esigned to do
so, and the Surfaces and also the controls (the Rudder, Ailerons, and
Elevator) will be working efficiently; but its attitude relative to
the earth will probably be more or less upside-down, for the action
of turning the Aeroplane's nose down results, as you will see by the
illustration B, in the right wing, which is on the outside of the
circle. travelling through the air with greater speed than the left-hand
wing. More Speed means more Lift, so that results in overturning the
Aeroplane still more; but now it is, at any rate, meeting the air as it
is designed to meet it, and everything is working properly. It is then
only necessary to warp the Elevator, as shown in illustration C, in
order to bring the Aeroplane into a proper attitude relative to the
earth."

"Ah!" said the Rudder, looking wise, "it's in a case like that when I
become the Elevator and the Elevator becomes me."

"That's absurd nonsense," said the Blackboard, "due to looseness of
thought and expression."

"Well," replied the Rudder, "when 'the Aeroplane is in position A and I
am used, then I depress or ELEVATE the nose of the machine; and, if the
Elevator is used, then it turns the Aeroplane to right or left, which is
normally my function. Surely our roles have changed one with the other,
and I'm then the Elevator and the Elevator is me!"

Said Lateral Stability to the Rudder, "That's altogether the wrong way
of looking at it, though I admit"--and this rather sarcastically--"that
the way you put it sounds rather fine when you are talking of your
experiences in the air to those 'interested in aviation' but knowing
little about it; but it won't go down here! You are a Controlling
Surface designed to turn the Aeroplane about its vertical axis, and the
Elevator is a Controlling Surface designed to turn the Aeroplane about
its lateral axis. Those are your respective jobs, and you can't possibly
change them about. Such talk only leads to confusion, and I hope we
shall hear no more of it."

"Thanks," said Efficiency to Lateral Stability. "And now, please, will
you explain your duties?"

"My duty is to keep the Aeroplane horizontal from Wing-tip to Wing-tip.
First of all, I sometimes arrange with the Rigger to wash-out, that is
decrease, the Angle of Incidence on one side of the Aeroplane, and to
effect the reverse condition, if it is not too much trouble, on the
other side."

"But," objected Efficiency, "the Lift varies with the Angle of