596 Scheme of a Table for all Time. [No. 116. 



The odd year 41 of the century being found on the outer card, the 

 division containing it is that by which the months are to be adjusted 

 throughout the year : the division containing the given month being 

 brought opposite that of the 41, the days of the month will be opposite 

 their proper week-days. For example, to find the week-days of the 8th 

 and 18th of June — June being brought opposite the 41, opposite the 8th 

 will stand Tuesday, and opposite the 18th stands Friday. la like man- 

 ner December being brought opposite the 41, opposite the 23rd stands 

 Thursday. For the 18th June 1815, the centurial adjustment re- 

 maining unchanged, June being brought opposite the year 15 on the 

 outer card, the 18th is seen opposite Sunday. The battle of Preston 

 happened on the 21st September 1745, Old Style, required the week- 

 day. The Old Style century I7th being brought to the 00, and Sep- 

 tember to the year 45, opposite the 21st stands Saturday. 



The battle of CuUoden was fought on the 16th April 1746, O. S. 

 required the week-day. The centurial adjustment remaining as before, 

 April being brought opposite the year 46, opposite the 16th stands 

 Wednesday. 



Thus the Table is used with equal facility for N. S. or O. S. dates. 



The second card having the full centuries of both styles, (which may 

 be continued at pleasure), shews at once those which have the same 

 w^eek-days. The O. S. centuries are continued by successive additions 

 of 7, and those of N. S. by additions of 4. The reason of which is, 

 that a Julian or O. S. century having 25 leap years, consists of 5200 

 weeks and 125 days. Now 125 days are short of 18 weeks by one 

 day, hence each Julian century commences on a week-day earlier by 

 one than did the preceding century ; so that the same week-days must 

 recur after a period of seven centuries. But in the New Style there are 

 three Gregorian centuries and one Julian ; and as a Gregorian century 

 has only 24 leap years, it consists of 5200 weeks and 124 days, being 

 two days short of 18 weeks. The loss of two days on each of the three 

 Gregorian, and one day on the Julian century, amounts to a week every 

 400 years, and hence the recurrence of the same week-days in the order 

 above mentioned. 



When Pope Gregory XIII. in 1582 introduced the New Style, the 

 object was to adjust the festivals in the Calendar to the same time of 

 the year as they held at the time of the Council of Nice in 325 ; ten 



