_THE EXTRACTION OF TANNING MATERIALS, AND THE MAKING OF EXTRACTS._
Leaching -- Early forms of leaches -- The press-leach system --
Handling of liquors -- Distributing troughs and valves -- Construction
of leaches -- Influence of temperature -- Use of silent boiling jet --
Closed extractors -- Sprinkling leaches -- Manufacture of extracts --
Decolorisation of extracts -- Soluble extracts -- Concentration of
extracts -- Yaryan evaporator -- Multiple effects -- The use of
extracts in the tannery -- Effect of temperature on extraction and
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