78 Prof. H. How on Oil- Coal. 
all the others, and secondly, that in all the bituminous coals but 
one the volatile matters are considerably less in amount than the 
fixed carbon, while in the cannel coals this is also the case with 
value of a coal is indicated by the weight lost in rie gn 
as above, from eight to ten per cent of what is generally sup- 
ape to be carbon and x dpa is really oxygen with nitrogen. 
the ratio of C: H apparently equal or nearly so to that in the 
substances in question, we observe that they all contain much 
more oxygen, and if we deduct the equivalent quantity of H 
in all, as is theoretically necessary for arriving at the heating 
power, we shall find this similarity greatly lessened; as thus, 
Cannel coal from Wigs, nines 565 none 
“ “ es 
“ “ 
Mineral “ Torbane Hill, 100:12°43 
“ Hillsborough, 100: 10°85 
. “ Fraser Mine, 100 : 12°48 
The last three substances should i 
prove, theoretically, the ex- 
cellent ‘Oil-Coals’ they are known to be. rse te practi- 
th 
=a of the manufacturin processes and the quality of sam- 
ples employed, but the following statement of the comparative 
* After allowing two per cent for nitrogen. 
