Paper, account of tin mines and working of tin in Cornwall by Christopher Merrett 'The Stones from which Tinn is wrought are sometimes found a foot or two below the surface of the Earth, but most usually betwixt two walls of Rocks (which are commonly of an Iron colour, of little or no affinity with the Tinn) in a Vein or Load (as the Miners call it) betwixt 4 and 18 Inches broad, or thereabout.' The pits dug to extract it are sometimes over 60 fathoms deep. The miners tell ghost stroies of supernatural 'sprites' that are released with damp subterraneous air that cause delusions, illness and death. Read at the Royal Society on 16 December 1663 Subject: Geology / Metallurgy / Industry / Mining 16 December 1663