beautiful rosettes tied together by the crystallizing force during the
descent of a snow-shower on a very calm day. The slopes and summits of
the Alps are loaded in winter with these blossoms of the frost. They
vary infinitely in detail of beauty, but the same angular magnitude is
preserved throughout: an inflexible power binding spears and spiculæ
to the angle of 60 degrees.

The common ice of our lakes is also ruled in its formation by the same
angle. You may sometimes see in freezing water small crystals of
stellar shapes, each star consisting of six rays, with this angle of
60° between every two of them. This structure may be revealed in
ordinary ice. In a sunbeam, or, failing that, in our electric beam, we
have an instrument delicate enough to unlock the frozen molecules,
without disturbing the order of their architecture. Cutting from
clear, sound, regularly frozen ice, a slab parallel to the planes of
freezing, and sending a sunbeam through such a slab, it liquefies
internally at special points, round each point a six-petalled liquid
flower of exquisite beauty being formed. Crowds of such flowers are
thus produced. From an ice-house we sometimes take blocks of ice
presenting misty spaces in the otherwise continuous mass; and when we
inquire into the cause of this mistiness, we find it to be due to
myriads of small six-petalled flowers, into which the ice has been
resolved by the mere heat of conduction.

A moment's further devotion to the crystallization of water will be
well repaid; for the sum of qualities which renders this substance
fitted to play its part in Nature may well excite wonder and stimulate
thought. Like almost all other substances, water is expanded by heat
and contracted by cold. Let this expansion and contraction be first
illustrated:--