Lessons in elementary physics / by Balfour Stewart.

Balfour Stewart

Date:: 1895

Credit: Lessons in elementary physics / by Balfour Stewart. Source: Wellcome Collection.

469/502 page 449

$armature will thence continue to vibrate backwards and forwards as long' as the key is pressed. When one bell has to be rung from several places (i, 2, 3) the circuits are arranged as seen in Fig. 145. At each of Fig. i45«. Fig. 145. these places a simple key (Fig. 145(1) called a push is placetl. It consists of a spring a of German silver which, when the button b is pressed, is brought into contact with a lower strip i', also of German silver. 440. Telegraphy.—With the aid of two different kiiuls of signals a code has been arranged very suitable for the purpose of communication to a distant place by electrical means. The code is known as the International Morse. It is based on the A \/ J x/// S w\ B Aw K A/ t/ _ c A/\ L \A\ u w/ D A\ IVI // V V«\/ E \ N A W \// F \\A 0 /// X A\/ G /A p \/A Y A// H \W\ 1 W . - Q /A/ R \A z /Av Fig. 146. use of ihc movcuumls lo Ihe left aiul right of .a g.ilvanomelcr needle, or on the length of lime the current is .dlowed to How, a short tiim- being denoted by a do! ;md a longer time by a </a.r/i equal In iluralioii to thn-e tiots. I low these signals are conibiiu-il to form at) alph.abet is shown in Fig. npj. (J G$

Lessons in elementary physics / by Balfour Stewart.

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