Chapter 451

(780/1. Mr. Popper had written about a proposed flying machine in which birds were to take a part.)

Down, February 15th, 1881.

I am sorry to say that I cannot give you the least aid, as I have never attended to any mechanical subjects. I should doubt whether it would be possible to train birds to fly in a certain direction in a body, though I am aware that they have been taught some tricks. Their mental powers are probably much below those of mammals. It is said, and I suppose truly, that an eagle will carry a lamb. This shows that a bird may have great power for a short distance. I cannot remember your essay with sufficient distinctness to make any remarks on it. When a man is old and works hard, one subject drives another out of his head.