. Practical wireless telegraphy; a complete text book for students of radio communication . ation will disappear and there will pass through the conductora momentary electric current. There are other elements which whenrubbed together will produce static chargesof electricity, but the foregoing exampleis sufficient to illustrate the for the production of electro-motive force by friction are known asstatic or frictional machines but since theybear no particular relation to the principlesinvolved in the functioning of wireless tele-graph apparatus, a description will not begiven.
. Practical wireless telegraphy; a complete text book for students of radio communication . ation will disappear and there will pass through the conductora momentary electric current. There are other elements which whenrubbed together will produce static chargesof electricity, but the foregoing exampleis sufficient to illustrate the for the production of electro-motive force by friction are known asstatic or frictional machines but since theybear no particular relation to the principlesinvolved in the functioning of wireless tele-graph apparatus, a description will not begiven. 14. Electricity by Chemical Action(Primary or Secondary Batteries).— A convenient and practical appar-atus for settingup a steady electro-motive force is the electrochemicalcell which consists of two dissimilarelements, in other words, two un-like metals immersed into a diluteacid or alkali solution. A simple cell, for example, consists ofstrips of zinc and carbon immersed in aconducting solution of sal ammoniac (am-monium chloride) as in Fig. 3. If the Fig. 3—Simple Electric 6 PRACTICAL WIRELESS TELEGRAPHY exposed terminals of these plates are joined by a metallic conductor, the cell is capable ofsupplying a continuous flow of electricity through the wire. It is observed as the currentflows that the zinc strip wastes away, in fact, the consumption of the zinc furnishes the electro-motive force necessary to drive the current through the cell and through the external chemical changes within the cell, consisting of copper and zinc strips immersed in adilute solution of sulphuric acid may be briefly described as follows: When the copperand zinc strips are connected together by a metallic circuit and the current begins toflow, the sulphuric acid attacks the surface of the zinc plate and forms a compound knownas sulphate of zinc. During the formation of this sulphate some of the hydrogen containedin the sulphuric acid is liberated in the form of bubbles which
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
