46 



it follows that 



i-iy 



Sir John Conroy on the 



•^0^'D-^-r + l)•^ 



( — lY [vB 



. or 



[May 18, 



(10«) 



^ t ^ _!• 



;jL) — n 



006) 



Observe that, since r, n are supposed positive integers, these symbolic 

 ratios always consist of a finite number of factors (viz. r, n respectively), 

 and are therefore always iuterpretable, w^hatever be the value of h. 



May 18, 1876. 



Dr. J. DALTON HOOKER, C.B., President, in the Chair. 



The Presents received were laid on the table, and thanks ordered for 

 them. 



The following Papers were read : — 



1. " Absorption- Spectra of Iodine."" By Sir John Conroy, Bart., 

 M.A. Communicated by A. G. Veenon Harcourt, Lee"s 

 Header in Chemistry in the University of Oxford. Received 

 April 12, 1876. 



Iodine, as is well known, when in very thin layers, appears red by 

 transmitted light ; and when in solution the colour of the liquid depends 

 not only on the amount of iodine contained in it, but also on the nature 

 of the liquid in which it is dissolved. 



Schultz-Sellack has pointed out (Pogg. Ann. vol. cxl. p. 334) that 

 the liquids in which iodine is soluble may be divided into two classes : — 



