VALUATION OF MANURES. 369 



needful to multiply the stated percentage, that is to say, the num- 

 ber of pounds contained in one hundred pounds, by twenty, which 

 is the number of hundreds in a ton, and this by the legal price for 

 each pound. Do this for each constituent and add them togctlier. 



For instance, if the label says that the manure contains 6 per 

 cent, soluble phosphoric acid, multiply 6 by 20, making 120, and 

 this by 25 cents (the price for each pound) the result is 3000 cents, 

 or $30. If it says 8 per cent, of insoluble phosphoric acid, mul- 

 tiply 8 by 20, making 160, and this by 6 cents, the result is 960 

 cents — $9.60. If it says 2.5 per cent, ammonia, multiply 2| by 

 20, making 50, and this by 35 cents, the result is 1150 cents, or 

 $11.50. Now add these together, and you have the sum of 

 $51.10, which is the amount for which manufacturer and vender 

 are responsible. 



A method shorter still answers equally well. Multiply the per 

 centage by double the member of cents for each pound ; add these 

 together, and jcm havo the number of dimes which a ton amounts 

 to. Place at the r^-ght hand one cypher, and point off two figures, 

 and you have the sum in dollars and cents. Thus, in the case just 

 supposed, you say 6 times 50 are 300 ; 8 times 12 are 96, and 2| 

 times 10 are 115 ; add these together and you have 511 ; place to 

 this one cypher, 5110, point off two figures, you have $51.10. 

 Any lad in the common schools familiar with addition, multiplica- 

 tion and decimals, can readily solve any problem which may arise 

 in this connection in a few minutes. 



Whenever any manure is offered for which more than one cent 

 per pound is demanded, refuse it, unless it contains a due per 

 centage either of potash, or of phosphoric acid, or of nitrogen. 



The efficacy of these in the production of crops is assured be- 

 yond doubt, not that all three are equally useful on all soils, or for 

 all crops, but each is very good when and where needed. It would 

 be going quite out of our path to attempt showing here when and 

 how and why one, or another, or all should be employed. Our 

 present purpose is simply to determine their commercial value. 



The fertilizing efficacy, or agricultural value of any substance 

 being assured, and its degree or amount where it is contemplated' 

 to apply it being estimated with such approximation as the nature 

 admits, the question next in order is, what ought the farmer to 

 pay for it ? — and the answer plainly is, as little as he can buy it 

 for ; and not then unless its agricultural value exceeds its com- 

 mercial value ; and by enough to offer reasonable probability of a 

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