\QO OBSERVATIONS ON BASALT, &C. 



the formation of cryftals, firailar to thofe defcribed, in the heart 

 of the radiated fperoids, while their exteriors ftill retained the 

 fibrous texture. 

 — Review of If it be confidered as extraordinary, that a change {hould 

 the facts under oe . e ff e cled, converting an apparently folid and homogeneous 

 view. mafs into an accumulation of radiated fpheroids, and that thefe 



radii (hould lofe their fibrous (tru&ure, and alTume the texture, 

 afpecl, and tenacity, of a compact, hard, and homogeneous 

 (tone, it is certainly much more extraordinary, that this 

 ftone {hould permit farther arrangement to proceed, and 

 fhould enable the cryftalline molecules which it contains in a 

 ftate of confufed aggregation, to arrange themfelves, and to 

 form cryftals which, although minute, are equal in the per- 

 fection of their forms, and in the brilliancy of their natural 

 polith, to the moft precious produces of crystallization. It is 

 alfo well deferving of obfervation, by how regular a march 

 the magnetic influence of the fubftance keeps pace with the 

 perfection of its arrangement, till it becomes fo powerful, 

 that fragments of the regenerated (tone are fufpended by the 

 attraction of a magnet. 

 The aftof cryf- It has been moft juftly remarked by Mr. Smithfon, that 

 talltzation is in- f ] ut ; on f ar f rom t, e j n g neceffary to cryftallization, effectually 

 compatible with # B . . 



folutionor fluid prevents its commencement ; for, while folution fubfifts, cryf- 

 combmatisn. tallization cannot take place. It may remain a queltion, whe- 

 ther previous folution be eflential, as a preparatory means of ob- 

 taining, by fubfequent evaporation, or cooling, the fmall parts 

 of bodies difengaged, fo that they may unite to form regular 

 cryftals. If by folution be only meant, that fimple action of 

 heat, or water, which merely counteracts the force of aggrega- 

 tion, and relieves the molecules from their bonds of union with 

 each other, it certainly is a requifite; but if by folution be 

 meant, that aftion of affinities by which not only the force of 

 aggregation is overcome, but the combinations which conftitute 

 the molecules are deftroyed, it obvioufly is not only unnecef- 

 fary but prejudicial to cryftallization ; as a new fet of molecules 

 mud be formed, by a new combination of the elementary 

 particles, before the formation of regular bodies can commence. 

 Sufpenfion is Tbe fufpenfion of the molecules ready to cryftallize, may be 

 neceffary ; but CO rrectly faid to be merely mechanical. Though the me- 



th is maybe call- * . . ' • 



cd mechanical, chanical action ot trituration can never be expected to refolve 

 even the moft eafily divifible body in its molecules, becaufe 



the 



