of some of the Cornish Mines. 361 



Composition of this sample: — 



Nitrogen 80'98 per cent. 



Oxygen . . . . . 18*95 ... 



Carbonic acid . . 0*065 ... 



99*995 



Sample 4. One gallon. 



Wheal Vor. — As before. 230 fathoms ; two men in a core ; 

 22 fathoms from shaft or winse, half an hour after firing a 

 hole ; specific gravity *994. 



Oxygen. 



Average of two experiments with hydrogen 17*22 



Average of three experiments with nitrous gas . . . 17*36 

 Average of three experiments with quadrisulphuret 1 i».a n 



ot lime J 



Average of three experiments with hydrogen on ] 



sample taken from bottle secured by mercury, as >- 17*20 



before J 



Average of two experiments from ditto with quadri-*\ - „ 



sulphuret of lime J 



Mean . . . 1 7*282 



Carb. acid. 

 Average of two experiments with lime water .... 0*08 

 Average of two experiments with alkaline solution . . 0*085 



Mean . . . 0*082 

 Sulph. hydrogen. 

 Average of four experiments with a cup of nitricl 

 acid standing over mercury, with sample of air i»0*08 p. ct. 



taken in a mercurial bottle *. . .J 



Also, a strong trace of sulphurous acid; therefore composition 

 of this sample, 



Nitrogen 82*556 per cent. 



Oxygen 17*282 ... 



Carbonic acid 0*082 ... 



Sulphuretted hydrogen . . 0*080 ... 

 Sulphurous acid strong trace 



100*000 

 Sample 6. A quart; also mercurial sample. 

 Wheal Vor, Penhale. — Slate. 36-fathom level; four men at 

 work in a dead end ; candle burned with difficulty ; specific 

 gravity 0*994«. 



Oxygen. 

 Average of two experiments with hydrogen .... 14*74 

 Average of two experiments with nitrous gas .... 14*77 



