COMBUSTION OF CHARCOAL. 301 



The plumbago emitted neither vapour nor smoke in No smoke, or 

 burning. The muriate of lime placed in the receiver, and ™£? ur ' em,t " 

 which was always weighed in a closed phial, acquired an 

 increase of 5 cent. [0*772 of a gr.]: but I learned from a 

 comparative experiment, that it absorbed a centigramme 

 [0*154 of a gr.] of water from the atmospheric air during 

 the time of its being put into the receiver and taken out 

 again. The gas employed for the combustion contained no 

 visible water, but it was in a state of extreme humidity ; 

 and the hygrometrical water in it, at the temperature of 

 25° [77° F.]» weighed 3*9 cent. [0*6 of a gr.]. As the and no water 

 muriate of lime must have acquired 4*9 cent. [0*754 of a gr.] P roduced - 

 by these two additions of weight, it does not appear, that 

 the plumbago produced any sensible quantity of water in 

 burning. 



The hidrosulphuret of potash indicated 189*75 parts of State of the gas 

 oxigen gas, and 10*25 of nitrogen, in 200 of the impure employed, 

 oxigen gas, which the receiver contained before the com- 

 bustion. Potash detected no acid gas in it. 200 other 

 parts of the same gas, nixed with 400 of hidrogen gas, 

 were reduced by detonation to 33 ; and consequently con- 

 tained 189 oxigen and 11 nitrogen. 



From 100 parts of the gas left after the combustion of Carbonic acid 

 the plumbago potash absorbed 63*42 of carbonic acid gas. ft)rmed ' 



After the separation of this acid gas, I examined whether No hidrogen 

 there were any hidrogen gas in the residuum, by detonating • volTe4, » 

 it with a mixture of equal parts of hidrogen and oxigen, and 

 treating with potash the gas remaining after the detonation. 

 These operations showed me, that the plumbago had given 

 out no hidrogen. 



The hidrosulphuret of potash indicated in 100 parts of 

 the gas, which the receiver contained after the combustion 

 of the plumbago [and abstraction of the carbonic acid], 87 

 parts of oxigen gas, and 13 parts of nitrogen. Another 

 100 parts were mixed with 200 of hidrogen gas, and reduced 

 to 40 by detonation. These 100 parts therefore contained 

 86*6*6 of oxigen, and 13*34 of nitrogen. According to the 

 process with hidrosulphuret, the 1750*4 cub. cent, of gas 

 found in the receiver after the combustion of the plumbago 

 contained 



Carbonic 



