5i8 FRANK D. ADAMS 



artichoke above mentioned. On the upper surface of the flattened 

 cake a large number of lines are seen which follow rude polygonal and 

 more or less concentric curves around the center of the surface, 

 which mark the borders of areas differing slightly in elevation. There 

 are also a few vertical lines running outward toward the corners. 

 These areas outlined on this surface are bases of rudely wedge- • 

 shaped forms which moved downward and outward. Thus the 

 whole mass flattened out (Plate V, Fig. a). 



A series of experiments was then made using prisms of Carrara 

 marble. In the first of these a prism 1.575 inches high and i . i inches 

 in diameter was embedded in alum in a copper tube, and the whole 

 was squeezed down under a load of 113,000 lbs. In this experiment 

 the tube, while retaining its original diameter at one end, spread out 

 under the pressure at the other, and the marble column developed a 

 graceful, rectangular, bell-shaped form, ornamented by the same 

 beautiful pattern of triangular leaves around the end where move- 

 ment had taken place. The height had been reduced to i . 2 inches 

 (Plate V, Fig. h). 



In the others the inclosing tube bulged at the middle in the usual 

 manner and yielded shapes like that of the column in Plate IV, 

 Fig. h, in which the zone of maximum movement was in the center of 

 the column, which was therefore ornamented by a frill of leafiike 

 forms in low relief. In these the load required for deformation 

 ranged from 133,000 to 197,000 lbs., the prisms being reduced in 

 height from i . 575 to from, i . i to i inch. 



A number of spheres i . 5 inches in diameter were then deformed 

 in heavy copper tubes. By the movement the spheres were flattened 

 to spheroids of wonderful form and beautifully ornamented, around 

 the zone of maximum movement, by a garland of the same graceful 

 leaflike shapes already described. The shearing which developed 

 these spheroids is exceedingly complicated, layer after layer of the 

 marble passing outward along the zone of maximum movement and 

 upward toward the axes of the spheroids, each partially overlapping 

 the one beneath, as shown in Plate V, Fig. c. The resulting sphe- 

 roidal mass, however, is a hard, solid body of marble and shows no 

 tendency to break in one direction rather than another. The move- 

 ments, although concentrated along certain planes, do not take 



