nhich are evolved iti Coat-Mines, 319 



tated with liquid potash, the residue amounted to 75 volumes. 

 This residue burned, as it appeared, with a flame which was 

 more blue and less yellow than the pit-gas which had not been 

 treated with chlorine. The chlorine had, therefore, decom- 

 posed only about the half of the pit-gas employed in the expe- 

 riment. 



Equal Volumes of pit-gas and chlorine did not act on each 

 other in the light of the sun ; but one volume of pit-gas and 

 two volumes of chlorine detonated over water with a very 

 feeble explosion, by which carbon was deposited, and muriatic 

 acid was produced in white vapours. Sometimes the detona- 

 tion ensued instantaneously, and in other instances not for 

 some minutes. The detonation seemed to depend chiefly on 

 tlie purity of the chlorine. If it was rendered impure by at- 

 mospheric air, no detonation ensued, and the water merely 

 rose slowly. The detonation also took place more readily 

 M hen the chlorine had been first admitted into the receiver, 

 because, in that case, the specifically lighter gas was forced to 

 ascend through the chlorine, and thus to become better mixed 

 with it. This was particularly the case in narrow receivers. 

 The detonation was best eff*ected in a cylinder 18 inches high, 

 and 1^ inch wide, when the mixture of gases occupied a space 

 10 inches high. Whenever it was exposed to the sun's light, 

 an instantaneous explosion was the result. The mixture at 

 first was expanded, white clouds were formed, and then the 

 water ascended, while a large quantity of carbon was depo- 

 sited. If the sun was only a little obscured by a cloud, there 

 was merely visible a white mist, which descended more espe- 

 cially from a small projection at the closed end of the cylinder. 

 The water, however, did not fall as in the rapid action, but 

 gradually rose while the mist was in the course of being 

 formed. If, even during this action, the cloud was removed 

 from before the sun, and a strong ray of sunshine fell on the 

 cylinder, still no detonation took place. During such a slow 

 action of the two gases on each other, carbon was never depo- 

 sited. If the mixture was left standing in the light of the 

 sun so long that the chlorine was entirely absorbed by the 

 water, a strong smell of oil of turpentine became percep- 



