1. This specification applies to the following materials in their use as extenders for paints :—
Barytes, natural barium sulphate, which may have been bleached.
Blanc Fixe, precipitated barium sulphate.
Witherite, natural barium carbonate.
Precipitated Barium Carbonate.
Whiting, calcium carbonate prepared from natural chalk.
Asbestine, natural hydrated magnesium silicate which may have been bleached.
China Clay, natural hydrated aluminium silicate substantially kaolinite suitably purified.
Silica.