﻿and some Applications to Pliysicul Measurements. 497 



This gives 



K„=12-62xlO-' ! c.o-.s. 



The mass susceptibility of the solution is 



K TOl =9'49xlO-« c.g.s., 



and the mass susceptibility of the water-free salt becomes 



K m = 39'5 x 10" 6 c.g.s. at 15° 0. 



This is in good agreement with the values given in the 

 Tabellen of Landolt and Bornstein, the mean of which is 

 3966xlO _G , but is considerably different from the value 

 recently given by Theodoridcs *, viz. 4'7'6 x 10" G c.g.s. 

 at 15°-2 C. 



V. Nickel Sulphate. — The specimen was in the form of 

 the green rhombic prism crystals which, on estimation, 

 were shown to have the composition JNiS0 4 , 7H 2 ; the 

 density of these crystals is (Thorpe and Watts) 1*950 gm. 

 per c.c. A mass of 1'438 gm. occupying a volume 0'737 c.c. 

 was used, having a length in the glass tube of approximately 

 7*2 cm. The observations are shown in Table VII. 



Table VII. 



Wave-length 



of Set 2 



in metres. 



Frequency 

 of Set 2. 



N. 



Frequency 

 of Set 1. 



»=N/2. 



Change in 



number of 



beats per sec. 



p—2dn. 



p/8. 



Tempera- 

 ture 

 degrees C. 





xio 5 



xio 5 





XIO" 6 





342 



8-77 



4-38 



263 



3-00 



16 



370 



8-12 



4-06 



2-44 



3-00 



16 



412 



7-29 



3-64 



216 



2-96 



16 



Mean jo/N = 2-99 Xl0~ 6 at 16°C. 



This gives 



K„ = 32-lxl0- 6 c.g.s., 



from which we get the mass susceptibility of the complete 

 salt to be 16'43 x 10~ 6 c.g.s. The percentage mass of NiS0 4 

 in one gram of salt is 55, and hence we obtain 



K TO = 29-9 x 10" 6 c.g.s. at 16° 0. 



The mean of the values in the Tahellen is 30 X 10" 6 c.g.s., 

 while Finke f finds for K v the value 29' 1 x 10 " 6 c.g.s. 



* Theodorides, Journ. d. Phi/s. III. i. p. 1 (1922). 

 t Finke, loc. cit. 



Phil. Mag. S. 6. Vol. 44. No. 261. Sept. 1922. 2 K 



