411 



most cheaply obtained in the form of guano. The 

 phosphates, whose quantity may be often increased 

 with advantage, are best supplied in the form of " super- 

 phosphate of lime." Other materials are less frequently 

 required. For further information on the subject of 

 the present section, the student is referred to works 

 which treat especially of Agricultural Chemistry. 



1030. " SUPERPHOSPHATE OF LIME." 



What is said 



of superphos- 1 he method employed in the manufacture 

 phateofiime? of supe rphosphate of lime," has been al- 

 ready given in the chapter on Salts. As in the case 

 of guano, its agricultural value depends on actual or 

 potential ammonia, and phosphate of lime. In propor- 

 tion as the phosphoric acid is in a soluble form, the 

 value is much increased. Additional information on 

 this subject is given in the Appendix. 



