VIII

HOW THE WHEELS WENT ROUND AT LAST


The hush of Christmas Eve lay upon the tumble-down cottage, and on the
soft fresh snow outside, and the lamps were burning quietly in the
workshop, where father and son were sitting before the finished Motor.

The little City was there too, but not between them now, though Newton
had taken off its brown paper cover in honour of the great event which
was about to take place.

In order to be doubly sure of the result, and dreading even the
possibility of a little disappointment, Overholt had decided that he
would subject the only chemical substance which the machine consumed to
a final form of refinement by heat, melting, boiling and cooling it, all
of which would require an hour or more before it was quite ready. He
felt like a man who is going to risk his life over a precipice, trusting
to a single rope for safety; that one rope must not be even a little
chafed; if possible each strand must be perfect in itself, and all the
strands must be laid up without a fault. Of the rest, of the machine
itself, Overholt felt absolutely sure; yet although a slight impurity in
the chemical could certainly not hinder the whole from working, it might
interfere with the precision of the revolutions, or even cause the
engine to stop after a few hours instead of going on indefinitely, as
long as the supply of the substance produced the alternate disturbance
of equilibrium which was the main principle on which the machine
depended.