"Then, if we take the heat units of these gases, we will find:


Heat units
Grammes. contained.

Marsh gas................ 48.0256 627,358
Olefiant gas............. 1.2534 14,910
Ethylic hydride.......... 6.7200 77,679
Hydrogen................. 1.9712 67,929
Carbonic oxide........... 0.7526 1,808
Nitrogen................. 3.7630 -----
Carbonic acid............ 1.2257 -----
Oxygen................... 1.1468 -----
------- -------
Totals 64.8585 789,694

"64.8585 grammes are almost exactly 1,000 grains, and 1 cubic foot of
this gas will weigh 267.9 grains; then the 100 liters, or 64.8585
grammes, or 1,000 grains, are 3,761 cubic feet; 3,761 cubic feet of this
gas contains 789,694 heat units, and 1,000 cubic feet will contain
210,069,604 heat units. Now, 1,000 cubic feet of this gas will weigh
265,887 grains, or in round numbers 38 lb. avoirdupois. We find that
64.8585 grammes, or 1,000 grains, of carbon contain 523,046 heat units,
and 265,887 grains, or 38 lb., of carbon contain 139,398,896 heat units.
Then 57.25 lb. of carbon contain the same number of heat units as 1,000
cubic feet of the natural gas, viz., 210,069,604. Now, if we say that
coke contains in round numbers 90 per cent. carbon, then we will have
62.97 lb. of coke, equal in heat units to 1,000 cubic feet of natural
gas. Then, if a ton of coke, or 2,000 lb., cost 10s., 62.97 lb. will cost