him than any other
well-defined crystal--much less, indeed, than some of the more complex
crystalline varieties, which attracted his interest because of the
difficulty of the problems they presented.

Like many another advance in science, Hauey's first great original step
in crystallography was the result of what would be called a lucky
accident. These accidents, however, be it noted, happen only to
geniuses who are capable of taking advantage of them. How many a man
had seen an apple fall from a tree before this little circumstance
gave Newton the hint from which grew, eventually, the laws of gravity!
Many a man, doubtless, had seen little boys tapping on logs of wood,
to hear how well sound was {178} carried through a solid body, without
getting from this any hint, such as Laennec derived from it, for the
invention of the stethoscope. So, too, many a person before Hauey's
time had seen a crystal fall and break, leaving a smooth surface,
without deriving any hint for the explanation of the origin of
crystals.

According to the familiar story, Hauey was one day looking over a
collection of very fine crystals in the house of Citizen Du Croisset,
Treasurer of France. He was examining an especially fine specimen of
calcspar, when it fell from his hands and was broken. Of course the
visitor was much disturbed by this accident. His friend, however, in
order to show him that he was not at all put out at the breaking of
the crystal, insisted on Hauey's taking it with him for purposes of
study, as they had both been very much interested in the perfectly
smooth plane of the fracture. As Hauey himself says, this broken
portion had a peculiarly brilliant lustre, "polished, as it were by
nature," as beautifully as the outer portions of the crystal; thus
demonstrating that in building up of so large a crystal there must
have been certain steps of progress, at any of which, were the
formation arrested, smooth surfaces would be found.

On taking the crystal home, Hauey proceeded further to break up the
smaller fragment; and he soon found that he could remove slice after
slice of it, until there was no trace of the original prism, but in
place of it a rhomboid, {179} perfectly similar to Iceland spar, and
lying in the middle of what was the original prism. This fact seemed
to him very important. From it he began the development of a theory of
crystallization, using this observation as the key. Before this time
it had been hard for