MAGIC STONES AND ELECTRIC GEMS 65
It
has been noted as a curious fact that none of the ancient writers who
treat of the loadstone recognized that the attractive energy exerted
by this substance on iron was also exerted by iron upon the loadstone;
on the contrary, they constructed many ingenious hypotheses to explain
why this was not the case.116 The strange fancy that in the
presence of a diamond a piece of loadstone was robbed of its
attractive force, must have arisen from an observation of the
well-known electric properties of the first-named stone, and from the
idea that the much more valuable stone should have the greater power.
Here, as in many other cases, we see how little interest was taken in
actual experiment by ancient writers, a pre-conceived idea of the
eternal fitness of things being the main criterion.
Spaniards
of the thirteenth century believed that the magnetic power of the
loadstone would depart from it if it were steeped in the juice of leek
or onion for three days ; but the virtue would return to the stone if
it were bathed in goat's blood. This recalls the queer notion that the
diamond could only be broken when moistened with goat's blood, both
fancies having their origin in the idea that goat's, or rather ram's
blood, was endowed with warmth and vitality to a higher degree than
other blood.
An ingenious magnetic oracle is described by De Boot.117 This
consisted of a round board, about the edge of which were marked the
letters of the alphabet, while in the centre there stood a small wooden
figure, set on a pivot, and holding extended in one hand a little wand.
One foot of this figure was slightly advanced and within it was
concealed a small iron ball. The experimenter held in his hand a wooden
sceptre, with a powerful loadstone at its top, and as he
""
Martin, " Observations et théories des anciens sur les attractions et
la répulsion magnétiques," in Atti dell' Accademia Pontefici dei Nuovi
Lincei, voi. xviii, p. 18 ( 1864-65).
""'Gemmarum et lapidimi historia," Lug. Bat., 1636, p. 466; Lib. II, cap. 204. 6
