lo Elements of Mineralogy, 



on it > calces of lead acl: on it more power-* 

 fully than on argill, but lefs than on calca- 

 reous Earth, and melt from y to 7 their 

 weight of it. 



The calcareous, ponderous magnefian and 

 argillaceous Earths being combinable with 

 all acids, may be called abforbent Earths, in 

 contradiftindtion to the filiceous> which 

 unites only to the fparry acid. 



Befides the general characters of thefe 

 Earths, here given, Mr. Bergman has obferved 

 and noted their different powers of abforbing 

 and retaining water; after moiftening equal 

 weights of filiceous land, chalk, magne- 

 fia, and Earth of alum, with as much water 

 as they could take up without dropping, 

 he found that the fand took % of its 

 weight, chalk I, magnefia i~> and Earth 

 of alum 2,1, and when all thefe moiftened 

 Earths were expofed to the fame heat, the 

 fand loft its water firft, then the chalk, then 

 the magnefia, but the argill, not until red-* 

 hot. 



Again one of the characters of argillaceous 

 Earth is the extreme fubtility and finenefs of 

 its integrant parts, which render it fmooth 

 to the touch, and (lowly feparable from water 

 when diffuied through it, alfo a certain vifci- 



dity 



