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.”
Samuel P. Langley was an astronomer and theoretical aerodynamics expert who is regarded as one of his era’s most famous and respected scientists. Along with working at the Harvard and Allegheny Observatories studying sunspots, Langley also invented the bolometer (a sensor to detect extremely minute temperature changes) and a steam powered flying machine that accomplished the first unmanned flight of a heavier-than-air flying machine.
It is likely that the “explosion photographs” referred to in this letter are related to Langley’s studies with the bolometer of the spectral measurements of solar and lunar radiation. It was through these studies that Langley was able to calculate the distribution of heat from the sun and determine the effect of various solar rays in relation to the transparency of the atmosphere. A fine artifact from the midst of Langley’s atmospheric explorations. In fine condition, with light brushing to signature due to premature closing of integral first page, scattered light toning, and four pin holes to edge. Pre-certified PSA/DNA and RRAuction COA.
This item is Pre-Certified by PSA/DNA
Buy a third-party letter of authenticity for
$50.00
*This item has been pre-certified by a trusted third-party authentication service, and by placing a bid on this item, you agree to accept the opinion of this authentication service. If you wish to have an opinion rendered by a different authenticator of your choosing, you must do so prior to your placing of any bid. RR Auction is not responsible for differing opinions submitted 30 days after the date of the sale.
