Twentieth century manual of railway and commercial telegraphy (1905)
Meyer, Frederic Louis, b. 1875 · Chicago, New York, Rand, McNally & Company · leaf 22
h the turns of the wirearound the soft iron cores within, these iron coresbecome magnetized by the inductive influence ofthe electric current and possess the power of attract-ing, with considerable force, the armature or pieceof iron which is kept just short of reaching thepoles or ends of the… … MANUAL OF TELEGRAPHY. 19 LESSON III.Iiistruments Employed. The key is a mechanicaldevice for opening and clos-ing a circuit. Describe its principalfeatures — A metallic leveron a trunnion, supportedby screws in the elevatedFig. 10. The Key. g^^j^g ^f ^ metallic base. On the bottom of this base are…
Telegraph
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