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A. M. W. DOWNING, M.A., D.SC, F.B.S., ON 



moon set with the twin stars on the first evening of the month, or 

 the second evening of the month, then the year would contain twelve 

 months. If it was not till the third evening that it set near Castor 

 and Pollux, the year would contain thirteen months. 



This was a very simple observation, and it was sufficient for the 

 needs of the ancient world for thousands of years. But then they 

 did not try to introduce an artificial regularity into either the month 

 or the year. It was very easy to assume that if we had been present 

 at the Creation we could have arranged things much better than 

 they were now ; we could have made the month exactly thirty daj r s 

 and the year exactly twelve months ; but as things actually were, 

 the month was not an exact number of days or of weeks, and the 

 year was not an exact number of days, weeks or months, and by no 

 possible device could we transform them, so as to make them 

 commensurate. 



But there was an advantage about the fact that the motions of the 

 heavenly bodies were irregular and incommensurable. Mr. Pearce 

 had said that we could save millions of pounds if we could make a 

 more symmetrical calendar. Supposing that were true, which was 

 much to be doubted, what was that saving when compared with the 

 immense advantage to mankind which had arisen from the irregu- 

 larities of the movements of the heavenly bodies 1 It was no 

 advantage to any particular man to make things so easy for him that 

 he never had to use his brains ; it would have been no advantage 

 to the race of men if God had given them no problems to work out. 

 The problems presented by the irregularities of the movements of 

 the heavenly bodies had given rise to the science of mathematics, and 

 upon mathematics all our mechanical science, our physical science, 

 our engineering, were built ; that is to say, the whole body of our 

 modern civilization. 



Mr. H. P. Hollis called attention to the recurrence of any parti- 

 cular day of the year as Easter Day and the intervals between such 

 successive recurrences. As an example, in this year April 4 is 

 Easter Sunday. Easter has not happened on that day since 1858, 

 fifty-seven years ago, but that particular date will be Easter Day in 

 1920, five years hence, and again in 1926, six years later. It is clear 

 why an occurrence of the same date may happen after five years, if 

 those five years include two leap years, for in that case the date 

 (April 4) will again be a Sunday, so that one condition is satisfied. 



