Joty—On. the Volume Change of Rocks and Minerals attending Fuston. 289 
GALVANOMETER SLIDE AT LV. THROUGHOUT. 
Galy. Micrometer. D2 -— Dy Temperature, 
Ty Centigrade. 
10-4 65 0:00552 410° 
12°7 85 0:00449 513 
17°5 166 000899 926 
20:0 200 0:01085 1070 
21°8 220 0:01192 1155 
23°9 244 0°01522 1250 
A new oven was inserted in the forceps and the platinum thermometer used in 
the previous experiments again employed. ‘This time the observations were as 
follows :— 
Galy. Micrometer. LT2— In Temperature, 
Dy Centigrade. 
11°8 85 0:00461 929° 
15:9 143 000775 820 
17°9 162 000878 905 
19°9 191 0:010385 1085 
22°4 216 0-O1170 1140 
23°1 231 0:01251 1200 
The bead used in the foregoing experiments was fused on a wire having a 
diameter of 0:005 inch. It was thought of interest to make a series of observa- 
tions with a bead of somewhat different dimensions and on a finer wire. The new 
bead had a diameter of 0:063 inch, and the wire upon which it was fused was 
0:003 inch in diameter. 
Galvy. Micrometer. In-Th Temperature, 
Ty Centigrade. 
12:7 89 0:0051 575° 
18-0 168 0:0096 975 
20°6 195 0-0112 1100 
22°6 220 0'0126 1205 
These experiments are plotted in figure 5 (see p. 290), where the round, 
square, and triangular marks refer to the first, second, and third series of 
experiments, respectively. 
The agreement between these results is satisfactory as showing the accuracy 
with which the readings are effected and their continuity from one oven to another, 
although these be even only approximately alike in dimensions. It appears, how- 
ever, that the employment of a good conductor of heat as a thermometer is 
