BOOK VIII. 



313 



A — Mortar. B — Open end of mortar. C — Slab of rock. D — Iron sole plates. 

 E — Screen. F — Launder. G — Wooden shovel. H — Settling pit. I — Iron 

 shovel, K — Heap of material which has settled. L — Ore which requires 



crushing. M — Small launder. 



