'Microscopic ail E s s a y s . 



68 3 



taken away, fo that the integrant parts fhall be approximated, 

 and be brought into contacl before they have taken the pofition 

 of their natural tendency, ' then they will join confufedly by fuck 

 ■fides as chance prefents to them.; they will, in fuch circum- 

 fiances, form folid maffes, whofe figures will not be determinate, 

 but irregular and various. 



Different falts affume different figures an cryflallization, and 

 are, by this means, eafily diftinguifhed from one another. But 

 ;befides the large cry Hals produced in this way, each fait is capable 

 >of producing a very different appearance of the cry ftalline kind, 

 when only a drop of the faline folution is made ufe of, and the 

 cryftallization viewed through a microfcope. For our know- 

 ledge of this fpecies of cryflallization we are indebted to Mr. 

 Henry Baker, who was prefented by the Royal Society with a 

 :gold medal for the difcovery, in 'the year 1744. Thefe micro- 

 scopical cry Hals he diflinguifhes from the larger ones by the name 

 of configurations ; but this term feems inaccurate, and the 

 diftinclion may be properly preferved by calling the large ones 

 the common, and the fmall ones the microscopical cryflals of 

 the fait. 



It has not yet been fhewn by any writer on v the fubjecl, why 

 falts mould affume any regular figure, much lefs why every one 

 fhould have a form peculiar to itfelf. Sir Ifaac Newton endea- 

 voured to account for this, by fuppofing the particles of fait to be 

 diffufed through the folvent fluid, at equal diftances from each 

 other; and that then the power of the attraction between the 

 faline particles could not fail to bring them together in regular 

 figures, as foon as the diminution of heat fuffered them to act on 



4 O 2 each 



