232 THE CULTURE OF FARM CROPS. 



Bones when dry, consist of 35 per cent, of gelatine ; 55 

 per cent, of phosphate of lime; 4 per cent, of carbonate of 

 lirne; 3 per cent, of phosphate of magnesia; and 3 per cent. 

 of soda; potash, and common salt. Usually the gelatine of 

 Indies is too valuable for the glue which is made from it to 

 be left in the bones, used for manure, and as this contains a 

 large proportion of nitrogen, the manurial value of the 

 bones is considerably decreased by its loss. The bone 

 mostly used is that which has been steamed to extract the 

 gelatine, and consists of phosphate of lime and the other 

 mineral matters. These however are exceedingly valuable 

 as plant food, and are desirable for their permanence in the 

 soil. The good effects resulting from an application of 1000 

 Ibs. of crushed bone per acre to grass land, have been per- 

 ceptible at the end of 30 years; thus showing bones to be 

 one of the cheapest, if not the cheapest, of all manures. 



As phosphoric acid, of which bone phosphate contains 48 

 per cent, of its weight, is a constituent of all farm plants, 

 bones are found valuable under all circumstances; upon all 

 soils, and for all crops; and never come amiss. The supply 

 is however limited to the product from the animals 

 slaughtered and the refuse of the factories where bone is 

 used in the arts. An analysis of common bone manure .is 

 given in the table above referred to. 



WOOL WASTE from woolen factories is an exceedingly 

 valuable fertilizer for some special uses. It is used exten- 

 sively in the European and English hop yards, and is ap- 

 plied yearly, being dug into the soil about the roots. Its 

 principal fertilizing property is derived from the nitrogen 

 and the sulphur it contains. Its analysis will be found be- 

 low. 



CASTOR OIL POMACE; SOOT FROM SO*T COAL; COT- 

 TON SEED ; AND LEATHER SCRAPS ; are used for manure 

 in localities where they can be procured without too much 

 expense for transportation. With the exception of the last 

 mentioned, these waste substances are of considerable value, 

 chiefly for the nitrogen they contain, and form an excellent 

 basis for enriching composts, or for top dressing grass lands. 



