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THE CANADIAN JOURNAL 
NEW SERIES. 
No. XXXI.JANUARY, 1861. | 
NOTE ON STELLIFORM CRYSTALS, WITH SPECIAL 
REFERENCE TO THE CRYSTALLIZATION OF SNOW. 
BY E. J. CHAPMAN, 
PROFESSOR OF MINERALOGY AND GEOLOGY IN UNIVERSITY COLLEGE, TORONTO. 
(Read before the Canadian Institute, December 15th, 1860.) 
As this Journal is not addressed exclusively to the scientific reader, 
but to the members of the Canadian Institute at large, it is necessary 
to offer a brief explanation of the more important questions involved 
in the general study of crystal-forms, before adverting to the special 
object of the present communication. 
The forms assumed by natural bodies are of two pene kid Ine 
(1) Accidental, depending not so much on the actual nature of the 
body, as on surrounding conditions; and (2), Essential or Regular. 
Accidental forms are most rare (if indeed ever truly present) in Organic 
Nature. Every plant and animal, and each portion of a plant and 
animal, has its one fixed and determinate form, never really departed 
from, except in the case of monstrosities. Amongst minerals, on the 
other hand, accidental forms, or such as are common, under certain 
circumstances, to all minerals, are of frequent occurrence. The 
Mineral Kingdom, however, possesses also its definite or essential 
forms. These, whether transparent or opaque, are termed crystals. 
So far, therefore, as regards the regular or essential forms of Nature, 
two form-producing powers appear to exist, vzz., vitality and crys- 
tallization. Forms which arise from a development of the vital force, 
. Vou. VI. A 
