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



VI. Cobalt Sulphate. — Tests were made with the salt in 

 the form of crystals and powder. 



{a) Tests on crystals. 



The salt proved on estimation to have the composition 

 C0SO4, 7H 2 ; the density of this salt is 1*950 gm. per c.c. 

 A mass of 1*1375 gm. was used which thus occupied a volume 

 0'583 c.c. The length of the crystal column was 6 cm. 

 The observations are shown in Table VIII. 



Table VIII. 



Wave-length 

 m 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/N. 



Tempera- 

 ture 

 degrees C. 



349 

 385 

 410 



xio 5 



8-60 

 7-80 

 7-32 



xio 5 



4-30 

 390 

 366 



4-28 

 3-85 

 3-59 



xio- 6 



497 

 4-94 

 491 



16 

 16 

 16 



Mean ^/N = 4-94 XlO" 6 at 16° C. 



This gives 



K r = 66-0xl0- e c.g.s., 



and thus the mass susceptibility o£ the complete salt is 

 33*85 X 10" 6 c.g.s. We thus obtain 



K m = 61-4 x 10" 6 c.g.s. at 16° C. 



(b) Tests on powder. 



A mass of 1*3150 gm. was used having a volume 0*674 c.c. 

 and occupying a length in the glass tube 5*5 cm. The 

 observations are shown in Table IX. 



Table IX. 



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/S. 



Tempera- 

 ture 

 degrees C. 



350 

 385 

 414 



XlO 5 



8-57 



7-80 

 7*25 



XlO 5 

 4-28 



3-90 



3-62 



4-88 

 4-45 

 4-14 



XlO" 6 

 570 



571 

 5-72 



16 

 16 

 16 



Mean jt?/N = 5-71 XlO" 6 at 16° C. 



