63 



TAB. CXXXIV. 



ARC ILL A hydrata. 



Hydrargillite. 



Class 2. Earths. Order I. Homogeneous. 

 Gen. 1. Argil. Spec. 2. Hydrargillite. 



Div. 1. Crystallized. 



Spec. Char. Argil in combination with water. 

 Syn. Hydrargillite. Davy in Phil. Trans. 



Wavellite. Bahington in Mr. Davy's Paper 

 in Phil. Trans. 



According to our system, we of necessity differ from 

 Dr. Babington in the name of this mineral. We venerate 

 Dr. Wavell as an old acquaintance, and have little doubt 

 but his name will be handed down to posterity as the first dis* 

 coverer of this substance, near Barnstaple. Through having 

 in my possession the valuable collection of W. Day, Esq., I 

 have had specimens of it several years under the title of a Zeolite 

 from Devonshire, and was going to figure it as such ; but 

 on examining and rinding it a very doubtful Zeolite, I put it 

 by for some future analysis or investigation. It happened, 

 however, luckily to fall into the hands of Mr. Davy, who 

 fully investigated it, and from the nature of its composition 

 he very properly names it Hydrargillite (from vSwp water, 

 and apyiXXog clay) ; and under so good an authority, we have 

 little else to do than to quote a part of his paper from the 

 Philosophical Transactions. 



ce The most common appearance is in hemisphcerical 

 groups of crystals" (on the surface of the gangue); " in 

 some instances it exists as a collection of irregularly 

 disposed prisms forming small veins in the stone : as yet I 

 believe no insulated or distinct crystals have been found." 



