PHILOSOPHICAL TRANSACTIONS 
OF THE 
ROYAL SOCIETY OF LONDON. 
Series A, Yol. 217. Pp. 51-79. 
[Plate 1.] 
THE GENESIS OF PLEOCHROIC HALOES. 
BY 
J. JOLY, Sc.D,, F.R.S., 
PROFESSOR OF GEOLOGY AND MINERALOGY IN THE UNIVERSITY OF DUBLIN. 
LONDON: 
PUBLISHED BY THE ROYAL SOCIETY, 
AND SOLD BY HARRISON^ AND SONS, ST. MARTIN’S LANE, W.C., 
Printers tn ©rtftmtrg to 
1917. 
Price Two Shillings. 
A 551. 
29 . 1 . 17 , 
