of some of the Cornish Mines. 363 



Oxygen. 

 Average of two experiments with hydrogen .... 15*1 

 Average of three experiments with nitrous gas . . . 15*2 

 Average of three experiments with quadrisulphurefl . K 

 oflime J l5 ' 15 



Mean . . . 15-15 

 Carb. acid. 

 Average of two experiments with lime water .... 0*14 

 Average of two experiments with solution of potash 0*15 



Mean . . . 0-145 

 Composition of sample : — 



Nitrogen 84*705 per cent. 



Oxygen 15*15 



Carbonic acid ... 0*145 



• # • 



• •• 



100-000 

 Sample 9. One quart. 

 Great Work. — As before. 1 50 fathoms from surface ; two 

 men in a core ; twenty fathoms from winse or shaft, directly 

 after firing a hole ; specific gravity -995. 



Oxygen. 



Average of two experiments with hydrogen 16*30 



Average of two experiments with nitrous gas . . . 16*40 

 Average of two experiments with quadrisulphuret "1 



of lime j 



Average of two experiments with hydrogen from \ lfl .. ft 



mercurial sample 



Average of two experiments with quadrisulphuret V __ 

 oflime from ditto J 16 ' 60 



Mean . . . 16*45 

 Carb. acid. 

 Average of two experiments with lime water .... 0*10 

 Average of two experiments with potash solution . . 00*98 



Mean . . . 0-099 

 Composition of sample : — 



Nitrogen 83*451 per cent. 



Oxygen 16*45 



Carbonic acid .... 0*099 



100*000 

 Sample 10. One quart. 

 Great Work. — As before. 125 fathoms from surface; twenty- 



