So far as appears on ancient pictographic works the kind of instruments and materials with which they were made can be inferred only from its aspect, though microscopic examination and chemical analysis have sometimes been successfully applied. A few examples relating to the topic are given as follows, though other descriptions appear elsewhere in this treatise. SECTION 1. INSTRUMENTS FOR CARVING. This title, as here used, is intended to include cutting, pecking, scratching, and rubbing. The Hidatsa, when scratching upon stone or rocks, as well as upon pieces of wood, employ a sharply pointed piece of hard stone, usually a fragment of quartz. The present writer successfully imitated the Micmac scratchings at Kejimkoojik lake, Nova Scotia, by using a stone arrow point upon the slate rocks. The bow-drill was largely used by the Innuit of Alaska in carving bone and ivory. Their present method of cutting figures and other characters is by a small steel blade, thick, though sharply pointed, resembling a graver. Many petroglyphs, e. g., those at Conowingo, Maryland, at Machiasport, Maine, and in Owens valley, California, present every evidence of having been deepened if not altogether fashioned by rubbing, either with a piece of wood and sand or with pointed stone. To incise or indent lines upon birch bark the Ojibwa, Ottawa, and other Algonquian tribes used a sharply pointed piece of bone, though they now prefer an iron nail. Examples of scratching upon the outer surface of bark are mentioned elsewhere. Several examples of producing characters on stone by pecking with another stone are mentioned in this paper, and Mr. J. D. McGuire (_a_), of Ellicott City, Maryland, has been remarkably successful in forming petroglyphs with the ordinary Indian stone hammer. Some of the results established by him are published in The American Anthropologist. SECTION 2. INSTRUMENTS FOR DRAWING. Drawings upon small slabs of wood, found among the Ojibwa, were made with a piece of red-hot wire or thin iron rod hammered to a point. Such figures are blackened by being burned in. When in haste or when better materials are not at hand, the Hidatsa sometimes drew upon a piece of wood or the shoulder-blade of a buffalo with a piece of charcoal from the fire or with a piece of red chalk or red ocher, with which nearly every warrior is at all times supplied. Mr. A. W. Howitt, in Manuscript Notes on Australian Pictographs, says: