TIO FRANK D. ADAMS 
A second series of experiments was then made with a view to 
ascertaining the effect produced by the introduction of the factor 
of heat. 
According to the investigations of Debray,’ the highest tem- 
perature to which calcite can be submitted in open vessels without 
decomposition is 450°C. This is the temperature which is sup- 
posed to exist at a depth of nine miles below the surface of the earth. 
Perforated columns of the limestone, identical in size and shape 
with those employed in the first series of experiments, were enclosed 
in heavy tubes of steel as before. The tubes having been heated 
to a temperature somewhat higher than 450°C., the column was 
inserted and the tube then allowed to cool and contract about it. 
The steel pistons were inserted in the usual manner and the whole 
being placed in a specially constructed heating apparatus, the rock 
was maintained at a temperature of 450°C. while submitted to the 
required pressure. 
An investigation into the relative expansion of the nickel steel 
and the Westerly granite carried out by N. E. Wheeler, B. Sc. of 
the Department of Physics of McGill University, shows that with 
a gradually rising temperature the granite at first expands more 
slowly than the steel and then more rapidly.2, The expansion 
curves intersect, i.e., both materials expand equally at a temper- 
ture of 4oo°C., and with the temperature of 450°C., at which all 
the experiments with two exceptions were conducted, the difference 
in expansion of the two materials is extremely small, the expansion 
of the granite being slightly greater, which serves only to cause 
the enclosing tube to hold the granite column a little more firmly. 
As it was impossible with the apparatus employed to maintain 
an absolutely constant temperature without the continuous atten- 
tion of the experimenter, these experiments at high temperatures 
could not be extended over periods of several months as in the case 
of the experiments conducted at ordinary temperatures. The 
shorter time during which the experiment lasted, however, was in 
a manner compensated for by increasing the pressure, a higher 
MiG Re 180 7003% 
2 “On the Thermal Expansion of Rock at High Temperatures,”’ Trans. Roy. Soc. 
of Canada, t910. 
