350 On the Dilatation of Crystals on Change of Temperature. 
that the parameters are as follows : — 
First temperature. Second temperature. 
a = 0-6919835, a' = 0-6899715, 
c=0-4145025, c' = 0-4134817, 
/3 = 99° 27' 22" S, 0' = 99° 37' 5"'2 ; 
whence 
a' — a c' — c 
__a c_ -002907584--Q02462712 
x ~ P'-(3 ~ 582-4 x cm. of T" ' 
(a) tan 
p — p 
X=180°-8° 57' 13""6 
and 
i/r= ; ^-^=35 47 / 41 // -8. 
The previous method gave as a first approximation 35° 44' 
10"-85 (page 295), and as a second approximation 35°46 / 32 //, 58 
(page 298). 
(b) S-S 1 = 
— a c —c 
a c 
sin p sin x 
-00444872 
~ sin 99 c 27' 22"'8 sin 8° 57' 13"-6 ; 
whence ^-8=0-00289776. 
The previous method (page 295) gave 0*0028987, and Neu- 
mann's result was 0*002892. 
(c) 8 2 _S = _ a _^ + ( a i _g) C os 2 (^+/3) 
a —a 
a 
= + -002907584 + 0-00289776 cos 2 135° 15' 4"-6 
= •004369172. 
Again, 
8 2 -S=-^+(S 1 -S)cos 2 ^ 
= •002462712 + -00289776 cos 2 35° 47' 41 // -8 
= •004369172. 
The previous method gave 0-0043757 (page 300); Neumann's 
result was 0-004371. 
[To be continued.] 
