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management and preparation of the apparatus, &c,

Mr. Weekes's Monthly Register was then placed on the table, and
the Society adjourned.



CHEMICAL SOCIETY OF LONDON.
[Continued from vol. xyiii. p. 520.]

May II, 1841. — " On a Simple and Cheap Method of preparing
Hydrochloric Acid absolutely pure, and of any required strength,"
by Wm. Gregory, M.D. Professor, &c.. King's College, Aberdeen.

Much difficulty is experienced in procuring pure and concentrated
hydrochloric acid for chemical purposes, the common commercial
acid containing various impurities, particularly sulphuric and sulphu-



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chemical Society. S29

rous acid6, free chlorine, chloride of iron and sulphate' of eoda ; these
aride from iin|Hirities contained in the materials employed; the
chlorine from the action of nitric or nitrous acid (often present in
oil of vitriol) on the hydrociiloric acid ; sulphurous acid from or-*
ganic particles in the common salt employed ; and chloride of iron
from the presence of that metal also in Uie salt. Pure and clean
materials are therefore the first requisite for a pure acid. Dr. Ghre«
gory finds, that if to one equivalent of salt two equivalents of sulphu«
ric acid diluted with a certain quantity of water be used, instead of
one equivalent as usually prescribed, the whole of the hydrochloric
acid may be expelled without a trace of sulphuric acid passing over
even into the first condensing bottle, and that two-thirds of the hy-
drochloric add distil over before water is volatilized ; on this obser-
vation the following process is founded.

Into a common Florence flask are introduced 4 ounces of the pu-
rest patent salt, and 5 fluid ounces of sulphuric acid of specific gra-
vity 1-600 ; a gentle heat is applied, and the gas which is then gene-
rated, is conducted by a bent glass tube into a four- ounce phial con-
taining 2 ounces of distilled water surrounded with snow or ice-cold
water. No safety tube is required, as the tube is made to dip only
about one-eighth of an inch into the water, so that should any
absorption take place the rise of a little water in the tube exposes
the extremity of it, so as to admit the air ; or, fi>r greater security,
a small bulb may be blown on the descending limb of the tube.
The gas is absorbed as fast as it comes over, and for the first hour
and one quarter the heat hardly requires to be increased ; if the tem-
perature of the surrounding water has been kept so low as 50^ the
2 ounces of distilled water will have increased in volume to 3 ounces
of colourless hydrochloric acid, fuming strongly, and having a spe-
cific gravity of 1*20 to 1*21, the gas passing over so dry that no part
of the tube becomes warm. This portion being removed, its place is
supplied by 2 ounces more of distilled water, and the heat gradually
increased and continued for an hour longer; by that time all the hydro-
chloric acid is expelled, with some water, and the 2 ounces of water
have become 3 ounces of hydrochloric acid of specific gravity 1*10.
Both portions are absolutely pure. If 3 ounces of water are used in
the first instance, 4*o fiuid ounces of acid of specific gravity 1*165
are obtained ; and then replacing the acid by 2 ounces of water, 3*5
ounces more of specific gravity 1*065. If 5 ounces of water are used
at once for condensing the acid and kept till the distillation is com-
plete, 7*5 fluid ounces of specific gravity 1*155 are obtained. Dr.
Clark finds sulphuric acid of a specific gravity of 1*65 to answer
still better than acid of 1*60.

Dr. Clark then exhibited to the Society his method of ascertain-
ing, quantitatively, the comparative hardness of water by means of
the common test of tincture of soap, illustrated by experimental
evidence, to prove the accuracy of wluch it was susceptible, and the
facility of its application. Dr* Clark hoped at a future meeting
to lay before the Society more mature details of the method ex-
hibited. ^



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8S0 (Mimical Smeh/.

May 18.— An extract of a letter from Mr. Maugham \nA read,
" On the Mode of treating Copper Ores, and the Ores of other
Metals combined with Sulphur, so as to ascertain the quantity of
Sulphur in such Ores, and also the quantity of Copper in the natire
Sulphuret."

A quantity of the powdered ore, sulphuret of copper, about 50 or
100 gndns, is placed in a porcelain tube traversing a small furnace,
and made red-hot ; after remaining for 5 or 6 minutes a portion of the
sul|)hur will be expelled ; a stream of oxygen gas is then passed over
it, the remaining sulphur is then rapidly given off as sulphurous and
sulphuric adds, and the copper thoroughly oxidized. By heating the
ore when first introduced into the tube it becomes slightly adherent,
which prevents any of it from being blown away by the oxygen gas.
The contents of the tube are then removed into an assay crucible,
with the addition of black flax and a little charcosl ; the whole co-
vered with dry carbonate of soda or borax, and submitted to a yellow
heat, when a button of copper is obtained. Mr. Maugham finds
that arsenic and other volatile metals that may happen to be present,
are oxidated and expelled by the heat; but should tin be present it
wiU be found with the reduced copper, and must be removed in the
usual way. The process ia known to be complete when no more
vapours are seen to issue firom the tube, or when the odour of sulphu-
rous add is no longer perceptible. It is, however, to be observed,
that white vapours will be seen even after the process is complete,
owing to a portion of sulphuric acid condensed in the tube returning
to the hot part. An assay of this Idnd takes about twenty minutes
to execute.

When the wet analysis is desirable, we have only to proceed as
before in the tube part of the process, and to dissolve the reddue in
the proper acids.

Mr. Maugham speaks fovourably of the use of chlorate of potash,
added to hydrochloric acid, for dissolving certain ores where nitro-
muriadc acid is generaUy employed, and afterwards expelling the ex-
cess of chlorine by heat ; the known inconveniences of nitric add in
certun cases are thus avoided.

The quantity of sulphur contained in the ore is ascertained by
elongating the tube traversing the furnace, so that it may dip into
a v€»sel containing water saturated with chlorine, by wluch means
the sulphurous acid is converted into sulphuric add, and the quantity
of sulphur found from the precipitate with chloride of barium.

A paper was read "On the Atomic Weight of Carbon," by Pro-
fessors Redtenbacher of Prague and liebig of Giessen*.

June 1. — ^Extract of a letter from Col. Yorke " On a Specimen of
Artifidal Arragonite."

« This substance was taken from the interior of a copper boiler
which was used to supply hot water for household purposes at Port
Eliot, Lord St. Oermaine's seat in Cornwall. The substance is about
•l^ths of an inch thick, and by its non-conducting power it caused,

* This paper is ^ven entire in our last Number, p. 210.



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Chemkal Soeteiy. 331

M I understood, the destruction of the boiler. On the surface which
was next to the copper it is coated by dioxide of copper, and the
mass appears made up of an aggregation of prismatic crystals, whose
axes are perpendicidar to the surface on which the incrustation
formed : under a microscope these crystals appear to be six-sided
prisms. I compared, under a polarizing microscope, portions of the
powder of Icebuid spar, and ef arragonite from Bilin, with the pow-
der of the specimen ; the latter agreed very closely in appearance
with that of arragonite.

" Among the powder of tiie specimen were seen some Tory aente
double six-sided pyramids; these with little doubt are similar to
those formed by G. Rose* by evaporating solutions of caibonate of
lime at a boiling heat, and described by him as resembling some
sapphire crystals.

'* On chemical examination it was evident that the specimen con-
sisted chiefly of carbonate of lime ; water, however, dissolved fe)m it
a small quantity of sulphate of lime.

" The following is the result of an analysb made on 10 grains, but
which does not pretend to minute accuracy :-^

Matter insoluble in muriatic acid, silica, with 1 .
oxides of iron and copper. J

Sulphate of lime • 1*8

Carbonate of lime 93-7

Carbonate of magnesia 3*2

100

" Deprived of its coating of dioxide of copper, three trials were
made of the specific gravity of its powder ; the sulphate of lime being
previously washed off with hot water.

" The two first trials were made by weighing about 80 grains of the
powder in a small spherical-stoppered phial (whose contents in di-
stilled water at 62° was previously determined), and then when filled
up with water, the third trial was made in the manner described by
Rose. The specific gravity being thus determined, the powder was
in each case dried, and slighUy ignited, (by which operation arrago-
nite, as is known, is converted into calcareous spar) and the specific
gravity again taken. The results were as follows : —

Spec Grav. Spec. Gnv.

before Ignition. after ignition.

1st trial 2-842 2708

2nd 2-828 2701

3rd 2-878 2-681t

Mean 2849 2696

The specific gravity of arragonite crystals from Bilin is 2*946.
"TTie highest specific gravity which Rose obtained of arragonite,

[• G. Rose*s paper, here referred to, on the formation of calc-spar and
arragonite^ will be found in Phil. Mag., Third Series, vol. xii. p. 465.-^Eo.}
t The losi by ignition on 43*8 grains was ss *08 grain.



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SS2 Chemical Society.

formed by evaporating solutions of carbonate of lime» he states
s2-836.

" Specific gravity of Iceland spar is 2* 72. I should suppose then that
there can be little doubt but that the specimen affords an example
of the formation of arragonite, and a verification of G. Rose's expe«
riments.

" I have since made two attempts at producing arragonite by Rose's
method of precipitation, but cannot boast of my success. The fol-
lowing is a note of the best experiment. A solution of 300 grains
of chloride of calcium, in 4 ounces of water at 212°, was mixed ra-
pidly with a solution of 330 grains of carbonate of ammonia in 8
ounces of water at 180°. The mixed liquor was not alkaline.

"The precipitate under the microscope consisted chiefly of radiating
spicular crystals, extremely minute, with occasional rhombohedrons.
The precipitate being washed, the specific gravity taken before dry-
ing came out sse 2*751, after drying it was below 2*7. During the
washing a slight crackling noise was heard, and I cannot help think-
ing the precipitate may have been thrown down as arragonite, but
changed into calc-spar during the washing and drying."

Professor Kuhlman of Lille presented specimens of Chalk hard-
ened by his process for the Silicification of Limestones, which con-
sists of immersing them in a solution of silicate of potash, expos-
ing to air for several days, and afterwards washing. Although the
chalk did not contain more than three or four per cent, of sDica,
it was capable of scratching many cements and marbles. In a
similar manner he could harden carbonate of lead and plaster of
Paris. He finds alkaline salts in all the limestones containing silica,
which are hydraulic, and believes that they originally resembled
ordinary chalk in purity, but have l)een partially silicified by infil-
tration of water containing an alkaline silicate in solution, or by a
natural process analogous to his artificial one.

Extract of a letter from Dr. R. F. Marchand of Berlin, " On the
Atomic Weight of Carbon.**

" I take this opportunity of communicating the results of experi-
ments relative to the atomic weight of carbon, which Professor Erd-
man and myself have very lately obtained. The difference between
the numbers recently given by Dumas and that of Berzelius was a
sufficient inducement for us to examine and repeat Dumas's experi-
ments, much occupied as we are with organic analysis. The bnm*
ing of diamonds in oxygen gas was easily effected by us in a porce-
lain tube, by a pretty high temperature. The apparatus employed
was very similar to that described by Dumas.

" The following are the results :^—
No. 1. 0*8062 gramme diamonds left a residue weighing OOOIO
gramme, and gave 2*9467 grs. carbonic acid, consequently
giving the atomic weight for carbon 75*19.
No. 2. 1*0867 gr. left a residue weighing 0-0009 gr., and gave

3*9875 grs. carbonic acid = carbon 74*84.
No. 3. 1*3575 gr. left a residue weighing 0*0018 gr., and gave
4*9659 grs, carbonic acid se carbon 75*10.



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JfUelligence and Miscellaneous Articles. SS3

No. 4. 1*6330 gr. left a residue weighing 0-0025, and gave 5*97945

= carbon 74*98*
No. 5. 0*7510 gr. left a residue weighing 00010, and gave 2*7490
s carbon 7503.
" Graphite gave the same numbers ; the residues were pure white
silex without a trace of oxide of iron ; —

No. 1. 1*4580 gramme native graphite left a residue weighing

0'0075, and gave 5'31575 grs. = carbon 75*05 atomic weight.

No. 2. 1*5746 gr. graphite left a residue weighing 0*037, and gave

5*6377 grs. = carbon 7502.
No. 3. 1*6578 gr. residue 0*0084, and gave 6*0385 = carbon

7518.
No. 4. 1*9040 gr. artificial graphite, residue 0*0105 gr., gave 6*9355
grs. ss carbon 75*10.
" The mean of these experiments give 75*07 ; we therefore consider
75 as the true number indicated by these experiments for the atomic
weight of carbon. It is remarkable that this number was fixed upon
theoretically by the English chemists, and has now been confirmed
by experiments. If we take the number 6*239 for hydrogen, with a
very small increase, viz. as 6*250, we arrive at the numbers for oxy-
gen, carbon and hydrogen, viz. 16, 12, 2, or 8, 6, 1."

A paper was read " On Malic Acid, and the Salts of Malic
Acid," by R. Hagen, M.D., translated and communicated by T. G.
Tilley, Esq. This paper will be found in the present Number, p. 306.
A paper was read " On Pyroxylic Spirit," by Andrew Ure, M.D.
A paper was read " On the Ferrocyanides," by R. Corbett Camp-
bell.

Both these papers will be inserted, entire, in a future Number
of the Philosophical Magazine.



XLVII. LUelligetice and Miscellaneous Afiicles.

PREPARATION OF LACTIC ACID AND LACTATES.

THE following process is recommended by MM. Boutron and E.
Fremy, for preparing lactic acid and its salts : — ^I'ake about 6
pints of milk, and add to it about 8 ounces of sugar of milk dissolved
in water. The mixture is to remain in an open vessel exposed to the
air, for some days, at a temperature of about 60^ Fahr. The liquor
has then become very acid, and is to be saturated with bicarbonate
of soda. In 24 to 36 hours it again becomes acid, and is to be again
saturated, and so on, until all the sugar of milk is converted into
lactic acid. When the conversion is reckoned complete, the milk is
to be boiled to coagulate the caseum, and it is to be filtered and
cautiously evaporated to the consistence of a syrup ; the product of
this evaporation is to be treated with alcohol, which dissolves tlie
lactate of soda ; to the alcoholic solution suflicient sulphuric acid is
to be added to convert the soda into sulphate, which is precipitated,
and the liquor filtered and evaporated yields lactic acid nearly pure ;
in order to obtain it perfectly so, it is to be saturated with chalk, and



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8S4 Intelligence and Miscellaneous Articles.

the lactate of lime fonned immediately crystallizes in perfectly white
mammillated masses, and ft^m this the lactic acid b procured hy the
well-known processes.

It is evident, observe the authors, that lactic acid may be satu-
rated by other bases, and they state that a chemical manufieu^turer
has prepared this acid from the sour water of starch-makers, by satu-
rating it with carbonate of lime. — Journal de Pharmacie, xzvii. 341.



PREPARATION OF FORMIC JETHER.

According to Wohler, the following process yields formic sether
in large quantity, and very readily : put into a retort ten parts of
starch and 37 parts of peroxide of manganese, intimately mixed in
very fine powder ; add to them a mixture of 30 parts of sulphuric
acid, 15 parts of highly rectified spirit of wine, and 15 parts of
water ; the mixture is to be gently boiled, and distillation continued
until the product contains no eether. In order to separate the water
and the alcohol, a sufiicient quantity of chloride of calcium is to be
dissolved in the product, and distillation is to be performed in a
water-bath ; the purification is to be completed by a second rectifi-
cation in the same manner.

M. Wohler states, that in the numerous experiments which M.
Kolbe made on this subject at his request, appearances presented
themselves which probably indicate the presence of a peculiar sub-
stance in this lether, requiring fresh experiments for elucidation:
when the fragments of fused chloride of oddum have been for some
time in contact with the aether which has been once rectified, and
are partly dissolved, it becomes of a deepish yellow colour, and de-
posits small, very fine colourless crystals on tiie sides of the vessel*
In general the colour disappears after a certain time ; it is probably
owing to chloride of iron ; and probably also the crystals are a com-
pound of chloride of calcium and alcohol, which are soluble in formic
aether, and may crystallize from it. — Journal de Pharmacie , tom. xxvii.
p. 91.

PREPARATION OF lODATE OF POTASH. BY M. MELLON.

When cold no action takes place between the above-named sub*
stances ; but if to chlorate of potash about three or four times its
weight of distilled water be added, and then heated to ebullition,
iodine added to the solution disappears in considerable quantity; the
liquor is colourless, and remains so until the equivalent of iodine
is exceeded ; after this the liquor becomes yellow and then brown ;
and, as a final result, there are obtained neutral iodate of potash
and chloride of iodine, with greater or less excess of the latter. If
the mixture be evaporated to dryness, the chloride of iodine is dis-
engaged, and the iodate of potash remains pure.

If the action of the iodine on the chlorate be stopped before an
equivalent of the iodine is added, the liquor even then contains
iodate of potash, and also chlorate [chloride ?] of iodine, correspond-
bg unquestionably to iodic add ; for if the liquor be strongly heated.



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Meteorological Observations* SS5

chlorind is disengaged, and there Temains chloride of iodine, which
giyes a precipitate of iodine with carbonate of potash.

According to M. Mellon, the formation of chloride of iodine ex-
plains the reaction that occurs : the iodine attracts the chlorine of
the chlorate, whilst the greater affinity of the iodine for the oxygen,
and the greater cohesion of the iodate, cause the iodine to enter into
the chlorate instead of the chlorine. The action M. Mellon repre-
sents thus: 5 CIO^KO + 61 = 510*, KO + ICP.

Journal de Pharmacie, torn, zxvii, p. 102.



PROFESSORSHIP OF OEOLOOY, UNIVERSITY COLLEGE, LONDON.

We have great pleasure in recording the establishment of a Chair
of Oeology in University College, and that Thomas Webster, Esq.,
formerly Secretary to the Geological Society, has been appointed to
occupy it.

Professor Webster's Course on Geology at the College, consisting
of Thirty Lectures, will commence on the first Tuesday in February
1842, and will be divided into three parts.

1. The description of such simple minerals as enter essentially
into the composition of rocks.

2. Geology, properly so called ; or the characters and superposi-
tion of the strata composing the crust of tlie globe, together with
an account of the various phienomena exhibited by them.

3. The application of the above subjects to the useful arts.



METEOROLOGIOAL OBSERVATIONS POR AUG. 1841.
Wiwidt. — August 1. Slight rain : cloudy and fine. S. Pine with clouds : rain.
S. Hainr: cloudy and mild : rain. 4. Cloudy and fine. 5. Fine: slight rain.
6f 7. ^ne. 8. Rain : cloudy and fine. 9. Very fine. 10. Very fine : rain.

11. Scormy and wet 19. Fine. IS. Cloudy. M. Rain: showery: elsarat
night. 15 — 17. Cloudy and fine. 18. Hasy : fine. 19, 20. Very fine. 21.
Cloudy. 22. Cloudy : slight rain. 23. Rain : cloudy and fine. 24. Showery :
dear. 25. Drissly. 26. Hasy and mild. 27. Heavv dew : doudy and hot.
S8— SO. Foggy in the mornings : very fine : evenings clear. 31. Overcast and
fine.

.fiesfon.— August 1. Fine: rain rjf. 2. Fine. 3. Cloudy: rain r.ic 4. Fine:
rain early a.m. 5. Cloudy : rain r.ic 6. Cloudy and stormy. 7. Cloudy : rain
r.w. 8» 9. Cloudy. 10. Fine. 11. Cloudy: rain early a.sc.: rain p.m. 12.
Stormy. 13. Cloudy. 14. Cloudy: rain early a.m. 15. 16. Cloudy. 17.
Fine : rain r.M. 18, 19. Fine. 20. Fine : thermometer 77^ half-past two r.M.
21. Fine : rain a.m. 22. Fine. 23, 24. Fine : rain early a.m. 25. Rain :
rain early a.m. 26. Cloudy : thermometer 75^ three-quarters past two r.if. 27.
Fine : thermometer 75° quarter.past ekven A.if. 28, 29. Fine. 30^ 31. Cloudy.

jipplegarih Matutf Jhmfrie»'Mre. — August 1. Fair, but cool and cloudy.
S. Fair and fine. 3. Wet a.m. i cleared and was fine. 4. Fair and fine. 5.
Rain all day. 6. Wet a.m. : cleared and was fine. 7. Wet, sUghtly. 8. Fine
though showery : thunder. 9. Wet a.m. : became fine. 10. Showery. 1 1. Fair.

12. Showery ill day. 13. Partial showers. 14. Wet a.m. : became fine. 15.
Fine till r.M.: then rain. 16. Wet a.m. : cleared r.M. 17. Fair throughout.
18. Fair A. M.: wet p.m. 19. Fair and warm: air electricaL SO. Wet nearly
all day : thunder. 21. Wet r.M. : fiood. 22. Fine and fair. 23. Occasional
sli(^t showers. 24. Wet p.m. and evening : thunder. 25. Showery. 26. Rain
early A.M. : cleared. 27. Fine : one shower a.m. 28. Wet morning : cleared^
$9. Fine but cloudy, ga Wet all day. 31. Fsur and fine.



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THE
LONDON, EDINBURGH and DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.



[THIRD SERIES.]



NOVEMBER 1841.



XLVIII. On the Chemical Sialics of Organized Beings*
By M. Dumas.

[The discourse of which the following is a translation, attracted, as we are
informed, much attention, on its delivery by M. Dumas. It formed the
concluding I^ecture of his course at the Ecole de MSdecine, and has just
been published. — ^£0.]

T IFE, whose painful masteries you are called upon to fa-
•'-^ thorn, exhibits among its phaenomena some which are ma-
liifestly connected with the forces that inanimate nature herself
brings into action, others which emanate from a more elevated
source, less within the reach of our boldest stretch of thought.

It has not been my province to accompany you in looking
with an inquisitive eye into all that part of your studies under
which those facts which appertain to the normal or irregular
exercise of the instincts of life arrange themselves. Still less
have we ever had to bring under our consideration those noble
faculties, by means of which the human intellect, mastering all
that surrounds it, breaking down all obstacles, bending all the
powers of nature to. its wants, has step by step made conquest
of the earth, of the seas, of the whole globe ; — a vast domain,
which our recollections, our presentiments perhaps, so often
make us consider as too narrow a prison. To others more
fortunate belongs the care of initiating you in these important
studies, the privilege of unfolding to you these lofty themes ;
our task, more humble, must be limited to the field of the phy-
sical phaenomena of life ; and there are still some which have
not found a place in our lectures.

It is specially, indeed, the functions of matter in the pro*
duction and growth of organissed beings, the part which it

Phit. Mag. S. df Vgl. 19. No. 125, Nov. 1841. Z



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338 M. Dumas on the Chemical Statics of Organized Beings.

takes in the accomplishment of the phsenomena of their daily



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