II4 FRANK D. ADAMS 
In the case of the granite the holes when filled are closed by 
what appear to be minute fragments of granite detached from the 
walls. In the case of experiment 358, after the removal of the 
steel the vertical hole as seen from either end was still open and 
was unaltered in size or shape for a distance of .08 and .24 inch 
respectively. Beyond that, however, it was blocked up. On 
removing the steel so as to expose the extremities of the transverse 
hole, it was found that one end of this hole was completely filled 
up, no trace of the opening remaining. The locus of the hole was 
occupied by what seemed to be a part of the rock, finer in grain 
than the rest and which looks as if it were a perfectly compacted 
mass of powdered granite. The other extremity of the hole had 
also been completely closed, although an outline marking its orig- 
inal position could be seen—it was filled with finely granular 
material clearly crushed granite, imbedded in which were a few 
relatively larger fragments giving to the whole the appearance of 
a breccia. 
In order to eliminate any error which might be conceived to 
have been introduced by the pistons expanding under the load and 
pressing against the sides of the steel tube, thus reducing the 
amount of pressure exerted on the rock and also to give the rock 
a better chance to deform by the application of the pressure to the 
center of the end faces instead of over the entire surface of the 
faces in question, another experiment was arranged in which the 
column and its enclosing tube were identical in all respects with 
those already described but the pistons were .4 inch in diameter 
while the column had the usual diameter of .5 inch. The proper 
load to give a pressure of 160,000 Ibs. per square inch, equivalent 
to a depth of 25 miles below the surface, was then applied by this 
smaller piston to the center of the end faces of the column, for a 
period of two and a half months, but no change whatever was 
produced in either the transverse or the vertical hole. 
A second series of experiments was then carried out with the 
Westerly granite in which the factor of heat was introduced. 
For the same reason as mentioned in the case of the Solenhofen 
limestone, the duration of the experiment was necessarily shorter 
than in the case of the experiments conducted at the ordinary 
temperature. The results of the experiments are as follows: 
