The Aeroplane Speaks. Fifth Edition

"My purpose in life, miss," said he, "is to keep the Aeroplane on its course, and to achieve that there must be, in effect, more Keel-Surface behind the Vertical Turning Axis than there is in front of it." Efficiency looking a little puzzled, he added: "Just like a weathercock, and by Keel-Surface I mean everything you can see when you view the Aeroplane from the side of it--the sides of the body, struts, wires, etc." "Oh, now I begin to see light," said she; "but just exactly how does it work?" "I'll answer that," said Momentum. "When perhaps 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."