VALUE OF FERTILIZERS. 325 



telligent men engaged in the manufacture and sale of thess artifi- 

 cial manures, and owing to more definite knowledge on the part 

 of the manufacturers and of the purchasers, it is not a difficult 

 matter to find manures well worth the money askecl for them. 



" A correct analysis," said I, " furnishes the only sure test of 

 value. * Testimonials' from farmers and others are pre-eminently 

 unreliable. With over thirty years' experience in the use of these 

 fertilizers, I would place far more confidence on a good and reli- 

 able analysis than on any actual trial I could make in the field. 

 Testimonials to a patent fertilizer are about as reliable as testimo- 

 nials to a patent-medicine. In buying a manure, we want to know 

 what it contains, and the condition of the constituents." 



In 1377, Prof. S. W. Johnson gives the following figures, show- 

 ing " the trade-values, or cost in market, per pound, of the ordi- 

 nary occurring forms of nitrogen, phosphoric acid, and potash, as 

 recently found in the New York and New England markets: 



Cents per pour.d, 



Nitrogen in ammonia and nitrates fci 



" in Peruvian Guano, fine steamed bone, dried aud 



fine ground blood, meat, and fish 



in fine ground bone, horn, and wool-dust 15 



" in coarse bone, horn-shavings, and fish-scrap 15 



Phosphoric acid soluble in water ls 



" " reverted," and in Peruvian Guano 9 



" insoluble, in fine bone and fish jruano 7 



in coarse bone, bone-ash, and 



bone-black 5 



" " " in fine ground rock phosphate... 3i 



Potash in hio-h-grade sulphate 



in kainit, as sulphate ti 



" in muriate, or potassium chloride G 



" These { estimated values,' " says Prof. Johnson, " aro not fixed, 

 but vary with the state of the market, and are from time to time 

 subject to revision. They are not exact to the cent or its fractions, 

 because the same article sells cheaper at commercial or manufac- 

 turing centers than in country towns, cheaper in large lots than in 

 small, cheaper for cash than on time. These values are high 

 enough to do no injustice to the dealer, and accurate enough to 

 serve the object of the consumer. 



"By multiplying the per cent of Nitrogen, etc., by the trade- 

 value per pound, and then by 20, we get the value per ton of the 

 several ingredients, and adrling the latter together, we obtain the 

 total estimated value per ton. 



" The uses of the ' Valuation ' are, 1st, to show whether a given 

 lot or brand of fertilizer is worth as a commodity of trade what it 

 costs. If the selling price is no higher than the estimated value, 



