pressure of 40 pounds, that the air and gas might mix properly at the
branch or fork, so we could get the best combustion and most heat from
our "blowpipe," for such it was. (Fig. 32.)

[Illustration: FIG. 31 and FIG. 32]

We were able to heat a tire so it could be moved in ten to twenty
minutes, and the machine may be said to have been satisfactory.

Gas, however, was not to be had at all places where it would be
necessary to change tires, and the item of cost was considerable.

To reach a result as good, if possible, experiments were begun with
coal oil (headlight oil). They were crude and unsatisfactory at first,
but soon success was reached.

A pipe was bent to fit the lower half of a wheel pretty closely and
then turned back under itself about the diameter of the pipe distant
from it. This under part had holes 1/10 in. diameter and 3 or 4 in.
apart drilled upon its upper side or under the upper pipe. Connected
with the upper pipe at its center was a pipe which ran to one side and
up to the can containing the kerosene. Between the can and the pipe
under the wheel was a stop cock, by which the flow of oil could be
controlled.

[Illustration: FIG. 33]

To use the device, open the cock and let a small amount of oil flow;
apply fire to the pipe under the wheel, and the oil in the upper pipe
is converted into gas, which flows out of the small holes in the lower