Bulletin92, Bureau of Chemistry, U. S. Department of Agriculture. 



PLATE 



FIG. 1 ORTHOCLASE DUST IN THE FINEST STATE OF SUBDIVISION POSSIBLE 





. 



FIG. 2. SAME POWDER AS SHOWN IN FIG. AGROUND, WET, DRIED, 

 AND REPULVERISED. 



(ENLARGED 25 DIAMETERS). 



