40 ROYAL SOCIETY OF CANADA 
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Results of One Heating of Nickel-Steel | Results of a Second Heating of Nickel— 




Cylinder. Steel Cylinder. 
Temperature. Total Expansion. | Temperature. Total Expansion. 
22°C: .0 mm. 22°C: .0 mm. 
120 .3612 128 .3078 
239 .6966 263.5 .1789 
221:9 .9259 353 1.0034 
424.5 1.1962 437 1.2019 
523 1.3394 (?) 542 | 1.4359 
624.5 1.6909 635 | 1.6468 
tal 1.7070 710 1.7062 
822 1.7833 829 1.8328 
922.5 2.2104 | 933 2.2217 
1010 2.4830 | 1009.5 2.5502 
859.5 1.7650 | 34.5 .2302 
736.5 12220770) Ar OO ARS PERC REAL cece PRE ee 
706 DL NES URS ES Oe eb i aes, ANR 
416 BDO Te ibs aed ive ay hese ga ? 
22 MARSTON 1 oa RO AMP OUT | 




It will be seen that much more is shown in this way concerning the 
real character of the thermal expansion than in investigations similar to 
that preliminary to this work, where simply two widely separated tem- 
peratures were taken and the average coefficient of expansion between 
these limits calculated. For instance, in the case of the diabase, it 
happens that between 20° C. and any temperature up to about 550° C. 
the coefficient of expansion is greater for the nickel-steel cylinder than 
for the initial heating of the diabase, while the reverse is true between 
20° C. and any temperature between about 550° C. and 1000° C. 
In the case of the rocks examined, there was no marked tendency 
of the permanent expansion to become less in the course of a few days 
or weeks. For example, the diabase cylinder, which measured 20.048 
ems. on February 1, measured 20.050 ems. in length on February 9, or 
practically the same within the limits of accuracy of such measurements 
with the vernier calipers used. The effect on this permanent expansion 
of cooling specimens of the diabase and granite to the temperature of 
liquid air was also tried. The diabase cylinder which had been subjected 
to the six heatings above mentioned, was kept in liquid air for about 
thirty minutes. Afterwards it was measured at 20° C., and its length 
found to be 20.053 cms. or practically the same as before the cooling to 
ei 
