378 
PROFESSOR F. D. ADAMS AND DR. J. T. XICOLSON 
Experiment K. 
Height before 
deformation. 
Height after 
deformation. 
Diameter 
before defor¬ 
mation. 
Diameter 
after defor¬ 
mation. 
Time of defor¬ 
mation. 
Crushing load after 
deformation in lbs. 
per sq. inch. 
1-53 
1-355 
1-002 
1-110 
124 days 
10,652 
The column was thus shortened by T75 inch, or 11 '4 per cent. 
On removing the pistons and slitting the tube open the marble within was found to 
be so hard and compact that it was necessary to insert a steel wedge between the two 
halves of tube and drive it in by means of a hammer in order to split the marble so 
that the adhering portions of the tube might be removed. The rock broke with a 
clear, even fracture along a vertical plane passing through the centre. 
Cones were not visible in this marble, the whole column (although not in so marked 
a manner as in the former experiments) presenting the dead white appearance 
characteristic of the deformed marble, although the ends of the column in contact 
with the plugs were a trifle less chalky in aspect than the rest of the rock. This 
difference was, however, by no means well marked, and little glistening cleavage faces 
could be seen throughout the whole mass of rock. One of the half-columns obtained 
by splitting the deformed marble was freed from the tube which still adhered firmly 
to it, in the usual manner. It separated as a single solid mass, which was quite 
smooth on the surface but stained with spots of a deep-brown colour where it had 
been in contact with the hot iron. The polish had, however, disappeared owing to 
the movements which had taken place over the surface, except on the ends and along 
a narrow zone at either end of the column where the lustre was still retained. The 
half-column was, of course, distinctly bulged. A photograph of bulged column, 
together with one of original size, is seen in Plate 23, fig. 5. 
In order to determine the strength of this limestone after deformation, the half¬ 
column was then placed in an Emery testing machine and tested in compression. The 
pressure was gradually increased without developing any signs of distress until a load 
of 4200 lbs. had been reached when it suddenly crushed to fragments. Rude half¬ 
cones appeared to have sheared in at either end, which, however, were not coincident 
with the traces of cones of the original marble, and strips split off the sides longi¬ 
tudinally, precisely as in the case of the columns of the original marble when tested 
in a similar manner. Columns of the original marble, in all respects identical with 
those employed in the experiment, as has already been mentioned, crushed at a pressure 
of between 11,430 and 12,025 lbs. per square inch. The crushing load of the marble 
of the deformed half-column is equivalent to 10,052 lbs. per square inch. Although 
therefore the two cannot be compared with absolute exactness, owing to their dif¬ 
ference iu shape, and to the fact that but a single test of the deformed marble was 
