[ 298 ] 



in Oxfordshire; it is likewise abundant in many other 

 parts of England; in Gloucestershire, Somersetshire, 

 Derbyshire, Yorkshire, &c. and requires only pulveri- 

 zation for its preparation. 



Some very interesting documents upon the use of 

 sulphate of iron or green vitriol, which is a salt pro- 

 duced from peat in Bedfordshire, have been laid be- 

 fore the Board by Dr. Pearson; and I have witnessed 

 the fertilizing effects of a ferruginous water used for 

 irrigating a grass meadow made by the Duke of Man- 

 chester, at Priestley Bog near Woburn, an account of 

 the produce of which has been published by the Board 

 of Agriculture. I have no doubt that the peat salt 

 and the vitriolic water acted chiefly by producing gyp- 

 sum. 



The soils on which both are efficacious are cal- 

 careous; and sulphate of iron is decomposed by the 

 carbonate of lime in such soils. The sulphate of iron 

 consists of sulphuric acid and oxide of iron, and is an 

 ,acid and a very soluble salt; when a solution of it is 

 mixed with carbonate of lime, the sulphuric acid quits 

 the oxide of iron to unite to the lime, and the com- 

 pounds produced are insipid and comparatively inso- 

 luble. 



I collected some of the deposition from the fer- 

 ruginous water on the soil in Priestley meadow. I 

 found it consisted of gypsum, carbonate of iron, and 

 insoluble sulphate of iron. The principal grasses in 

 Priestley meadow are, meadow fox-tail, cook's-foot, 

 meadow fescue, florin, and sweet scented vernal grass. 

 I have examined the ashes of three of the grasses, 



