ject, attracted light bodies, was really our modern tourmaline. In
modern times the Dutch found this mineral in Ceylon and, because it
attracted ashes and other light substances to itself, called it
_aschentriker_--that is, attractor of ashes. Others had still further
experimented with this curious substance and its interesting
electrical phenomena. It remained for Abbe Hauey, however, to
demonstrate the scientific properties of tourmaline and the relations
which its electrical phenomena bore toward the crystalline structure
of the mineral. He showed that the electricity of tourmaline decreases
rapidly from the summits or poles toward the middle of the crystal. As
a matter of fact, at the middle of the crystal its electrical power
becomes imperceptible.

He showed also that each particle of a crystal {183} that exhibits
pyro-electricity is itself a source of the same sort of electricity
and exhibits polarity. His experimental observations served to prove
also that the pyro-electric state has an important connexion with the
want of symmetry in the crystals of the substances that exhibit this
curious property. In tourmaline, for instance, he found the vitreous
charge always at the summit of the crystal which had six faces, and
the resinous electricity at the summit of the crystal with three
faces.

His experiments soon showed him, too, that there were a number of
other substances, besides tourmaline, which possessed this same
electrical property when subjected to heat in the crystalline stage.
Among these were the Siberian and Brazilian topaz, borate of magnesia,
mesotype, sphene, and calamine. In all of these other pyro-electrical
crystals, Hauey detected a corresponding deviation from the rules of
symmetry in their secondary crystals to that which occurs in
tourmaline. In a word, after he had concluded his experiments and
observations there was very little left for others to add to this
branch of science, although such distinguished men as Sir David
Brewster in England were among his successors in the study of the
peculiar phenomena of pyro-electricity.

It may naturally enough be thought that, born in the country, of poor
parents, and compelled to work for his living, Hauey would at least
have the advantage of rugged health to help him in his {184} career.
He had been a delicate child, however; and his physical condition
never improved to such an extent as to inure him to hardships of any
kind. One of his biographe