HISTORY OF CHRONOLOGY. 767 



year brings back computed time 24 2r6 = 2'4 hours behind real 

 time. To lose a whole day at this rate will require 10X400 = 4,000 

 years. 



This arrangement seems simple enough to us now, but it required 

 a convention of astronomers, summoned to Rome for this purpose, ten 

 years to effect the adjustment. This is called the change from Old to 

 New Style. It also changed the dominical letter, which occurred in 

 this wise : 



The dominical letter of 1582 was G, and, A being always the let- 

 ter for the 1st of October, that day must have been Monday, and in 

 regular order the 17th would have been Tuesday, whose letter was C. 

 The change was made by calling the 5th day, which was Friday, the 

 15th, whence Saturday became the 16th and Sunday the 17th, whose 

 letter we have just seen was C, whence C instead of G became the 

 dominical letter for that year, N. S., and by this all subsequent Sun- 

 day letters were regulated. C is the fourth letter in backward order 

 from G, hence the dominical letter of any year, N. S., was four letters 

 backward from the letter belonging to that year O. S., and remained 

 so until 1700, after which IST, S. is but the third letter from O. S. because, 

 according to N. S., 1700 is not a leap-year and has but one dominical 

 letter. In O. S. it would be leap-year, and would have two letters. 

 For the same reason, after 1800 N. S. it is only the second letter back- 

 ward from O. S., after 1900 only the first backward, and so continues 

 until 2100 the year 2000 making no difference, as it is a leap-year in 

 both styles. After 2100, Sunday letter N. S. is the same as that of O. S., 

 and gains one letter each succeeding century, except those which are 

 multiples of four hundred, so that, in every nine hundred years after 

 2100, the N. S. and O. S. Sunday letter correspond. This furnishes a 

 perpetual almanac. 



This ai-rangement of the calendar, whose complete cycle is four 

 hundred years, is called the Gregorian, from the name of Pope Greg- 

 ory, through whose instrumentality it was made. It was adoj^ted 

 shortly afterward by all the Catholic countries of Europe ; but Protes- 

 tant countries refused to adopt it, notwithstanding its obvious superi- 

 ority and correctness, because it was originated by Catholics. En- 

 lightened public sentiment compelled its adoption in course of time, 

 and an act was accordingly passed by the British Parliament in 1752, 

 almost two centuries later, ordering that the 3d of September should 

 be called the 14th, the error having by that time amounted to eleven 

 days. The change was, however, not popular among the masses, be- 

 cause it changed the time of long-established festivals, and members 

 of Parliament were insulted in the streets by the rabble calling after 

 them : " What have you done with the days ? " " Give us back the 

 days you stole ! " 



We have already seen that tables were constructed showing on 

 what days each new moon would fall in the whole lunar cycle, but, 



