4 oo THE POPULAR SCIENCE MONTHLY. 



amorphous simply means not crystallized. Furthermore, the crystal- 

 line condition is connected with the amorphous condition by an uninter- 

 rupted series of gradations, as has been proved by the labors of Vogel- 

 sang and Lehmann. The former of these observers dissolved sulphur 

 in sulphuret of carbon, and thickened it by mixing with it Canada bal- 

 sam, the viscosity of which caused a delay in the crystallization at the 

 will of the experimenter. By this method he substantiated a group- 

 ing of the matter into globulites, or minute isolated spheres ; then into 

 margarites, or files of spheres joined to one another. He next produced 

 trichites, which are abundant in the obsidians a kind of extremely 

 fine threads of mineral, containing an internal channel, and rolling up 

 in the most irregular fashion ; microliths, under the various forms of 

 longulites or belonites ; and, finally, the crystallites and crystalline 

 skeletons of Lehmann ; and these, in their turn, led to real crystals. 

 Each of these states presents itself as a more perfected condition than 

 the one that precedes it, as a new aj)pearance and complication of 

 physical properties. Why, then, abruptly break the chain, and, hav- 

 ing recognized the passage from the animal to the plant, and from 

 the plant to the crystal, deny the transition, otherwise very visible, 

 from the crystal to the amorphous body, and pretend that this is only 

 a cadaver ? Bodies sometimes crystallize under remarkably slight in- 

 fluences ; under prolonged vibrations, as in the wire of suspension- 

 bridges ; depressions of temperature, like tin ; or a simple molecular 

 action, as do arsenious acid and barley-sugar. Glasses, according to the 

 most general opinion, are constituted of an infinite number of inter- 

 laced crystals too minute to be distinguished by our microscopes, but 

 which may be forced to arrange themselves in groups, and thus appear 

 visible, by means of a prolonged roasting. In science we must be on 

 our guard against absolutely affirming what our senses do not perceive, 

 but we must be equally wary of supposing that things possess the 

 same limits as the instruments which we are using to-day, but which 

 the ingenuity of an inventor may bring to a greater perfection to- 

 morrow. 



In any case, especially if we restrict individuality to the definite 

 chemical compound, the species is more clear in mineralogy than 

 in biology, because it is more simple. The study of the structure 

 of minerals is comparative inorganic anatomy, and, when crystallog- 

 raphers measure angles, refer the infinite variety of different solids 

 to regular geometrical types, and class them in one or another of the 

 six categories of crystalline systems, they perform the work of anato- 

 mists. To cite their names would be to write the history of miner- 

 alogy over again. We should have to begin with Erasmus, Bartholin, 

 Huygens, and Stenor, and end with the immense number of those who 

 are now engaged with crystallography. 



The crystal does not, then, appear suddenly any more than the 

 plant or the animal. It passes through an embryonic state, the general 



