166 IMPORTANCE AND VALUE 



Here I fear the objection that this calculation is too 

 low. I have sought to raise, and even to double it ; 

 but then, in estimating the price of the most famil- 

 iar artificial manures, a value so disproportionately 

 high was introduced for several, that they could be 

 brought into no sort of agreement with the opera- 

 tion of the latter, as ascertained by experience. Bad 

 guano, which often consists in greatest part of phos- 

 phate of lime, would then acquire nearly the same 

 value as the best, whereas experience speaks loudly 

 to the contrary. In support of my assumption^ it 

 may be alleged that in England nearly the same 

 price is regarded as correct, as may be inferred from 

 the experiments instituted and made public by Mr. 

 Lawes, respecting the action of the natural phos- 

 phate of lime (phosphorite). Hence it would rather 

 follow, that even in Germany the price above speci- 

 fied may be still somewhat reduced, inasmuch as 

 bones, with which, in the experiments referred to, the 

 action of phosphorite is compared, fetch in England 

 a higher sum than with us. In sugar-refiners' refuse 

 the price of the phosphate is likewise something 

 lower than that above mentioned. 



If phosphate of magnesia is more particularly ex- 

 hibited in the analysis, it must be reckoned at the 

 same price as phosphate of lime. So, too, when 

 both combinations are taken together under the 

 designation of phosphoric acid earths. 



If phosphoric acid and lime are individually 

 valued, then 1 lb. of phosphoric acid may be esti- 



