Fish Manures. 17 



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 phospho- 

 ric acid, and from these he deduces as a mean 4£ cents the pound 

 as the value of phosphoric acid when present in the form of phos- 

 phate 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 evaluation is based upon the market price of the 

 commercial super-phosphates of lime. Mr. Way of the Royal 

 Agricultural Society, however, estimates the value of phosphoric 

 acid in its soluble combinations at only 10^ 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, Prof. 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 available ammonia present.. This kind 

 of guano, however, now 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. John- 

 son at 4 cents the pound ; but this alkali rarely enters to any 

 considerable extent into any concentrated manures, and may there- 

 fore be neglected in estimates of their value. 



The use of fish as a manure has Ions: been known : on the 

 shores of Scotland, Cornwall, Brittany, some parts of the United 

 States, and on our own sea-coasts, the offal from fisheries, as well 

 as certain bony fishes of little value for food, are applied to the 

 soil with great benefit. The idea of converting these materials 

 into a portable manure was however I believe first carried into 

 effect in France by Mr. Demolon, who seven or eight years since, 

 erected establishments for this object on the coast of Brittany and 

 in Newfoundland. For the details of this manufacture I am 

 indebted to the Chimie Industrielle of Payen. Concarneau, in 

 the department of Finisterre, is a small town whose inhabitants 

 are employed in fishing fur sardines, and it is the refuse of this 

 fishery which is employed in the manufacture of manure. The 

 offal is placed in large coppers and heated by steam until 

 Canadian Nat. 2 yol. iv. no. i. 



