the Amorphism of Solid Bodies. 271 



ties. Mineral kermes probably owes its colour to amorphous 

 sulphur. 



Many bodies possess such power of crystallization, that they 

 cannot be produced amorphous in a solid condition. The phos- 

 phate of lead has been long known and celebrated on this ac- 

 count. It crystallizes immediately when it solidifies, and at the 

 same time emits a strong light, as I remarked many years ago. 

 Bismuth oxide, and several other bodies, present a similar pheno- 

 menon. I believe I am not far wrong in stating, that all products 

 of fusion, namely, all substances acted on by the blowpipe, which, 

 previous to their being solidified are transparent, and after it 

 not transparent, or only translucent, crystallize either in whole 

 or in part, and in reality form extremely fine granular crystal- 

 line masses, which, as is well known, are never perfectly trans- 

 parent. It seems to me also not improbable, that glassy arsenic 

 acid loses its transparency by being kept, owing to its being gra- 

 dually converted into a crystalline mass. 



The question now presents itself. Can we regard the passage 

 of a crystalline body to the state where there is no form, as a 

 chemical process ? and can we regard as a peculiar and distinct 

 inorganic species, a formless body which has the same material 

 substratum as a crystalline substance, as, for example, opal and 

 quartz ; or must we unite one with the other as mere varieties ? 

 Since it is not merely the absence of form which distinguishes 

 formless from crystalline bodies, but also the remarkable differ- 

 ence in the compactness (which is usually less considerable in 

 the former than in the latter), in the hardness, in the optical 

 phenomena, and in the chemical relations; I think it is just as 

 proper to consider two such substances as distinct species, as 

 two which have a different fundamental form, but the same 

 chemical composition. But as the want of form is not a posi- 

 tive property, and consequently a character of specific distinction 

 is awanting to amorphous bodies, we cannot place them in the 

 same rank as substances possessing form, and I therefore pro- 

 pose to term them subspecies (after specien). 



Accordingly, the first question is already answered, and in 

 this way, — that we must consider the conversion of crystalline 

 to uncrystalline bodies as a chemical process ; since by it they 

 are specifically or qualitatively altered. In no case can such ? 



T 2 



