ultimate particles or atoms; but this definition is hypothetical; for
the ultimate particles or atoms are mere creations of the imagination. I
will give you a definition which will have the merit of novelty, and
which is probably general in its application. _Chemistry relates to
those operations by which the intimate nature, of bodies is changed, or
by which they acquire new properties._ This definition will not only
apply to the effects of mixture, but to the phenomena of electricity,
and, in short, to all the changes which do not merely depend upon the
motion or division of masses of matter."

Cuvier, in one of a series of lectures, delivered at Paris, in the
spring of last year, says, "the name chemistry, itself, comes from the
word _chim_, which was the ancient name of Egypt;" and he states
that minerals were known to the Egyptians "not only by their external
characters, but also by what we at the present day call their _chemical
characters_." He also adds, that what was afterwards called the Egyptian
science, the Hermetic art, the art of transmuting metals, was a mere
reverie of the middle ages, utterly unknown to antiquity. "The pretended
books of Hermes are evidently supposititious, and were written by the
Greeks of the lower Empire."


Crystallization.

Why are the crystals collected in camphor bottles in druggists' windows
always most copious upon the surface exposed to the light?

Because the presence of light considerably influences the process of
crystallization. Again, if we place a solution of nitre in a room which
has the light admitted only through a small hole in the window-shutter,