DEPTH OF ZONE OF FLOW IN THE EARTH’S CRUST 113 
were first made at the ordinary temperatures. The following 
table shows the results obtained: 
TABLE III 
SHOWING THE EFFrects PRODUCED WHEN COLUMNS OF WESTERLY GRANITE—AT THE 
ORDINARY TEMPERATURE—ARE SUBMITTED TO PRESSURES EXISTING AT 
SUCCESSIVE DEPTHS WITHIN THE EARTH’S CRUST 
‘ Pressure Kilocmnen Depth Repre- Te On OE 
Peoeient ae ek si Gant. Ecbeel ay he D Bases Results 
QO cane 128,000 9,000 | 20 miles 24 mos. Holes unaltered— 
No movement. 
BU ote pis sci 160,000 II,250 | 25 miles 25 mos. Holes unaltered— 
(See PlateII, Fig.a). 
15 Oct cic 199,000 13,990 | 30.86 miles 15 hrs. Holes unaltered— 
No movement— 
BOGS AB tee 200,000 14,060 | 31 miles 25 mos. Transverse hole un- 
(100 tons to altered. Vertical 
sq. inch) hole partly closed 
at one end by 
rock powder. 
Bee sacle 222,500 15,040 | 35 miles 23 mos. Transverse hole 
completely filled. 
Vertical hole 
largely filled with 
rock powder— 
(Seen Pilate: 
Fig. b). 
It is thus seen that granite at the ordinary temperature, but 
under the conditions of cubic compression which obtain in the 
earth, will sustain a load of about too tons to the square inch, that 
is to say, a load rather more than seven times as great as the crush- 
ing load of the granite at the surface of the earth under the condi- 
tions of the ordinary laboratory test. 
In this connection an observation made by P. W. Bridgman is 
of interest, namely, that under an external hydrostatic pressure 
amounting to 24,000 atmospheres, or 360,000 pounds to the square 
inch, continued for 3 hours the cavity of a sealed glass tube did 
not close or show any sensible change in size or form." 
Reference has been made to the nature of the movement 
observed in the case of the Solenhofen limestone, which seemed 
to be due in part to flow and in part to fracture. 
sae Quoted by R. A. Daly in his paper on the ‘‘Nature of Volcanic Action,” Pro. 
Am. Acad. of Arts and Sciences, June, 191i, p. 53. 
