ine--is dead. The statements of eyewitnesses, when
taken on such occasions, are often misleading. One person heard a
crash, and saw something fall away from the machine. Another declares
the engine stopped suddenly and that the machine "fell like a stone."
Another says he is sure he saw one of the wings fold upwards and the
machine swing and fall. And so on. It is extremely difficult, even for
a technical eye-witness, to be sure of what he sees when things happen
quickly and at a distance from him; while the statements of
non-technical people, who are not trained in observation, are
generally so unreliable as to be useless.

It has happened often therefore, far too often, in aeroplane
fatalities that have happened from time to time, that the cause of
such accidents has, even after the most careful investigation, had to
be written down a mystery. But in more than a few cases, though the
evidence has been far from conclusive, it has been considered that a
pilot has been guilty of some error of judgment. There were puzzling
instances, notably in the early days of flying, when airmen began
first to make cross-country flights, of engines being heard to fail
suddenly, and machines seen to fall to destruction. That engines
should break down was not surprising; they were doing so constantly;
but there was no reason why, even if they did fail, a machine should
fall helplessly instead of gliding. But what was thought to have
happened, in more than one of these cases, was that the pilot, through
an error of judgment, had failed to get down the bow of his machine
when his motor gave signs of stopping. The craft concerned were, it
should be mentioned, "pusher" biplanes; and the same rule applied to
them, in cases of engine failure, as has been explained in a previous
chapter, and as is emphasised nowadays in the instruction of the
novice. But in those days the beginner had frequently to learn, not
from wise tuition, but from bitter experience; and he was lucky, often,
if he learned his lesson and still retained his life. On certain
early-type biplanes, for instance, machines with large tail-planes,
and engined as a rule by a motor which was giving less than its proper
amount of power, it was most dangerous for a pilot if, on observing
any signs of failing in his engine, he sought to fly on in the hope
that the motor would "pick up" again, and continue its work. Directly
there was a tendency of the motor to miss-fire, or lessen in th