Astronomer and aeronautical pioneer, he was later Secretary of the Smithsonian Institution. ALS signed 'S. P. Langley,' two pages, 5 x 8, Allegheny Observatory letterhead, May 19, 1884. Letter to a general. In full, 'Let me return my thanks for your kind remembrance of my wishes about the explosion photographs which are at hand. I will venture to assume that I may use these if desirable in a publication unless I hear from you, that is, that there is any objection.' In fine condition, with light brushing to signature due to premature closing of integral first page and some light toning. RRAuction COA.
