NOEMAL SULPHATES OF POTASSIUM, RUBIDIUM, AND CESIUM. 
485 
Summary of the Kesults for the Linear Coefficients of Expansion, 
Collating the mean values given at the foot of each of the foregoing tables, the 
following is a statement of the essential results of the work as regards the linear 
coefficients. 
Mean Coefficients of Linear Exjiansion, a + ht, between 0° and f. 
Potassium Sulphate. 
For the direction of the axis a .. . O’OOO 036 16 + O'OOO 000 014 4L 
„ „ h . . . 0-000 032 25 + 0-000 000 014 IL 
„ „ c . . . 0-000 036 34 + 0-000 000 041 St. 
Rubidium Sulphate. 
For the direction of the axis «... 0-000 036 37 + 0-000 000 020 St. 
„ „ h . . . 0-000 032 14 + 0-000 000 018 4L 
„ „ c . . . 0-000 034 63 + 0-000 000 038 Ot. 
CcBsium Sulphate. 
For the direction of the axis «... 0-000 033 85 + O'OOO 000 021 At. 
„ ,, h . . . 0-000 031 95 + 0-000 000 018 2L 
„ „ c . . . 0-000 035 90 + 0-000 000 041 At. 
In abbreviated notation will next be given a list of the true coefficients. The 
suffix attached to a indicates the axial direction. 
True Coefficients a of Linear Expansion at C, or Mean Coefficients between any 
Two Temperatures whose Mean is t. a. — a 2ht. 
Potassium Sulphate. 
a^= 10-® (3616 + 2-88^). 
a, = 10"® (3225 + 2-82i). 
a, = 10-® (3634 + 8-260. 
Rubidium Sulphate. 
a„= 10"® (3637 + 4-060. 
aj, = 10-® 03214 + 3-680. 
= 10“® (3463 + 7-600. 
Ccesium Sulphate. 
10-® (3385 + 4-280. 
a, = 10-® (3195 + 3-640. 
a, = 10-® (3590 + 8-280. 
