Bulletin 92, Bureau of Chemistry, U. S. Department of Agriculture. 



PLATE it. 



FIG. 1 ORTHOCLASE ROCK GROUND WET IN AN AGATE MILL FOR THREE HOURS. 







, 



.- 



u. 





? % 



fc ; * 



4 . . ^ 





FIG. 2. WET GROUND ORTHOCLASE STAINED WITH METHYLENE BLUE. 

 (ENLARGED 25 DIAMETERS). 



