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 152
entfrom some office. When an operator,in sending a message, opens his key,the breaking of the circuit stops thecurrent, demagnetizes the relays andallows their springs to draw back thearmature levers, e. This breaks eachlocal circuit and demagnetizes eachsounder, the spring of which raisesits… … Fig. 231.
Electricity · Magnetism
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