106 FRANK D. ADAMS 
varying from a few hours to two and a half months. Upon the 
conclusion of the experiment, the apparatus was removed from the 
press; the pistons, which could be readily withdrawn, as well as 
the disks of paper if any had been employed, were removed. The 
question as to whether the vertical or longitudinal hole had under- 
Fic. 2—Showing the Column of Rock with a vertical and a transverse hole 
drilled through it, enclosed in a heavy tube of nickel steel. 
gone any constriction was determined by ascertaining whether 
the wire would still pass through the hole which it had been drawn 
to fit, the slightest change in size being readily detected. The 
steel tube with its enclosed rock column was then placed in a lathe 
and the steel surrounding the middle portion of the column was 
turned off until only a film remained. This, where it covered the 
