276 ■ MANUAL OF AGRICULTUKE. 



lation, the importation of the extra quantity needed from abroad, 

 and the immense amount of manure stuffs now applied, and 

 when, in addition we brino; to mind the truths of all chemical 

 elements being indestructible, and all such as compose the food 

 of man and the lower animals being voided, some as gases, indeed, 

 but the vast proportion in the form of fluids and solids, it must 

 be allowed, that if its soil were the reoipient of all these which are 

 now lost, the fertility of Great Britain would naturally increase at 

 an indefinite ratio. But, on the contrary, we see a gigantic illus- 

 tration of wastefulness — the excreta of the inhabitants, and the 

 other valuable manurial substances of our great cities and towns, 

 poured into rivers, which are converted by the process into 

 gigantic open sewers fatal to life, rollinc^ everything to the sea. 

 Where a regular course of rotation is observed, the general rule 

 is, to apply to the green crops all the farm-yard manure with 

 others, in quantity sufficient for all the requirements of every 

 subsequent crop of the rotation. But the practice of supple- 

 menting this application by another of specific manures for the 

 successive crops, is now rapidly extending, under the influence 

 of scientific farminc^. 



Farm-yard manure, consisting as it does of the excreta of the 

 various animals of the farm, and the straw of the cereals and 

 other waste matter, contains all the elements requisite for plant 

 life. The litter of fully grown animals, fed upon rich food, with a 

 large proportion of nitrogenous and phosphatic substances, evi- 

 dently affords a more valuable manure than does that of stock fed 

 upon a poorer dietary, or that of young growing animals. Such 

 manure, too, made under cover, or sheltered from exposure to 

 rainfall, must also of necessity present a better quality than 

 when it has been exposed to the open atmosphere and the wash- 

 ing action of rain. The following table from Stephens shows the 

 proportions of the ingredients of one ton of farm-yard manure : — 



?> 

 >» 





Guano is composed of the excreta of marine fowls and the re- 

 mains of their bodies, and it is chieflv found accumulated in thick 

 deposits on several islands off the Peruvian coast, which are never 

 visited by rain. Their situation in a rainless zone has prevented 

 the w^ashing away of the valuable constituents of these strata, 

 which are found consolidated into a dry unfermented mass. The 

 following is the analysis of a first-class Peruvian guano : — 



