[ 154 ] [Sept. Ij 
PROCEEDINGS OF LEARNED SOCIETIES. 
NATIONAL INSTITUTE o/FRANCE. 
Particulars of an exact Analysis of Ve¬ 
getable and Animal lAatter^ by MM.. 
Oay-Lussac and Theyard, reac? loth 
January, 1810. 
W HEN we hud conceived the pro¬ 
ject of analysing animal and vege¬ 
table matters, ' the first consideration 
which presented itself to our serious al- 
teiuiun was to transform, by means of 
oxvgeh, .the vegetable and animal sub¬ 
stances into water, carbonic acid, and 
«zot-€. ^ It was evident that, if we could 
succeed in operating the transfo'vinaiion 
so as to collect all the gases, this analysis 
wonld be accomplished' with' very great 
precision and simplicity. 'Two obstacles 
presented themseNes; one was to burn 
comoletely the hydrogen and the carbon 
of tliese substances, and" the other To 
operate the combustion in close vessels-. 
We could expect to surmount the first 
diiticulty only by means of the metallie 
oxides which easily give up their oxygen, 
or by the hyper-oxygenated muriate of 
potash. Some experiments soon made 
us give the preference to the above salt, 
•which succeeded beyond ail expectatioii. 
It was not quite so easy, however, to 
overcome the latter difficulty"; for we 
could not attempt combustion in a retort 
fuli of mercury. To prevent the matter 
from being burnt, the retort must have 
been broken; it became necessary to 
fmdVan apparatus, therefore, in which 
•ft’e might-— 
1, Burn portions of substance so small 
as not to fracture the vessels. 
9. To make a great number of succes¬ 
sive combustions^ in order that the re¬ 
sults miglit be perceptible. 
3,-To collect th« gases as they were 
formed. ' . 
An^apparatus of the above description 
is formed of three distinct pieces; one is 
a veVy thick glass tube, closed at its 
low'cr extremity by the blow-pipe, and 
open at its upper end, about two deci¬ 
metres in lengtli, and eight millimetres in 
breadth: it has laterally five’centimetres 
from its aperture; 'a very small tube also 
of glass, which is soldered to it, and 
which resembles that which we should 
adapt to a retort for receiving the gases. 
The other piece is a copper ferule mfo 
which' we insert the open extremity of the 
large glass tube, and with wtiich it is 
imited by means of a mastic which melts 
only at 40°. The last piece is a peculiar 
kind of stop-cock, in which the whole* 
merit of the apparatus consists. The 
key of this stop-cock lias no hole through 
it, and turns in every direction without 
giving vent to the air; there is simply 
about the..middle of it a cavity capable v^f 
receiving a small pea; but this cavity is 
such,th.at, being in its upper positio;i,it cor¬ 
responds to a small vertical funnel which 
penetrates the socket, and of which it 
forms, in some measure, the extremity of 
the beak, and which, when brought back 
to its lower position, communicates wah, 
and is a continuation of, the body of the 
stop-cock, which is hollow, and is screwed 
to the ferule. Thus, when we put small 
fragments of any matter into the funnel 
and turn the key, the cavity is soon tilled, 
and carries the matter into the body of 
the stop-cock, from wliich it falls into 
the ferule, and from thence to the bot¬ 
tom cf the glass tube. 
If this substance, therefore, be a mix¬ 
ture of hyper-oxygenated muriate of pot¬ 
ash and of vegetable substance in proper 
proportions, and if the lower part of the 
glass tube be sufficiently warm, it will 
briskly take fire; the vegetable substance 
will then be instantaneously destroyed and 
transformed into water and carbonic 
acid, which will be collected over mer¬ 
cury with the oxygen gas issuing by the 
small lateral tube. 
In order to execute thisoperation ea'sily, 
we may conceive that it is necessary tliat 
the matter be detached entirely from the 
cavity and fall to the bottom of the tube. 
For this purpose it is made up into small 
balls, as will be mentioned presently: 
we may also conceive that it is.necessaty 
to inquire w-hat is the proper quantity of 
hyper-oxygenated muriate for burning 
completely vegetable substance. We 
must even take the precaution to employ 
at least one-half more than this substance, 
requires, in order that the combustion 
may be complete. 
But of all the inquiries which ought to 
precede the operation, the most impdr- 
ttiht is the analysis of the hyper-oxyge- 
nated muriate employed; for upon this 
all the calculations of the experiments 
are in a great measure founded. 
All this being well understood, it w-jll 
be easy to analyse a vegetable substance 
. with the hyper-oxygenated muriate. The 
substance is to be ground on a porphyry 
slab with tlie greatest care, as also tlie 
hyper- 
