102 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, which 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. Scarcely 

 any heat is necessary to produce these configurations, for the spirit quickly evapo- 

 rates, and the crystals that originate are of short duration, in consequence of the 

 camphor itself being volatile. The crystals of camphor are very minute, the 

 entire length of a branch being 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. Another combination consists of six broad and beautiful leaves 

 diverging from a common centre. In some of the specimens the leaves are with- 

 out 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 is a trans- 

 parent, dagger-shaped crystal, with the blade, handle, and guard all complete. 

 The crystals are quite small, the breadth of the main stem, in some, being only 

 one Jive-hundredth part of an inch; and yet, small as they are, these minute forms 

 exhibit with distinctness, when the light falls upon them in a proper direction, the 

 full, rich, and vivid play of the prismatic colors. 



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

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



