Secondly, that it be not too long exposed, so as that the whole bulk be frozen, for oftentimes, in such cases, by reason of the swelling the of Ice, or from some other cause, the curious branched Figures disappear.
Thirdly, an artificial freezing with Snow and Salt, apply'd to the outside of the containing Vessel, succeeds not well, unless there be a very little quantity in the Vessel.
Fourthly, If you take any cleer and smooth Glass, and wetting all the inside of it with Urine, you expose it to a very sharp freezing, you will find it cover'd with a very regular and curious Figure.
II . Observables in figur'd Snow.
Schem.
Fig. 2.Exposing a piece of black Cloth, or a black Hatt to the falling Snow, I have often with great pleasure, observ'd such an infinite variety of curiously figur'd Snow, that it would be as impossible to draw the Figure and shape of every one of them, as to imitate exactly the curious and Geometrical Mechanisme of Nature in any one. Some coorse draughts, such as the coldness of the weather, and the ill provisions, I had by me for such a purpose, would permit me to make, I have here added in the Second Figure of the Eighth Scheme.
In all which I observ'd, that if they were of any regular Figures, they were always branched out with six principal branches, all of equal length, shape and make, from the center, being each of them inclin'd to either of the next branches on either side of it, by an angle of sixty degrees.
Now, as all these stems were for the most part in one flake exactly of the same make, so were they in differing Figures of very differing ones; so that in a very little time I have observ'd above an hundred several cizes and shapes of these starry flakes.
The branches also out of each stem of any one of these flakes, were exactly alike in the same flake; so that of whatever Figure one of the branches were, the other five were sure to be of the same, very exactly, that is, if the branchings of the one were small Perallelipipeds or Plates, the branchings of the other five were of the same; and generally, the branchings were very conformable to the rules and method observ'd before, in the Figures on Urine, that is, the branchings from each side of the stems were parallel to the next stem on that side, and if the stems were plated, the branches also were the same; if the stems were very long, the branches also were so, &c.
Observing some of these figur'd flakes with a Microscope, I found them not to appear so curious and exactly figur'd as one would have imagin'd, but like Artificial Figures, the bigger they were magnify'd, the more irregularites appear'd in them; but this irregularity seem'd ascribable to the thawing and breaking of the flake by the fall, and not at all to the defect of the plastick virtue of Nature, whose curiosity in the formation of most of these kind of regular Figures, such as those of Salt, Minerals, &c.