226 Composition and Value of Guano. 



£ s. d. 



The ammonia 8*12 per cent, amounts to 182 lbs., which at 



6d. per lb. is worth . . . . . . .4110 



The phosphate of lime 21*09 per cent, amounts to 472 lbs., 



which at Id. per lb. is worth . . . . .19 6 



The potash at (say) 3^ per cent, amounts to 78^ lbs., which 



at 2\d. per lb. is worth 0 14 8 



Giving 6 15 2 



as the value of a ton of this specimen of guano. 



Although those who are familiar with the characters of a good 

 guano would, from an inspection of the specimen, be led to a 

 doubt of its possessing the full ammoniacal value, there is nothing 

 striking or peculiar in its appearance, and nine-tenths of the pur- 

 chasers of the manure would receive it without suspicion. It is 

 only by chemical analysis that this point can be decided. The 

 farmer's only safety in the purchase of guano is in the character 

 of the dealer from whom he obtains it, or in the knowledge of its 

 composition as determined by analysis. 



Of the money-value of Saldanha Bay guano I have already 

 incidentally spoken (page 218). 



Its selling price closely approximates to what it should be were 

 the phosphate of lime and ammonia calculated in the same way 

 as in Peruvian guano. 



It cannot, however, be too often remarked, that the value of 

 these two varieties of guano is of an essentially distinct character. 

 It will not do to suppose that, because they are sold at a fair 

 price in relation to their composition, they may be employed 

 indifferently, and that 10/. spent in one will be employed to the 

 same advantage in the other. If the object of the agriculturist 

 is to make use of an ammoniacal manure, he will not attain that 

 object by the purchase of Saldanha Bay guano. On the other 

 hand, if he seeks to add phosphate of lime to his soil, the use of 

 Peruvian guano would be a most expensive method of doing so. 

 Without therefore attempting to point out the exact circumstances 

 in which it would be advisable to apply the one or the other, it 

 is right that it should be distinctly understood that they are by no 

 means to be used indifferently. 



Appendix 



