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