cast on, nor any water jacket,
for they thought the engine would be kept cool merely by being placed in
the open air. The front end of the engine was secured to the vehicle by
four bolts which passed through the halves of the bearings and onto four
projections on the open end of the engine. As the crankshaft of this
engine was retained in constructing the present engine, it is logical
to assume that the bearings were the same also. The head was cast as a
thick disc, with both intake and exhaust valves located therein, and was
bolted onto the flanged head end of the engine.

Inside the cylinder was the strange arrangement previously suggested by
C. E. Hawley. To the connecting rod was attached a rather ordinary
ringed piston, over which was fitted a free, ringless piston, machined
to fit closely the cylinder bore. This floating piston could move freely
a distance equal to the compression space. The intention was that on the
intake stroke, suction would open the intake valve, which had no
positive opening arrangement, and draw in the mixture which then was
compressed as in a regular Otto engine. Fired by the hot-tube ignition
system, the force of the explosion would drive both pistons down,
forcing the outer one tight against the head of the smaller one, and at
the end of the stroke the longer wall of the outer piston would strike
an arm projecting into the cylinder near the open end, moving forward
the exhaust valve rod to which the arm was attached, thus pushing open
the valve in the head.[13] On the exhaust stroke the unrestrained outer
piston moved all the way to the head, expelling all of the products of
combustion and pushing the exhaust valve shut again. With a bore of four
inches or less, this engine, Charles believed, should develop about
three horsepower and run at a speed between 350 to 400 revolutions per
minute.[14]

As no ignition system had yet been provided, they prepared a 4-1/2-inch
length of one-quarter inch iron pipe, closed at one end, and screwed the
open end into the head. Heating this tube with an alcohol burner would
cause ignition of the mixture when a portion of it was forced into the
heated tube toward the end of the compression stroke. No attempt was
made at this time to use the electrical make-and-break circuit used in
their second engine, as the free piston would have wrecked the igniter
parts on the exhaust stroke, and the push rod located on the end of the
piston would have prevented the