49.58 | 57.85| 75.16|
Hydrogen ...........| 20.02| 26.16| 29.03| 35.92 | 9.64| 14.45|
Nitrogen ...........| Nil. | Nil. | Nil. | Nil. | 23.41| 2.89|
Heat units .........|728,746 |698,852 |627,170 |745,813 |592,380 |745,591 |
--------------------+--------+--------+--------+--------+--------+--------+

"We will now show how the natural gas compares with coal, weight for
weight, or, in other words, how many cubic feet of natural gas contain as
many heat units as a given weight of coal, say a ton. In order to
accomplish this end we will be obliged, as I have said before, to assume
as a basis for our calculations what I consider a gas of an average
chemical composition, viz.:

Per cent.
Carbonic acid............................ 0.60
Carbonic oxide........................... 0.60
Oxygen................................... 0.80
Olefiant gas............................. 1.00
Ethylic hydride.......................... 5.00
Marsh gas............................... 67.00
Hydrogen................................ 22.00
Nitrogen................................. 3.00

"Now, by the specific gravity of these gases we find that 100 liters of
this gas will weigh 64.8585 grammes, thus:

Weight,
Liters. grammes.

Marsh gas................. 67.0 48.0256
Olefiant gas.............. 1.0 1.2534
Ethylic hydride........... 5.0 6.7200
Hydrogen.................. 22.0 1.9712
Nitrogen.................. 3.0 3.7632
Carbonic acid............. 0.6 1.2257
Carbonic oxide............ 0.6 0.7526
Oxygen.................... 0.8 1.1468
-------
Total................................... 64.8585

"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...............