on the Combujtion of the Diamond. ids 
Jume was found to be exa&ly 122 decilitres, the internal 
column of the mercury above the level of the tub was 47 
_ _ millimetres; the barometer being at 759°96 millimetres, 
_  {FruGidor 19, year VI.) the centegrade thermometer at 
21°25, the real volume, at a mean preflure and tempera- 
ture, was_112.426 decilitres, or 11242°66 cubic centimetres. 
I ftill invited M. Humboldt to co-operate with us in exa- 
mining the nature of this refiduum of gas. It was transferred 
in his prefence into a pneumatic tub prepared on purpole 
with diftilled water, and received into four large flafks. The 
trial was made by the fame in{truments. and with the fame 
. nitrous gas, which had férved for the oxygen gas before the 
combuftion, and confequently containing from o°og to 0°10 of 
azotic gas. The trials made on portions extracted from dif- 
ferent flafks varied from 37 to 34 in the quantity of the re- 
fiduum of gas, in a mixture of 100 parts of gas examined with . 
300 parts of nitrous gas. 
_ I thall not even take the mean term, I thall flop at the 
weakeft, which indicates four hundredth parts of carbonic 
acid gas, which, I think, I can affert to be rather below than 
above the truth; fince a portion of this fame gas, brought 
into contact with ammonia, under a receiver, experienced a 
diminution of 4°5, per cent. 
Let us now eftimate the carbonic acid gas which entered 
into the compofition of the 192 centigrammes of carbonat 
| of barytes. According to Pelletier, whole accuracy is well 
known in refearches of this kind, 160 of this earthy falt con- 
tain 22 of acid gas *, which gives 42°24 for 192; and as the 
cubic centimetre of gas weighs 1°847 milligrammes, it fol- 
_ lows that the 42°24 centigramimes reprefent 228-621 cubic 
centimetres, If we now add, on the one hand, the 449 cubic 
_ centimetres, found in the refiduum of the gas after combnf- 
_ tion, and which, as we {aw, formed the four hundredth parts; 
and deduét, on the other, the fame quantity from the acitform 
fluid in which the combuftion was effected, it refults, that in 
11470 cubic centimetres of oxygen gas contained in the bal-~ 
loon, there remained, after the combutftion, only 107933 that 
*y 677 were confumed; that thefe 677 cubic centimetres of 
+ Annales de Chimie, Vol. XXI, p, 135. 
oxygen | 
