Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.
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is termed resinous, since on each of these bodies, although electrized in the same manner as exactly as possible, the effect of the former is repulsive, and that of the latter is attractive. As experiments teach us that all bodies in nature upon being rubbed acquire one or the other of these two electricities, the following law is deduced : — 1. That there is an attraction between two bodies electrized, the one as by glass, the other as by wax. 2. That there is attraction between an electrized body and a body that is not so. 3. That there is a repulsion between two bodies that are elec- trized by the same source of electricity, and consequently if pos- sessed of the same kind of electricity, whether that be positive or negative. Dynamic Electricity. While the naturalization of an appreciable electricity is being brought about, either through the air as a spark, or invisibly through a conductor, it is said to be in a dynamic condition, for it is moving. This term is therefore applied to all electricity in motion, as where the positive and the negative are supposed to be travelling towards each other through a conductor, and consti- tuting a current, and at the same time neutralizing each other. This denomination includes therefore all electricities that are not included in the denomination of static, as before mentioned; but we must here except natural electricity. The dynamic state of a given electricity may be only instan- taneous, or it may be more or less continuous. It is instantaneous when there is an electric discharge, and consequent neutraliza- tion of the accumulation; or it is continuous where there is a source of constantly renewing supply, as through a closed con- ductor of a battery, and this is termed the continuous dynamic condition, or electric current; and hence we say that the con ductors, and whatever body is included between the poles of those conductors of a battery, are traversed by a current. And here lies the gist of the whole matter: the works that can be accomplished between these two tips of wires, called poles,