Small, Sidney Aylmer, 1876- [from old catalog] · Chicago, F. J. Drake & co · leaf 156
pointedii° east of north, it gradually swung over till in 1657 itpointed true north, it kept on till in 1816 it pointed 240west of north and then it swung back so that in 1907 itpoints about 150 west of north. It seems as if it tookabout 320 years to make a complete swing. Question 24. What name is… … Fig. 72. Dipping Needle. Question 25. What is a compass? Answer. The usual compass is a magnetic needle sus-pended over a card bearing the names of the points ofthe compass and sometimes the 3600 of the circle aremarked out. Fig. 71. 155 ELEMENTARY ELECTRICITY Question 26. Why do home made…
Electricity
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