CHAPTER XXI.

_THE GRINDING OF TANNING MATERIALS._

Primitive methods of grinding -- The bell mill or coffee mill -- Disc mills -- Disintegrators -- Carr’s disintegrator -- Carter’s disintegrator -- Adjustment of disintegrators -- The Williams pulveriser -- Myrobalans and Valonia crushers -- Sawing mills -- Shaving mills -- Dyewood cutting machines -- Screening of ground materials -- Hatching of bark -- Disintegrators and fire insurance -- Dust from disintegrators -- Chain conveyors -- Belt conveyors -- Vibrating conveyors PAGE 316