a fruitful cause of accident, that
structural weakness of machines which has led, when conditions have
been unfavourable, to a sudden collapse in the air. But apart from
weakness in construction, and notably in accidents with early-type
machines, there was the risk attached to mistakes in design, which
produced machines which were unstable under certain conditions--and
the dangers also which were due to inefficient controlling surfaces.
It was no uncommon thing, in pioneer days, for a machine to be built
which would not respond adequately to its elevator or rudder; though
this unpleasant fact might not be discovered by the pilot until he was
actually in flight, and perhaps at some distance from the earth. In
one case, which is authenticated, a two-seated monoplane of a new type
was tested at first in a series of straight flights, and found to be
promising in its behaviour. A skilled pilot then took charge of it,
and, carrying a passenger, proceeded to some more ambitious flights.
Steering the machine away across the aerodrome, and flying at a low
elevation, he approached a belt of woods. The machine was too near the
ground to pass over the tops of the trees; so the aviator decided to
make a turn, and fly parallel with the wood. But when he put his
rudder over, so as to bring the machine round in a half-circle, he
found to his dismay that there was no response. In the design of the
machine, as it was found afterwards, the rudder had been made too
small: it would not steer the machine at all. In the little space that
was left him, and to avoid crashing into the trees, the pilot had to
bring his craft to earth in such an abrupt dive that it was wrecked
completely. He and the passenger, though, escaped unhurt.

Carelessness has, fairly frequently, played its part in aeroplane
disasters. Sometimes a pilot has been careless, or perhaps in a hurry,
and has failed to locate some defect which, had it been seen and
attended to, would have saved a disaster when a machine was in flight.
Such inattention, which is sufficiently dangerous in the handling of
any piece of mechanism, is deadly in its peril when those who are
guilty of it navigate the air. A man who brings out a machine time
after time, and ascends without examining it carefully, is adding
vastly to the risks that may attend his flight; and the same remark
will apply to the carelessness of mechanics; though as a class, in
view of the arduous nature of their work, and of