182 GLAISHER, ON SNOW CRYSTALS. 



crystallization ; three of its prisms, it will be perceived, are 

 in a more advanced stage of formation than the other three. 

 Sir Edward Belcher informs me that he intends to adopt this 

 as an example of intermediate crystalline formation in his 

 appendix to the work he is now preparing on the meteorology 

 of the Arctic seas. 



On February 17, there fell an inconceivable variety of 

 crystals, at times accompanied with light snow, but, for the 

 most part, alone. The minimum of the preceding night was 

 18°, the temperature at 9h. was 22°, and the maximum of the 

 day was 33°. Figs. 8 to 15 are some among the large 

 number that I was able to sketch at intervals throughout the 

 whole of the day. Figs. 8 and 9 were very minute, but 

 exhibited, as seen through a Coddington, a considerable degree 

 of solidity, the prisms being either cubes, hexagonal, or cut 

 with many facets. I sketched nearly twenty varieties on this 

 day, and was surprised at their similarity ; they were evidently 

 formations under nearly identical conditions. 



On February 21, I was fortunate enough to secure some 

 good observations of double crystals. I had observed many 

 previously, but had not before been in a condition to record 

 them witli success. The minimum of the preceding night 

 was 20 9°, the temperature at 9h. was 21°, and the maximum 

 for the day was 30 2°. 



I particularly noticed the two specimens, figs. 16 and 17, 

 which were at least 0* 4-inch in diameter, and were composed 

 of solid prisms grouped around the radii of the crystal. I have 

 endeavoured to communicate solidity to tljese figures, which 

 struck me as being intensely beautiful and rich in point of 

 effect. I should, perhaps, mention, in the event of the 

 drawings not sufficiently explaining tliemselves, that a double 

 crystal is that in which two crystals are united by an axis 

 at right angles to the plane of each. The rays of the under 

 crystal most frequently fell intermediate between, and a little 

 projected beyond those of the upper. 



I have yet to speak of an order of crystals, more complex 

 and exhibiting a more graceful arrangement than any I have 

 yet shown to you. I refer to those which combine lamina? 

 and prisms with the leafy or arborescent formation. I am 

 indebted for drawings of two specimens of this class to a lady 

 of my acquaintance, Mrs. King, who, it will be remembered 

 by the readers of the ' Illustrated London News,' on a former 

 occasion, kindly supplied to me the fruit of her observation. 

 (See fig. 8.) 



The first to which I shall refer is as graceful a combination 

 as can possibly be imagined, and exliibits a nucleus com- 



