The first announcement of the discovery of these diamonds from the Cañon Diablo meteorite was made by Dr. A. E. Foote, and not long after Professor Koenig’s determination of their character, the present writer suggested an experiment that would afford absolute proof that the material was really diamond. This was to charge a new skaif, or diamond-polishing wheel, with the supposed diamond dust obtained from the meteorite; should the material polish a diamond there could be no doubt as to its character. On September 11, 1893, this experiment was tried at the Mining Building of the World’s Columbian Exposition. After the skaif had been charged with the residuum separated from the meteorite by Dr. O. W. Huntington, it was given a speed of 2500 revolutions to the minute, and in less than fifteen minutes a small flat surface had been ground down and polished on a cleavage-piece of rough diamond held against the wheel. The experiment was then repeated several times on other diamonds and always successfully. This showed conclusively that the residuum of the meteorite contained many minute diamond fragments.[183] A most important group of meteorites were found in 1886 in Brenham township, Kiowa County, Kansas, by some of the farmers of this district in the course of their farming operations.[184] Entirely unaware of their scientific value, the finders used these objects to weight down haystacks, or for similar uses to which they would put small boulders. In all some twenty of these specimens have been recovered, varying in weight all the way from 466 pounds down to a single ounce. Most of them were taken from an area of about sixty acres, although some were scattered over a wider tract. The largest piece of the group, that on which the farmers had bestowed the fanciful name of the “moon meteorite,” had lain only three inches beneath the surface of the ground and broke a ploughshare when it was first struck; none of the masses appear to have been buried deeper down than from five to six inches. The largest mass measures twenty-four inches across the widest part and fourteen and a half at the thickest part. These Kiowa meteorites are in a sense gem-meteorites, for a number of beautiful and brilliant olivine crystals occur in them; many are in two distinct zones, the inner one being a bright transparent yellow, while the outer one is of a dark brown iron olivine, in reality a mixture of troilite and olivine. The character and composition of the worked iron of meteoric origin found in some of the Turner group of Indian mounds, in the Little Miami Valley, Ohio, indicate that the latter may perhaps be brought into connection with this group of meteorites. For here, as in the Frozen North among the Esquimo, and in a number of other cases, the iron available for primitive man was mainly that of meteorite origin.