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Re: [Phys-l] Newton's birthday

While it is true that Julian dates are currently and in the 1900s 13 days
apart from Gregorian, in the 1800s they were 12 days apart, and in the 1700s
they were 11 days apart, and in 1600s and 1500s 10 days apart. The two
calendars get 1 day apart except for a century divisible by 4. So Dec 25,
1642 coincides with Jan 4 according to my reckoning. Now of course if you
wish to go with the Julian calendar, it would be the 7th, but England
adopted the Gregorian calendar so it has been officially blessed and
Newton's birthday is considered to be Jan 4.

There is some funny business in the conversion because the difference is -1
in the year zero. I had always thought that the 2 calendars were 14 days
apart. The article on the calendar is at:

There is also some other historical funny business in that both old and new
style dates and the beginning of the year are changed and mixed. Apparently
England began the civil year in March 25. Why did they not just go back to
the old March 1 beginning of the year, but why the 25th?

John M. Clement
Houston, TX

-----Original Message-----
From: [mailto:phys-l-] On Behalf Of Leigh Palmer
Sent: Monday, January 04, 2010 12:35 PM
Subject: [Phys-l] Newton's birthday

According to my Julian calendar* December 25, 2009 coincides with 7
January 2010 Gregorian. I think that is the proper anniversary of Isaac
Newton's birth. Google's a bit early.


*Intercal, a very nice Macintosh application written by Dennis A. Elliott
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