[86] Harlan I. Smith, Archaeology of the Thompson River Region, Publ. Jesup North Pacific Expedition, Vol. I, fig. 352 _d_, p. 418; James Teit, The Thompson Indians, _ibid._ figs. 125, 126. p. 184; perhaps also the beaver tooth knife, _ibid._ fig. 49, p. 144. [87] Otis T. Mason, Report U. S. National Museum, 1897, pt. 1, pp. 725 et seq. [88] M. Weiss, Die Völkerstämme im Norden Deutsch-Ostafrikas, p. 421 et seq.; also G. Tessmann, Die Pangwe, p. 222; Jan Czekanowski (Ruanda) l. c. (see p. 111) p. 155. [89] G. Schweinfurth, Im Herzen von Afrika, 3d ed. p. 349. [90] E. W. Smith and A. M. Dale, The Ila-speaking Peoples of Northern Rhodesia, Vol. I, p. 199. Another example illustrating our point is presented by the hammers used by the Indians of the northwest coast of North America. The coast tribes of Washington use a hand hammer made of a single bowlder with a lateral striking head, the tribes of Vancouver Island, a hand hammer also made of a single bowlder, with a cylindrical shaft and a flat striking head at the lower end[91]; those of northern British Columbia a heavy hammerstone lashed to a large wooden handle. [91] Franz Boas, The Kwakiutl of Vancouver Island, Publications of the Jesup North Pacific Expedition, Vol. 5, pp. 314 et seq. In another way habits of movement or position find expression in household furniture and dress. Tribes among which squatting on the ground is habitual do not use stools or chairs. Those in the habit of lying on their sides do not use neck rests which are found among people with elaborate hair dress that lie on their backs. The clothing of women is adapted to the manner in which they carry their children. The hood of the Eskimo woman of Baffinland accommodates the child that is carried on the back. The wide boot of the women of Southampton Island and of the ancient styles of Hudson Strait served to protect the child that was carried on the hip. It is hardly likely that the habits of the people originated from forms of the household goods they used. It is much more probable that the inventions were determined by older habits. In later times the relation may have been reversed, in so far as each generation stabilizes its habits in accordance with the objects to which it is accustomed. A similar permanence of form of utensils which are adjusted to definite motor habits exists in modern times, as is illustrated by the rigidity of form of many tradesmen’s tools or the permanence of the keyboard of the piano. The same conservatism, although based on the training of another sense organ, is found in the stability of the forms of the letters of our alphabet. In writing, both the firmly established motor habits and the fixity of the associations between visual image and form, help to stabilize old forms and to make difficult innovations.