390 C H E M 
The whole apparatus being removed into the fhade, we 
began on the 9th to draw put the pipe which ferved as a 
fupp'ort, and obferved on it two flight fiflures occafioned 
by the contraction, and a fpot of four or five millimeters 
' in diameter, the center of which had a vitreous appear¬ 
ance, and its edges a reddifti hue. On examining it with 
a magnifying-glafs, we obferved at the lowed point a 
fpace of two or three millimeters diameter, the furface 
of which was really vitrified, but of a tarnifhed and un¬ 
equal colour. We diftinguifhed a particle of white glafs, 
pure and brilliant, formed into a globule, with fome 
Imaller portions of the fame nature, and two fmall glo¬ 
bules of a'vitreous fubftance, which had a greenilh red 
colour. 
On one fide we obferved on the edges feveral other 
very fmall globules interlperfed in a yellowifli ground, 
and on the oppofite a flight tinge of very bright red with 
very fmall reddilh points. A particle of white earthy 
matter was at firft taken for a fragment detached from 
the edges of the pipe, but it was found friable, and afcer- 
tained, by the ftain it left on gold, to be oxyd of mer¬ 
cury. This examination being finilhed, we introduced 
into the globe five meafures of fatilrated water of barytes, 
each of 46-5 cubic centimeters. The liquor immediately 
aflumed a milky appearance, and there was a diminution 
in the volume of gas, which, calculated by means of the 
attached paper fcale, amounted nearly to 300 cubic cen¬ 
timeters. Thus we might Hop here, and confider the 
experiment as terminated, and, by making fome allow¬ 
ance for the errors unavoidable in fuch manipulations, 
' make the refult tally with the amount, determined 
before by the noble experiment of Lavoifier and La 
Place, of the refpeflive quantities of carbon and oxygen 
which form the carbonic acid. Mr. Tennant feems to 
have done the fame thing lately after the combuftion of 
the diamond by nitre. But we fliould only have con¬ 
firmed what was before known, or fuppofed to be known. 
Our objefl was not only to obferve, with more attention, 
what took place during the aft of combuftion, but to af- 
certain, as accurately as poflible, the nature and quantity 
of the produft, and the reader will find that the labour 
undertaken on this fubjeft has not been fruitlefs. 
The liquor was agitated in the globe to mix the white 
matter which had been depofited. We drew out four 
meafures three quarters of the five we had introduced, 
by making ufe of the fame inverted bottle filled with 
mercury, and which we raifed on the infide by means of 
an iron ftalk compofed of feveral pieces, which could be 
adjufted by fcrews, as Ihewn at fig. 7, in the plate. We 
introduced into the balloon three new meafures, each 
containing the fame quantity of diftilled v'ater, which 
was Ihaken in the infide to detach and colleft w'hat ad¬ 
hered to the fides. Thefe united liquors, being imme¬ 
diately filtered in an open filter, left 19a centigrammes 
(36-142 ) of carbonat of barytes dried in the heat of boil¬ 
ing water. 
It may be readily judged what was our aftonifhment, 
when proceeding to examine the liquor, inftead of find¬ 
ing in it a flight excefs of uncombined barytes, we ob¬ 
ferved that it changed neither the colour of turmeric, 
nor that of logwood ; and that, on the contrary, it afted 
on an infufion of turnfole as water charged with the car¬ 
bonic acid- The prefence of this acid unequivocally raa- 
nifefted itfelf, when we poured upon it a few drops more 
«f barytes water, which immediately rendered it turbid. 
It was neceflary to add even 4-65 centimeters of this wa¬ 
ter to faturate and precipitate the remaining acid gas. 
Being informed by this phenomenon that the produftion 
of the gas had been more confiderable than we expefted, 
and that fome of it Hill remained mixed in the aeriform 
fluid in the balloon, we took every meafure neceflary to 
determine the quantity. This we were luckily enabled to 
do by the divifions which had been marked on thefcales, 
the orifice of the globe having never been yet taken out 
of the mercury. 
I S T R Y. 
When the barytes water was taken but, the apparent 
volume was found to be exaftly 122 deciliters, the inter¬ 
nal column of the mercury above the level of the ciftern 
was forty-feven millimeters; the barometer being at 
759-96 millimeters (Fruftidor 19, an. 6, of the republic, 
or 1798,) the centegrade thermometer at 21-25, the real 
volume, at a mean preflure and temperature, was 112,426 
deciliters, or 11242-66 cubic centimeters. 
I Itill invited M. Humboldt to co-operate with us in 
examining the nature of this refiduum of gas. It was 
transferred in his prefence into a pneumatic ciftern pre¬ 
pared on purpofe with diftilled water, and received into 
four large fiaiks. The trial was made by the fame in- 
ftruments, and with the fame nitrous gas, which had 
ferved for the oxygen gas before the combuftion, andcon- 
fequently containing from 0-09 to o-io of azotic gas. The 
trials made on portions extrafted from different flafks 
varied from thirty-one to thirty-four in the quantity of 
the refiduum of gas, in a mixture of 100 parts of gas ex¬ 
amined with 300 parts of nitrofts gas. I fhall not even 
take the mean term; I (hall ftop at the weakeft, which 
indicates four hundredth parts of carbonic acid gas, 
which, I think, I can aifert to be father below than above 
the truth ; lince a portion of this gas, brought into con- 
taft with ammonia, under a receiver, experienced a di¬ 
minution of 4-5 per cent. 
Let us now eftimate the carbonic acid gas which en¬ 
tered into the compofition of the 192 centigrammes of 
carbonat of barytes. According to Pelletier, whofe ac¬ 
curacy is well known in refearches of this kind, 100 of 
this earthy fait contain twenty-two of acid gas, which 
gives 42-24 for 192 ; and as the cubic centimeter of gas 
weighs 1 ’847 milligrammes, it follows that the 42-24 cen¬ 
tigrammes reprefent 228-621 cubic centimeters. If we 
now add, on the one hand, the 449 cubic centimeters, 
found in the refiduum of the gas after combuftion, and 
which, as we faw, formed the four hundreth parts; and 
deduft, on the other, the fame quantity from the aeriform 
fluid in which the combuftion was eftefted, it refults, 
that, in 11470 cubic centimeters of oxygen gas contained 
in the balloon, there remained, after the combuftion, only 
10793 ; that 677 were confumed; that thefe 677 cubic 
centimeters of oxygen gas, in the ratio of 1-3577 milli¬ 
grammes each, produced, with the 199-9 milligrammes 
of the diamond, 1117-96 milligrammes of carbonic acid. 
In the laft place, that, inftead of the proportions 0-28 of 
combuftible fubftance, and 0-72 of acidifying principle, 
obferved in the combuftion of carbon, the proportion was, 
for the combuftion of the diamond - 17-88 of carbon. 
82-12 o f oxygen. 
100-00 
Though it was not poflible for me to doubt fafts de¬ 
duced from calculation, I at firft hefitated to admit dif¬ 
ferences fo confiderable in the manner in which the fame 
combuftible united itfelf to oxygen in the quantities it 
could take up, and the produfts of its combuftion ; in a 
word, a carbonaceous combuftible more abundant in real 
combuftible matter than charcoal itfelf, and which at 
the fame time differed fo much from it in the degree of 
temperature neceflary to determine the aCtion of its affi¬ 
nity. But I foon began to refleft, ift. That this would 
not be the only inftance of the firft degree of the oxyda- 
tion of an acidifiable bafe having been operated with 
great difficulty, while the acidification was afterwards 
completed with the utmoft facility. 2d. That feveral fub- 
ftances of the fame kind prefented to us alfo thefe two 
characters; a greater abundance in real carbon, and 
greater refiftance to inflammation; fo that they naturally 
placed themfelves in an intermediary rank between the 
diamond and charcoal. Thefe two considerations, ftill 
ftrengthened by the fimilarity of the phenomena obferved 
during the courfe of our two experiments in the paflage 
of the diamond to the (late of carbonic acid, appeared to 
me to throw a ray of light on this fubjeft hitherto fo ob- 
fcure, 
Jn 
