240 THE FLOW OF SOLIDS. 
For the preliminary tests it seemed desirable to have a holder which 
could be opened, so as to show the compressed material in position, and 
finally the following form was adopted: 
Diagram of apparatus used in work on high pressures. 
B 
Fic. 1.—Longitudinal section. 
Fia. 2.—'Transverse section. 
Fig. 1 shows a longitudinal section on A A of Fig. 2. Fig. 2 shows 
a transverse section across the holder on the plane BB of Fig.1. HE E 
are the two halves in contact at h h, inclosing the cylindrical hole F,in 
which the substance to be pressed is placed. hh are strips of tissue 
paper, used as packing between two halves. I and I’, Fig. 1, are the 
two pins, acting as pistons, fitting into the hole F, to transmit the 
pressure; a a and a a are copper “ gas-checks,” placed in front of these 
pins, to flare out and fill tightly the hole, preventing any escape of 
material. Figs. 1 and 2 are about one-sixth of natural size. Fig. 3 
shows the manner in which the apparatus was held in the testing ma- 
‘chine and the pressure applhed. P P P and P’ P’ P’ are the jaws of 
the hydraulic clamps of the machine (capacity 1,000,000 pounds). H 
Hare merely blocks to enable the clamp to properly hold the holder 
KE. Nisa block to hold the back stationary pin in place. The let- 
tering in Figs. 1 and 2 apply in Fig. 3. V V is the hydraulic clamp 
on the fixed end of the testing machine where the pressure is weighed. 
The block B B moves on a spherical surface (R R) on the plate T T, 
thus permitting the adjustment of the face of O perpendicular to the 
line of pressure or parallel to the rear surface of the pin I. To apply 
the pressure, the movable clamp P P’ is forced toward V V by a 
hydraulic piston, thus forcing the holder E E over the pin resting 
against O; the pressure on O is measured by the hydraulie balance 
of the machine. In this manner a total compressive power of one 
million pounds was available, but as the pins yielded at 110,000 pounds 
per square inch, the tests were not carried above 6,409 atmospheres, 
or 96,000 pounds per square inch. 
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