NITROGENIZED PHOSPHATIC MANURES. 293 



TABLE XCL— ANALYSES OF NORWEGIAN FISH GUANO. 



To tell the truth, fish guano has nothing in common but the name 

 with the different guanos which have been described in this treatise, 

 for it contains nitrogen in a different form and less assimilable than 

 in guanos properly so called. 



Whale Guano. — Guano is also prepared from whale debris ; 

 this product is similar to the preceding. Whale flesh contains in 

 the fresh state about 5 per cent of nitrogen, and in the dry fat- 

 extracted state about 14 per cent. The bones of the whale contain 

 3| per cent of nitrogen and 23 per cent of phosphoric acid. 



Crab Guano approaches fish guano. It is prepared from a 

 species of sea-crab or lobster, of which there is enormous con- 

 sumption on the coast of the North Sea. They are steamed, the 

 substance pressed, then it is roasted on plates, and finally reduced to 

 fine powder by grinding like fish guano. It is in the form of a 

 bright yellow powder mixed with fragments of shells, and contains 

 on an average 8 per cent of nitrogen and 3 per cent of phosphoric 

 acid. There is also a manufactory of crab guano at Oporto, Portugal. 



To appreciate the fertilizing value of the manures just described, 

 it must be borne in mind that the greater part of their nitrogen 

 exists not under the form of readily decomposable gelatine, but as 

 a horny substance, which moreover always retains a certain amount 

 of fat. These manures therefore act slowly, after the style of raw 

 bone dust ; if spread in autumn they decompose sufficiently in the 

 winter to become active in the spring, supposing always that they 

 have not been buried too deeply. Meat meal and fish meal 

 dissolved by sulphuric acid with equal nitrogen and phosphoric acid 

 content are^ of the same value and produce the same effect as bone 

 superphosphate ; it is therefore more rational to use these manures 

 in their soluble condition. The consumption of fish guano assumes 

 every year a new extension. The best sorts are used to feed cattle 

 and chickens, while the ordinary sorts are used as manure. The 

 price in the market per 100 kilos, (say 2 cwt.) was the following at 

 the end of December, 1907 : — 



Norwegian fish guano, 8 x 12 per cent 

 British „ ,,8x9 „ 



„ 7 X 11 





22-80 to 23-10 francs. 

 21-55 to 20-85 

 17-80 to 18 



