FERTILIZERS AND MANURES. 79 



"Thomas Slag is more familiarly known as odorless phos- 

 phate It is also known under several other names, such 

 as basic iron slag, Thomas scoria, phosphate slag, etc. 

 This is a comparatively new source of phosphoric acid 

 compounds. It is a by-product formed in the manufac- 

 ture of iron and steel from certain kinds of iron ore con- 

 taining phosphorus compounds. In the process phos- 

 phate of lime is formed, which is ground to a fine 

 powder."* 



* Geneva, N. Y. Experiment Station Bulletin, No. 94, pp. 315 to 321. 



