of Central Somerset. 21 



During many months of the year such thin surface soils in 

 hilly districts, after they have been drained, remain as cold and 

 almost as wet as before. When the temperature of the air 

 becomes more genial to vegetation, and the weather much drier 

 than during the other and greater part of the year, the clay-land 

 on the Polden Hills becomes sufficiently dry and warm to allow 

 vegetation to make a start ; and the abundance of mineral food in 

 the land then rapidly pushes forward the herbage, and causes it 

 to grow with much luxuriance, especially if the summer tem- 

 perature is high, and just sufficient dew or gentle rain falls to 

 keep the clay from cracking. On the hills, and on naturally 

 cold, stiff land, this period of rapid growth takes place much 

 later in the season than in less retentive and warmer soils. In 

 districts where scouring prevails, the haymaking season is gene- 

 rally later than in other localities ; but, although delayed, the 

 grass-crop on the worst scouring meadows in most seasons does 

 not quite sufficiently mature, and in consequence of the immature 

 and green condition in which the grass is cut down, the hay 

 scours. 



Pastures which do not scour, though situated in the same 

 district where scouring land abounds, either have a more porous 

 subsoil or the blue lias-clay lies at a depth not reached by the 

 roots of plants. On such land the herbage has a chance to 

 make a start earlier in the season, and to grow more regularly 

 and to get more readily matured than on scouring land. 



Lias clay-land thus often scours, not because it is too poor 

 or because it is too wet, or because it contains something or 

 other inimical to vegetation but because it is very abundant 

 in plant-food ; and, from the peculiar position of the subsoil on 

 scouring land, its depth and impervious, highly tenacious cha- 

 racter cause a too luxuriant growth of the herbage during 

 the warmer summer months. Consumed in this condition 

 the herbage is immature and scours, even when made into 

 hay. 



But should the summer be long and warm, and a farmer have 

 the discretion to delay haymaking, he will find that scouring 

 land will produce, in his case, good wholesome hay. In wet 

 summers, and during the rainy part of the year, the evil ceases 

 either altogether, or is much less aggravated than during the dry 

 and warm summer months. This is perfectly intelligible, for it 

 is during the warm and dry summer months that young immature 

 clover-leaves and grass-shoots are most abundantly developed on 

 scouring land. For the same reason the grass on water-weadows 

 scours most during the summer months, and not during the 

 winter and early part of the spring. 



