VEGETABLE MANURES. 1 45 



as usually allowed to remain for months exposed to the 

 weather, must lose much of their valuable (qualities. By 

 adopting the precautions which I described as necessary, in 

 the management of farm-yard dung, much of this loss may be 

 prevented. The fresh weeds are also frequently placed in 

 the drills with the potato sets, and, thus used, produce a 

 most abundant crop, though the potatoes are said to be more 

 waxy than those grown on farm dung. It is necessary to 

 prevent the sets coming into immediate contact with the 

 weeds, as they are said to be injured when placed upon it; 

 applied to cabbages, they are found greatly to improve their 

 flavour. The fresh weeds are usually employed at the rate 

 of 30 tons to the statute acre. 



218. Composition of sea-weedft. — As taken from the sea or 

 cut from the rocks, sea-weeds contain a very large amount 

 of water; the leaves {frond) of the bladder- wrack, and 

 the stalks and leaves of the tangle, which are highly valued 

 by the farmers on our coasts, contain in the 100 parts 

 respectively as follows: — 



A ton therefore of the above weeds, mixed together, would, 

 when fresh, convey to the soil about 123 lbs. of mineral 

 ingredients. 



219. Formerly, enormous quantities of sea- weeds were 

 bunied on the coasts of Ireland and Scotland for the sake of 

 the soda (44), which is one of the chief constituents of their 

 ashes; but at present that alkali is procured from other 

 sources, and only a limited amount of kelp^ as the fused ashes 

 are termed, is prepared for the use of the Iodine manufac- 

 turer (page 48, note). From several analyses of the kelp 

 prepared on the north-east coast of Ireland, I was some time 

 ago induced to recommend it to the attention of farmers, as 

 a valuable and convenient source of the saline matters 

 removed from our fields by cultivation, and especially for 

 supplying the alkalies so essential to the gi'owth of the potato 



