ON AN EXPERIMENTAL INVESTIGATION INTO THE FLOW OF MARBLE. 399 
hammering, a movement which in metals as a general rule, as in marble, is 
facilitated by increase of temperature 
6. There is therefore a flow of marble just as there is a flow of metals under suit¬ 
able conditions of pressure. 
7. The movement is also identical with that seen in glacial ice, although in the 
latter case the movement may not be entirely of this character. 
8. In these experiments the presence of water was not observed to exert any 
influence. 
9. It is believed, from the results of other experiments now being carried out but 
not yet completed, that similar movements can, to a certain extent at least, 
be induced in granite and other harder crystalline rocks, and that several 
structures developed in these rocks in nature in highly contorted regions can 
thus be reproduced. 
Explanation of Plates. 
PLATE 22. 
Fig. 1. The machine used in the investigation. A marble column is in process of 
deformation. The experiment is being carried out in the absence of moisture 
and at the ordinary temperature. The small boiler on the extreme right 
does not belong to this machine. 
Fig. 2. Thin section of the marble from Alte Kirke, Andermatt, Switzerland. The 
grains are slightly flattened in a horizontal direction, and are repeatedly 
twinned in almost every case. On the right there is a fine-grained 
aggregate which represents a remnant of the original fine-grained limestone, 
from the recrystallisation of which the marble was derived. The structure 
resembles that of Carrara marble artificially deformed at 300° or 400° C. 
Photographed between crossed Nicols. X 70 diameters. 
Fig. 3. Thin section of the limestone or marble from Griesbach, in the Erzgebirge. 
The smaller grains have probably been derived from the breaking down of 
larger individuals, a portion of one of which is seen. All the grains show 
most pronounced polysynthetic twinning, two sets of lamellae crossing one 
another being visible in most individuals. Movement on gliding planes is 
also pronounced, the structure being identical with that produced by the 
artificial deformation of Carrara marble at 300° C. or 400° C. Photographed 
between crossed Nicols. X 70 diameters. 
PLATE 23. 
Fig. 1. On the left the iron tube enclosing the marble of Experiment A is shown 
ready to be placed in the machine. On the right the same, after the 
marble had been slowly deformed during a period of 64 days. 13/14 of 
natural size. 
