[ 296 J 



tures, employing in some cases larger, and in some 

 cases smaller quantities of gypsum ; and I used 

 pigeons' dung in one instance instead of flesh, and 

 with precisely similar results. It certainly in no case 

 increased the rapidity of putrefaction. 



Though it is not generally known, yet a series of 

 experiments has been carried on for a great length of 

 time in this country upon the operation of gypsum as 

 a manure. The Berkshire and the Wiltshire peat- 

 ashes contain a considerable portion of this substance. 

 In the Newbury peat-ashes I have found from one 

 fourth to one-third of gypsum ; and a larger quantity 

 in some peat-ashes from the neighbourhood of Stock- 

 bridge : the other constituents of these ashes are cal- 

 careous, aluminous, and siliceous earth, with variable 

 quantities of sulphate of potassa, a little common salt, 

 and sometimes oxide of iron. The red ashes contain 

 most of this last substance. 



These peat-ashes are used as a top dressing for 

 cultivated grasses, particularly sainfoin and clover. 

 In examining the ashes of sainfoin, clover, and rye 

 grass, I found that they afforded considerable quanti- 

 ties of gypsum ; and this substance, probably, is inti- 

 mately combined as a necessary part of their woody 

 fibre. If this be allowed, it is easy to explain the rea- 

 son why it operates in such small quantities ; for the 

 whole of a clover crop, or sainfoin crop, on an acre, 

 according to my estimation, would afford by incinera- 

 tion only three or four bushels of gypsum. In exam- 

 ining the soil in a field near Newbury, which was ta- 

 ken from below a foot-path near the gate, where gyp- 



