Hiscox, Gardner Dexter, 1822?-1908 · New York, The Norman W. Henley publishing co. · leaf 62
he curved slot is made proportionalto the length of the two arms of the pencil lever. 155. AMSLERPLAN-IMETER.—E is the fixedpoint; F the tracer. Thedisc has a sharp edge anda cylindrical section dividedand read from a vernier scale.*A worm screw and indexwheel indicate the number of revolutions of…
Mechanical movements
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