Text-book of medical and pharmaceutical chemistry . coil lies very close to and parallel with theadjoining turns of the same wire, and that these consecutiveturns may be considered as constituting a series of parallelwires. In fact, every variation of the current in the wire A B, 66 MEDICAL CHEMISTRY. Fig. 28, generates electro-motive force in the contiguous induced current is thus produced in the wire A B, whichobeys the same laws as that induced in the independent wire,C D, and in the direction opposed to the battery current, whenthe latter is made or increased, and in the same dire
Text-book of medical and pharmaceutical chemistry . coil lies very close to and parallel with theadjoining turns of the same wire, and that these consecutiveturns may be considered as constituting a series of parallelwires. In fact, every variation of the current in the wire A B, 66 MEDICAL CHEMISTRY. Fig. 28, generates electro-motive force in the contiguous induced current is thus produced in the wire A B, whichobeys the same laws as that induced in the independent wire,C D, and in the direction opposed to the battery current, whenthe latter is made or increased, and in the same direction whenit is broken. This current is known as the primary inducedor extra current. During the making or increasing of thebattery current this extra current, acting against tlie batterycurrent, retards or resists it, and hence is not felt at the poles Pand P. At the break this current goes in the opposite direc-tion, and, as there is nothing to resist it, may be felt with itsfull force at P and P. This current is therefore interrupted, Fig. and is felt only at the break of the battery current, and alwaysin the direction of this current. The primary induced, or extracurrent, is feebler than the secondary, because the length of wireacted upon is shorter. As we have just seen, the make extra cur-rent retards the battery current, so that it takes an appreciabletime for this current to attain its maximum force ; and the makeinduced current is weakened in proportion to the longer time re-quired. The secondary current developed at the time of makingthe battery current is therefore weak, and its physiological andchemical effects almost inappreciable. The break, secondary,as well as primary, is developed with its full electro-motive forceinstantaneously ; hence, it alone has an appreciable effect whena resistance such as the human body is put into the circuit. MAGNETISM. 67 71. Influence of the Core.—As we have stated in Art. 54,when a galvanic current is sent through a coil of
Size: 2032px × 1229px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1, booksubjectpharmaceuticalchemistry
