* 



Composition and Value of Guano. 217 



2d. a lb., since it can be bought at this price in a perfectly 

 soluble condition; that it has less than half this value will pre- 

 sently appear. 



Thus far the argument has been extremely simple : it is quite 

 easy to fix a price upon the phosphate of lime derived from 

 mineral substances, because their entire value is referable to it ; 

 but the cost of this substance in bones or in guano is of more 

 difficult decision, because in the latter cases a second element is 

 introduced into the calculation ; in bones, for instance, there are 

 two chief sources of agricultural value — the gelatin, or nitrogenous 

 matter capable of yielding ammonia, and the earthy phosphates. 

 We must establish the money value of the one before we can 

 calculate the cost at which we purchase the other. 



Not to anticipate the argument which will be adduced when 

 speaking of ammonia, it may be sufficient in the present place to 

 observe that ammonia may be bought, in a fit state for agricultural 

 use, and in almost unlimited quantity, at something under 6d. alb. 



Raw unboiled bones contain* 6*00 per cent, of nitrogen, 

 which, when converted by decomposition into ammonia, would 

 furnish about 7 '3 per cent, of the latter ingredient. Upon this 

 presumption 1 cvvt. of bones will eventually furnish 8 lbs. of am- 

 monia. In the following calculations the price of raw and crushed 

 bones is estimated at 5/. 10s. a ton, or 5s. 6d. a cwt. If the whole 

 quantity of ammonia which bones can gradually furnish existed in 

 them, or was capable of being supplied by them as readily as it is 

 by guano, then it would be quite fair to calculate it at the price 

 just now named, that is to say, at 6c/. a lb. But it is not so ; there 

 is reason to believe that bones will remain in the ground a great 

 length of time unaltered, and, valuable as is the prolonged action 

 of the animal matter, it seems necessary to make a considerable 

 reduction for the tardiness of its action when compared with that 

 of ammonia. If we are allowed to deduct one-fourth of the 

 whole sum on this ground, then A.\d. a lb. will be the price of 

 ammonia as so furnished. It should be clearly understood that 

 this sum is only fixed by way of argument, and to assist in setting 

 a value on phosphate of lime ; when the latter point has been 

 satisfactorily determined, the argument may be reversed, and 

 brought to bear again upon the value of ammonia in bones. 



At \\cl. a lb. the 8 lbs. of ammonia supplied by 1 cwt. of bones 

 will be worth 3s. To the oil or fat of bones we cannot well 

 ascribe any agricultural value ; opinion is divided as to its agency 

 as manure, but there is very little doubt that bones are better 

 rather than worse for its removal — a circumstance, however, which 

 does not set the question at rest ; however this may be, the am- 



See Appendix. 



