THE 



SCIENTIFIC PROCEEDINGS 



OF THE 



ROYAL DUBLIN SOCIETY. 



Yol. XII. (N.S.), lo. 19. JULY, 1909. 



A NEW FORM OF POLARIMETER FOR THE 



MEASUREMENT OF THE REFRACTIVE 



INDEX OF OPAQUE BODIES. 



W. F. BARRETT, F.R.S., 



PROFKSSOR OF KXPEKIMENTAL PHYSICS, EOYAL COLLEGE OF SCIENCE FOE IBELAND. 



[ A uthors alone are responsible for all opinions expressed in their Communical/ons.] 



DUBLIN : 



1>U13L1SHED BY THE liOYAL DUBLIN SOCIETY, 

 LEINSTER HOUSE, DUBLIN. 



WILLIAMS AND NORGATE, 

 U, HENRIETTA STREET, COVENT GARDEN, LONDON, W.C. 



1909. 



Price Sixpence. 



■^,^m^n\nstit^. 



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