[LB040339], Letter from Alfred Ord Tate to E A Bowers, May 3rd, 1890
https://edisondigital.rutgers.edu/document/LB040339
Transcription
May 3, 1890 Mr. E.A. Bowers, 1117 Tenth Street, N.W., Washington, D.C. Dear Sir:- In reply to your letter on 21st ultimo addressed to Mr. Edison, would say that, with the quad. in proper adjustment the polarity of the polar relay is not affected by the operation of the home key only, for the reason that the hime key sends no current through it. But when home and distant keys are simultaneously depressed, polar relay reverses under combined action of both. Yours very truly, A.O. Tate Private Secretary