CHAPTER XX.

_THE SAMPLING AND ANALYSIS OF TANNING MATERIALS._

The International Association of Leather Trades Chemists -- The American Official Association of Agricultural Chemists -- The sampling of material -- Preparation of solution for analysis -- Extraction of solid materials -- Total soluble matter -- Evaporations of solutions -- The weighing of residues -- The determination of non-tannins -- The hide-powder filter method -- The hide-powder shake method -- Determination of moisture -- Colour-measurement PAGE 300