arly days of aviation. Anxiously he
wondered "Are tunnels always straight?" and with what relief, keeping
on a straight course, he picked up the line again some three miles
farther on!

Now at last the Pilot sees the sea, just a streak on the north-eastern
horizon, and he knows that his flight is two-thirds over. Indeed, he
should have seen it before, but the air is none too clear, and he is not
yet able to discern the river which soon should cross his path. As he
swiftly speeds on the air becomes denser and denser with what he fears
must be the beginning of a sea-fog, perhaps drifting inland along the
course of the river. Now does he feel real anxiety, for it is the _duty_
of a Pilot to fear fog, his deadliest enemy. Fog not only hides the
landmarks by which he keeps his course, but makes the control of the
Aeroplane a matter of the greatest difficulty. He may not realize it,
but, in keeping his machine on an even keel, he is unconsciously
balancing it against the horizon, and with the horizon gone he is lost
indeed. Not only that, but it also prevents him from choosing his
landing-place, and the chances are that, landing in a fog, he will smash
into a tree, hedge, or building, with disastrous results. The best and
boldest pilot 'wares a fog, and so this one, finding the conditions
becoming worse and yet worse, and being forced to descend lower and
lower in order to keep the earth within view, wisely decides to choose
a landing-place while there is yet time to do so.

Throttling down the power of the engine he spirals downwards, keenly
observing the country below. There are plenty of green fields to lure
him, and his great object is to avoid one in which the grass is long,
for that would bring his machine to a stop so suddenly as to turn it
over; or one of rough surface likely to break the under-carriage. Now is
perfect eyesight and a cool head indispensable. He sees and decides upon
a field and, knowing his job, he sticks to that field with no change of
mind to confuse him. It is none too large, and gliding just over the
trees and head on to the wind he skilfully "stalls" his machine; that
is, the speed having decreased sufficiently to avoid such a manoeuvre
resulting in ascent, he, by means of the Elevator, gives the Aeroplane
as large an angle of incidence as possible, and the undersides of the
planes meeting the air at such a large angle act as an air-brake, and
the Aeroplane, skimming over the ground, lessens its