the consumption of a gallon of the same oil, so that the cost would be
a shade higher, all other factors remaining the same, while with the
Van Steenbergh process both grade of oil and consumption of fuel vary
from either of these processes. In order to obtain a thousand cubic
feet of 22-candle gas, two and a half gallons of the lighter grade oil
would be consumed, and I am informed that there is now no difficulty
in obtaining oil of the right grade in London in bulk at 4d. per
gallon, which would make the cost:

s. d.
Two and a half gallons of oil........... 0 10
Thirty pounds of coke................... 0 21/4
Labor and purification.................. 0 2
Charge on plant......................... 0 03/4
------
1 3

And the enriched coal gas would, therefore, cost 1s. 3/4d. per thousand,
the extra 11/2-candle power having been gained at an expense of 3/4d. or
1/2d. per candle.

Tabulating these results we have--Cost of enriching a 16-candle gas up
to 17.5 candle power per 1,000 cubic feet by cannel coal, 4d.; by
Maxim-Clarke process, 2-6/10d.; by Lowe or Springer water gas, 11/2d.;
by Van Steenbergh water gas, 3/4d.

In reviewing this important subject, and bringing a wide range of
experimental work to bear upon it, I have, as far as is possible,
divested my mind of bias toward any particular process, and I can
honestly claim that the fact of the Van Steenbergh process showing