Mrs. (Jane Haldimand) Marcet.

Conversations on chemistry .. online

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flowers, but so prepared by the organs of the bee, .and so mixed
with its own substance, as to be decidedly an aniroaLproduct. Bees*
wax is naturally of a yellow color but it is bleached by long expo-
sure to the atmosphere, or may'be instantly whitened by the oxy-

— • ' i . I ■ • t t i I

1448. Do pure curds make good cheese ?
J449.0n what does the quantity of cheese depend .?

1450. From what is spermaceti obtained ?

1451. What is ambergris ?

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^ortadc acid. The combastion of wax is^far more perfect than
that of tallow, and con&equently produces a greater quantity of lig^ht
and heatj

QLac isi substance very similar to wax In tbe niannerof hs fofm-
afton ; it is the product of an insect, which collects its ingredients
from flowers, apparently for tl)e purpose of protectingrts eggs from
injury. It is formed into dfeils, fabricated with M^uch skill as
those of IhjB honey comb, but differently arranged. ^The principal
use of lac is in the manyfEtcture of sealing-wax, and in making var-
oist)es and lacquer^

Qd\i<k^ civets ^nQ castor^ are other particular productions, from
dincrent species of quadrupeds. The two first are very powerful
perfumes ; the latter has a nauseous smell and taste, and is only
used medicinally)

Caroline* Is ir from this substance that castor oil is obtained ?

Mrs, i?. No. Far from it, for castor oil is a vegetable oil, ex-
pressed from the seeds of a particular plant ; and has not the least
resemblance to the medicinal substance obtained from the castor.
^ilk is a peculiar secretion of the silk worm, with which it.buitd»
iS^est or cocoon. This insect was origiqally brought to Europe
from China^ Silk in its chemical nature, is very similar to tne
hair and ^ol of animals ; whilst in the insect it is a fluicJ, which is
coagulated, apparently by uniting with oxygen as soon as it comes
in coiitact with the air. ' The moth of the si Ik- worm ejects a liquor
which appears to contain a peculiar acid, called bombiCf the pjroper-
ties of which are but very little known.

Emily. Before we conclude the subject of ihe animal economy,
shall we^ not learn by what steps dead animals return to their ele-
mentary state?

Mrs. B. Anim»l matter, although the most complicated of all
datural substances, returns to its elementary state by one single
spontaneous process,(the putrid ferme7iiatiom By this, the albu-
men, fibrine, &c. are slowly reduced to the state of oxygen", hydro-
gen, nitrogen and carbon ; and thus the circle of changes through
which rtiese principles have passed is finally completed. They first
quilted their elementary form, or their combinatimi with unorgan-
ized matter, to enter into the vegetable system. Hence they were
transmitted to the animal kingdom ; and from this they return again
to their primitive simplicity, sobn to re-enter the sphere of organ-
ized existence. ^

When all the circumstances necessary to produce fermentation
do not take place, animal, like vegetable' matter, is liable to a par-
tial or imperfect decomposition, which converts it into a combusti-
ble substance very like spermaceti. I dare say that Caroline, who
- i^ so fond of analogies, will C.onsidef this a kind of animal bitumen.

Caroline. And why should 1 not, since the processes which pra-
dqce these substances are so similar?

J^lrs. B. There is, however, one considerable difference; the state
of bitumen seems permanent, whilst that of animal substances, thus
imperfectly decomposed, is only transient ; and unless precautions
be taken to preserve thetn in that state, a total dissolution infallibly

1452. How does wax compare with tallow for combustion ?

1453. Whatislae? , ^

1454. What account conld yoii give of silk .?

145d. How does dead animal matter return to its original state ?



ensues. This cirfcumstance, of the occasional odnvertkm of animal
matter into a kind of spermaceti, is of Tate discovery. ^ manufac-
ture has in consequence been established near Bristpl,TB which, bj
exposing the carcasses oT horses and ojher animals for a length of
time under water, the muscular parts are converted into this sper-
maceti^ike ifbstanceJ The bones afterwards undergo a different
process to prepuce h^shorn, or; more'properlj ammonia, and phos-
phorus J and *e skin is prepared for leather. ,

Thus art contrives to enlarge the sphere of useful purposes, for
which the elements were intended by nature,; and the productions
of the several kingdoms are frequently arrested in their course, and
T^riously modified, by human skill, which compels them to contri-
bute, under new form's, to the necessitiies or luxuries of man.

But all that we enjoy, whether produced by the spontaneous ope-
rations of naturie or the ingenious eiForts of arl, proceed alike from
the goodness of Providence.— To God alone man owes the admira-
ble faculties which enable him to improve and modify the produc-
tions of nature, no less than those productions themselves. In con-
templating the works of the creation, or studying the inventions of
art, let us, thererefore, never forget the Divine Source from wliich
they proceed ; and thus every acquisition of knowledge will pr^xve
a lesson, of piety and virtue.



Aphlogistic, or ^laihelefiB Lamp.

" In the con-
struction of thia
Lamp, the ob-
ject is^ to keep a
coil of ivire in a
state of ignition,
' without ieither
flame or smoke.
The principle
' oti which it is
constructed, I
believe, was first
discovered by
Sir H. DaFy.
He found that
on heating the
end of a pi^ce 6t
pJalinawire red
hbt^ and in6taQt<»

Fif. 1. A. T*rt Coil of PlttiB* wire. B. Th« J-lwi tube coaUi«|njf the jy . boldiug it
miok. Fi^. 2. Tbe LjLinp complete., 1>. The tMbe for ohwrinf. near-thcSWrfaC©

1466. What manufticture is it mentioned hfis recently been form-
ed in Bristol i*^ ' ^ •

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of tome ether, placed in a wine glass, the wire was kept at a red
beat as long as the experiment was continued.
' Whether Sir Humphrey pursued the subject any further, 1 am
not infor^ned. It is most probable, however, that he did not, as it
is slated in a London paper of the last year, that Prof. Ure of Glas-
gow, had determined the circumstances which modify the perform-
aoceof thelamp, andthat one constructed by himwas in full operar
tion in that city (London) and had excited much pubh'c curiosity.
This notice contained some directions, concerning thiesize of the
jwire, to be used, and the manner of coiling it. I have however seen
no description of this lamp wiiich would enable one readily to con-
struct it. The following may therefore, interest such readers, as
have seen an account of so curious a discovery.

The principle on which the aphlogisiic lamp is constructed in*
volves two conditions, which are absmule|y requisite, viz. that we
make use of a combustible substance which evaporates at a Iqw de-
gree of heat, and a metal which is a bad conductor of caloric. For
th,e combustible, alcohol seems best suited to this purpose. Sulphu-
riceth cr, awde from its high price, and disagreeable smell, I have
sometimes found to fail ; the ignition ceasing without any obvious
cause. . ^

In regard to the metal, gold and silver, both fail in consequence
of the rapidity with which they conduct caloric. Silver, tod, would
sooa be destroyed by the in tense heat. Iron, although so bad a con-
ductor, as to remain ignited for a time, soon fails, being converted
into red oxide. Platina seems to 'be th6 only metal adapted to our
. purpose, being a slow conductor of caloric, and not easily oxidated
at the highest temperatures.

This is to be drawn into wire of 56-1000 or 60-1000 of ian inch in
diameter, being about the size of card, or brass wire. No.- 26. Ex-
perience has slMJwn that this size succeeds better than any other. —
If larger, the heat is carried off too fast,and the ignition ceases. If
much finer, it does not retain sufl&cient heat at the lower part of the
coil to keep up the evaporation of the alcohol from the wick.

The coihng of t^e wire, and the adjustment of the wick, are the
most difficult parts of the construction.

The coil, A. ^g. 1. page 322, is made by winding the wire round
a piece of wood, cut of the proper size and shape. The size is de-
termined by the bore of the glass tube, allowing for the diameter of
the wire. The shape is plane cylindriciil in that part which enters
the tube ; and slightly conical where it projects above the ttibe, as
/seen in the figure. (I believe this is the best shape, though I have
succeeded as well when the coil was of the same^bape throughout.)

In winding the coil, it is best that the turns of the -wireshoula
come in contact. Afterwards it is to *be gently extended, so as to
leave the turns as nearly as possible to each other, without touching.
.. The diameter of the coil is about one sixth of an inch where it en*
ters the tiibe. ' Its length half an ineh, or a little less, containing
from twenty to thirty turns of the wire. The projection abote the
tube is about' one half the length.

B.'Fig.'l. is a glass tube* t>ootaining a cotton wick^^bich by ca-*
pillary attraction carries the 'alcohol up to the platina coih The
Jength of this is arbitrary, being from one to three or fourinches.-—
The bore is about the sixth of an inch, so as barely to admit the coik
"^he wick, consisting of eight or ten threads,' is first drawn througb '

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tbe tube/ andtben introduced about bait way into tbe ootl, so as (a
come even with 'le top of tbe tube* This requires very nice adjust-
ment. If the wick is too tiig^b the wire is rapidly cooled by the al'
cobol, and ignition cea?es in a few moments. -If too low, the evap-
oration by the heat of tbe \vire is insufficient. If^ however, the
other parts are well constructed, a few trials wiM ensure success.

Fig. 2. sbovTS the lamp compete. The body' of it is a low vial or
inkstand r capable of holding about two- ounces of alcohol. It is
stopped accurntely wilh a cork, which is covered for ornament,
with tin foil. The aperture for admitting the tube and wick, is^made
with a hot iron. .

D. is a smair tube through which the alcohol is poured. A drcpr
ping tube .is convenient for ibis purpose, but a small funnel is easily
made by cutting off aji inch of the neck of. a broken retort, into
which is pushed a cork, and through this a small quill. Another,
orifice stifl, for letting off the air> as the alcohol goes in, may be
made through the cork. The orifices, of course, are to be stopped,
to prevent evaporation, after tbe lamp b chargfed.

When the lamp is completed and charged, the alcohol is inflamed
by holding the coil in the blaze of a candle. After letting it burn for
a few minutes, the flame is blown out, wlien if every thing is properly
adjosted, the wire will continue red hot until this alcohol is exhausted.

The explanation ivh}' the ignition of the wire is permanent, Seems
to be sufl&ciently simple. Alcol»el, when in the state of vapour, coo^
bines with oxygen ^ith great facilit^v. The temperature of the wire
is first raised by the dan>e of the candleJo about 600 degrees, Fah-
renheit^' This degree'of heat is such as to effect the combustion of
the alcohol with the oxygen of tbe • atmosphere. When this is once
effected, the caloric extricated by the oombustion of tbe alcohol, is
snfficfent to keep the coil at a red heat, which again is the tempera-
tare at which the alcohol is combustible, so that one portion of alco-'
hoi by the absorption of oxygen, and tliO consequent extrication of
beat, lays the foundation for the combustion of another portion; and
as the aLlc()hol rises in a constant stream,, so the effect b constant.
The stre:ira of vapour is much increased by the heat of tbe lower-
part of the coil, where k embraces the wick, and the temperatun^
of the alcol>ol is inoreascd before it reached the part of the coil
,wbere combustion is effected. Sometimes tbe last, or upper tarn of
ibe wire only is kept red hot.

This lamp, though one of tbe most curious inventions of tire dge,
is not merely a curiosity. The facility and certainty with.whkh by
means of a match, a vlight maybe obtained from it,, constitutes its
utility. The proper matches for this purpose are prepared by dtp*
ping the common brimstone matcbes into a ps^te made by mixing
two parts of white sugar with one part of chlorate (oxy muriat) 3t
potash. The red^FreD<?h matcbes are of this kind, and answer tbe
purpose completely.

In cases where a light migbt be^anted, but a constant one would

'^be offensive, this lampmigbt be a great convenience \ a light being

immediately obtained by merely touching a match to the plalina

odii, .and then to the wick of the candle. Physicians or others whe

are liable to be called up in the night would also find- it convenieiif.

The apblogistic lamp, with the proper matches, may he obtained
,ftt Mr. Charles. Hosraer'syanety Store,in this City.

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Acetates. Compounds formed by the combination of a base with acetic acid.

Adds. Compoauds formed by the combination of oxygen with certain el^
mentary bodies, formmg in general, a class of substances which are sour
to the taste, and which unite with alkalies and metallic oxyds to form salts.

^cidules. Substances formed by the natural combination of some acids
with a quantity of potash. 1 he oxalic and tartaric acids are examples.

^«r(/br}n fluids. Elastic fluids. Atmospheric air, and the gases are of this
kind. Their aeriform state is owing to the caloric with which their bates
are combined.

Affinity y chemical. A term used lo express that peculiar propensity which,
substances of different kinds have to unite with each other, as acids and
alkalies, &c.

' qf aggregation. That force is so called by which substances of tb«

lame kind tend to unite, without changing tbeif qualities.

of composition. That force by wnich substances of different kinds

combine, and fbrm a third, which differs from either of the two first, be-
fore the combination. Thus muriatic acid and soda form common salt.

Albumen. Coagblable Ivmph. It is contained in animal substances, as tb«
serum of the blood. iThe white of eggs is aH>umen.

Alcohol. Rectified spirit of wme. It is always the same^ from whatever
kind of spirit it is distilled.

AUcaUes. . Peculiar substances which have a caurtic burning taste, and a
strong tendency to combination, particularly, with acids, and with water.

Alloys. A combination of any two metals, except mercury. Brass is aa
alloy of copper and zinc.

ApfuUgam, A mixture of mercury with any other metal.

Analysis. Separation of the constituent parts of compounds, for the pur-
pose of detecting their composition. This is done by re-agents.

Annealtng. Rendering substances tough, which before were brittle. Tkt
metals are annealed by heating them red hot, and then cooling them

Arseniates. Salts formed by the combination of a basd with the arsenic acid .

Ascote. This name is given by the French chemists to nitrogen, which see.


balsams. Resinous, semi-fTuict substances, which are obtained from certain .

trees by making incisions.
Sarometer, An mstniment which indicates the variations of the prd^sur«
« of the atmosphere^ as thermometers do of heat and cold.
. Base. A term used by chemists to denote the substance to which an acid

is anited to form a salt. Thus soda is the base of common salt.
-Bnuroofsf. Salts formed by the union of the benzoic acid with a base.
BUne-pipe. An instrument to increase and direct the flame of a lamp for

the analysis of minerals, and for other chemical purposes.
Borates. Salts formed by the combination of any base with theacid of borax.

^^■^eotit. A chemical term fonnerly applied to describe cJulk, marble
and all other combiaatioiM of line witb ooibeiiic aqid. ^^y GooqIc


Calcination, The application of heat to saline, metallic, or other snbstan-
ces ; so regulated as to deprive them of moisture, &c. and yet preserve
them in a pulverulent form.

Caloric. The chemical tern for the nalter of fieat.

free. Is caloric in a separate state, or, if attached to other sosbtan-

ces, not chemically united with them.

'— latent. Is the term made use of to express that portion of caloric
which is chemically united to any substance, so as to become a part of
the said ^ubetance.

Calorimeter. A<n instrument for 4MeertatniBg the quantity #f caloric disen-
gaged from any substance that may be the object of experiment.

Calx. An old term made use of to describe a metallic oxide.

Camphoraieg. Salts formed by the combination of any base with the cam-
phoric acid.

Caprillary. A term usually applied to the rise of sap in Tegetables, or the
rise of any fluid in very^small tubes ; owing to a peculiar kind of attrac-
tion, called capillary attraction.

Carbon. The basis of charcoal.

Oarhonaies. Salts formed by the combination of any base with carbonic acid.

Carburets. Compound substances, of which carbon forms one of the con-
stituent parts. Thus plumbago, which is composed of carbon and iron,
is called carburet of iron.

Causticity. That quality in certain substances by which they burn or cor-
rode animal bodies to which they are applied^ It is best explained by the
iloctrine of vchemical affinity.

Chalybeate. A term descriptive of those mineral waters which are iropr^-
nated with iron.

Charcoal. Wood burnt in close vessels : it is an oxide of carbon, and gen-
erally contains a small portion of salts and earth. Us carbonaceous mat-
ter may be converted, by combustion into carbonic acid gad.

Chlorine. A name lately given to the substance usually called oxy-mariatic
acid. Its compounds are called by the name of their bases with.the end-
ing of one. As phosphorane, sulphurane, &c. *

Chromatet. Salts formed by the combinatioyi of any base with the chromic

Citrates. Salts formed by the combination of any base with citric acid.

Coal. A term applied to the residuum of ai^ dry distillation of animal or
Vegetable matters.

Cohesion. A force inherent in all the particles of all substances, excepting
light and caloric, which prevents bodies, from falling in, pieces.

Mtmbades. Salts formed by the combination of any base with the coUun-
bic acid.

CtmbintUion, A term expressive of a true <^iemcai union -of t«(0 or iwit0
substances ; in mixture.

Combustibles. Certain substances which are capable of combiniI^' more or
less rapiifly with ox^Egen. They are divided by chemistfl into ain^le w^
compound ^mbustitues.

Combustion. The act of absorption of oxygen by combustible bodies from
atmospheric or vital air. The word decombuition is sometimes usc^.bj
the French writers to signify the opposite operation.

Crucibles. Vessels of indispensable use in chemistry m the various opef^-
tions effusion by heat. They are made of baked eaitbi or metal, in the
form of aa inverted cone.

Crystallization. An operation of nature, in which various earths, sdtf,
and metallic substances, pacs from a fluid to a solid state, assuming c^-
tain determinate geometrical figures.

Crystallization, water of. That portion v^hi6h is combined with tflta in tbe-
act of cryatalliziiig, and becomes a component part of the said nliBe t^b-

Qupel. A vessel made of calcined bones, mixed with a snail proportion of

. clay and water. Jt is used whenever geld and silver are'renned, hj mrit-
ing them with left<?. TlMpraceMisoidledcwpaUttioB^ j

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D. . '

Decomposition. The separation of the constituent principles of compouBd
bodies by chemical means.

D^agration. The vivid combustion that is produced whenever nitre, mix-
ed with an inflammable substance, is exposed to a red heat. It may be at-
tributed to the extrication of oxygen from the nitre, and its being trans-
ferred to the inflammable body ; as any of the nitrates or oxygenized mu-
riates will produce the same eflfect.

Deliquescence of solid saline bodies^ signifies their becoming moist, or liquid,
by means of water which they absorb from the atmosphere in consequence
of their great attrcMStions for that fluid.

Deoxidize, (formerly deoxidate.) To deprive a body of oxygen.

Deoxidizement. A term made use of to express that operation by which one
substance deprives another substance of its oxygen. It is called unburn-
ing a body, by the French chemists.

Detonation. An explosion with noise. It is most commonly applied to the
explosion of nitre, when thrown upon heated charcoal.

Digestion. The effect produced by the continued soaking of a solid sub-
stance in a liquid, with the application of heat.

Digester J Papih's. An apparatus for reducing animal or vegetable substan-
ces to a pulp or jelly cxpeditiouslv.

DistUlaiion. A process for separ aiing the volatile parts of a substance fW>m
the more fixed, and preserving them both in a state of separation.

Ductility. A quality of certain bodies, in consequence of which they may
be drawn out to a certain length, without fracture.

Dulcijication. The combination of mineral acids with alcohol. Thus we
have dulcified spirit of nitre, dulcified spirit of vitriol, &.c.


Edulcoraiion, Expressive of the purification of a substance by washing with

Effervescence. An intestine motion which takes place in certain bodies, oc-
casioned by the sudden escape of a gaseous substance.

Efflorescence, A term commonly applied to those saline crystals which be-
come pulverulent on exposure to the air, in consequence of the loss of a
part of the water of crystallization.

Elasticity. A force in bodies, by which they endeavour to restore themsolves
to the Dosture from whence they were displaced by an external force.

. Elastic Jluids. A name sometimes given to vapours and gases. Vapour is
called an elastic fluid*; gas, a permanently elastic fluid.

Elective Attractions, A term used by Bergmann and others to designate
what we now express by the words chemical affinity. When chemists
first observed the power which one compound substance has to decompose
another, it ^ was imagined that the minute particles of some bodies had a
pf eference for some other particular bodies ; hence this property of mat-
ter acquired the term elective attraction.

Elements. The simple, constituent parts of bodies which are incapable of
decomposition ; the;^ are frequently called principles.

Empyreuma. A peculiar and indeticribably disagreeable smell, arising from
the burning of animal and vegetable matter in close vessels.

Ethers. Volatile liquids Ibrmed by the distillation of some of the acids with

Evaporation. The conversion of fluids into vapour by heat. This appears
to be nothing more than a gradual solution of the aqueous particles in at-
mospheric air, owing to the chemical attraction of the latter for water.

Eudiometer. An instrument invented by Dr. Priestley for determining the
purity of an^ given portion of atmospheric air. The science of investiga-
ting the difiereut kinds of gases is called eudiometry.


Fsrmeniaium, A peealiar spontaneous motion which takes place in all ve||e-
table matter, wnen exposed for a certain time to a*prop£c degree of tem-
perature. Digitized by Vj'

tSB A ▼0CAB17£ilJEr

Mbrine. That «rbite fibipus subatance which is left tiler fireely washing the
coagulumofthe blood, and which chiefly composes the muscular fibre.

fltmeri. In chemical language, are solid, dry substances, reduced to apow-
der by sublimation. Thus we have flowers of arsenic, sal. ammoniac, of
sulphur, 9lc. which are arsenic, sal. ammoniac, and sulphur, unaltered ex-
cept in appearance.

Ftuates. Salts formed by the combination of any base with fluoric acid.

Fluidity. X term applied to all liquid substances. Solids are converted to
fluids by combining with a certain portion of caloric.

f^ux. A substance which is mixed with metallic ore, or dther bodies, to
prdmote their fusion ; as an alkali is mixed with silex in order to form glass.

Fulmtnation. Thundering, or explosion with noise. We have fulminating
silver, fulminating gold, and other fulminating pdwders, which explode
with a loud report by friction, or when slightly heated.

Tusion. The stale of a body which was solid m the temperature of the at-
mosphere, and is now rendered fluid by the artificial application of heat.

Online LibraryMrs. (Jane Haldimand) MarcetConversations on chemistry .. → online text (page 40 of 43)