. A treatise on electrolysis and its applications to therapeutical and surgical treatment in disease . of the earliest and simplest mechanical forms of resistance coil, orRheostat (flow-arrester), is that which was invented by Wheatstone (illus-trated in Fig. 12). >In this instrument a longer or shorter piece of wire, made of a feeble?Ganots Physics, 1869, i>. 817. 8(3 ELECTROLYSIS. metal lie conductor (German silver alloy), is interposed in the externalcircuit by winding, or unwinding, from one brass spool on to anotherspool made of insulated material like hard rubber. This coarse metho
. A treatise on electrolysis and its applications to therapeutical and surgical treatment in disease . of the earliest and simplest mechanical forms of resistance coil, orRheostat (flow-arrester), is that which was invented by Wheatstone (illus-trated in Fig. 12). >In this instrument a longer or shorter piece of wire, made of a feeble?Ganots Physics, 1869, i>. 817. 8(3 ELECTROLYSIS. metal lie conductor (German silver alloy), is interposed in the externalcircuit by winding, or unwinding, from one brass spool on to anotherspool made of insulated material like hard rubber. This coarse methodof interposing various amounts of resistance will not produce very nice oraccurate means of measurements, nor is it a convenient instrument forpractical work; it has, therefore, been superseded by other more compactforms of mechanical arrangement which will be obvious from their de-scription, but the principle of these instruments remains the same. Itis not so necessary for medical uses to have an accurate measurement asto have some contrivance of easy application. None are perfectly accurate,. Fig. V2. and the nearer they approach accuracy the more costly they become. Aresistance box which can be made to interpose measured units of resis-tance, within an error of one hundredth of the whole amount used, issufficient for all practical purposes, because the variations in the conduc-tibility of the human body are so great, that an error of an hundredth iscomparatively very small. Oftentimes, a fluid rheostat will answer the purposes equally well;though the action of this form of interposed resistance is objectionable,because it has the disadvantage which arises from a varying amount ofcorrosion, which attacks the metallic conducting surfaces, and will thusproduce irregular obstructions to the transmission of the electrical current,A liquid rheostat can be extemporized out of a short piece of glass tubing,which may be tilled with water to produce high resistances, or, with asoluti
Size: 1538px × 1625px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookidtreatiseonelectr00amorric
