THE FIRE-AXNIHILATOR. 203 



but while the first exhibited the utmost avidity 

 for combination, this was resolutely indifferent 

 to every substance. Animals were intoxicated 

 when immersed in the first ; they were suf- 

 focated on immersion into this. Such were the 

 opposing qualities which at the time of their dis- 

 covery were found to exist in the important gases, 

 oxygen and nitrogen. 



The celebrated chemists, Scheele and Lavoi- 

 sier, both arrived, and each independently of 

 the other, and of Dr. Priestley, at the same 

 conclusions, and stated the composition of the 

 atmosphere in terms, which, considering the 

 great imperfection of their method of analysis, 

 were wonderfully near the truth. Thus the bare 

 fact was shaped out air is not a simple or 

 elementary fluid ; its constituents are oxygen 

 and nitrogen ; and these are mixed together in a 

 certain proportion. 



blown through the mine ; the next day it was inspected, all 

 was found safe, and the workings were resumed. From this 

 may be learnt the value of even a moderate knowledge of 

 chemistry. Mr. Phillips's " Fire Annihilator," which ia a 

 machine for pouring out a stream of gas upon a fire, and put- 

 ting it out by excluding the combustibles from the access of 

 the oxygon of the air, acts upon similar principles to this plan 

 of Mr. Gurney's ; but the gases evolved are different, consist- 

 ing of the products of the combustion inside the apparatus 

 of sulphuric acid, chlorate of potash, and sugar, together with 

 some portion of steam. 



