Letters on natural magic, addressed to Sir Walter Scott (1832)
Brewster, David, 1781-1868 · London : John Murray · leaf 135
READING COINS IN THE DARK. 115 been long known, though never explained, of decy- phering the inscriptions on worn out coins. This is done by merely placing- the coin upon a hot iron : Fig. 23. Fig. 24. … An oxidation takes place over the whole surface of the coin, the film of oxide changing- its tint with the intensity or continuance of the heat. The parts, however, where the letters of the inscription had existed, oxidate at a different rate from the sur- rounding parts, so that these letters…
Scientific recreations · Magic
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
