3 



' In 1804-, in the month of March, I examined 

 the temperature in a water meadow near Hungerford, 

 in Berkshire, by a very delicate thermometer. The 

 temperature of the air at seven in the morning was 

 29. The water was frozen above the grass. The 

 temperature of the soil below the water in which the 

 roots of the grass were fixed, was 43. 



In general those waters which breed the best fish 

 are the best fitted for watering meadows; but most of 

 the benefits of irrigation may be derived from any kind 

 of water. It is, however, a general principle, that wa- 

 ters containing ferruginous impregnations, though 

 possessed of fertilizing effects, when applied to a cal- 

 careous soil, are injurious on soils that do not effer- 

 vesce with acids; and that calcareous waters which are 

 known by the earthy deposit they afford when boiled, 

 are of most use on siliceous soils, or other soils con- 

 taining no remarkable quantity of carbonate of lime. 



The most important processes for improving 

 land, are those which have been already discussed, 

 and that are founded upon the circumstance of remo- 

 ving certain constituents from the soil, or adding 

 others or changing their nature; but there is an opera- 

 tion of very ancient practice still much employed, in 

 which the soil is exposed to the air and submitted to 

 processes which are purely mechanical, namely, 

 fallowing. 



The benefits arising from fallows have been much 

 over-rated. A summer fallow, or a clean fallow, 

 may be sometimes necessary in lands overgrown with 

 weeds, particularly if they are sands which cannot be 



