Thus the air of the sky literally permeates the bird, flesh and bone alike, and aerates it entire. And the circulation of sky through the whole bird acts as a radiator or cooling system of the flying ...

Ch. 1. Evolution of the two-surface flying machine -- ch. 2. Theory development and use -- ch. 3. Mechanical bird action -- ch. 4. Various forms of flying machines -- ch. 5. Constructing a gliding ...