Note 502 — MINERAL POISONS. (continued 4)

“A small portion of mercury was put through a funnel into a clean dry bottle, capable of holding about six ounces, and formed a stratum at the bottom not one-eighth of an inch in thickness; particular care was taken that none of the mercury should adhere to the upper part of the inside of the bottle. A small piece of leaf-gold was then attached to the under part of the stopper of the bottle, so that when the stopper was put into its place, the leaf-gold was enclosed in the bottle. It was then set aside in a safe place, which happened to be both dark and cool, and left for between six weeks and two months. At the end of that time it was examined, and the leaf-gold was found whitened by a quantity of mercury, though every part of the bottle and mercury remained, apparently, just as before. This experiment has been repeated several times, and always with success. The utmost care was taken that mercury should not get to the gold, except by passing through the atmosphere of the bottle. I think therefore it proves that at common temperatures, and even when the air is present, mercury is always surrounded by an atmosphere of the same substance.”—On the vapour of mercury at common temperatures, by M. Faraday, Chemical Assistant at the Royal Institution. Journal of Science and the Arts, vol. 10, p. 354.