THE SCIENCE OF A SNOW-FLAKE. 
51 
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i 
lamellar flakes of snow, of the most regular and beautiful forms, 
are always seen floating in the air, and sparkling in the sun- 
beams ; and the snow which falls in general is of the most 
elegant texture and appearance.” 
The principal configurations of the snow- crystals are thus 
arranged by Dr. Scoresby : — 
1. Lamellar. 
2. A lamellar or spherical nucleus, with spinous ramifications 
in different places. 
3. Fine spiculse, or six-sided prisms. 
4. Hexagonal pyramids. 
5. Spiculse having one or both extremities affixed to the 
centre of a lamellar crystal. 
The first kind appears to admit of almost infinite variety, the 
more remarkable being tiie stelliform, having six points 
radiating from a common centre. Fig. 14 is typical of this 
species. See also figs. 1, 2, 3, 4, o, 6, and 20, 21, 22, &c. It 
occurs in the greatest abundance when the temperature 
approaches the freezing point. The regular hexagon (figs. 26, 
27, 28) occurs in moderate, as well as in the lowest, tempera- 
tures ; the structure of those crystals is, however, more delicate, 
and their size is diminished as the temperature is lowered. The 
aggregation of hexagons is a beautiful species (figs. 17, 18, 
19), admitting of endless variety. Again, the combination of 
hexagons with radii or spines and projecting angles are no 
less interesting, and they are far more numerous than the former 
(figs. 9, 10, 11, 12, are typical. Several others are repre- 
sented in the Plate). Of the second general division there 
appears to be but two or three species. The fundamental 
figure is of the kind already described; and from the lateral 
and terminal planes there arise small spines like the collateral 
ramifications of figs. 23 and 24. The third class contains ex- 
amples of very delicate crystalline forms, sometimes like figs, a 
and B. The finest specimens, however, resemble white hair cut 
into lengths, but so small and clear as not easily to admit of an 
exact determination of their figure. Occasionally they are 
found with a fibrous or a prismatic structure. The fourth class, or 
pyramids, generally hexagonal, are very rare (figs. 31, 32). They 
were observed by Dr. Scoresby on but one occasion ; and the 
crystals of the last species named are nearly as rare, having 
been seen only on two occasions (figs. 29, 30). The examples 
to which references have been given, and the other figures, such 
as 7, 8 — 15, 16, 25, on the Plate, will fully illustrate the general 
character of those curious and beautiful forms which are assumed 
by water under the conditions necessary for the formation of 
snow. 
Let us examine, by the lights which we have, the pheno- 
