Modern electricity and magnetism, theoretically and practically considered (1885)
Avery, Elroy M[cKendree], 1844- [from old catalog] · New York and Chicago, Sheldon and company · leaf 16
or a common lath. The end ofthe stick may be made to follow therubbed rod round and round. Place theblackboard pointer or other stick in awire loop (Fig. 121) or stiff paper stirrup suspended by a stout silk threador narrow silk ribbon. It may be madeto imitate the actions of the balancedstraw or…
Electricity · Magnetism
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