THEORY of Electricity.—The theory most readily understood, and which most satisfactorily explains the various electrical phenomena, is as follows:—
"That every substance and every atom of the world is pervaded by a peculiar, subtle, imponderable fluid which is termed Electricity, but which is not known to exist, or remains in a state of electrical equilibrium, until evoked by certain causes."
The effect of causing a disturbance of this equilibrium is to increase the normal, or natural, electricity in some particles, and to equally decrease it in other particles, i.e. what one loses the other gains. An excess of natural electricity is denoted by the term positive, or mathematical symbol (+) while a deficiency is denoted by the term negative, or symbol (-).
Like electricities repel each other.
That is to say, two bodies charged with an excess of, or positive, electricity, being brought together repel each other, neither wishing to increase the excess that has been evoked in them.
Similarly in the case of two bodies charged with a deficiency of, or negative, electricity, neither wish to add to the deficiency already there.
In both these cases there can be no tendency to electrical equilibrium, which is the principle at work. In the former case, there being already too much, more will but increase the disturbance.
In the latter case, further deficiency will but add to the irregularity.
Unlike electricities attract each other.
That is to say, if two bodies, one charged with positive, or having an excess of electricity, the other charged with negative, or having a deficiency of electricity, be brought together, they will attract each other; both being desirous of altering their existing state, the one by decreasing its excess, and the other by decreasing its deficiency of electricity.