As to the polish on these things, there are some who contend that it is due to action of the soil, that a patina or coating of some sort accumulates. In other words, the polish is said to be a result of chemical action. Others have thought it due to long-continued use. Some spades, hoes, and flint celts exhibit this polish, others do not. The polish appears on specimens which look as if they had been long used. Yet all specimens showing much use do not exhibit the polish. But the most significant thing to my mind in favor of the theory that the polish is due to use, lies in the fact that it is not found on long flakes, spalls, or blades from quarries where flint suitable for agricultural implements was taken out and removed. Some of the quarry pits must be very old, yet polish does not appear on specimens found there. Again, if polish is due to some elements in the soil of river terraces, then one would suppose that the whole surfaces of the implements would be polished. But only the ends are polished, and always the end used in digging—that is, the edge of the spade. May 5, 1910, I lectured in Springfield, Illinois. Spades are numerous in the region lying between Springfield, Illinois, and the Mississippi River. Therefore, I took occasion to inquire particularly into the circumstances observed when spades were found, in order to settle this question as to polish. A number of gentlemen, who have collected several hundred spades, furnished me with much information with reference to conditions under which spades are found. Mr. H. M. Braun of East St. Louis, who lives near the Cahokia group of mounds, has one hundred and eighty-seven spades and more than a hundred hoes and two or three hundred flint celts and rough chipped implements in his collection. Mr. Braun informs me that no one who has found or collected spades could by any possibility believe that the polish is the result of chemical action. His reasons are as follows: First, that the polish is found on spades irrespective of location; that is, a spade may be found in the Mississippi bottoms, where the soil is very rich, or on the upland, or near a quarry. And it may or may not be polished. Second, that spear-heads, arrow-points, and knives of the same material as the spades do not show the polish. Third, that spades, hoes, and projectile points of the same material, from the same field, do not exhibit this polish. It is only the spade which has long been used, the edge of which is polished. If the polish is due to chemical action, the same polish would be found on small as well as large objects, or all the objects of a given locality would present that polish. In view of these facts, it is beyond question that the polish is due to use, and it is quite clear that any one who takes the opposite point of view is not familiar with the locality and conditions under which spades are found. [Illustration: FIG. 168. (_S. about 1–6._)