5. Statement of Results.—It is recommended, when full analysis is given, that the Statement should be made in the following manner:—
(1) Tanning Matters Absorbed by Hide.—Obtained by deducting the “soluble non-tanning matters” found by evaporating the hide-powder filtrate from the “total soluble.”
(2) Soluble Non-Tanning Matters.—Found by evaporation of filtrate from hide-powder filter.
(3) Insoluble.—By deducting “total soluble matter” from the “total dry matter.”
(4) Moisture.—Determined by drying a portion at the temperature adopted in the determination of “total soluble.”
If other determinations are given they shall form a separate additional statement.
Density.—The statement of densities of extracts, etc., should be given as specific gravity in preference to arbitrary degrees, such as Baumé, Twaddell, etc.
Section V.—Colour Measurement.
Colour Measurement.—It is recommended that the method used by English chemists, namely, measuring with Lovibond’s Tintometer (as described by Professor Procter and Dr. Parker, Journ. Soc. Chem. Ind., 1895, 125), shall be used, and the results stated in units of red, yellow and black. The measurement may be made on the solution used for analysis, but must be calculated to one containing 0·5 per cent. of tanning matter, in a centimetre cell.