CRYSTALLIZATION OF GOLD. A small glass-stoppered vial, containing a solu tion of gold in a mixture of nitric and muriatic acids, had stood neglected for a considerable time (perhaps four or five years) in a cupboard. Upon accidentally examining it, it was found a portion of the acid had escaped, and the gold crystalliz ed. This effect had probably been pro moted by a flaw in the vial, which extend ed through the neck, and a little way down its length. The stopper in conse quence must have been slightly loosened, and thus allowed more space for the for mation of a thin dendritie crystallization of the gold. This was further continued down the.inner surface of the vial and was there sufficiently thick to admit the impression of minute, but distinct crys tallization facets. A small crystallized lump of gold lay at the bottom of the vial; but supposed to have been originally at tached to the rest, and merely by its weight, as has since observed to be the ease in another portion. Around the
stopper, and along the flaw, there was a saline concretion, which tasted like sal ammonia; and as ammonia was kept in the same cupboard, it had probably uni ted with the muriatic acid as it exuded. On examining some other metallic so lutions, it was found that a similar separation of the metal had taken place in a vial- containing a solution of pla tins, and in another, containing a so lution of palladium. In both these cases, a thin, interrupted, and dentritic lamina of metal might be seen between the stopper and the neck ; but the crys tallization had proceeded no further. On unstopping the vial containing the tins, the lamina (as might have been expected) immediately disappeared in the form of a slight muddy These facts, if multiplied, may, per haps, serve to throw some light upon the mode in 'which the dcntritio laminas of native gold, silver, &c., are formed in rocks.