Fig. 17. A Magnet
"Well, is magnetism the same as electricity?"
"Both exhibit the same manifestations. Magnetism is nothing more than a body charged with electricity. The electricity, which appears to travel around the conductor (A), extends out for some distance from its body, and produces what is called a magnetic field. This is the case whether the magnet is a permanent one, like the earth, or whether the conductor is charged by a dynamo."
"What is the difference between the north and the south pole?"
"There is really no difference. The terms north or south and positive or negative are mere relative designations, and are distinguished simply by the movement or direction of the travel of the current. You will remember when we made the battery, it was shown that the current, outside of the battery, moved from the positive to the negative pole. That was merely stating that it moved from the north to the south pole outside of the earth, and from the south to the north pole inside of the earth. The current is, therefore, from one magnetic pole to the other."
"What I cannot understand is why the magnetic poles should be at the north pole and at the south pole."
"The magnetic poles are not at the poles of the rotation of the earth, but hundreds of miles away, to one side of the poles on which the earth rotates; but they are near enough to the real poles, for all purposes, so that the needle points to what we call the north pole of the earth. Any magnetized body must have these two opposite poles. If it is a body, like a bar of iron, one end is called north and the other south. Look at this other sketch (Fig. 18) and you will see how the currents flow in the two magnets. In this case the large body (E) represents the earth and the small body (M) the magnet. Now notice that the current going around the large body moves to the right, or to the north pole, whereas the current in the small magnet (M) flows in the opposite direction."