486 MR. A. E. TUTTON ON THE THERMAL DEFORMATION OF THE CRYSTALLISED 
A comparison of the coefficients of expansion along analogous directions in the 
three salts is presented in the following table, which also includes a comparison of 
the coefficients for the particular temperature of 50°. 
Com'parative Table of the Linear Coefficients of Expansion for the Three Salts. 
The Constant a, the Coefficient of Expansion at 0°, 
Crystallographical axial 
direction. 
K 2 SO 4 . 
Rb2S04. 
CS 2 SO 4 . 
a 
0-000 036 16 
0-000 036 37 
1 
0-000 033 85 ’ 
h 
•000 032 25 
•000 032 14 
•000 031 95 
c 
•000 036 34 
•000 034 63 
•000 035 90 
Sums of values for all 1 
three directions : J 
0-000 104 75 
0-000 103 14 
0-000 101 70 
1 
The Constant h. Half the Increment of the Coefficient per Degree. 
Axial direction. 
K2SO4. 
Rb 2 S 04 . 
CS2SO4. 
a 
0-000 000 014 4 
0-000 000 020 3 
0-000 000 021 4 
h 
•000 000 014 1 
•000 000 018 4 
•000 000 018 2 
c 
•000 000 041 3 
•000 000 038 0 
-000 000 041 4 
Sums of values for all I 
three directions; J 
0-000 000 069 8 
0-000 000 076 7 
0-000 000 081 0 
ajoo, the Coefficient of Expansion, a = a 2bt, for 50°. 
Axial direction. 
K2SO4. 
Rb 2 S 04 . 
CS2SO4. 
a 
0-000 037 60 
0-000 038 40 
0-000 035 99 
b 
•000 033 66 
•000 033 98 
•000 033 77 
c 
•000 040 47 
•000 038 43 
•000 040 04 
Siuns of values for ain 
three directions: J 
0-000 111 73 
0-000 110 81 
1 
0-000 109 80 
1 
It will be observed that in the preceding table the sums of the values of each 
constant for the three axial directions of each particular salt are taken. These sums 
represent the constants of the cubical coefficients of expansion. For when the 
