258 



MR. J. C. MAXWELL GARNETT 



TABLE V. Index of Refraction of Colloidal Solution of Silver for Sodium Light 



(X = -589). 



* The solutions were prepared by CAREY LEA'S method of precipitating silver nitrate with ferrous 

 citrate they were subsequently dialysed for 60 hours. 



Thus the mean refractive index of silver in water at 18'6 was n = T3367, while 

 the refractive index of water at 187 was v = 1-3331. Taking the specific gravity of 

 silver as 10, the volume proportion silver was /x = '00116. 



The values of the functions and a! for sodium light and water at v = T3331 are, 

 according to Table II., a= 1-571 and a' = 1-333. Substituting these values of v, p., 

 and a in equation (10), namely 



we obtain 



n' = *(l + f/ia), 

 n' = ^(1-00273) = 1-33674. 

 Similarly, from equation (9), 



n" v \ 1 H ua' 



2f 

 we have 



n" = v (1-002078) = 1-33587. 

 Comparison of these values of n' and n" with the observed value, namely n = 1'3367, 



