[ •? ] 



ftand him rightly, they have aflumed only in confequence of 

 flow cooling, and not merely by a heat either ftationary or gra- 

 dually increafed ; confolidation only being the effedl of fuch 

 treatment. 



This confolidation, Sir James calls cry/ldilization, a term which 

 feems to me highly improper ; for according to every fenfe in 

 which this term has ever been employed, whether that operation 

 was perfedl or confufed, it denotes at lead an union of particles 

 previoufly difperfed through a liquid medium ; they muft there- 

 fore be at liberty to move through this medium in order to 

 coalefce and re-unite to each other ; if both they and the medium 

 itfelf coalefce and confolidate, this aflion is called coagulation^ 

 as happens in what was called the offii hebnontii and the jelly 

 formed by the liquor filicum ; but in Sir James's experiment we 

 find the confolidation to take place in a fragment of glafs, which 

 Hill retained its folid ftate, and confequently the particles were 

 not at liberty to move towards each other ; .this confolidation 

 muft therefore evidently have arifen from fome internal change 

 in the conllitution of the glaffes in which it was obferved ; what 

 thefe changes may have been I fhall now examine : In the firft 

 place it. is highly probable that filex, argil and lime, and flightly 

 oxygenated calx of iron, whatever be their affinity to each other 

 when duly proportioned, require like all folids to abforb in their 

 paffage to a liquid Itate a certain portion of latent heat ; but 



when 



