64 M. Karsten's Ohserxmtimis and Experiments on 



kept at an ardent heat at the two ends. From this arrangement, 

 there resulted that the decomposition was produced as complete- 

 ly as possible, and that, consequently, there was no reason to 

 dread the disengagement of a considerable quantity of carbonic 

 oxide gas, along with the carbonic acid gas, as happens, when a 

 single lamp only is employed, even with the assistance of a re- 

 verbere de tole. The length of the decomposition tube, so far 

 from being an obstacle, on the contrary, allowed a simple sup- 

 port to be adapted to it, suitably disposed for keeping it. 



In each of the analyses, there was employed 0.1 gramme, of 

 the substance to be decomposed, after being reduced to an im- 

 palpable powder, and dried at the temperature of boiling water. 

 This 0.1 gramme was pounded, and very accurately mixed with 

 four grammes of deutoxide of copper, completely dried. All the 

 other usual precautions were equally taken. In such an analy- 

 sis, the augmentation of weight which the muriate of lime expe- 

 riences, makes known the quantity of water that is formed, and' 

 from this the quantity of hydrogen disengaged is inferred. The 

 quantity of carbonic acid which is formed, makes known the 

 quantity of carbon. With regard to this, M. Karsten admits, 

 with Berzelius, that water contains 11.06 per cent, of hydrogen, 

 that the cubic foot (Rhine measure) of carbonic acid gas, weighs 

 0.03543668 of a gramme, and that there are 0.009797952 of a 

 gramme of carbon in it ; which is much about the same thing, 

 as saying with M. Thenard, that carbonic acid is composed of 

 27.68 of carbon, and 72,32 of oxygen by weight, or that, with 

 respect to volume, there are in this acid one volume of vapour 

 of carbon, and one volume of oxygen, condensed into a sino-le 

 volume. (See Thenard's Traite de Chimie, Paris, 1821, tit. ]. 

 p. 644. The same work says, that water is formed of 88-90 of 

 oxygen, and 11.10 of hydrogen in weight, or of one volume of 

 oxyen gas, and two volumes of hydrogen gas, ibid. p. 553.) 



On the other hand, by a direct experiment of carbonization, 

 the contents in charcoal of the substance analyzed, are determin- 

 ed, for a perfectly dry state of that substance. The charcoal 

 thus obtained is then burnt, and the quantity of ashes or 

 earthy parts calculated, that occur in the tenth part of a 

 gramme of the substance analyzed. With regard to the quan- 

 tity of oxygen, it is inferred by the way of difference. For 



