104 VIEWS OF THE MICROSCOPIC WORLD. 



with this motion, the same elegant radiated figures start forth, perfect in form, 

 on the ground over which passes the creative wave. These configurations are 

 extremely beautiful, and consist of delicate crystals, which radiate from a centre, 

 most commonly in six branches, jvhich are nearly of the same length. They 

 are formed like fern-leaves, wide at the base, and gradually tapering to a point, 

 the fringes at the sides being composed of slender, 'feathery crystals. Beautiful 

 configurations of this kind are exhibited in the plate at C, D, E, F, and G. A 

 and B are branches of fern-like crystals of a different type, and at H a crystal 

 is seen having the form of a cross. Scarcely any heat is necessary to produce 

 these configurations, for the spirit quickly evaporates, and the crystals that 

 originate are of short duration, in consequence of the camphor itself being vol- 

 atile. The crystals of camphor are very minute, for the entire length of the 

 branch a, 5, is only the one hundred and twenty-fifth part of an inch. 



SAL AMMONIAC, OR MURIATE OF AMMONIA. The crystals of this salt are 

 among the most elegant of those which the microscope reveals, and the prepared 

 solution crystallizes with great facility. The change commences at the edges of the 

 film, and at those places on the surface where the liquid is thinnest ; and 

 from these points sharp, broad, dagger-shaped crystals push out in all directions. 

 The crystal appears at first as a single stem of the most perfect transparency, 

 but as it advances it throws out at each side blunt crystals of different lengths, 

 parallel to each other, and, usually at right angles to the main shoot. These 

 lateral spurs increase in length until the middle of the principal crystal, when 

 they gradually diminish in extent until they vanish at its remote extremity. 

 The lateral branches often extend from the principal crystal to a considerable dis- 

 tance, and are themselves studded with minute crystals at the side, which also 

 shoot out at right angles ; and from these again similar systems proceed to an 

 indefinite extent. This mode of crystallization is shown in three figures deline- 

 ated in drawing 155. Here is likewise displayed in three others another combina- 

 tion, consisting of six broad and beautiful leaves diverging from a common cen- 

 tre. In one of the specimens the leaves are without branches ; but in the others 

 they break forth into crystals on either side ; and each of the six stems becomes 

 a silvery spray. A very common form, which is likewise here exhibited, is a 

 transparent, dagger-shaped crystal, with the blade, handle, and guard, all com- 

 plete. Beautiful as these delineations are, they can but faintly represent the 

 exquisite delicacy of the originals, with their distinct outlines, symmetrical combi- 

 nation, and perfect transparency. The crystals are quite small, the breadth of 

 the main stem at a, in one of the figures, being only one-jive-hundredth part 

 of an inch ; and yet, small as they are, these minute forms exhibit with dis- 

 tinctness, when the light falls upon them in a proper direction, the full, rich, and 

 vivid play of the prismatic colors. 



MURIATE OF BARYTES. When the muriate of barytes is dissolved in water, 

 it forms a clear and colorless solution, which speedily crystallizes on the glass 



