ANIMAL MANURES. 1 39 



TIL Quantity/ of water ^ and mode of applying it. — When 

 undiluted vitriol is poured upon bones, violent action is pro- 

 duced, but continues for a very short time, as the gypsum, 

 which is the first new compound formed, covers the surface 

 of the pieces of bone with a crust, which prevents the acid 

 from coming into contact with the unaltered portions, and, in 

 consequence, its action is retarded, and a perfect solution is 

 not procured. If you drop some concentrated vitriol upon a^ 

 piece of limestone, there is a bubbling up, or effervescence, 

 from the escape of carbonic acid gas, but it continues only 

 for an instant. A crust of gypsum forms and protects the 

 stone from the acid ; but, if you use vitriol diluted with water, 

 the action and escape of gas continue for a much longer time. 

 The best plan, therefore, is to thoroughly moisten the bones 

 you intend to dissolve, by pouring over them a quantity of 

 water, and allowing them to soak in it for an hour or two 

 before adding the acid. The quantity of water used should 

 be three or four times that of the vitriol to be employed. 

 This mode of applying the water obviates the trouble of 

 mixing together the vitriol and water in a separate vessel, as 

 some recommend, and the heat generated, by adding the 

 strong acid to the moistened bones, greatly facilitates the 

 decomposition, and hastens the preparation of the compound. 



207. Animal substances occasionally employed as Manures. 

 — In addition to bones and guano, there are several animal 

 substances used as manures in England and on the continent, 

 but which are seldom or only casually applied by the Irish 

 farmer. Of these substances, therefore, only a brief account 

 will be necessary. Fish and shell-fish have long been con- 

 sidered most valuable fertilizers. It is, indeed, complamed, 

 that unless made into a compost with soil, they prove too 

 strong for the land. On the east coast of Scotland, Stephens, 

 in The Book of the Farm, informs us that, in the fishmg 

 villages, where the fish are smoked or salted, the refuse is 

 pm-chased by the farmers, and constitutes an efficient manure 

 for every kind of crop. *' Thirty barrels of fish heads and 

 guts, half of cod and half of haddock, are," he states, 

 " enough of manure for one acre. The barrel contains thirty 

 gallons, and four make a cart-load. The refuse sells at 

 Is. 6d. per barrel. In preparing fish refuse for manure, it is 

 emptied from the barrels on a head-ridge of the field to be 

 manured, and mixed with a quantity of eai'th, sufficient to 



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