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From: Kai_Henningsen@ms.maus.de (Kai Henningsen)
Newsgroups: comp.lang.pascal
Subject: Re: Leap year function
Message-ID: <16990@ms.maus.de>
Date: 7 Jun 91 17:52:00 GMT
Article-I.D.: ms.16990
Distribution: world,comp
Organization: Maus Mailbox Netz - UUCP-Gateway Bremen
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Stephen Baillie baillie%mullauna.cs.mu.OZ.AU @ SUB schrieb am Mi 05.06.1991,
03:07 A18353@SUB in Cl-Pascal:

SB>It was because of a discrepancy between the number of days in a year in the
SB>old (Julian?) Calendar, ie one without leap years, and the actual passage
SB>of the earth around the sun (did I get that the right way around? ;-> )

In fact, no .. see below.

SB>The year was out of sync with the sun by 11 days, so at the same time as
SB>introducing leap years they cut a few days to make things line up again.
SB>Caused quite a stir among the superstitious peasants who thought they
SB>were losing a few days out of their lives!

That, however, is ok ...

SB>I think that pre-1722 there were no leap years, so your program may try to
SB>compensate for this too.

It's like this: before the Gregorian calender, we had the Julian calender, so
named after one Julius Caesar, I believe, who in the year 46 BC reformed the
then-without-leap-years calender to include one every four years - this made a
calendar year of 365.25 days instead of 365. (That's why we have a month called
july: before, it was quintilis ...) As the actual year length is more like
365.2422, however, this still caused problems. In 1582 (not 1722) pope Gregor
the umpteenth decided enough was enough, dropped the 5.-14. october(!) and
invented some more leap days, bringing the year to 365.2425 days. The
difference of about 0.0003 days/year makes an error of one day in 3000 years -
we might as well forget that :-)

However, there is more. Not every nation accepted Gregor's decision at once.
Russia, for example, officially adopted the Julian(!) calender as late as
1.1.1700(!) (tsar Peter the great), then dropped 13 days at the start of
february 1918(!) to switch to Gregorian.

I think they were the last to do it, and nowadays nobody uses the Julian
calender any more.
--
Kai Henningsen  Internet: kh@ms.maus.de
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