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mines, one of which yielded, on the centner or 1600ounces, half an ounce of noble metal, of which one fifth wasgold and the rest silver : from the fame quantity of ano-ther he obtained no less than sixty ounces of silver,and eight ounces and a half of gold : but the gold, ashe observes, is by no means proper to the pyrites, or anessential part of its composition, having been only casuallyintermixed, as it is in stones and other minerals in the goldmines.

Many have been deceived also by some of the talcs :of which there is one species, naturally of a grey colour,which in a moderately strong fire changes to a gold yel-low ; and another, naturally of a glittering gold colour,which receives no change from moderate fire : both thesebodies have a further resemblance to gold, in impartinga deep yellow tincture to strong aqua regia. By repeateddigestion in fresh aqua regis, all the colouring matter maybe extracted, and the earthy part left white : but the so-lution yields no gold, and is found to be no other than asolution of iron. Reaumur observes that spangles of theyellow talc are frequent in the sands of some rivers, andthat they may readily be distinguished from gold, whichthey have often been taken for, by viewing them witha magnifying glass; the gold particles found in rivers be-ing constantly smooth, with the edges rounded, while thetalky ones are rugged and sharp-edged.

II. Separation of gold from earthy and fony bodies by water.

Gold intermixed with earthy bodies in small particlesor dust, is separated by washing with water, which carriesoff the lighter earth, and leaves the more ponderousmetal behind : the great gravity of gold renders it bet-ter adapted to this way of separation than any of the othermetals. There are sundry variations in the manner of

conduct-