53 MODERN HIGH FARMING. 



Their extensive use in the manufacture of phosphorus has, how- 

 ever, so much enhanced their commercial value, that we may look 

 upon them as beyond the reach of the agriculturist. 



When dissolved in sulphuric acid and mixed with nitrogenous 

 materials, or farm-yard offal, to form complete manures, they may 

 be considered as occupying the very foremost place in the order of 

 merit as fertilizing agents. 



They are frequently used with nitrate of soda, in the raw crushed 

 st:ite, as a dressing to sandy soils and pasture lands ; but we have 

 personally found their action in these cases to be very slow, and 

 their assimilation a work of time, so that we cannot recommend 

 a continuance of the practice. 



BONE Asn results from the burning of bones and is chiefly ex- 

 ported from the cattle-raising districts of South America, where, 

 fuel being scarce, the bones are burnt in the process of extracting 

 the fat from the slaughtered oxen. 



ANIMAL CHARCOAL OR BONE BLACK is justly esteemed by all 

 those who are fortunate enough to obtain it on reasonable terms. 

 It is an excellent absorbent, and is extensively used in sugar refin- 

 eries, being only delivered to agriculture when it has lost its powers 

 of discoloring the juices. 



BONE MEAL is the impalpable powder of bones, from which a 

 steam process has succeeded in extracting all the gelatine. 



The following table shows the general composition of these ma- 

 terials : 



Containing Nitrogen 3.72 Traces. 1.58 



SULPHATE OP AMMONIA is largely obtained from animal urine, 

 but chiefly from the ammouiacal liquor derived from gas works 



