heavier engines, and that in a way plays into the hands of
our enemy, Gravity, besides necessitating a larger Surface
or Angle to lift the Weight, and that increases the Drift.''

``Very well,'' from Efficiency, ``I'll do my best, though
I'm so shy, and I've just had such a bad time at the Factory,
and I'm terribly afraid you'll find it awefully dry.''

``Buck up, old dear!'' This from several new-comers,
who had just appeared. ``We'll help you,'' and one of
them, so lean and long that he took up the whole height of
the lecture room, introduced himself.

``I'm the High Aspect Ratio,'' he said, ``and what we
have got to do to help this young lady is to improve the
proportion of Lift to Drift. The more Lift we can get for a
certain area of Surface, the greater the Weight the latter
can carry; and the less the Drift, then the less Thrust and
Power required to overcome it. Now it is a fact that, if
the Surface is shaped to have the greatest possible span,
i.e., distance from wing-tip to wing-tip, it then engages more
air and produces both a maximum Reaction and a better
proportion of Lift to Drift.

``That being so, we can then well afford to lose a little
Reaction by reducing the Angle of Incidence to a degree
giving a still better proportion of Lift to Drift than would
otherwise be the case; for you must understand that the
Lift-Drift Ratio depends very much upon the size of the
Angle of Incidence, which should be as small as possible