In time of spring I have hunted over the slippery meadows of our shores for the instinct-led travellers from the deep, coming to the shallow tidal zone to propagate their tribes. And in the golden season I have watched the sportive play, in rocky pools o’ershadowed by these graceful weeds, of iridescent annelide and cilia-paddled beroe—have tracked the skipping shrimps along the silvery sands, or have patiently followed the Patella vulgaris in its solemn march to graze upon the verdant ulvæ, and again returning at the change of tide to adjust its conical house with stately nicety on its proper site.
III.
ON THE CRYSTALS OF SNOW AS APPLIED TO THE PURPOSES OF DESIGN.
By JAMES GLAISHER, F.R.S.
I.
NOW, in the ordinary acceptation of the word, is suggestive of a soft flocculent matter of considerable opacity, falling in flakes, and, as compared with water, of little density—a foot of fresh-fallen snow producing but from a tenth to a twelfth part of water. Snow, however, does not always fall in flakes; under certain conditions of atmosphere and temperature it occasionally falls in groups of slender needle-like particles or spiculæ, which under the microscope exhibit no structural detail worthy of remark, but are irregular and jagged in outline. This is one of the most imperfect forms of snow crystallization, and occurs generally at a temperature but little above freezing, and at the commencement of a severe and continued frost, or immediately preceding a general thaw.
At other times a light feathery snow may be seen to fall, composed almost entirely of stars of six spiculæ or radii, united in the centre by a white molecule. These are seldom less than from four to five tenths of an inch in diameter, and are generally collected in tufts of half-a-dozen or more together, which in calm weather waft uninjured to the ground. Sometimes these are mixed with other stars of more intricate figure, to be spoken of presently. [Fig. 1] illustrates this variety, and is enlarged to double the proportions of the original.