St. John, Thomas M. (Thomas Matthew), b. 1865 · New York, T. M. St. John · leaf 89
?ig. 109. … current passes through the coils the armature comesdown until a stop-screw strikes firml} upon the metalframe, making the down click. As soon as the distant THE EI.ECTRIC TELEGRAPH. 87 key is raised, the armature is firmly pulled back andanother click is made. The two clicks differ in sound,and can…
Electricity
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