Book II Chapter 27

The Centre of the Magnetick Virtues in the earth is the centre of the earth; and in a terrella is the centre of the stone.

R ays of magnetick virtue spread out in every direction in an orbe; the centre of this orbe is not at the pole (as Baptista Porta reckons, Chap. 22), but in the centre of the stone and of the terrella. So also the centre