Experimental science. Elementary, practical and experimental physics (1890)
Hopkins, George M. (George Milton), 1842-1902 · New York, Munn & co. · leaf 656
h the needle. To one of these pins iscemented a thin paper arrowhead, and upon the other pinis placed a small drop of solder to counterbalance thepaper. The compass thus formed is provided with a glass cover,separated from the scale by narrow strips of wood. Thebaseboard upon which the compass is… … ^M^ ^ <^?;^
Physics · Lantern projection · Electric apparatus and appliances
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