and their combinations. The visitor should examine the cases in the order in which they are arranged, beginning with the cases marked 1 and 1A. These two cases contain specimens of native Iron. Native iron has nearly always proved to be of meteoric origin; and the specimens are here arranged in the order in which they have been found. They have fallen from the heavens at different places, and at different periods. The largest known aerolite is that which fell in Brazil, and was no less than eight feet in length. These huge solid masses of iron, discharged from the clouds in a burning state, may well set the brains of philosophic men to work, to unravel the splendid mystery that contrives laboratories high up in the air, from which dense tons of pure iron are discharged upon our earth. Humboldt, discarding the Laplaceian theory that aerolites were detached masses of the moon, which ignited on reaching the oxygen that surrounds our globe, asserts that they are Lilliputian planets, having their system as we have ours; that they are identical with shooting stars, and that they occasionally fall to the earth by coming within the attraction of a body of overpowering magnitude. In the case with these meteoric specimens of native iron are specimens of native Copper--not often found in a pure state; native Lead, of meteoric origin; one specimen, exhibited in the form of a medal, having been cast out of the crater of Vesuvius about two hundred years ago; and native Bismuth, which expands as it cools. In the second case the visitor will particularly notice the beautiful threads of native Silver from the Hartz Mountains; and the various forms in which pure silver is found; native Mercury, and combinations of mercury and silver called native amalgam, some moulded into figures by Mexican miners; native Platinum from Siberia; and Palladium. The third case of the series is resplendent with samples of native Gold--a metal that plays so powerful a part in the affairs of men--that has roused the fiercest passions of mankind, and been coveted by human beings from the remote times when the Phoenicians dreamt of golden lands in the east. Half of this table case is covered with native gold and alloys. Pure gold is generally found in separate crystals or grains, but the metal is mostly found combined with other substances. It is alloyed, for manufacturing purposes, with copper and silver.