. Medical electricity; a practical treatise on the applications of electricity to medicine and surgery. y even be short circuited for days withoutimpairing its strength, whereas a Leclanche or a Partzwould run down in a few hours under these batteries are portable or permanent. Theportable consist of small elements (Smee, Grenet, Stohrer,etc.) and a single fluid, and are so arranged that the ele-ments can be lowered into or raised out of the exciting fluidwhen not in use (see Fig. 18). The permanent batteriesare composed of large cells with two fluids, and are fixedin so
. Medical electricity; a practical treatise on the applications of electricity to medicine and surgery. y even be short circuited for days withoutimpairing its strength, whereas a Leclanche or a Partzwould run down in a few hours under these batteries are portable or permanent. Theportable consist of small elements (Smee, Grenet, Stohrer,etc.) and a single fluid, and are so arranged that the ele-ments can be lowered into or raised out of the exciting fluidwhen not in use (see Fig. 18). The permanent batteriesare composed of large cells with two fluids, and are fixedin some convenient position. Whether movable or not, abattery of many elements requires mechanical contrivancesfor working it. The portable batteries are fitted with amovable selector, which is so arranged that various num-bers of cups can be interpolated in the circuit. Permanentbatteries are arranged in combinations, and are worked bya pole-board on which are placed brass knobs communicat-ing with the various sets or combinations of cups (Fig. 29). Fin. 2q. 9 9 ? o » © to # «» 0. Flemmings key-board. These sets are on one side usually from one to ten, and onthe other from ten to fifty, sixty, ninety, or any other num- 60 ELECTRO-PHYSICS. ber of cups of which the battery may be composed. Bymeans of a selector any possible number of cups from oneup to the limit of the battery may be selected for the desiredapplication. The pole-board should also contain a polaritychanger, an arrangement for quickly changing the poles,a commutator, and an interrupter (rheotome), whichmay run either by clock-work or by an electro-magnet, forinterrupting the current slowly or quickly as may be neces-sary. Besides these, pole-boards are usually supplied witha galvanometer, a rheostat, or resistance coils. The ordi-nary galvanometer, which, theoretically, measures the forceof the current, does not actually afford constant and relia-ble indications, and can be depended on only to indicatethe direction
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectelectro, bookyear1887
