C 165 - 3 



m which there is a due mixture of sand, finely divided 

 clay, and carbonate of lime, with some animal or ve- 

 getable matter ; and which are so loose and light as 

 to be freely permeable to the atmosphere. With res- 

 pect to this quality, carbonate of lime and animal and 

 vegetable matter are of great use in soils ; they give 

 absorbent power to the soil without giving it likewise 

 tenacity : sand, which also destroys tenacity, on the 

 contrary, gives little absorbent power. 



I have compared the absorbent powers of many 

 soils with respect to atmospheric moisture, and I have 

 always found it greatest in the most fertile soils : so 

 that it affords one method of judging of the produc- 

 tiveness of land. 



1000 parts of a celebrated soil from Ormiston, 

 in East Lothian, which contained more than half its 

 weight of finely divided matter, of which 11 parts 

 were carbonate of lime, and 9 parts vegetable matter, 

 when dried at 212, gained in an hour by exposure to 

 air saturated with moisture, at temperature 62, 18 

 grains. 



1000 parts of a very fertile soil from the banks 

 of the river Parret, in Somersetshire, under the same 

 circumstances, gained 16 grains. 



1000 parts of a soil from Mersea, in Essex, 

 worth 45 shillings an acre, gained 13 grains. 



100O grains of a fine sand from Essex, worth 

 "28 shillings an acre, gained 1 1 grains. 



1000 of a coarse sand worth 15 shillings an acre, 

 gained only 8 grains. 



1000 of the soil of Bagshot-heath gained only # 

 grains. 



