﻿496 Mr. M. H. Belz on the Heterodyne Beat Method 



and a volume 0*551 c.c. The observations are shown in 

 Table V. 







Table V. 







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. 



2) = 2dn. 



p/W. 



Tempera- 

 ture 

 degrees C. 





xio 5 



XlO 5 





XlO" 6 





335 



8-95 



4-47 



3-39 



3-79 



16 



340 



8-83 



4-41 



334 



3-78 



16 



363 



872 



413 



3-13 



3-79 



16 



400 



7-50 



3-75 



2-84 



3-79 



16 



Mean i?/N = 3-79 Xl0~ 6 at 16°0. 

 We find hence 



K c = 54-0xJ0" 6 c.g.s., 



which gives for the mass susceptibility of the complete salt 

 29-8 x 10" 6 c.g.s. The percentage mass of FeS0 4 (NH 4 ) 2 S0 4 

 in one gram of salt is 72*5, and hence we obtain 

 K W =4M x 10" 6 c.g.s. at 16°C. 



The values given in the Tabellen of Landolt and Bornstein 

 of K w for the salt when examined in the form of a solution 

 at 18° C are 44 x lO" 6 , and 45 x 10~ 6 c.g.s. 



IV. Nickel Chloride. — The salt was examined in the form 

 of a solution in air-free water. The volume of the specimen 

 was 1*572 c.c. and occupied a length in the glass tube of 

 approximately 7*4 cm. The density was determined to be 

 1*332 gm. per c.c, and an electrolytic estimation yielded 

 0*255 gm. NiCl 2 per c.c. The observations are shown in 

 Table VI. 



Table VI. 



Wave-length 



of Set 2 



in metres. 



Frequency 



of Set 2. 



N. 



Frequency 

 of Set 1. 



w=N/2. 



Change in 



number of 



beats per sec. 



p=2dn. 



P/N. 



Tempera- 

 ture 

 degrees C. 



, 355 

 380 

 404 



XlO 5 

 8-45 



7*90 



743 



xio 5 



4-22 

 3-95 

 371 



2-12 

 1-99 



1-88 



XlO -6 

 2-51 



2-52 



2-52 



15 

 15 

 15 



Mean p/N =2-52x10' at 15° C. 





