In addition to aërolites, properly so called, or bodies known to have come to us from outlying space, large metallic masses exist in various parts of the world, lying in insulated situations, far remote from the abodes of civilization, whose chemical composition is closely analogous to that of the substances the descent of which has been witnessed. These circumstances leave no doubt as to their common origin. Pallas discovered an immense mass of malleable iron, mixed with nickel, at a considerable elevation on a mountain of slate in Siberia, a site plainly irreconcilable with the supposition of art having been there with its forges, even had it possessed the character of the common iron. In one of the rooms of the British Museum there is a specimen of a large mass which was found, and still remains, on the plain of Otumba, in the district of Buenos Ayres. The specimen alone weighs 1400 lbs., and the weight of the whole mass, which lies half buried in the ground, is computed to be thirteen tons. In the province of Bahia, in Brazil, another block has been discovered weighing upward of six tons. Considering the situation of these masses, with the details of their chemical analysis, the presumption is clearly warranted that they owe their origin to the same causes that have formed and projected the aërolites to the surface. With reference to the Siberian iron a general tradition prevails among the Tartars that it formerly descended from the heavens. A curious extract, translated from the Emperor Tchangire's memoirs of his own reign is given in a paper communicated to the Royal Society, which speaks of the fall of a metallic mass in India. The prince relates, that in the year 1620 (of our era) a violent explosion was heard at a village in the Punjaub, and at the same time a luminous body fell through the air on the earth. The officer of the district immediately repaired to the spot where it was said the body fell, and having found the place to be still hot, he caused it to be dug. He found that the heat kept increasing till they reached a lump of iron violently hot. This was afterward sent to court, where the emperor had it weighed in his presence, and ordered it to be forged into a sabre, a knife, and a dagger. After a trial the workmen reported that it was not malleable, but shivered under the hammer; and it required to be mixed with one third part of common iron, after which the mass was found to make excellent blades. The royal historian adds, that on the incident of this _iron of lightning_ being manufactured, a poet presented him with a distich that, "during his reign the earth attained order and regularity; that raw iron fell from lightning, which was, by his world-subduing authority, converted into a dagger, a knife, and two sabres."