U.S. patents covering time keeping mechanisms (1892)
United States. Patent Office · [Washington : United States Patent Office] · leaf 551
■. NORHI& PCT6RG CO. kHOTOLiTMO. WASHINGTON. O, C. (No Model.) 17 Sheets—Sheet 12. G. E. HUNTER. MECHANISM FOR TESTING WATCH BALANCES AND HAIR SPRINGS. Patented Jan. 17, 1893. No. 490,202, … o
Clocks and watches
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