Chicago, October 10, 1901
I have read with very great interest your letter of 6th and greatly esteem your ingenious experiments on air reactions. I can find no fallacy in your methods. I find however that Lilienthal's coefficients were obtained in natural wind, which he claims to give much greater values than for the same surfaces driven in still air. I am endeavoring to get a blueprint of his Plate VII to enclose in this letter.
Whether there is any other cause for the discrepancies you have found, I will now proceed to enquire. I have in past years gathered some materials on air resistances, and these will be at your service.
I will tomorrow write you at greater length, as I find I cannot get the blueprint today.
Chanute's next letter to Wilbur, October 12, 1901