With the possibility of turning the cancellation of the electrical condition of space into a continuous process, it became possible to observe that the neutralization of electric charges entails the appearance of heat and magnetism. We must now ask which are the qualities of electricity on the one hand, and of heat and magnetism on the other, which account for the fact that where electricity disappears, the two latter forces are bound to appear. Since magnetism is the still unknown entity among the three, we must now deal with it.