150 Dr Bischof's Examination of Three Inflammable Gases 



to form an explosive mixture. The experiments are attended 

 with some difficulties. It is necessary to pay particular at- 

 tention that the two gases are as intimately united with each 

 other as possible. This is best accomplished by first admit- 

 ting the atmospheric air and then the inflammable gas into 

 the tube (by which the latter, being lighter, is forced to ascend 

 through the former), and then to move the tube, closed by 

 the thumb, several times up and down. 



The determination of the maximum of the atmospheric air 

 is more difficult than that of the minimum at which the mix- 

 ture ceases to detonate. If, when making experiments for 

 the purpose of finding the latter, we are near the proportion 

 in which the gaseous mixture ceases to be detonating, a lively 

 detonation ensues with a certain proportion, by means of 

 the electric spark, while, on the other hand, not the slightest 

 detonation takes place when one part less atmospheric air is 

 added. The more the atmospheric air exceeds that mixture 

 in which the strongest explosion occurs, the more is the vio- 

 lence of that explosion diminished. Lastly, it comes to this, 

 that a detonation, it is true, takes place, but the whole quan- 

 tity of the inflammable gas is no longer consumed ; for the 

 more the atmospheric air is increased, the less is the gas di- 

 minished by detonation. 



For practical purposes, it would be sufficient to know the 

 proportion of the inflammable gas and the atmospheric air in 

 which the detonation takes place, without, however, being 

 accompanied by destructive consequences. This, however, is 

 not to be ascertained by means of the detonation-tube. There 

 is nothing else left, then, but the determination of the pro- 

 portion of the two gases in which a strong electric spark still 

 causes a diminution of volume. This will be the proportion 

 in which, though a detonation might occur in the pit, there 

 would be no danger for the miners. 



The following are the results of a large number of experi- 

 ments, in which the power of detonating of the inflammable 

 gas from the Welleswe%ler Stollen (W), and from the Artesian 

 well in the coal-pit in the principality of Schaumburg (S), is 

 determined comparatively. 



1. One part of inflammable gas from W. did not detonate 



