HORTUS GKAMINEUS WO BU R N F.N SIS. 255 



It is however a general principle, that waters containing 

 ferruginous impregnations, though possessed of fertilizing 

 eft'ects when applied to calcareous soils, are injurious on soils 

 that do not effervesce with acids ; and that calcareous 

 waters, which are known by the earthy deposit they afford 

 when boiled, are of most use on siliceous soils containing 

 no remarkable quantity of carbonate of lime." — Agricultural 

 Chemistry , p. 305 et seq.* 



The proper business of irrigation begins in October, and 

 is carried on till April, according to circumstances. In cold 

 backward situations it is continued latest, and in warmer 

 soils it is generally finished in February. As soon as the 

 latter-math is eaten bare, the water-carriages are cleared out, 

 and the stops and sluices made good. The water is then 

 admitted on the land, and suffered to remain for two or three 

 weeks, with a dry interval of a day or two ; or, according to 

 others, the water is continued on the meadow two weeks at 

 first, then laid dry for one week, and again laid under water 

 for two weeks more. The state of the orass affords the best 

 rule to judge of the frequency of waterings. It is a general 

 principle to make the meadows as dry as possible between 

 every watering, and to stop the water the moment any scum 

 appears on the surface, for that indicates the land has had 

 water enough ; in fact, it is caused by the fermentation ex- 

 cited by the decay of the grass. As soon as the land has 

 been sufficiently dry after the last watering in February or 

 March, the early grass, of which there is always an abun- 

 dance, is consumed by ewes and lambs, if a breeding flock 

 of sheep is kept. In order to prevent the sheep from tram- 

 pling too much of the grass at first, some farmers use hurdles, 

 by which they portion out the consumption of a day. Open 

 spaces are left in the hurdles, to give the lambs free range of 

 the meadow at large. Mr. Davis says, that one acre of good 

 grass will be sufficient for five hundred couples for a day. 



* To what Sir H. Davy has stated, may be added two other cir- 

 cumstances which operate as special excitements to the growth of 

 flooded grass, namely, the rapid motion of the water, which in- 

 creases its temperature : and to the fleece of water, which, while it acts 

 as a covering against the contact of cold air, admits the full action of 

 light upon the grass. — Ed. 



