104 VIEWS OF THE MICROSCOPIC WORLD. 



with great rapidity, and the swift advance of their spreading configurations gives 

 full employment to the eye of the observer. A represents the primitive crystals 

 as seen at the edges of the film, but the two most common forms are running 

 vines and plume-like tufts, consisting of numerous crystallized branches of the 

 most delicate structure. The first is often seen originating in a single stem, which. 

 as it grows, soon breaks up into a thousand curved shoots, that interlace and 

 entwine with each other, composing a kind of irregular crystallized network 

 extending over the surface before occupied by the liquid. The lateral spurs are 

 short, forked, and disposed along the stem without any particular regard to sym- 

 metry; and are often loaded with comparatively heavy crystals, the whole pre- 

 senting an appearance not unlike a spray of withered herbage fringed with crystals 

 of hoar-frost. The second kind has numerous slender ramifications radi?*ing from 

 a single stem, each filament Deing studded at the side with minute crystals. 



These glittering plumes are scattered in profusion over the whole field of view, 

 amid the sparkling network of crystallized vines, and the union of these rich and 

 radiant configurations dazzles the eye with visions of rare and surpassing beauty. 



A singular form is sometimes presented, in which the solution crystallizes m circles 

 around a particle of sediment ; the circles are gemrned with crystals at the sides, 

 and terminate in branching sprigs as graceful as the leaflets of a flower. These 

 delicate sprays are very small, the breadth of the crystals measuring only one-six- 

 teen hundred and sixtieth part of an inch. 



SULPHATE OF SODA, OR GLAUBER SALTS. This salt crystallizes slowly by the 

 application of a gentle heat, and exhibits a great diversity of combinations, 

 which are, for the most part, massive, and stand boldly out upon the surface of 

 the glass. One variety commences in a spicular cluster, similar to that delineated 

 at A in drawing 158, the branches of which spread out in long needle-shaped 

 crystals on every side, which, intersecting with others of similar nature, frequently 

 form an irregular crystallized lattice work. Sometimes long and massive crystals 

 radiate from a common centre like the spokes of a wheel. Another variety of 

 crystal, of a delicate white color, broad, pointed, and shaped like a feather, is 

 often seen advancing in the field of view, and sending forth its glittering filaments 

 on either hand. In other parts of the crystallized film, a number of these crys- 

 tals are beheld ranked side by side, like the teeth of a comb, and the surface ot 

 each is itself studded with still smaller crystals. Rich, starry crystals are also 

 found, like those displayed in group B, and the other forms which are here de- 

 lineated are scattered in profusion amongst the rest. Very beautiful figures are 

 frequently observed near the edges of the drop where the salt is r.iost abundant. 



Two of these are exhibited at C and D, the first of which is a heavy transparent 

 configuration of considerable thickness with serrated sides, formed of single dia- 

 mond-shaped crystals. The second is a very singular crystalline structure, and 



