Jan nary, iQ'() 



5, 6 



PROCEEDINGS 



OP THE 



ROYAL IRISH ACADEMY 



Volume XXXIV, Section A, Nos 5, 6 



W. R. W. ROBERTS 



ON THE EQUATION OF THE TANGENT AT A GIVEN 

 POINT ON A UNI-NODAL OUARTIC CURVE 



H. C. PLUMMER 



ON THE SYMMETRICAL OPTICAL INSTRUMENT 



DUBLIN 



HODGES, FIGGIS, & CO., LTD. 



LONDON: WILLIAMS & NORGATE 



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