DEPTH OF ZONE OF FLOW IN THE EARTH’S CRUST 111 
pressure for a relatively shorter time producing in the case of plas- 
tic deformation the same effect as a relatively lower pressure for a 
longer period. While therefore the temperature, except in the last 
experiment, was maintained at 450°C., equivalent to a depth of 
g miles below the surface, the pressure was increased until it was 
equivalent to a depth of 15 miles below the surface, while the time 
varied from 70 seconds to 70 hours. The results obtained are set 
forth in the following table. 
TABLE II 
TABLE SHOWING THE EFFECTS PRODUCED WHEN COLUMNS OF SOLENHOFEN LIME- 
STONE—HEATED TO 450°C.—ARE SUBMITTED TO PRESSURES EXISTING AT 
DEPTHS OF 10 AND 15 MILES WITHIN THE EARTH’S CRUST 
Pressure : Depth Equi- 
| et Ue oe [RED | WIRES | Time Result 
Sq. Inc Employed 
AS Ome 450°C. 64,000 4,500 to miles 7 hrs. | Holes remain un- 
changed. No 
movement of any 
kind. 
BUA een se 450°C. | 96,000 6,750 | 15 miles | 7osecs. | Holes become 
slightly con- 
tracted. 
BO2 Wear. 450°C. | 96,000 6;750 . | 15 miles 7 hrs. | Holes become 
slightly con- 
tracted. 
GOW fe oar 450°C. 96,000 6,750 15 miles | 25 hrs. | Holes become 
slightly con- 
tracted. 
OU Os saad 450°C. | 96,000 6,750 15 miles | 7ohrs. | Holes become 
slightly con- 
tracted. 
DG awcpar eee 450°C. |. 96,000 6,750 15 miles | 7ohrs. | Holes become 
slightly con- 
tracted. 
BOGaco cos 490°C. | 96,000 6,750 15 miles | 7ohrs. | Transverse hole 
to closed com- 
Griese Oe pletely. 
In this series of experiments it is to be noted that when the 
rock is submitted to the maximum temperature which can be 
employed without decomposing it, namely 450°C., which is equiva- 
lent to a depth of nine miles below the surface of the earth, no 
effect is produced if the pressure be raised to that which obtains 
at a depth of 10 miles. If, however, the pressure is still further 
increased till it reaches that to which the rock would be exposed 
