It has been already proved, that when the globe is put in motion, and your hand is applied to it, it grinds to pieces the air between the globe and the hand, and so rarefies and expands it, and sends it off with great force, in the same manner, as light is sent from any body of fire in action; as may be seen, if the electrical machine is set at work in the dark; when the emission from the glass globe will appear lucid.
The wires which are hung over the glass globe, by the smallness of their pores, admitting nothing through them but light, and light being a body so subtil, as to penetrate the pores of all other bodies, even to the very center of the earth; the interstices of the wires are filled with it from one end to the other.
As the light is one continued body, throughout the whole extent of the wire, the force it receives at the end next the glass globe, is immediately, and at the same instant of time, communicated to the other end, let the length or extent of the wire be ever so great. As, for example, a pipe of any length, being filled with any sort of fluid, as water; if you force in more water at one end, the same moment, and in the same quantity, it will be forced out at the other.
By these experiments in electricity, we find that fire and light are produced as has been before observed, only by breaking the air to pieces, and putting it in motion; and that fire and light are in all bodies, water and ice not excepted; for, if a piece of ice is hung at the end of the wire, it will set fire to spirit of wine, as well as an egg.
The iron wire by the closeness of its pores prevents the surrounding air from entering it, and by that means at the same time forms a kind of canal for the light to pass through.
Having thus as I conceive, given a tolerable clear account, and, I hope, a true one, how and by what means, the various phænomena in electricity are produced; I suppose, it will not be a very difficult task, to form a judgment, what disorders electrical operations are likely to be applied to, with hopes of service; as also in what others they are likely to be detrimental.
As the heat and redness of the blood, may be easily proved, to be in proportion to the quantity and motion of the light it contains; so, wherever the blood is heated to a great degree, as in fevers, Inflammations of all kinds &c. there we are to expect the worst and most pernicious consequences, from the use of electricity.
But, on the contrary, as the nerves have been proved to act by a subtil fluid that passes through them, and that they, by the closeness of their pores, will not admit a fluid to pass through them, whose particles are much larger than those of light; the consequences we must often expect from such a make, must be obstructions; and as the light in electricity is forced through our bodies and nerves, with great violence, it seems very reasonable to think, that where these obstructions are not too violent, there they may be broken through and removed by its power, of which we have had many instances, especially in palsies.
This is also confirmed by the success of the present practice of physick; for, the greatest relief, in these cases, is always found to proceed from volatile and penetrating medicines. But, care should be taken, not to administer electricity, to a person of weak and decayed nerves, instead of one whose nerves are obstructed.
FINIS.