CRYSTALLOGRAPIIY. 5 
in long feathered lines over the glass—Jack Frost’s work being, 
the making of crystals. Water cannot solidify without crystal. 
lizing, and neither can iron nor lead, nor any mineral material, 
with perhaps half a dozen exceptions. Crystallization produces 
masses made of crystalline grains when it cannot make distinct 
crystals. Granite mountains are mountains of crystals, each 
particle being crystalline in nature and structure. Tne lava 
current, as it cools, becomes a mass of crystalline grains. In 
fact the earth may be said to have crystal foundations; and if 
there is not the beauty of external form, there is everywhere 
the interior, profounder beauty of universal law—the same iaw 
of symmetry which, when external circumstances permit, leads 
to the perfect crystal with regular facets and angles. 
Crystals are alone in making known the fact that this law 
of symmetry is one of the laws of cohesive attraction, and that 
under it this attraction not only brings the particles of matter 
into forms of mathematical symmetry, but often develops scores 
of brilliant facets over their surface with mathematical exact- 
ness of angle, and the simplest of numerical relations in their 
positions. Crystals teach also the more wonderful fact that 
the same species of matter may receive, under the action of this 
attraction, through some yet incomprehensible changes in its 
condition, a great diversity of forms—from the solid of half a 
dozen planes to one of scores. The following figures represent a 
few of the forms in a common species, pyrite, a@ compound of 
iron and sulphur, 

