The shape of this meteoric mass is very peculiar; and, at first, it would hardly be recognized as the identical specimen figured by Mr. Bartlett at Tucson, especially as this gentleman estimated its weight at 600 pounds only. Instead of being, as Mr. Bartlett supposed, a mass supported on two legs, it is, in reality, a ring of metal, of very irregular dimensions, of which about one-quarter was buried in the ground, in order to support it in a convenient position for use as an anvil, when it was seen by him at Tucson. The dimensions of this ring are as follows: Greatest exterior diameter 49 inches. Least exterior diameter 38 ” Greatest width of central opening 26½ ” Least width of central opening 23 ” Greatest thickness at right angles to plane of ring 10 ” Width of thickest part of the ring 17½ ” Width of narrowest part 2¾ ” The weight of the mass corresponds, taking the specific gravity at 7.2, with a circle-ring, having an average width of one foot, and a thickness of a small fraction less than eight inches—the diameter of the circle represented by the exterior of the ring being assumed as four feet. On examining with a magnifying glass a fractured surface of the mass, it was seen at once to be different in composition from the Carleton Meteoric Iron, and my conjecture that Prof. Smith was mistaken in supposing that he analyzed a fragment from the mass figured by Mr. Bartlett, was confirmed.[3] It is now almost certain that Messrs. Brush and Smith did analyze fragments of the same meteoric iron. The Ainsa Meteoric Iron contains a large per centage of a white—almost transparent—silicious mineral, having a vitreous lustre, which may be olivine; but the amount seems larger than that in the Carleton mass. The Smithsonian Institution will undoubtedly cause a chemical investigation to be made of this superb meteoric mass, and it will be interesting to compare its composition with that of the Carleton meteorite, as the two were found so near each other that they may be supposed to have formed portions of the same body, and to have fallen at the same time. The photograph was taken by Mr. Watkins, at my request, partly to be sent abroad as a specimen of the high degree of perfection which has been attained by this gentleman in this department of art, and partly that an exact representation might be secured of this very remarkable body, in case it should be lost or captured on its way to Washington.