Sect. III. Agriculture and Vegetation. 6 1 



p. d. into the mixture of the infufion, and 

 galls ; it took immediately a brownifli co- 

 lour, and afforded a plentiful precipitation, 

 which, in twenty-four hours, had taken a 

 purple colour. 



I boiled a quantity of the earth for half 

 an hour in water, flrained and evaporated 

 it. A white faline fubflance remained in 

 the proportion of 6 grains to each ounce, 

 which tafled exactly like fait of fleel. This 

 fait difTolved in water, turned fyrup of vio- 

 lets green, as does fait of fleel ; and took a 

 deep black colour with galls : Sufficient 

 proofs of its being fait of fleel. Nor cart 

 its white colour be any objection ; for fait 

 of fleel reduced by trituration, evaporation, 

 &c. to a powder, is white ; and the fait 

 which I procured, was a powder. 



IT appears, then, beyond all doubt, 

 that this fubftance confifls of an earthy 

 body like clay, about an eightieth part of 

 (alt of fleel, and a fmall proportion of the 



vitriolic 



