842 Mr. R. T. Lattey on the Dielectric 



Some experiments were also made in which the leads 

 were cut down to a minimum; this reduced / to 285 cms. 

 The results are indicated by an asterisk. 



Table VIII. — Dielectric Constant of Glycerol. 



(All these observations were made at 17°-18° C, except 

 that for \ = 45'5, which was at 14° C). 



\. D. 



152 52-85 



123 49-85 



103 53-05 



98 50-9 



91-2 5195 



83-3 52-15 



74 52-15 



47-3 49-5 



45-5 (53-05) 



42-6 ............ 4905 



35-5 51-0 



33-2 50-05 



Mean 51-15 



In the case of water the most careful determination seems 

 to be that of Turner 59 , viz. 81*12. The somewhat varied 

 values by other observers found for glycerol indicate that D 

 for this liquid is dependent on the frequency ; at the same 

 time it must be borne in mind, when comparing the results 

 of different observers, that it is by no means easy to obtain 

 glycerol free from water or to prevent its contamination by 

 water. The various values found in the literature for D and 

 for the square of the refractive index (?i 2 ) are collected 

 below : — 



Observer. Metres. I). n?. 



Thwing 58 . . . 



. 10 



56-2 





Drude 18 > 19 > 20 > 21 . 



. 2 





39-1 





0-75 





25*4 





0-73 



19-1 







J5 



16-5 





v. Lang 36 . . . 



. 0-085 





14-1 



Eckert 24 . . . 



. 0-057 





14-4 



Merczyng 40 . 



. 0-045 





16-8 



Lampa 35 . 



. 0-008 





34 





0-006 





3-1 





0-004 





2-62 



