52 THE CURIOUS LORE OF PRECIOUS STONES
secret of his success. Some of these wonder-working agates were black with white veins, while others again were entirely white.5
The
wearing of agate ornaments was even believed to be a cure for insomnia
and was thought to insure pleasant dreams. In spite of these supposed
advantages, Cardano asserts that while wearing this stone he had many
misfortunes which he could not trace to any fault or error of his own.
He, therefore, abandoned its use; although he states that it made the
wearer more prudent in his actions.6 Indeed, Cardano appears
to have tested the talismanic worth of gems according to a plan of his
own,—namely, by wearing them in turn and noting the degree of good or
ill fortune he experienced. By this method he apparently arrived at
positive results based on actual experience; but he quite failed to
appreciate the fact that no real connection of any kind existed
between the stones and their supposed effects. In another treatise
this author takes a somewhat more favorable view of the agate, and
proclaims that all varieties render those who wear them "temperate,
continent, and cautious ; therefore they are all useful for acquiring
riches.7
According
to the text accompanying a curious print published in Vienna in 1709,
the attractive qualities of the so-called coral-agate were to be
utilized in an airship, the invention of a Brazilian priest. Over the
head of the aviator, as he sat in the air-ship, there was a network of
iron to which large coral-agates were attached.
5
Albertus Magnus, " Le Grand Albert des seeretz des vertus des Herbes,
Pierres et Bestes. Et aultre livre des Merveilles du Monde, d'auleuns
effetz causez dauleunes bestes," Turin, Bernard du mont du Chat (e.
1515). Liv. ii, fol. 8 recto.
* Cardani, " De subtilitate," Basilea?, 1560, p. 460.
* Cardani, " De gemmis," Basilea?, 1585, p. 323.
