FISH MANURE SEA-WEED. 133 



20'7 of phosphorus pentoxide, and a small quantity of copper. 

 The nitrogen was almost all as nitrates. An American 

 analysis" gives as the composition of bats' guano 

 Water , r . ... 4OO % 



Nitrogen ... ... 8-2,, 



Potash ... ... 1-3,, 



Phosphorus pentoxide... 3 '8 ,, 



Fish manure or fish guano. The bodies of fish are highly 

 nitrogenous and their bones in particular contain large quanti- 

 ties of phosphates. They therefore form a valuable manure 

 and are often used whenever, through an unusual glut in the 

 market, the price falls sufficiently. Then, too, the refuse of 

 fish their heads, bones, and other offal is now manufactured 

 into manure, especially in Norway. In America the refuse 

 from the manufacture of Menhaden oil is an important manure. 

 The flesh of whales is also used as manure. In general the 

 most objectionable ingredient in fish guano is the oil, which 

 prevents or hinders the fermentation and decay of the manure by 

 repelling water. The following table shows the average amounts 

 of fertilising material in various kinds of fish manure : 



Norwegian Raw fish Cod American 



fish guano. refuse guano. dried fish. 



Water ... ... 8-0% 5OO% 6-2% 12-8% 



Nitrogen ... ... 9-0,, 3'0,, 9-0,, 7-3 ,, 



Calcium phosphate ... 22-0 ,, 3-8 ,, 26-0 ,, 18-2 ,, 



Oil ... ... up to' 15-0 ,, 



Sea-weed, which is plentiful on some coasts, forms a cheap 

 and valuable manure. It has one great advantage its rapidity 

 of decomposition, which causes it to be a quick-acting manure. 

 Its composition may be gathered from the following analyses : 



* Bulletin 15, U.S. Dept. of Agriculture, 1893. 



