GENERAL MANUEES ANIMAL AND VEGETABLE 303 



in the soil and produces considerable mechanical effects. 

 The large proportion of chlorides in seaweed has been 

 urged as a theoretical objection to its use, but practi- 

 cally it has been found 1 to produce quite as good results 

 as an equal quantity of farmyard manure. In some 

 districts it is much esteemed as manure for roots, es- 

 pecially mangolds, but as it is somewhat deficient in phos- 

 phoric acid, much better results are obtained when a 

 quantity of phosphatic manure is applied in conjunction 

 with it. 



Waste Cakes and Feeding Stuffs. Some oil cakes are 

 unfit for feeding purposes owing to the presence of 

 poisonous ingredients, e.g., castor and mustard seeds, 

 rancid oils, etc. Cargoes of grain and other feeding 

 stuffs are sometimes damaged by sea water, become 

 mouldy, or are otherwise spoilt. All these are fairly 

 rich in nitrogenous matter and other plant foods and 

 may be used as manure. Cakes are generally the 

 richest, but the presence of oil retards their decom- 

 position. They contain from 2*5 to 7 per cent, of 

 nitrogen, 0*5 to 1*5 per cent, of potash, 1 to 3 per cent, 

 of phosphoric acid, and 5 to 10 per cent, of oil. They 

 are sometimes de-oiled and ground up very fine. This 

 accelerates their action and greatly increases their 

 manurial value. 



The quantities of fertilising ingredients in a ton of 

 some of the cakes is shown below : 



1 Hendrick. Trans. H. & A, S. (1898). 



