"The iron pointer suspended freely and with the utmost precision in equilibrium on its axis, and then touched and excited with a loadstone, dips down to a fixed and definite point below the horizon (e.g. in the latitude of London it dips nearly 72 degrees) and there stands. But because of the wonderful agreement and congruency manifested in nearly all and singular magnetic experiments, equally in the earth itself and in a terrella, (i.e. a spherical loadstone), it seems (to say the least) highly probable and more than probable that the same pointer... will at the equator stand in equilibrium on the plane of the horizon."