Society of Glass Technology · [Sheffield] · leaf 149
Fig. 4.- -The Rockwood Silica Companys Sand-quarry at Rockwood,Michigan. … Fig. 5.—Photomicrograph by reflected light ofglass-sand from Rockwood, Mich. (RockwoodSilica Company); magnified 17 diameters. [To face p. 7£ EXPLOITATION OF GLASS-SANDS IN THE UNITED STATES. 73 The following notes, dealing with the actual working of twodeposits (one of which has come into…
Glass
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
