Now the first poker is charged, it contains electricity, its particles are twisted. What effect will it have on the second poker?
It is found that the second poker undergoes a certain change, but when it is removed to a distance from the first poker all trace of this change disappears.
On the end nearest the first poker—on the handle—is found silk electricity; on the end furthest from the first poker—on the black end—is found glass electricity.
A BC D
+ +- +
Let A B be one poker, the + representing the charge of glass electricity. Let C D represent the other poker, the - representing the induced silk electricity, the + the glass electricity in it.
Let A be the handle of the first, B its black end. Let C be the handle of the second, and D its black end. To explain this let us bring in our imaginary principle. Let us suppose that when a charged body is brought near an uncharged body, but is separated from it by some medium through which electricity cannot pass—let us suppose that by some agency the twist in the charged body calls up an image twist in the body opposite it. Thus, due to the twist in the first poker there will be an image twist in the handle part of the second poker.
But the strings of particles in the second poker are not twisted as a whole; they are twisted in such a way that if they are removed from the first poker, the twist, whatever it be, disappears.
Now this would obviously be effected if we suppose the same thing to go on in the second poker as took place between the first poker and the second. Let the twist in the handle end C of the second poker be accompanied by the production of an image twist in the black end D. And let us take this as a fair account of our observations. If a body, which as a whole does not undergo a twist, has one part of it twisted, then there will be the image twist in the other part of it. I say that the poker as a whole is not twisted, and all that this means is that if it be removed from the electrical influence it is found to be not charged; and the idea which we may form is this: the strings of particles are twisted like the two strips of paper round the pencil; they are twisted so that they will exactly unwind if left alone.
Now of course all these suppositions are merely provisional, and must be dismissed unless seen to be mechanically possible; but for the present we are trying to see if our assumption will fit in with facts. And our assumption is that there is in nature a power which amongst the molecules produces that as a real thing which in our larger mode of existence only occurs as a simulacrum and appearance. Our looking-glass images are not real, but we suppose that real images are produced amongst the molecules.[3]
We have seen that if we make a certain supposition as to the calling up of an image twist by a twist of molecular matter, then the main facts of electricity are capable of an explanation, which, involving merely the motion of ordinary matter, is far preferable to the idea of there being a mysterious fluid, and more in harmony with our present ideas of electricity.