“In contrast to the obdurate nephrite, a block of kersantite was selected. This kersantite is from New Jersey, and is a much tougher stone than was generally used for the common stone axe or celt found in the eastern portion of the United States. The block was exceedingly rough when first taken in hand, yet it required less than two hours’ labor with an ordinary quartzite hammer to produce a comparatively well-finished axe. A good idea of the time necessary to manufacture such an implement is thus afforded. The polishing was done with sand and water rubbed with a smooth piece of quartzite, the time required being included in the time specified.” In his later paper in the _Anthropologist_, for July, 1893, Mr. McGuire continues his observations. He considers that all chipped implements show a special fracture, and therefore the weight of the hammer and its material and shape “are all important elements to be considered; the intended implement must be struck with a certain weight and force, and at a particular angle, to accomplish the desired result.” Mr. McGuire, in his papers, follows out more in detail what Mr. Sellars originally observed many years before any of the experiments by men connected with the Smithsonian Institution were made. Mr. McGuire calls attention to the difference between the heavy hammer and the light hammer-stone:— “The battering hammer is commonly a discoidal stone, having a rounded periphery, with a pit on each flat surface intended to hold the thumb and middle finger, whilst the index finger is placed on the periphery. The pits are but slight depressions, but are sufficient to prevent the stone from slipping as the blow is given, and at the same time enable the workman to raise the index finger slightly, and thus save the jar which would otherwise in a few minutes disable the arm. The blows with the battering hammer are given at the rate of two hundred or more a minute, which would be impossible with the ordinary chipping hammer. With this hammer rapidity is essential, and the blow is ordinarily given to a broad surface, and no deliberation is necessary. Battered objects are numerous and vary greatly in size; consequently the hammer is found to vary likewise.” [Illustration: FIG. 212. (S. 2–3.) Collection of W. P. Agee, Hope, Arkansas. ] Figs. 209, 210, and 211 present eighteen hammers from various portions of the United States. The pitted stone, the round hammer-stone, and the other rude grooved hammer are tools, as we have seen; but the more carefully worked grooved hammer served a different purpose. On the Plains large hammers were frequently made and used by Indian tribes that subsisted on the buffalo, as it would be impossible to break the larger bones of that animal with ordinary hand-hammers.