Experimental science. Elementary, practical and experimental physics (1890)
Hopkins, George M. (George Milton), 1842-1902 · New York, Munn & co. · leaf 645
edto the lantern, has a circular aperturefor the passage of light, and is providedwith two springs for holding twopieces of plate glass connected togetherwith Canada balsam. The upper and inner corners of theglass are beveled up to within a short distance of the ends,forming a groove or trough for… … Brewsters Disk. Fig. 597.
Physics · Lantern projection · Electric apparatus and appliances
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