American astronomer, physicist, and aviator (1834-1906), who conducted some of the first manned flights with his Army-funded Aerodrome aircraft; he also served as the third secretary of the Smithsonian Institution. TLS signed “S. P. Langley,” two pages on two adjoining sheets, 4.5 x 6.75, Smithsonian Institution letterhead, May 12, 1899. Letter to Mrs. Michaelis, in part: "I have Frank's letter and that of Professor Ames, and as I understand that it will be of service to Frank, I am willing to provide for his having the opportunity to attend to these examination papers on the stated days in June. My intervention, however, Mr. Ames will doubtless understand, will be chiefly formal." In fine condition, with some light soiling to the signed page.