219 



lum, of the performance of the telescope, and of the ma- 

 chinery by which it is moved, will then appear in the Pro- 

 ceedings. 



May 9. 

 SIR Wm. R. HAMILTON, LL.D., President, in the Chair. 



William Blacker, Esq. and the Rev. James Booth were 

 elected members of the Academy. 



James Mac CuUagh, Esq. was elected Secretary of the 

 Academy, in the room of the Rev. Dr. Singer, resigned ; 

 and Dr. Kane was elected Secretary of Council. 



A paper, by the Rev. Dr. Hincks, " On the True Date 

 of the Rosetta Stone," was read. 



The date usually assigned to this monument, on the au- 

 thority of Dr. Young, is the 27th March, 196 b. c, according 

 to the proleptic Julian reckoning ; the true date, as deter- 

 mined by Dr. Hincks, is the 27th March, 197 b. c. Taking 

 the former date for granted, M. Letronue has drawn from it 

 a great many inferences, which the error of a single year en- 

 tirely vitiates. These inferences relate to the history of 

 Ptolemy Epiphanes, and to the mode of computing the years 

 of his reign and of the reigns of other Egyptian kings ; as 

 also to the various priesthoods of royal personages that are 

 mentioned on the Ptolemaic monuments. The conclusions 

 of M. Letronne, and those which are to be deduced from 

 the corrected date, are exhibited by the author in parallel 

 columns. 



The President made some remarks on the day of the 

 Vernal Equinox at the time of the Council of Nice. 



It has been stated by some eminent writers on astronomy, 

 for example by Brinkley and Biot, and seems to be gene- 

 rally supposed, that the vernal equinox in the year 325, a. d. 



