Shot of man laying tray of six briquettes on clay and limestone display on table, sign "Test for Structural Clay Products". Shot of display of bricks, sign "Suitable for Face Brick". Shot of briquettes, limestone, clay display, sign "Test for Refractories" on table. HACS of display of various products made from industrial minerals including record, carborundum wheel, glass, salt, porcelain, insulator.