alike caused by its cycle. One cylinder and piston suffices to carry out
its whole action. Its cycle is: First outstroke, gas and air sucked into
the cylinder; first instroke, gas and air compressed into space; second
outstroke, impulse due to ignition; second instroke, discharge of
exhausted gases. When working at full power, it gets one impulse for every
two revolutions; this seems to be a retrograde movement, but,
notwithstanding, the advantages obtained are very great. The igniting
arrangement is in the main similar to that used on the rack and clutch
engine. The engine has been exceedingly successful, and is very
economical. The Otto compression engine consumes 21 cubic feet of gas per
I.H.P. per hour, and runs with great smoothness.

In 1876 I commenced my work upon gas engines, and very soon concluded that
the compression system was the true line to proceed upon. It took me two
years to produce a workable engine. My efforts have always been directed
toward producing an engine giving at least one impulse every revolution
and, if possible, to start without hand labor, just as a steam engine
does. My first gas engine was running in 1878, and patented and exhibited
in 1879. It was first exhibited at the Kilburn Royal Agricultural
Society's show.

This engine was self-starting, gave an ignition at every revolution, and
ignited without external flame. It consisted of two cylinders, a motor,
and a compressing pump, with a small intermediate reservoir. Suitable
valves introduced the mixture of gas and air into the pump, and passed it
when compressed from the reservoir to the motor cylinder. The igniting
arrangement consisted of a platinum cage firmly fixed in a valve port;
this cage was heated in the first instance by a flame of gas and air
mixed; it became white hot in a few seconds, and then the engine was
started by opening a valve.