by a gust of air the Aeroplane is blown out of its course
and points in another direction, it doesn't immediately
fly off on that new course. I'm so strong I pull it off the
new course to a certain extent, and towards the direction
of the old course. And so it travels, as long as my strength
lasts, in a more or less sideways position.''

``Then,'' said the Keel-Surface, ``I get a pressure of
air all on one side, and as there is, in effect, most of me
towards the tail, the latter gets pressed sideways, and the
Aeroplane thus tends to assume its first position and course.''

``I see,'' said Efficiency, and, daintily holding the Chalk,
she approached the Blackboard. ``Is this what you mean?''

``Yes, that's right enough,'' said the Keel-Surface, ``and
you might remember, too, that I always make the Aeroplane
nose into the gusts rather than away from them.''

``If that was not the case,'' broke in Lateral Stability,
and affecting the fashionable Flying Corps stammer, ``it
would be a h-h-h-o-r-rible affair! If there were too much
Keel-Surface in front, then that gust would blow the Aeroplane
round the other way a very considerable distance.
And the right-hand Surface being on the outside of the turn
would have more speed, and consequently more Lift, than
the Surface on the other side. That means a greater proportion
of the Lift on that side, and before you could say
Warp to the Ailerons over the Aeroplane would go--probable
result a bad side-slip''