Allen, Charles Ricketson, 1862- [from old catalog] · New York, H. Holt and company · leaf 237
Fig. 105. I. A support is made of glass tubing or rod bent into theform shown in Fig. 105. This is set into a support of wood about4 in. square and i in. thick (a piece of a cigar-box for example),to which it may be more firmly attached with sealing-wax. Fromthis support a magnetized… … Fig. 107. 3 x 4 in.; supports 3 in. high. Pins driven into the base preventthe needle from swinging too far. The needle is loaded and sus-pended as in I. III. A temporary substitute for a compass may be constructedby suspending the needle from the bottom of an inverted tumbleras in Fig. 107. The…
Physics
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