It will be well now to turn for a few moments to the gas obtained by cracking the light petroleum oils by themselves.  The Russian and American petroleum differ so widely in composition that it was necessary to see in what way the gases obtained from them differed; and to do this, equal quantities of American naphtha and a Russian naphtha were cracked, by passing through an iron tube filled with coke, and in each case heated to a cherry red heat, the gases being measured, and then analyzed, with the following results: 

American.   Russian. 
No. of cubic feet per gallon...    72       104
——­      ——­
Hydrogen.......................   26.0      45.3
Methane........................   41.6      22.3
Ethane.........................   12.5      13.9
Olefines.......................   14.1      11.6
Carbon monoxide................    3.3       3.5
Carbon dioxide.................    1.7       2.3
Oxygen.........................    0.8       1.1
Nitrogen.......................    Nil.       Nil.
-----     -----
100.0     100.0

Showing that, if the Russian oil is a little lower in illuminants, it quite makes up by extra volume, but it seemed to me to deposit a much larger proportion of carbon.

Taking 21/2 gallons of American naphtha, it would give roughly 180 cubic feet of gas of the above composition, while the remaining gas would be the ordinary water gas.  Taking the analysis of this as given, and calculating from it what would be the composition of a mixture of it with the naphtha gas, we obtain: 

Calculated.   Actual. 
Hydrogen......................  47.09       42.09
Methane.......................   5.48       11.27
Olefines......................   2.53        7.59
Ethane........................   2.17        6.32
Carbon monoxide...............  30.07       18.65
Carbon dioxide................   3.78        2.32
Oxygen........................   0.56        0.17
Nitrogen......................   7.17        8.25
Sulphureted hydrogen..........   1.15        2.84
------      ------
100.00      100.00

Showing how great the effect is of the diluents in the water gas in preventing the overcracking of the hydrocarbons, as shown by the increase in the percentage of them present in the finished gas; while the enormous reduction in the amount of carbon monoxide present is due to the interaction between it and the paraffin hydrocarbons in the presence of red-hot carbon, a point which makes the Van Steenbergh apparatus enormously superior to any of the superheater forms of plant.

After all said and done, however, the reactions taking place, although they have an intense fascination for the chemist, are not the factors which the gas manager deems the most important, the cost of any given process being the test by which it must stand or fall; and it will be well now to consider, as far as it is possible, the expense of enriching coal gas by the various methods I have brought before you.