THE 



SCIENTIFIC PROCEEDINGS 



OF THE 



ROYAL DUBLIN SOCIETY. 



Vol. XIII. (I.S.), lo. 30. PEBETTAET, 1913. 



A METHOD OF MICROSCOPIC MEASUREMENT. 



BY 



J. JOLY, Sc.D., F.R.S., 



PKOFESSOK OF GEOLOGY AND MINERALOGY IN THE UNIVERSITY OF DUBLIN. 



[A ufhors alone are responsible for all opinions expressed in their Oommunications.^ 



DUBLIN : 



PUBLISHED BY THE ROYAL DUBLIN SOCIETY, 



LEINSTER HOUSE, DUBLIN. 



WILLIAMS AND NORGATE, 



14, HENRIETTA STKEET, COVENT GARDEN, LONDON, W.C. 



1913. 



Price Sixpence. 



