there is no distortion of the warp strings and the twisted woof will lie in regularly arranged loops. Any lack of automatic control will bring about irregularities of surface pattern. [Illustration: Fig. 3. Coiled basketry.] [Illustration: Fig. 4. Twined basketry.] A pot of well-rounded form results also from complete control of a technique. Primitive tribes make their pottery without the aid of the potter’s wheel, and in most cases the potter builds up his vessel by the process of coiling, analogous to the coiling of a basket. Long round strips of clay are laid down spirally beginning at the bottom. By continued turning and gradual laying on of more and more strips in a continued spiral the pot is built up. Complete control of the technique will result in a perfectly round cross section and in smooth curvatures of the sides. Lack of skill will bring about lack of symmetry and of smoothness of curvature. Virtuosity and regularity of surface and form are here also intimately related. [Illustration: Fig. 5. Chipped flint implements: _a_ North America; _b_ Egypt.] A similar correlation is found in the manufacture of chipped stone implements. After the brittle stone has been roughly shaped it is given its final form either by pressure with an implement that squeezes off long, thin flakes or by indirect chipping. In the former case the flaking implement is held in the right hand and by sudden pressure with the point of the flaker long flakes or small bits are removed from the surface. When the worker has attained complete control of this technique his pressure will be even and executed with equal rapidity; the distances between the points of attack will be the same and he will move his flaker in regular lines. The result is a chipped implement of regular form and surface pattern in which the long, conchoidal depressions caused by the flaking off of thin chips are of equal size and regularly arranged (fig. 5). When indirect chipping is applied the thin part of the object which is to be worked is placed on a hard, sharp edge and by a smart blow on the body of the flint a strong vibration is produced which results in a break just over the sharp edge. In this way, place and size of the flake are perfectly controlled by the expert craftsman. Quite similar are the conditions in woodwork. The smoothing of large surfaces is generally done with the adze. A skilled worker handles his adze automatically. The strength of the stroke and the depth to which it enters the surface of the wood are always the same and the chips removed have always the same size and form. The workman will also move the adze in even lines and strike the surface at even distances. The result of automatic action is here, also, evenness of surface and regularity of surface pattern (fig. 6).