MANUKES, THEIK KIKDS AKD USES. 35 



subsisted upon fish, contain considerable quantities of 

 phosphate of lime from the bones, and ammonia from 

 the flesh of the fish. According to the quantity of rain 

 in the climate whence they are obtained, the amount of 

 ammonia will vary. Their value depends principally 

 upon the quantity of ammonia, which already exists, or 

 may be formed by their further decomposition. Next to 

 ammonia, the soluble phosphoric acid is the most valuable 

 constituent, and after this potash is next in importance. 

 Guano from the Chincha Islands contained from fifteen 

 to twenty per cent, of ammonia; but notwithstanding 

 the exhaustion of the entire supply, and that the guanos 

 from other sources, as the Guanape, are poorer in am- 

 monia, and contain more of the less valuable constituents, 

 Peruvian guano retails at the former price. 



Proprietors of city stables make no provision to save the 

 most valuable portion of the droppings of their stock the 

 urine and gardeners near cities supplement their stable 

 manure with strong, soluble commercial ammoniacal fertil- 

 izers, by which, in a measure, they do away with the neces- 

 sity of completely fermenting it. Their reliance is not 

 mainly upon the fertilizer, and if they are sure of the am- 

 monia, it is all they desire; but it is otherwise with those 

 who have to depend chiefly upon the commercial article. 

 Gardeners need not be chemists, but they need to profit 

 by the experiments and scientific teachings of the chem- 

 ist, or be swindled by the dishonest manipulator of the 

 article upon which their success depends. The gardener 

 who purchases an artificial fertilizer should know what 

 element his land or crop requires. The law enacts that 

 each package of a fertilizer shall be accompanied by a 

 chemical analysis of its contents. The Agricultural De- 

 partment of Georgia has published a tariff of values of 

 the important ingredients in fertilizers, by means of which 

 any one may calculate the approximate agricultural value 

 per ton of any such fertilizer. (See Appendix.) These 



