The leading theory suggests that lodestones are magnetized by the strong magnetic fields surrounding lightning bolts.

And what we need to do is reconnect with those really primal parts of ourselves and make some decisions and say, You know, I think I would like to put CDs across the wall there.

From these experiments, he concluded that the Earth was itself magnetic and that this was the reason compasses point north (previously, some believed that it was the pole star (Polaris) or a large magnetic island on the north pole that attracted the compass).