59 PREPARATION OF CLAYS. the grindstones or rather of the flutccl c\'Hnclers allows of easy crushing of the lumps. … l""'^'- 37- — Crushing Mill with Movable Pan (Whitehead). Universal Pounder and Crusher. — These are used to reduce hard bodies to small fragments. They are composed (Fig. 41) Fig, 38. — Crushing Mill with Movable Pan (Whittaker).