. The Americana : a universal reference library, comprising the arts and sciences, literature, history, biograhy, geography, commerce, etc., of the world . the receiving operator an ad-vantage over the sending operator who couldonly send from ,30 to 40 words per minute atbest speed. By means of the keyboardtransmitter a speed of transmission approach-ing the speed of transcription by the type-writer is obtained. This use of the type-writer was accompanied by a new arrange-ment of the sounder, which is now placed in abox, or resonator, mounted on an adjustable rodthat brings the sounder in clos
. The Americana : a universal reference library, comprising the arts and sciences, literature, history, biograhy, geography, commerce, etc., of the world . the receiving operator an ad-vantage over the sending operator who couldonly send from ,30 to 40 words per minute atbest speed. By means of the keyboardtransmitter a speed of transmission approach-ing the speed of transcription by the type-writer is obtained. This use of the type-writer was accompanied by a new arrange-ment of the sounder, which is now placed in abox, or resonator, mounted on an adjustable rodthat brings the sounder in close proximity tothe ear of the operator. Lightning Arresters.—Lightning dischargestend to follow telegraph wires into cablesacross rivers, and into the telegraph offices,causing damage to the cables and instru-ments. Damaee is sometimes caused also bythe contact of telegraph wires with electriclight and power wires. To prevent as far aspossible damage from these causes, lightningarresters and fuses are placed at points justoutside of cables and at points where thewires enter offices. A combination lightningarrester and fuse wire is shown in Fig. Fig. 8. Lightning Arrester and Fuse Wire. F is a small fuse wire carried on a strip ofmica m which is tipped with metal at eachend, and held by metal clips 11 n. c repre-sents two small blocks of carbon separatedby a thin sheet of mica, and held in positionby metal tension springs n n. The left-handblock is connected to ground at the post g;the right-hand block is connected to thescrew A from which a wire leads to the ap-paratus. The line wire is connected to thescrew L. A strong current passing throughthe fine wire r will fuse it: a lightning dis-charge will jump to ground by way of thecarbon blocks: in either case protecting thecable or instruments. Telegraph Szvitchboards.— Switchboards are TELEGRAPHY employed in telegraph offices for the pur-pose of facilitating the testing of wires, andthe assignment of different wires to dif
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Keywords: ., bookcentury1900, bookdecade1900, bookidamericanauni, bookyear1903
