12 CEMENT POWDERS AND CEMENT LIQUIDS SOLD TOGETHER FOR PREPARING SELF-HARDENING ACID, ALKALI AND WATERPROOF CEMENTS IN SITU BY CONSTRUCTION WORKERS IN SETTING BRICKS, TILE AND IN THE PREPARATION OF LININGS, PUMPS, VALVES, PIPES AND IMPELLERS; CAULKING COMPOUNDS, FIBRE GLASS SHEET AND ASPHALT IN BULK AND SHEET FORM