314 THE LABRADOR PENINSULA. CHAP. xvni. 



Phosphoric acid, 3 T % pounds at 4i cents . . $0-153 

 Ammonia, 3J pounds at 14 cents .... 0-525 



'At 68 cents the 100 pounds, this manure would be 

 worth $13-60 the ton. The sulphuric acid is of small 

 value, corresponding to 80 pounds of plaster of Paris to 

 the ton, and we do not take it into the calculation. The 

 somewhat larger amount of phosphoric acid in the second 

 specimen, is probably derived in part from the ashes of 

 the sawdust, and in part from the clay. The value of 

 this manure would be $10-88 the ton. 



calculations made by Professor S. W. Johnson of New Haven, Connecticut, 

 which are based on the prices of manures in the United States in 1857. In 

 order to fix the value of phosphoric acid in its insoluble combinations, he 

 has taken the market prices of Columbian guano, and the refuse bone-ash of 

 the sugar refiners, which contain respectively about 40 and 32 per cent, of 

 phosphoric acid, and from these he deduces as a mean 4J cents the pound as 

 the value of phosphoric acid when present in the form of phosphate of 

 lime. This would give $1-44 as the value of 100 pounds of bone-ash, and 

 $1-60 for the same amount of the guano, while they are sold for $30 and 

 $35 the ton. 



The value of soluble phosphoric acid has been fixed by Dr. Volcker in 

 England, and by Stockhardt in Saxony, at 12 cents the pound. This valua- 

 tion is based upon the market price of the commercial super-phosphates of 

 lime. Mr. Way, of the Eoyal Agricultural Society, however, estimates the 

 value of phosphoric acid in its soluble combination at only 10j cents the 

 pound ; and Mr. Johnson, although adopting the higher price, regards it as 

 above the true value. 



In order to fix the real value of ammonia, Professor Johnson deducts from the 

 price of Peruvian guano, at $65 the ton, the value of the phosphoric acid which 

 it contains, and thus arrives at 14 cents the pound for the price of the avail- 

 able ammonia present. This kind of guano, however, commands a price 

 considerably above that which serves for the basis of the above calculation ; 

 and both Volcker and Stockhardt fix the value of ammonia at 20 cents the 

 pound. The price of potash as a manure is estimated by Mr. Johnson at 4 

 cents the pound; but this alkali rarely enters to any considerable extent into 

 any concentrated manures, and may therefore be neglected in estimates of 

 their value. 



