THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OP SCIENCE. 



TFIFTH SERIES.] 



DECEMBER 1899. 



LV. On Accidental Double Refraction in Liquids. By Bkuce 

 V. Hill, A.M., Felloio in Physics, University of Nebraska, 

 Lincoln *. 



MAXWELL f,in 1874, found that Canada Balsam became 

 double-refracting when agitated with a spatula. 



KundtJ, in 1881, performed a series of experiments on this 

 subject. He produced a strain in the liquids to be studied by 

 putting them between two concentric cylinders, the outer one 

 of which was fixed, while the inner one rotated. The strain 

 was studied by means of the spectrum of the interference- 

 band produced by a plate of gypsum between the polarizer 

 and analyser. He found that colloids in solution became 

 strongly double-refracting, while crystalloids showed no such 

 effect. 



De Metz§, working with an apparatus similar to that of 

 Kundt, but with the substitution of a Babinet's compensator, 

 showed that, in the oils, the amount of double refraction pro- 

 duced is proportional to the speed of rotation of the cylinder. 

 He also found that this effect decreases with rise of tempera- 

 ture, but not in direct proportion. 



Umlauf || studied the effects of speed and temperature in 

 solutions of the colloids. His results agreed with those of 

 De Metz. 



In 1897 Mr. J. E. Almy H[ studied the subject in this labora- 

 tory. His apparatus consisted of a cast-iron chest within 



* Communicated by Prof. D. B. Brace. 

 t Collected Papers, vol. ii. p. 379. 



X Wied. Ann. xiii. p. 110. § Ibid. xxxv. p. 497. 



Ibid. xlv. p. 304. H Phil. Mag. xliv. p. 499. 



Phil. Mag. S. 5. Vol. 48. No. 295. Dec. 1899. 2 M 



