st as brute animals or
men, when they are awakened out of sleep, move and put forth their
strength. Here one must marvel at a demonstrable error of B. Porta, who,
while rightly opposing a very old falsehood about the diamond, in speaking
of a power contrary to that of the loadstone, introduces another still
worse opinion; that forsooth iron, when touched by a diamond, turns to the
north. "If" (he says) "you rub a steel-Needle on a Diamond, and then put it
in a Boat, or thrust it through a reed, or hang it up by a Thread, it will
presently turn to the North, almost as well as if it had been touched with
the Loadstone; but something more faintly. And, what is worth noting, the
contrary part will turn the iron to the South: and when I had tried this in
many steel-Needles, and put them all into the Water, I found, that they all
stood equi-distant, pointing to the North." This indeed would * be contrary
to our magnetick rules. For this reason we made an experiment with seventy
excellent diamonds, in the presence of many witnesses, on a large number of
spikes and wires, with the most careful precautions, floating (thrust, of
course, through their corks) on the surface of water; never, however, could
we observe this. He was deceived by the verticity acquired from the earth
(as stated above) in the spike or wire of iron itself, and the iron itself
turned aside to its own definite pole; and he, being ignorant of this,
thought it was done by the diamond. But let the investigators of natural
phenomena take heed that they are not the more deceived by their own badly
observed experiments, and disturb the commonwealth of letters with their
errors and stupidities. Diamond is sometimes designated by the name of
_Sideritis_, not because it is made of iron or because it draws iron, but
on account of its lustre, resembling flashing steel; with such a lustre do
the choicest pieces of diamond shine; hence by very many writers many
qualities are imputed to diamond which really belong to siderite loadstone.

* * * * *

{144} CHAP. XIIII.

The Placing of a Loadstone above or below a magnetick
body suspended in aequilibrium changes neither the power
_nor the verticity of the magnetick body._

Quietly to pass this over would be improper, because a recent error arising
from a defective observation of Baptista Porta must be overthrown; on which
he (by an unfortunate repetition) even writes three chapters, namely,