some hundreds of horse power for use on board ship, to be supplied with
gas from one of his gas producers modified to suit the altered
conditions.

Summarizing the ground over which we have passed, we find the origin of
the gas engine in the minds of the same men as were first to propose the
steam engine, Huyghens and Papin, 1680 and 1690. Greater mechanical
difficulties and ignorance of the nature of explosives caused the
abandonment of the internal combustion idea, and the mechanical
difficulties with steam being less, the steam engine became successful,
and triumphed over its rival. The knowledge and skill gained in the
construction of steam engines made it possible once again to attack the
more difficult problem, and simultaneously with the introduction and
perfecting of the steam engine, the gas engine idea became more and more
possible, the practicable stage commencing with Lenoir and continuing with
Hugon, Millein, Otto and Langen, F.H. Wenham, then Otto and Clerk. In
1860, 95 cubic feet of gas produced one horse power for an hour; in 1867,
40 cubic feet accomplished the same thing; and now (1885) we can get one
horse power for an hour for from 15 to 20 cubic feet of gas, depending on
the size of the engine used.

Considered as a heat engine, the gas engine is now twice as efficient as
the very best modern steam engine. It is true the fuel used at present
is more expensive than coal, and for large powers the steam engine is
the best because of this. But the way is clearing to change this. Gas
engines as at present, if supplied with producer gas, produced direct
from coal without leaving any coke, as is done in the Siemens, the
Wilson, and the Dawson producers, will give power at one-half the cost
of steam power. They will use 7/8 of a pound of coal per horse power per
hour, instead of 1-3/4 lb., as is done in the best steam engines. The