926 LHE JOURNAL OL (GEOLOGY: 
is shown in Fig. 5, and in the simplest form in Fig. 4@, and in 
the upper lines at the second escarpment of Fig. 6. 
In Fig. 5 the arch is shown complicated by a most important 
agency, namely, drag. This will be shown to be the source and 
explanation of some of the complicated phenomena observed in 
the wax. Experiment 6 was designed to determine the effects 
upon the moving wax of the drag from the bottom of the box. 
As noted above, it was necessary to induce drag. This was done 
by a pause in the shove allowing the wax to flatten slightly and 
adhere to the bottom. The currents marked by the lines in the 
wax descended upon the surface in the rear of the escarpment 
and where there retarded by friction, the upper part was carried 
forward by the general movement of the wax and the result is a 
curve reaching far to the rear of the escarpment, with a sharp 
curve passing back much closer to the escarpment and reaching 
the bottom of the box. Fig. 5 and the anterior portion of the 
wax in Figs. 7, 8 and 1o (in the latter it is to be noted that 
the curve is flattened by the unavoidable falling forward of the 
front of the wax as it cooled in its box). 
It was now desired to ascertain what became of the recurved 
currents under conditions of recurring obstructions and of being 
carried forward over a plane surface. The first of these ques- 
tions was answered incidentally in experimenting on the second, 
and its consideration may be retained till the last. 
Experiments 7 to 11 were designed to answer the first ques- 
tion and the results are seen in Figs. 6, 7, 8, 9 and Io. 
Experiment 7 was considered a failure because of the great 
reduction of the internal capacity of box and consequent accel- 
eration of the motion of the wax and the inability of the currents 
to reach the bottom and become affected by drag. Fig. 6. 
Experiment 8. The narrow valley and proximity of the 
escarpments produced a clogging of the wax and almost total 
disappearance of the characteristic curve, however enough 
remains to prove its existence. The lower layer and the second 
layer show drag respectively after the first and third escarpments, 
while the upper recurves only at the extremity. 
