the Amoiphism of Solid Bodies. 269 



can hardly resist the thought, that it has originally been anal- 

 cime, — potash-analcime making with the soda-analcime one for- 

 mation *. The potash-analcime free from water, and, as leu- 

 cite, would have an entirely different form if it were in reality 

 crystallized. We cannot expect to find soda-analcime in leavas 

 owing to its fusibility; but potash-analcime can well occur in 

 the relations under which it is at present met with. When soda- 

 analcime is surrounded by fire-proof clay, and strongly heated 

 in the fire, it is changed to soda-leucite. 



In the mineral kingdom, several other amorphous bodies be- 

 sides opal occur, which have been formed in the moist method, or 

 by coagulation, as allophane, psilomelane, uranium-ore (tiran- 

 pecherz), copper-green, thraulite, Scc.all of which contain silica, or 

 rather opal, and might therefore be termed Opalates. To this 

 group we might also perhaps unite gadolinite. Haiiy, it is true, 

 thought he observed in that substance external crystalline planes ; 

 but its interior is so constituted, that, if we do not imagine we 

 see crystallization every where, we cannot believe that the power 

 of crystallization has been exerted during its formation. The 

 remarkable phenomenon of incandescence which it presents when 

 heated to a certain point, is probably a consequence of its tran- 

 sition from the formless condition to the state when it has a crys- 

 talline structure, or, if I may use the expression, of the awaken- 

 ing of the power of crystallization. I believe generally, that the 

 acquiring crystalline structure, and the change of structure 

 (transformation), in bodies, exercise great influence on the phe- 

 nomena of heat and light in many chemical processes. 



Many inorganic bodies having their origin in the organic 

 kingdom, are formless and coagulated, and many of them are 

 quite incapable of crystallization. Such are all mineral-bitu- 

 mens and mineral-coals, and also many other component parts 

 of organic bodies, as the species. of resin and gum, and animal 

 jellies. 



• By formatioD, 1 understand what is included under organic species, 

 which, retaining the ground-type, pass into one another by the change of vi- 

 carious component parts ; for example, alum, epidote, garnet, hornblende, 

 augite, grey copper (Fahlerz), &c. There are sometimes larger, sometimes 

 smaller, series of intermediate members, whose extremes represent the pure 

 species, which, as yet, are still partly ideal. 



VOL. XVIII. NO. XXXVI. APRTI, 183-5. T 



