WASHINGTON, D. C., April 16, 1900.
DEAR MR. MANLY:
I am reminded of the consequence that I have, in connection with Mr. Chanute and perhaps Mr. Huffaker, attached in the past to the possibility of directing the bird, and consequently the flying machine, by the mere inflection of the wing, that is, by changing its angle; and you recall to me that Mr. Huffaker at one time proposed to arrange a wing, with some provision of a spring, which should enable it to change its angle automatically. . . . .
I have been noting this ability to guide by the slight inflection of the wing, in my studies of the Jamaica buzzard, and am ready to say that I think, while the quarter-sized working model of the great aerodrome is building, it will be worth while to make some arrangement of the frame or wing-holder which will make it possible to test this idea. I will endeavor to work out something of the kind more in detail myself, but whatever it is, it will apparently involve the ability of the wing to rotate about a line passing nearly through it lengthwise, and an allowance for this; if not in the wing itself, then in the wing-holder; will need to be made while the present model is under construction.
I will request you to especially look out for this, as far as you can on these indications.
Very respectfully yours,
S. P. LANGLEY,
Secretary.
The instructions and suggestions contained in this letter and in many conferences on the subject were never carried out by the writer, on account of the extreme pressure of the work already on him which had for its object, not the production of a flying machine which would embody all of the control which we wished it to have, but which would be burdened only with such devices and arrangements as would enable it to transport a human being, and thus demonstrate the practicability of human flight.
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