THE 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



JANUARY 1891. 



I. The Refraction and Dispersion of Fluorbenzene and allied 

 Compounds. By J. H. Gladstone, Ph.D., F.R.S., and 

 George Gladstone*. 



DR. Sidney Young recently had the kindness to place 

 at our disposal an interesting series of compounds for 

 optical examination. They were the halogen substitution- 

 compounds of benzene described by him (Journ. Chem. Soc. 

 1889) ; substances that had been prepared with great care, 

 and which were redistilled before they were handed to us. 



The following were the determinations of the principal 

 lines of the solar spectrum : — 





Temp. 

 C. 



o 



22-8 

 22-5 

 23-5 

 22-2 



Density. 



Refractive Index. 



A. 



c. 



D. 



F. 



Gr. 



H. 



Fluorbeuzene ... 

 Chlorobenzeno . . . 

 Eromobenzene ... 

 lodobeuzene 



1-0207 

 1-1047 

 1-4928 

 1-8300 



1-4563 



1-5135 

 1-5469 

 1-6054 



1-4606 

 1-5184 

 1-5505 

 1-6124 



1-4646 

 1-5232 

 1-5577 

 1-6197 



1-4751 



1-5354 

 1-5715 

 1-6374 



1-4849 

 1-5469 

 1-5846 

 1-6537 



1-4933 



1-5573 

 1-5961 

 1-6699 



* Communicated by the Authors. The greater part of this paper was 

 communicated to the British Association, September 1890. 



Phil. Mag. S. 5. Yol. 31. No. 188. Jan. 1891. B 



