566tii ORDINARY GENERAL MEETING, 



HELD IN COMMITTEE ROOM U THE CENTRAL HALL, 

 WESTMINSTER, ON MONDAY, MARCH 15th, 1915, 

 AT 4.30 p.m. 



Lt.-Col. G. Mackinlay, Chairman of Council, presided. 



The Minutes of the preceding Meeting were read and confirmed. 



The Secretary announced the election of Lady Jane Taylor, and of 

 the Rev. J. W. Fall, M.A., as Associates of the Institute. 



The Chairman said that the Institute was most fortunate in having 

 for their consideration that afternoon a paper by Dr. A. M. W. Downing, 

 for many years a Fellow of the Royal Society, and Superintendent of the 

 Nautical Almanac. He greatly regretted that Dr. Downing was not 

 able to be personally present with them, and in his absence would 

 call upon the Secretary to read his paper on " The Determination of 

 Easter Day." 



THE DETERMINATION OF EASTER DAY. By A. M. W. 

 Downing, M.A., D.Sc., F.R.S. 



IN order to understand clearly the principles underlying the 

 determination of the date of Easter in any year it is 

 desirable, in the first place, to make ourselves acquainted 

 with the definition of Easter given in the English Prayer Book. 

 This definition has been handed down to us from the time of 

 the Council of Nicrea, A.D. 325, and is designed to preserve, as 

 nearly as possible, the same relation between the times of 

 celebration of Easter and of the Passover as obtained at the 

 time of the Resurrection, and especially that the former should 

 not be celebrated before, or on the same day as, the latter ; hence 

 the second clause of the definition : " Easter Day is always the 

 first Sunday after the full moon which happens upon, or next 

 after, the 21st day of March ; and if the full moon happens 

 upon a Sunday, Easter Day is the Sunday after." This 

 definition (though copied from the Act of Parliament which 

 regulates the matter for us) requires a further explanation to 

 make it perfectly clear. The " moon " referred to is not the 



