They had to practise for two or three years before they were
satisfied with the results of their experiments: neglecting no
detail, profiting by their failures, and moving logically from
step to step. They never attempted an experiment rashly: there
was always a reason for what they did. In fact, their success
was due to systematic progress, achieved by wonderful
perseverance.

But now, for a short time, we must leave the pioneer work of the
Wright brothers, and turn to the invention of the petrol engine
as applied to the motor car, an invention which was destined to
have far-reaching results on the science of aviation.



CHAPTER XX
The Internal-combustion Engine

We have several times remarked upon the great handicap placed
upon the pioneers of aviation by the absence of a light but
powerful motor engine. The invention of the internal-combustion
engine may be said to have revolutionized the science of flying;
had it appeared a century ago, there is no reason to doubt that
Sir George Cayley would have produced an aeroplane giving as good
results as the machines which have appeared during the last five
or six years.

The motor engine and the aeroplane are inseparably connected; one
is as necessary to the other as clay is to the potter's wheel, or
coal to the blast-furnace. This being the case, it is well that