CHAPTER XXIV.
OIL TANNAGES, AND THE USE OF OILS AND FATS IN CURRYING.
Primitive use of oil in leather manufacture — Chamoising and the production of washleather — Manufacture of Moellon, or Dégras — Sod oil — Formaldehyde leathers — “Crown” and “Helvetia” leathers — Theory of oil leathers — Processes of currying — Theory of the stuffing process — Hand-stuffing — Drum-stuffing — Stuffing of dry leather — “Spueing” and its causes — Fat-liquoring PAGE [378]
CHAPTER XXV.
DYES AND DYEING.
Coal-tar colours — Acid and basic colours — Theories of dyeing — Fixation of colours on leather — Mordants and mordant colours — Curriers’ inks — Glazes and finishes — “Assistants” in dyeing — Bronzing — Fading of colours — Practical methods of leather dyeing — Use of dyewoods — Iron “strikers” — Tannin blacks — Staining — Theory of colour-mixtures — Finishing dyed leathers — Testing of dyes — Injurious effects of metals in dyeing PAGE [394]
CHAPTER XXVI.
EVAPORATION, HEATING AND DRYING.
Theory of evaporation — Boiling point and vapour-pressure — Consumption of heat in evaporation — Heat-units — Mechanical energy of heat — Evaporation by “multiple effect” — Vapour-pressure of atmospheric moisture — Wet and dry bulb thermometers — Heat and air required in leather-drying — Loss of heat by buildings — Quantity of heat given by steam and hot-water pipes — Screw-fans for drying — Centrifugal fans — “Turret” dryer — Downward ventilation — Arrangement of steam-pipes — Hot water pipes PAGE [420]
CHAPTER XXVII.