XXXVI WORK IN THE UPPER HOUSE 183 



sect. I was rather surprised at the marked difference 

 between this and the upper layer. 



Underneath this second piece of baize was another 

 layer of sand, on the removal of which the third layer 

 of baize was found to be thrown into folds. This again 

 differed greatly from, though it evidently followed the 

 same general law as, the preceding. The ridges are 

 narrower and more pronounced, the valleys more 

 precipitous. There is also a marked tendency for each 

 ridge to present a central longitudinal division. 



A fourth layer of baize was separated from the third 

 by about 1| inches of sand, and from the bottom of 

 the apparatus by a similar layer. This fourth layer 

 of baize differs from the third in somewhat the same 

 manner as the third differs from the second. The ridges 

 are narrower, shorter, more precipitous, and more broken 

 up. The intervening spaces form wide, flat valleys. 



In another experiment sand and layers of baize were 

 arranged as before, but the weight was placed on one 

 side, in consequence of which the material was more 

 easily pressed up. 



In this case the ridges followed the edges, though not 

 closely, leaving a central hollow. Here, also, in the 

 upper layer of cloth the slopes were more gentle, the 

 eminences more rounded, the hollows less deep. In 

 the second layer of cloth the country is more rugged, 

 the elevations higher, the hollows deeper. Here too 

 several of the ridges have a tendency to become double, 

 with, in some cases a smaller ridge commencing in the 

 depression. The elevations and hollows only follow 

 roughly those of the upper layer. There are two main 

 ranges, with a broad intermediate valley. One of the 

 main ridges has secondary transverse folds. 



The third layer again has only a general resemblance 

 to the second. The folds are more numerous, narrower, 

 and more precipitous. 



The fourth or lowest layer presents a central plain, 

 bounded by two high, one moderate, and one low, 

 series of hills. 



The models seem also to show that some hollows, 

 which might on the earth's surface have been regarded 

 as evidence of sinking, are in reality only relative, and 

 due not to depression, but to the elevation of surrounding 

 ridges. 



