17fi COMBUSTION 0* CHARCOAL AND OF HIDROGEN. 



Experiment Thi» globe was furnished with a cock, and two conduct- 

 ing wires. After having exhausted it of air, I detonated in 

 it a mixture of equal parts of oxigen gas aud hidrogen gas 

 obtained by dissolving sublimed zinc in sulphuric acid. 

 After the acid gas had been absorbed by the barytes water, 

 I extra ted the residuary gas by means of the airpump, and 

 introduced a fresh mixture of gasses similar to the former, 

 which I detonated. These operations I repeated, till I had 

 effected the complete combustion of '2*91 cub. dec. [177 

 cub. inches] of hidrogen gas at 0'73 met. [28*7 inches] of 

 the barometer, and 18*75° of the thermometer \0h'75° F.]. 

 The carbonate of barytes formed weighed 6 cent. [0*926* of 

 a gr.]. Admitting with Klaproth, that 100 parts of car- 

 bonate of barytes by weight contain 22 of carbonic acid, 

 we shall find, that the 1000 parts of hidrogen gas by mea- 

 sure formed on combustion 2*6 of carbonic acid. This 

 comes sufficiently near to the quantity deduced from the 

 absorption by potash, to allow the two results tq be consi* 

 dered as nearly similar. 

 Leas earbonic I enter into these particulars, because the quantity of 

 bv the French c* 100 ™ a c»d, which the French chemists obtained from the 

 chemists. combustion of hidrogen gas extracted by means of zinc, in 

 their grand experiment on the composition of water*, was 

 equal only to a thousandth part of the hidrogen; while in 

 my experiments the quantity of this acid was about three 

 times as great, whether the zinc 1 employed were purified 

 or not, or the hidrogen gas were obtained by any other me-» 

 thod and considered as pure. 

 Water from J n the first disputes on phlogiston and the nature of hi- 

 tion of oxigen dr°g en gas, some chemists announced, that the residue of 

 and hMrogen the detonation of oxigen and hidrogen gasses precipitated 

 uiehmewatcr. Hmewater. Cavendish and Lavoisier carefully repeated this 



* These gentlemen agree, that they could only estimate by approxi- 

 mation the quantity of hidrogen gas in the 987 cubic inches left after 

 the combustion ; but they estimated it at no more than a sixteen thou» 

 >-andth part. It appears probable to me, that it was more considerable, 

 since phosphorus was capable of producing a detonation in it. I believe 

 too,. *bat this hidrogen gas was highly oxicarburctted, 



experiment 



