THE MANURING OF THE CANE. 



Cotton seed cake is largely used in Louisiana, and the other forms of 

 organic nitrogen are used to a certain extent in Java, where they form products 

 of the country ; some quantity of these materials also finds its way from India 

 to Mauritius. The refuse of indigo factories is also used in Java, and in 

 Mauritius the refuse from aloe fibre factories. 



Dried blood, as it comes on the market, contains from 10 per cent, to 16 

 per cent, of nitrogen. 



Fish scrap is of very variable composition, containing from 5 per cent, to 

 8 per cent, nitrogen, and from 5 per cent, to 7 per cent, phosphoric acid. 



Tankage is the residue from packing houses, and is of variable composition ; 

 as it contains considerable quantities of bone it is also a phosphatic manure. 

 It is similar in action and composition to fish scrap. 



Guano. The original Peruvian guano has long been exhausted, and the 

 guanos now on the market are of recent origin. They differ much in composition 

 from those of long accumulation. Some bat guanos contain an extraordinarily 

 high amount of nitrogen, reaching up to 30 per cent. 



Cyanamide is a synthetic compound of the formula CaCN 2 ; it is sold 

 under the name lime nitrogen, German nitrate, or even as lime nitrate, from 

 which it must be carefully distinguished ; as it appears in commerce it contains 

 about 20 per cent, of nitrogen. 



Nitrate of lime is manufactured and put on the market as a basic nitrate 

 of composition Ca (OH) N0 3 . It contains about 12 per cent, of nitrogen, 



Gypsum. This material is sulphate of lime, and, in a sense, can not be 

 regarded as a manure ; it acts indirectly as a source of potash, which it sets free 

 in soils ; it is also used as a corrective of soil alkalinity. 



Bwie manures contain from 4 per cent, to 6 per cent, of nitrogen, and from 

 40 per cent, to 50 per cent, of phosphate of lime; this form of manure is sold 

 as half-inch, quarter-inch, or as bone meal or dust, and is frequently steamed 

 to remove the fats. The nitrogen is of little availability, and the phosphates, 

 unless the bones are finely ground, are but slowly assimilated. 



Mineral phosphates contain from 25 per cent, to 35 percent, of phosphoric 

 acid, and are occasionally used without previous treatment intended to render 

 the phosphoric acid soluble. 



Superphosphates usually contain about 20 per cent, soluble phosphoric 

 acid, and in the form known to the trade as ' double superphosphate ' up to 

 40 per cent, to 50 per cent. They are prepared from mineral phosphates by 

 the action of sulphuric acid. 



asio slag is the material obtained as a waste product in the ' basic ' pro- 

 cess of steel manufacture ; it usually contains from 15 per cent, to 20 per cent, 

 phosphoric acid, and from 40 per cent, to 50 per cent, of lime, a portion of 

 which exists as free lime. 



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