12 



ART 8.— S. XAKAMUEA. 



In the tables III ft — III,, which relate to a set of experiments on 

 NaCl solution, w obs is the value of the index of refraction at a point x 

 deduced from 6 by the equation (4), and n cal is that value of n cal- 

 culated by putting B and B x or b and l^ obtained by harmonically 

 analysing ?/ ob3 in the equation (6) or (6'). A is n ob3 — ?/ caI and 



shows how soon 6 2 , b 3 become insignificantly small. In these 



experiments, the angle « of the prism=45° 2' 25." 



Table III a 



Time=31. Jan. 14 h 58 m ; temperature=l0°,7 C 



Spect. reading for the normal = 329° 53' 10". 



B = 1.34749, 

 B l =+ 0.0 If» 93, 



B,= +0.00207, 

 B.= -0.00453. 



