]921.] Basic Slag Problems. 525 



2. Whether the open hearth slags are inferior to Bessemer 

 slags when applied in quantities containing equal amounts of 

 phosphorus. 



3. Whether finely-ground mineral phosphates differ greatly 

 in value from basic slag. 



4. W^hether the manurial effect of basic slag is wholly 

 dependent on its phosphate content, or whether other con- 

 stituents (manganese, etc.) should be considered of value. 



To test the first three problems, a series of experiments has 

 been arranged at Rothamsted on meadow land laid in for hay. 

 and on root crops; also a feeding trial with sheep (six plots, each 

 of approximately 2 acres). The fourth problem is more difficult, 

 hut it is being studied, in the first instance, in pot experiments at 

 "Rothamsted. The results so far obtained from the fourth series- 

 lend no support to the idea that manganese is of value. 



