42 ROYAL SOCIETY OF CANADA 
—182° C. The effect on the granite seemed to be exactly similar. The 
cylinders were placed in a copper trough but little longer than the 
specimens themselves, and the bubbling of the liquid air as it was boiling 
next to the ends of the trough interfered with focusing micrometer mi- 
croscopes on the ends of the rock, so, unfortunately, no satisfactory 
measurement of the coefficient of expansion between —182° and 0° C. 
was obtained. 
In the following tables (See also Figure VIII.) are given the approxi- 
mate values of the coefficient of expansion per degree Centigrade at 
intervals of 100° C. These values were calculated from the slopes of 
expansion curves of Figures IV., V, and VI., at the various points consi- 
dered. They are given for the initial heating and also for one of the 
later heatings. 






Coefficient of Expansion Coefficient of Ex- Coefficient of Ex- 
for Diabase. pansion for Granite | pansion for Marble. 
Tempera- First Fifth First Fourth First Fifth 
ture. Heating. | Heating. | Heating. | Heating. | Heating. | Heating. 
100°C. | 62.7x10-7| 48.7x10-7| 90.7x10-7| 66.3x10-7| 82.3x10-7| 28.3x10-7 
200 89.8 | 55.7 139.6 63.4 181 92.3 
300 123.4 73.9 198.7 56.1 239 127.3 
400 163 77.6 (253.8 62.2 276 179.2 
500 233 88.4 331.7 82.3 IE ane 
600 374 116.8 430 122 GA hile PRE aes 
700 210 115.6 467 OBA Ar Nes 
800 126.6 91.2 402 10 2 UC ie homer: 
900 94.2 59.8 249.7 BOSS Me ot Some ee 
1000 (a ee NA ER A 159.4 MED rc go ie hee 





At this point it is interesting to compare the above results for low 
temperatures with those previously published. Those given by Reade 
are, for granites xx» per degree Fahrenheit and for marbles, 
mr Which gives for granite 88.53 x 10-7, and for marbles 97.40 x 
10-* per degree Centigrade. The results of the experiments under the 
direction of Col. Totten, above referred to, are equivalent to 86.85 x 10-7 
for granite, and to 102.02 x 10-7 for marble, per degree Centigrade. For 
the more accurate results obtained by Hallock in experiments upon 
several specimens of marble, between about 20° and 100° C. see reference 
above. It will be seen that the results obtained by the author for the 
lower temperatures are of the same order as those previously obtained. 
