Microscopical Essa.ys, 685 



vifible. Hence cryflallized fub (lances have been often miflaken 

 for organized ones, and vice verfa. They differ, however, efTen* 

 tially in their growth and origin. Organized beings fpring from 

 a germ, in which all the eliential parts are concentrated, and 

 they grow by intufception ; whereas cryflallized fubuances in- 

 creafe by the fucceflive appofiti-on of certain molecules, of a de- 

 termined figure, which unite in one comnion mafs.. Thus 

 cryflallized beings do not grow, properly fpeaking ; though their 

 fubftance is augmented, they are not preformed, but formed 

 daily. 



We have already (hewn, page 163, how to prepare the various 

 falls for microfcopical obfervations. The beautiful cry utiliza- 

 tions reprefented in PI. XXX. and XXXI. were produced- in the 

 manner there defcribed. 



Fig. 2, Plate XXX. fhews the microfcopical cryftals of nitre. 

 Thefe fhoot from the edges with very little heat, in flattifh figures., 

 of various lengths, and exceedingly tranfparent, the fides nearly, 

 parallel, though rather jagged, and tapering to a point; after a 

 number of thefe are formed, they often diffolve under the eye, 

 and difappear entirely; but in a little time new (hoots will pufh 

 out, and the procefs go on afrefh. Beautiful ramifications are 

 formed round the edge, and many regular figures are to be ob- 

 ferved in different parts of the drop. Fig. 2 is the real fize of the 

 drop. 



Fig. 3, Plate XXX. is a drop of diflillecl verdigreafe, as it ap- 

 peared when viewed by the microfcope. There is a difference in* 



the- 



