the breadth of the narrow fillet! 
the length of which must be 15 or 16 feet French (16 or 17 English^ to form a foil- 
ing piece from 28 to 30 inches long. This fillet, heated to a cherry red in saccessire 
portions, is coiled into as close a spiral as possible, upon a mandril about two-fifths of 
an inch in diameter. The mandril has at one end a stout head for drawing^ it ^J^ 
means of the hanmier and the grooves of the anvil, previous to every heating. Toe 
welding is performed upon a mandril introduced after each heat ; the middle of the 
barrel being first worked, while the fillets are forced back agunst each other, along the 
surface of the mandril, to secure their perfect union. The original plates having in the 
fbrmation of the ultimate long riband become very thin, appear upon the sor&ceoi 
the barrel like threads of a fine screw, with blackish tints to mark the jonctiona u 
making a double-barrelled gun, the two are formed from the same bundle of slips? the 
coils of the one finished fiUet being turned to the right hand, and those of the other to 
the left. 

The barrels forged, as above described, ft-om a bundle of steel and iron plateslaid 
alternately together, are twisted at the forge several times, then coiled and welded as 
usual. Fifteen workmen concur In one operation : six at the forge; two at tbe 
boring mill; seven at filing, turning, and adjusting; yet altogether make only^^ 
pairs of barrels per week. In the first instance, it will be understood, that, for (he 



n of the mperior bureU, t, handle of hone-ihoe dbUs ii welded into ■ flit 
bar, limilar bar* of icrap neel are made, andtheae are made np into a bundle, — a bar 
of iron, aad > b«r of cteel — of eight or twelve ban, Thii ii again welded into ooe bar, 
and the result u, when the sorface it poliihed, that the difference in the texture of the 
Ti ia disdoctl^ Tiiible. Now, if two bare of iron and one of iteel, or two ban 


a and a 

9of ii 

_ _ a Tarietj in the pattern of (he finiibed bar. 

In constmcting the barrel thii bar tDsy be twiited op (ingly, ai deacribed, or two ban 
differing m pattern may be welded together, and then twiated. It i« nmii to place two 
bara logetfaer, to twist one into a screw and lesTe tbe other plain, or to giTC one a 
light band twiat and the other a left handed one, or lometiiDea three ban are em- 
plojed, and bj twining or otherwiae preTiooily to welding tha ban together and 
taming or twisting the compound bar into B cylinder, a great rarieiy of pattemi are 
prodn<»d on the finiibed barreL 

The breeching ii of three kinds : the common ; the chamber, plog, or mortar, 
fy. T6S : and the patent, fig. 763. The common was formerly nsed for soldier*' 
musqnet* and inferior pieces. The le- ygg 

cond is a trifling improrement apon it 
la the patent breeching, tbe screws do 
not interfere with tbe tonch-bote, and the 763 

ignition ia qnicker in tbe main chamber. 

The only locks which it is worth 
wbile to describe are those apon the per- 
cussion prindple, as flint locks have 
ceased to be employed. Forsyth's lock 
(Jig- 764) wsi an ingenious cootriiance. 
Itfa«s a magaitne a, tbr containing thede- 
(onating powder, which reTOlves round 
a rotler b, wboae end is icrawed into the 
brveeb of the barreL The priming pow- 
der passes through a small hole m the 
roIleT, which leads to a channel in com- 
mnnication with the chamber of the gon. 

The pan for holding the priming ii 
placed immediately over the little hole 
in the roller. There is a steel panch c, 
in the magaiinev whose under end stands 

above the pan, ready to ignite tbe priming when struck npon the top by the cock d, 
whenerer the trigger i» drawn. The punch, immediately after bemg driven down 

into the pan, it raited by the action of a spiral spring. For each explosion, the 
magaiine must be turned so far round as to let fall a portion ot the pereuasion 
powder iolo the pan ; after which it is turned back, and the sEeel punch recovers its 
I»oper position for striking another blow into tbe pan. 

Tbe mventioQ of the copper percustion cap was another great improvement upon the 
detonating plan. Fig. T6S represents the ordinary percussion lock, which is happily 
diveMed of three awkward projectious npon the flint lock, namely, the hammer, 
bMDiuer apriog, and the pan. Nothing now appears upon the plate of the lock, but 
tbe code or striking hammer, which inflicts Uie striking blow upon the percussion 
op. It is concave, with a small metallic ring or border, called a shield or fence, for 
the purpose of enclosing the cap, as it were, and preventing its splinten doing ii^ury 
to the sportsman, as auo protecting againat (he line of flame which may issue ttoia 
tbe touch-hole in the cap-nipple. This is screwed into the patent breech, and i* per- 
forated with a amall hole. 


The safety look of Dr. Somerrille if, in its essential featore, a slide stop or catch, 


placed ander the trigger, i^^fig- 766. It is palled forward into a notch in the tiiggtri 
by means of a spring b, npon the front of the goard, which ia worked by a kej c, 


pressing upon the spring when the piece is discharged. In another safety plan there 
IS a small movable curved piece of iron, a, which rises throngh an opening n, in the 
lock- plate c, and prevents the cock from reaching the nipple, as represented in the 
figure, until it is drawn back within the plate of the lock when the piece is fired. 

To fire this gun, two different points must be pressed at the same time. If ^ 
accident the key which works the safety be touched, nothing happens, becanse the 
trigger is not drawn ; and the trigger touched alone can produce no effect, because it 
is locked. The pressure must be applied to the trigger and the key at the sidk 
instant, otherwise the lock will not work. 

The old French musket is longer than the British, in the proportion of 44*7S inches 
to 42 ; but the French bayonet is 15 inches, whereas the British is 17. 

Eng. DimeotloDi. Fr. DiBWMh"*- 

Diameter of the Bore .... 
Diameter of the ball - - - - 
Weight of the ball in oz. - - - 
Weight of the firelock and bayonet in lbs. 
Length of the barrel and bayonet - 

Within these few years a great many contrivances for fire arms have been bronght 
forward, and several have been patented. The first is that of Charles Random. 
Baron de Berenger. Ft^. 767 shows the lock and breech of a fowling piece, v>th * 
sliding protector on one of the improved plans ; a is the hammer, h the nipple of J^ 
touch-hole, c a bent lever, turning upon a pin, fixed into the lock-plate at (2. /r 
upper end of this bent lever stands partly under the nose of the hammer, and while "^ 

0-75 in. 

0-69 UL 










chat sitnatioD stops it fh>m striking the nipple. A sMder gfh, connected with the 
onder part of the gun-stock, is attached to the tail of the bent leyer at i ; aiid when the 


piece la brought to the shoulder for firing, the hand of the sportsman pressing against 
the bent fwrt of the slider at o, forces this back, and thereby moves the end of the 
lever c forwards from under the nose of the cock or hammer, as shown by the dotted 
lines. The trigger being now drawn, the piece will be discharged ; and on removing 
the hand firom the end jTi of the slider/, the spring at h acting against the guard, will 
force the slider forward, and the lever into the position first described. 

Mr. Bedford, gun-maker, of Birmiugham, introduced a modification of the lock for 
small fire-arms, in which the application of pressure to the sear spring for dischargiug 
the piece is made by means of a plug, depressed by the thumb, instead of the force of 
the finger exerted against the trigger. Fig. 768 represents a fowling piece partly in 


actioo. The sear spring is shown at a. It is not here connected with the trigger as 
in other locks ; but is attached by a double-jointed piece to a lever b, which turns upon 
a fnlcmm pin in its centre. At the reverse end of this lever an arm extends forwards, 
like that of an ordinary sear spring, upon which arm the lower end of the plug c is 
intended to bear ; and when this plug is depressed by the thumb bearing upon it, that 
end of the lever b will be forced downwards, and the reverse end will be raised, so as 
to draw up the end of the sear spring, and set off the piece. For the sake o£ pro- 
tection, the head of the plug c is covered by a movable cap d, forming part of a slider e, 
which moves to and fro in a groove in the stock, behind the breech end of the barrel ; 
this slider e is acted upon by the trigger through levers, which might be attached to 
the other side of the lock -plate; but are not shown in this figure to avoid confusion. 
AVhen the piece is brought to the shoulder for firing, the fore-finger must be applied 
as usual to the trigger, but merely for the purpose of drawing back the slider e, and 
uncovering the h<»d of the plug ; when this is done, the thumb is to be pressed upon 
the head of the plug, and will thus discharge the piece. A spring bearing against 
the lever of the slider e, will, when the finger is withdrawn from the trigger, send the 
slider forward again, and cover the head of the plug, as shown. 

The Rev. John Somerville, of Currie, in April, 1835, obtained a patent for a further 
invention to prevent the accidental discharge of fire-arms. It consists in hindering 
the hammer from reaching the nipple of a percussion lock, or the flint reaching the 
steel of an ordinary one, by the interposition of movable safety studs or pins, which 
protrude from under the &lse breech before the hammers of the locks, and prevent 
them from descending to strike. These safety studs or pins are moved out of the 
way by the pressure of the right hand of the person using the gun only when in the 
act of firing, that is, when the force of the right hand and arm is exerted to press the 
butt end of the stock of the gun against the shoulder while the aim is taken and the 
trigger pulled. In carrying the gun at rest, the proper parts of the thumb or hand 
do not come over Mr. Somerville's movable buttons or studs. 

Fig. 769 is a side view of part of a double percussion gun $ Bndjig. 770 is a top or 
plan view, which will serve to explain these improvements, and show one, out of many, 
methods of carrying Uiem into effect a is the stock of the gun ; b the barrels ; c the 
breech ; d th^ nipples $ s the false breech, on the under side of which the levers which 



work the lafbty stads orpins are placed ; p is the shield of the fUse breech; atriggen; 
K the lock-plate; and z the hammers » all of -which are eonstmcted as vsoal : a a ir 



the safety studs or pins, which protrode before the shield f, and work throngli goide 
pieces on the ander side of the &lse breech. The button piece is plseed in the 



position for the thumb of the right hand to act upon it ; but when the pressure of the 
ball of the right thumb is to produce the movement of the safety studs, it most \x 
placed in or near the position k ; and when the heel of the right hand is to effect the 
movements of the safety studs, the button piece must be plaeni at l, or nearly Ba 

In these last two positions, the lever (which is acted upon by the button piece 
to work the safety studs through a slide) would require to be of a different shape 
and differently mounted. When the hammers are down upon the nipples after dis- 
charging the gun, the ends of the safety pins press against the inner sides of the 
hammers. When this invention is adapted to single-barrelled guns, only one pis. o, 
one lever and button piece will be required. 

Mr. Richards, gun-maker, Birmingham, patented a modification of the copper eap 
for holding the percussion powder as represented >^. 771 ; in which the powder m 
removed from the top of the cap, and brought nearer the mouth; a being the top.^ 
the sides, and c the position of the priming. The dotted lines show the direction of 
the explosion, whereby it is seen that the metal case is opened or distended ool/ » 
a small degree, and not likely to burst to pieces, as in the common caps, ^^f?^ 
between a and c being occupied by a piece of any kind of hard metsl i loldcfedor 
otherwise fastened in the cap. 

George Lovell, Esq., Director of the Royal Manufactory of Arms at Enfield, intro- 
duced an improvement upon the priming chamber. He forms it into a verticti 
double cone, joined in the middle by the conunon apex; the base of the upptrecM 
bein^ in contact with the percussion cap, presents the most extensive snrfiioe totbe 
fulmmate upon the one hand, while the base of the under one being in a line with the 
interior surface of the barrel, presents the largest sur&ce to the gunpowder cbaii;«, 
upon the other. In the old nipple the apex of Uie cone being at its top, afforded very 
ii^udiciously the minimum surface to the exploding force. , 

Gum, Eifling of€kt Barrels, — The outside of rifle barrels is, in general, ocH^ 
After the barrel is bored, and rendered truly cylindrical, it is fixed upon the nflmg 
machine. This instrument is formed upon a square plank of wood 7 feet longi ^ '^^^ 
is fitted a tube about an inch in diameter, with spiral grooves deeply cut inteniai'/ 
through its whole length ; and to this a circular plate is attached about 5 inehtf 
diameter, accuratel^r divided in concentric circles, into from 5 to 16 equal parts, w'* 
supported by two rings made fast to the plank, in which rings it revolves. An »J* 
connected with the dividing graduated plate, and pierced with hdes, through which s 
pin is passed, regulates the change of the tube in giving the desired number of gr^o^ 
to the barrel. An iron rod, with a movable handle at the one end, and a steel cntttf 
in the other, passes through the above rifling tube. The rod is covered with a core pt 
lead one foot long. The barrel is firmly fixed by two rings on the plank, standing ii^ 
a straight line on the tube. The rod is now drawn repeatedly through the barrel, fr^ 
end to end, until the cutter his formed one groove of the proper depth. The po> ^ 



then dufted to another hole in the dividing plate» and the operation of grooviog is 
repeated till the whole number of riflings is completed. The barrel is next taken oat 
of the machine, and finished. This is done by castin|p upon the end of a small iron 
rod a core of lead, which, when besmeared with a mixture of fine emery and oil, is 
drawn, for a considerable time, by the workmen, fh>m the one end of the barrel to the 
other, till the inner surftuie has become finely polished. The best degree of spirality is 
found to be from a quarter to half a revolution in a length of three feet 

Military RiJUa. — An essential improyement in this destmcdTC arm has been in- 
trodnced into the British sendee. 

The intention in all rifles is to impart to the ball a rotatory or spinning motion 
roond its axis, as it passes out through the barrel. This object was attained, to a 
certain degree, in the rifles of the old pattern, by cutting seyen spiral grooves into the 
inside of the batrel, in the manner shown hy fig. 772, the spherical ball,y^. 77d, being 
a little larger than the bore, was driven down with a mallet, by which the projecting 
ribs were forced into the surface of the ball, so as to keep it in contact with their 
curvatures, during its expulsion. Instead of this laborious and insecure process, the 
barrel being now cut with only two opposite grooves, fig. 774, and the ball being formed 
with a projecting belt, or zone, round its equator, of the same form as the two grooves, 
fig. 775» it enters so readily into these hollows, that little or no force is required to 
press it down upon the powder. So much more hold of the barrel is at the same time 
obtained, that instead of one quarter of a turn, which was the utmost that could be 





safely given in the old way, without danger of stripping the ball, a whoU turn round 
the barrel in its length, can be given to iht two grooved rifles ; whereby a far more 
certain and complete rotatory motion is imparted to the ball. The grand practical 
result is, that better practice has been performed by several companies of Uie Rifle 
Corps, at 300 yards, than could be produced with the best old military rifles at 150 
yards; the soldier being meanwhile enabled to load with much greater ease and 
despatch. The belt is bevelled to its middle line, and not so flat as shown in the figure. 

This mode of rifiing is not, however, new in England. In fact, it is one of the 
oldest upon record ; and appears to have fallen into disuse from faults in the execution. 
The idea was revived within the last few years in Brunswick, and it was tried in 
Haoover also, but with a lens-shaped {Linaenflrmig) ball. The judicious modifica- 
tions and improvements it has finally received, have brought out all its advantages, 
and rendered it, when skilAilly used, a weapon of unerring aim, even at the distance 
of 700 yards. 

The locks, also, for the military service generally, are receiving important Im- 

Ifr. LovdVs Lock. 

provements. In Loveirs lock the action of the main spring is reversed, as shown by 
fig. 776 ; thus rendering the whole mechanism more solid, compact, and convenient } 



while the ignition of the charge is effected hy percussion powders in a eofiper eap. 

Mr. Lovell, inspector of smaU arms for her Majesty's service, and director cf the 

777 7gl Boyal manufactory, at Enfield Chase, directed his mind to tb€ 

constraction of a snre, simple, and strong musket, with r\iA, 
under his superintendence, the whole of her Majesty's soldim 
were long provided. He has also furnished them vith a 
, short, but clear set of instructions for the cleaning aDdIna!lag^ 
ment of these excellent arms, illustrated by a series of wood 
engravings. From this little work the following notice is 

^t^. 777. The barrel, reduced to one-seventh size, a, the 
breech ; 6, the nipple^seat or lump ; c, the back sight ; i, the 
back -loop ; e, the middle loop ; /I the swivel-loop; 9, thefroot 
loop, with the bayonet-spring attached ; A, the front sight; 
t, the muzzle. 

Fig. 778. The breech-pin, half size, a, the tasg; &,the 
neck ; c, the screw threads ; </, the face. 







Fig. 779. The bayonet-spring, two ways, half size, a, the 
shank ; 6, the neck ; c, the hook ; </, the mortice. 

Fig, 780. The nipple, full size, a, the cone ; 6, the sqcares ; 
c, the shoulder ; d, the screw-threads ; e, the touch-hole. 

779 780 


V— / 

Fig. 781. The rammer reduced to one-seventh size, flithe 
head ; 6, the shaft ; c, the screw threads. 

Fig. 782. The lock, outside, half size, a, (he plate ; A. the 
cock ; c. the tumbler-pin ; f/, the hollow for the nipple seat 

Fig. 783. The lock, inside, half size, showing all the parts 
in their places with the cock down at bearer, a, the msij- 
spring; 4, the sear-spring ; c, the sear; rf, the tumbler; e, the 
bridle ; /, the main-spring-pin ; g^ the sear-pin ; A, the Ktr- 
spring-pin ; t, the bridle-pin. 

Barrel-welding by Machinery. — The barrels of mnsqwB, 
birding-guns, &c., or what are called plain, to distingaish thfo 
from those denominated stub or twisted barrels, have of We 
years been formed by means of rolls, a process in which tne 
welding is first effected on a short shib of thick iron, and tbM 
the barrel is brought down to its destined length and ^''^'^^ 
repeatedly passing it between a pair of rolls, that hare Men 
, previously grooved to the exact ^ape of the barrel intcndw 

to be mad^. . 

The iron being thoroughly refined, and reduced into flat burs by the process de 
scribed, is cut by the shears into slabs or lengths of 10 to 12 inches, ^^ 1^? 
lOj lbs. weight, or less, according to the description of gun-barrel that is "^*?°5J 
to be taiade. These slabs are then heated, and bent in their whole length, 
means of conveniently goooved bending rolls, until they assume the form of roog 
tubes, of the kind of section shown by a. Jig. 784. They are then placed on tw 
hearth of the reverberatory furnace, and brought to a full welding heat, and » 
soon as the edges of a tube come to a semi-fluid state, it is taken oat and pa^ 
between rolls having grooves somewhat smaller in diameter than the exterior of tfl 




tnbe; hj which means the tabe is perfectly welded (Vom end to end; and if care be 
taken in the management of the heat, and the janctore be kept clear of dirt and 
cmders» the iron irill be found perfectly homogeneoos in erery part, and there will be no 

appearance whatever of the seam where the the edges came together. These tnbes 
are repeatedly heated, and passed between the barrel rolls, which are of sofficient 


diameter to admit of gradually decreasing grooves, the whole length of the intended 
barrel being indented on their sur&ces. 

To preserve the tabular form, and insure regularity in the size of the bore during 
the w^elding process, they are taken out of the furnace, by thrusting into them a tool 
called a mandril, b. Jig. 786, which consists of a long rod of iron, having a short steel 
treblett on its end, of the diameter that the bore of the barrel is meant to be. This 
rod is ao adjusted by means of a strong iron plate c, near its handle, which is of wood, 
and long, that when passed with the heated tube on it between two transverse holding 
bars, the short steel treblett i> shall be foimd exactly between the point of impact of the 
barrel rolls, e, b. 



The adhesion of the hot iron to the suHkce of the rolls is Strong enough to draw 
the tube off the mandril, which thus keeps the bore open fVom end to end, and by 
repeating the process through the whole series of grooves in the rolls, the barrel is 


gradually elongated, and broogfat down to the exact form reqoind ; aoj npcfflmi 
length at the mnaale is then cut off. The breach end is then a4jaited by tiie haanttr 
— a triple-seat welded on by band if it be intended for a percoflsaon lock ; and dun the 
barrel is ready to go forwaid to the mill to be bored, tamed, and finished. 

Gun barrels formed by this mechanical method are foond to stand proof better tki 
those worked by hand, because the heat is more eqoalised ; and any imperfectiou in 
the original mass of iron are more dispersed over the whole extent of the tabe. 

Of late years large strides have been made towards increasing the efficacy of mili- 
tary fire-arms. 

The first attempt to inproye the rifle in nse in the French army, was that propoied 
by M. Delvigne, an officer of the royal ex-goard (^fg. 786), in which the opper 


orifice of the chamber that contuned the powder took the form of a cap, wherein tb« 
ball (somewhat wider in diameter) was receiyed, and by two or three smutblovKrf 
a heay}'-headed rammer (also capped out for the purpose) became expanded laterallv, 
and thus the rotary motion was imparted to it by the spiral grooves of the barrel m 
passing oat Colonel Poncharra suggested the addition of a wood bottom or sabot 
under the ball and a greased woollen patch ; and Colonel Thonyesino proposed Ify. 
787) a steel stem or pillar about 2 inches long inserted into the face of the breech- 


pin ; round this pin the charge of powder was received, and the diameter of the bill 
when resting on the top of me pin, was enlarged by the blows of the heary-faettled 
rammer, as suggested by Delvigne. 

This system took the name of " Carabine H Tige,*' and has been very generally intro- 
duced for the service of fusilier battalions in continental armies ; very grave olgectioDi, 
however, have been found agunst it in use, fh)m the impossibility of keeping the cbsmber 
(or part round the pin) clear ; and from the severe labour to the soldier in nnuniDg 
down and enlarging the diameter of the ball sufficiently to insure the rotsry motioo 

But if the ultimate results thus attained with spherical balls turned out not entirely 
satisfactory, it was made clearly manifest, in the course of the experiments ctnied 
on, that no insuperable difficulty stands in the way of rendering the ^re of inftntrj voy 
much more accurate and powerful, by the use of rifled barrels throughout thearmjr, tnd 
thus leading to a verification of the prediction made by Robins above one hundred jetfi 
a^o, that " whatever state shall thoroughly comprehend the nature and advantageKif 
rified barrel pieces, and having facilitated and completed their oonstructioD, shall in- 
troduce into their armies their general use, with dexterity in the management of then, 
will by this means acquire a superiority which will almost equal any thing that bas 
been done at any time." 

But besides smoothing the way to such an essential improvement, it has been elicited 
of late years, that when the accuracy of fiight is secured by the rotary motion deri^ 
from the rifling, the bullet, instead of being limited to the form of a sphere as hereto* 
fore, may, up to certain limits, be elongated with considerable increase of dettnctiTe 
effect ; and with an augmentation of range very much beyond any thing that b^ 
hitherto been considered to lie within the reach of small arms — placing them, in^'* 
with reference to artillery and cavalry, in the first place instead of the last 

An immensely extended field has thus been opened to experimenters. 1st. ModI| 
Didion proposed a true oval (Jig. 7 88) as the best form of bullet, so that* when atof^ 
by the blows of the heavy rammer and widened in its diameter, it might be brcMig&t 
nearer to the spherical shape before leaving the barrel. . , 

2nd. Mons. Delvigne took a patent for a bullet (fig, 789) under the designation rf 
" Cylindro Ogivale ; " it had a conical opening behind, in which he imagined that On 
force of the powder would exert itself with sufficient energy to expand the lead ptf|f>** 
nently, and so make the ball take the rotatory movement derived fh>m the rifiingt ^' 
out any feitigue to the soldier in loading : with this projectile, indeed, the operatiootf 
but slightly more difficult than with the ordinary cartridge and smooth barreb. 



The bullet (Jig, 790) of the «* Carabine I, Tige " was oalled ** Cylindro Coniqae,** and 
was Mid to pngiew this adyantage over the preceding, that, being brought more to a 
point in front, it bored its way through the air with greater ease, and thus retained 

788 789 790 791 792 


greater velocity, and of course, more extended range; and with this bnllet it was that 
Moos. Tamisier introduced three sharp-edffed cbaonels round it, which he stated were 
necessary to keep its flight steady, by offenng a resistance to the action of the air. 

Finally Mons. Minie, an officer of the French line, suggested {fig, 791) the addition of 
a denoyau or culot to the hollow ball of Delvigne. This, in the form of a little cup 
made of sheet iron, is placed in the orifice of the conical hollow of the ball behind, and 
by the enerj^ of the powder is driven into the ball, enlarging its diameter permanently, 
and thus giving all the accuracy of the rifle, with nearly the same fiusility of loading 
as with the plam barrel. 

The principle of the invention, as thus developed, has, we learn, been adopted by our 
government for the general use of the army, seeing that it offers so great advantages 
over the system of plain barrels, but the bullet {fig. 792), as modified by the Inspector 
of Small Arms, has on its exterior no channels, they being found not only useless as to 
steadying the flight of the projectile, but absolutely injurious in lowering its velocity. 
The bullet in its improved form too, being more truly balanced in its proportions, 
and made by mechanical means instead of b^ casting, has no tendency to the gyrations 
which appear to have so puzzled French artillerists, and for which they have invented 
the word ** derivation," and wasted much learned disquisition. 

Bat even if it were ever to happen, which is not likely, that these various projectors 
could be brought to agree as to the best form of projectile, they will then find out, 
that although by the general introduction of rifled and elongated bullets an immense 
advantage has been realised over plain barrels, their plans, based as they all are upon 
a system of loading at the muzzle, are at best but one step in advance ; and that a good 
sound military fire-arm loading at the breach will, after all, remain the great desideratum 
— an arm tlmt, without any less accuracy or power to reach masses of artillery or 
cavalry at a thousand yards' distance, will enable the soldier to triple the quantity of 
his fire at any moment that he may be called upon to repel a charge of cavalry or 
attack or defend a breach at close quarters ; of such simple construction, and so easily 
handled in every position of the body, that the soldier can pour every shot of his most 
murderous fire upon the enemy with unerring precision, whilst he himself may lie 
coolly behind a stone or in a ditch in entire security. 

These are no longer wild imaginings, although so many hundreds of attempts towards 
the same object, from the earliest period to Uie present day, have been one after another 
seen invariably to fail. The Germans have been long and steadily pursuing the great 
object, until at length Herr Dreysa, of Sommerda in Thuringia, has succeeded, after 
more than twenty years of continued labour, in establishing a musquet, under the name 
of ** Zundnadelgewehr," which if not quite perfect, is so well adapted for the uses to 
which it is applied that the "Prussians have armed the whole of their line and the 
Landwehr with this weapon. 

The needle musket (fig, 793) consists of a strong socket a, open on the upper side 

and screwed on to the barrel 6, which is rifled in the usual manner ; within this socket 
is a slider c, which in fiict constitutes the lock, as it contains the spiral spring and 


mechanism that prodaee ignition by percossion ; it has a stoat hebel, or hindle, bj 

which it is moved backwards and forwards freely. The cartridge {fig. 794) eoniitti 

794 of the ball a, the sabot 6, or bottom of hard paper, and holding the 

priming matter, and lastly the charge of powder c, the whole beiog mide 

&k up in paper pasted together. In use the slider being drawn btck, the 

//\\ soldier puts the cartridge with the point of the bidl in fixmt into the 

// \\ open breach of the barrel, pushes the slider forward, and Mcmei in 

close junction by a turn to the right against an inclined edge of the 

open socket. The spiral spring is then brought into action by prasiog 

the spring case forward with the thumb. 

To Captain Drayson, B. A., we are indebted for the following. The 
Enfield rifle, which has lately been approved of for the use of the tmj, 
is constructed principally by machinery. 

The factory at Enfield, at which this arm is maDofactored, is coniidered 
one of the most complete establishments in the world. 

The barrel, lock, wood-work, furniture, and bayonet are all conitmcted 
at Enfield, and as each portion is made exactly of the same size aod shjpe, 
a part of one rifle will fit into the same part of another. 

The total length of this weapon, including bayonet, is 6 ft Oi in. bog, 
and weighs 9 lb. 3 oz. ; the barrel is 3 ft 3 in. in length, and weighs 4 Ih. 
8 OS. ; the diameter of bore is *577 inch. The bullet is elongated, and rotates on leariog 
the piece like a spherical bullet The general figure of the bullet is cylindrical, batitt 
iVont end is rounded, and its rear end has a conical-shaped cavity. In the Minie 
rifle, some of which were introduced into the service, a small iron cap was placed in 
the hollow at the rear end of the ball for the purpose of causing the ballet to 
expand, but in the Enfield rifle this opening is filled by a wooden plug instead. 
This dbninishes the fouling of the bore, and answers all the purposes of expansion. 

The bullet is *568 inch, length 1*062 inch, weight 530 grains. The barrel is proTed 
at Enfield, and when flaws are supposed to exist as much as 1 5 drams of powder 
have been fired, without bursting the barreL The service charge is 2^ drams. The 
weight of 60 rounds of ammunition including 75 caps is 5 lb. 8 oz. 

The bore has three grooves, each groove forms a spiral of } a turn in 3 fleet 3 inches. 
The rifle is sighted up to 900 yards, but an effective range may be obtained bejood 
that distance. 

The number of rifles lately turned out at Enfield is from lOOO to 1200 per week; 
but there is shortly to be an mcrease in this quantity, when it is expected that opwards 
of 1 600 per week will be turned out 

For neatness and completeness of workmanship, as well as for efficiency, the EDseid 
rifle is undoubtedly superior to any other fire-arm yet in use. 
FIRE BRICKS. See Bricks and Clat. 

FIRE-DAMP; the carburetted hydrogen of coal-mines, produced, in some css«, 
by the slow decomposition of the coal itself; in others, it is probably the resolt of um 
chanffes in the constitution of the vegetable matter of which the coal itself is formed, 
which has been confined under great pressure in the interstitial spaces of the coal beds 
or rocks