The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 131
,5 M R Q F Fig. 110.—Full size tects the apparatus from small currents of considerableduration. Fig. 109 gives a section of the fuse tube, and Fig.110 an enlarged section of the lower part. … M ETA l COVE-R
Telephone
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