[D9202ABJ], Letter from Smithsonian Institution, Samuel Pierpont Langley to Thomas Alva Edison, June 16th, 1892
https://edisondigital.rutgers.edu/document/D9202ABJ
Transcription
June 16, 1892 Received June 20 1892 Ans’d Sept 14 1892 My dear Mr. Edison: In accordance with your kind permission, I forward to your laboratory four small galvometer mirrors to be platinized. They are all optically correct and quite valuable little pieces, having been selected from a large number. Three are quite small, being one centimetre each in diameter; these are to be platinized only on the polished, concave side. The fourth is a somewhat larger one, two centimetres in diameter, and is to be platinized on both sides. Please bear in mind the importance of not depositing the platinum thickly, but only in the very/thinnest layer which will make a good reflecting surface. I shall be very glad to get these as soon as you may be pleased to authorize their construction. With renewed thanks for your kindness, I am Very truly yours, S.P. Laugley Secretary Thomas A. Edison, Esq., Orange, N.J. Mr. Maguire The mirrors are finished and ready to be sent back to. San Tart[?] Washington. I could be better with the smallest ones, if the glass were polished from. The first pealinizing has spoiled them. Chas Werth