i 



f)f lighting the J^lines so as to prevent its Explosion. 447 



One measure of it required for its complete combustion bv 

 tlie electric spark nearly two measures of oxygen, and thev formed 

 nearly one measure of carbonic acid. 



Sulphur heated strongly, and repeatedly sublimed in a por- 

 tion of it freed from oxygen by phosphorus, produced a consi- 

 derable enlarg-ement of its volume, sulphuretted hydrogen was 

 formed, and chare oal precipitated ; and it was found that the 

 volume of the sulphuretted hydrogen produced, when it was ab- 

 sorbed by solution of potassa, was exactly double that of the 

 fire-damp decomposed. 



It did not act upon chlorine in the cold ; but, when an elec- 

 tric s])ark was passed through a mixture of one part of it with 

 two of chlorine, there was an explosion, with a diminution to 

 less than l-4th, and much charcoal was deposited. 



The analysis of specimens of gas sent to my friend John 

 George Children, Esq, by Dr. Clanny, afforded me similar re- 

 sults ; but they contained variable quantities of carbonic acid 

 gas and azote. 



Different specimens of these gases were tried by the test of 

 exposure to chlorine both in darkness and light: they exhibited 

 no marks of tlie presence of olefiant gas or hydrogen ; and the 

 residuum produced in' detonation with chlorine showed them to 

 be free from carbonic oxide. 



It is evident, then, that the opinion formed by other chemists 

 respecting the fire-damp is perfectly correct; and that it is the 

 same substance as the inflanmiable gas of marshes, the exact 

 chemical nature of which was first demonstrated by Mr. Dalton; 

 and that it consists, according to my view of definite propor- 

 tions, of 4 proportions of hydrogen in vreight 4, and one pro- 

 portion of charcoal in weight ll*.). 



I made several experiments on the combustibility and explosive 

 nature of the fire-damp. When 1 part of fire-damp was mixed 

 with 1 of air, they burnt by tlie approach of a lighted taper, but 

 did not explode ; 2 of air and 3 of air to 1 of gas produced si- 

 milar results. When 4 of air and 1 of gas were exposed to ;i 

 lighted candle, the mixture being in the quantity of 6 or 7 cu- 

 bical inches in a narrow-necked bottle, a flame descended through 

 the mixture, but there was no noise : i part of gas inflamed 

 with (J parts of air in a similar bottle, produced a slight whi.stlin,^ 

 sound: 1 part of gas with S parts of air, rather a louder sound: 

 1 part with 10, I 1, 12, 13 and 14 parts, still inflamed, but the 

 violence of combustion diminished. In 1 part of gas and 15 

 parts of air, the candle burnt without explosion witli a greativ 

 enlarged flame; and the effect of enlarging the flame, but in a 

 gradually diminishing ratio, was produced as far as ^0 parts of 

 air to 1 of ga?. 



Tlic 



