St. John, Thomas M. (Thomas Matthew), b. 1865 · New York, T. M. St. John · leaf 26
be made from a horse-shoe magnet without in-juring it. 31. Magnetic Needlesand Compasses. If abar magnet be suspendedby a string, or floatedupon a cork, which caneasily be done with themagnet made from a sewing-needle. Fig. 24, it willswing around until its poles point north and south. Suchan… … Fig. 25. 24 ABOUT MAGNETS AND MAGNETISM. ular compass, a magnetic needle is supported upon a pivot.Compasses have been used for many centuries b} mar-iners and others. Fig. 25 shows an ordinarj^ pocketcompass, and Fig. 26 a form of mariners compass, inwhich the small bar magnets are fastened to a…
Electricity
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