[LCN Newscast] Intro. to the Urban Forest, Feb 28. (When is Leap Day?)

[newscast@lists.lakeclaire.org]

Introduction to the Urban Forest
2004 Feb 28 Saturday 10-noon
Frazer Center Atrium
1815 Ponce de Leon Ave. NE

A seminar and guided walk through the Frazer Center Forest.  Learn about
local native plants, the Piedmont ecosystems, and what you can do to
protect our urban treasures.  

Sponsored by Friends of the Frazer Center Forest and Lake Claire Neighbors.

Please save the date!
For more information, contact Kathy Evans.
e-mail: zoning@lakeclaire.org
phone: 404-377-6781


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When is Leap Day?

Answer:  February 24, tomorrow (it is also Mardi Gras this year)!


Mark this under the "weird but true" category...

The Roman calendar was counted backwards from certain monthly milestones.

In 45 B.C. Julius Caesar decreed that in leap years the "6th day before
Kalendae of March" should be doubled.  So in contrast to our present
forward counting system, in which we introduce an extra date (29 February)
on our calendars, the Romans had the same date twice in leap years.  The
doubling of the 6th day before Kalendae of March is the origin of the
word "bissextile" ("twice sixth," it's not a dirty word).  If we create
a list of equivalences between the Roman days and our current days of
February in a leap year, we get the following: 

7th day before Kalendae of March (23 February)
6th day before Kalendae of March (24 February)
6th day before Kalendae of March, twice (25 February)
5th day before Kalendae of March (26 February)
4th day before Kalendae of March (27 February)
3rd day before Kalendae of March (28 February)
the day before Kalendae of March (29 February)
Kalendae of March (1 March)

You can see that the extra 6th day (going backwards) falls on what is today
24 February.  When Pope Gregory XIII promulgated the new calendar in 1582,
only the calculation of leap years changed, not the extra day itself.
For this reason 24 February is still technically considered the "extra day"
in leap years.  However, at certain times in history the second 6th day
(25 Feb) has been considered the leap day.

Why did Caesar choose to double the 6th day before Kalendae of March?
It appears that the leap month Intercalaris/Mercedonius of the pre-reform
calendar was not placed after February, but inside it, namely between the
7th and 6th day before Kalendae of March.  It was therefore natural to have
the leap day in the same position.

So, someone born on Feb 29 does not have one birthday every four years,
but on non-leap years it falls on Feb 28.  Likewise someone born on
Feb 27 on a non-leap year, actually has his birthday on Feb 28 on
bissextile years.  However, someone born on Feb 24 of any year, or
Feb 25 of leap year, actually has five birthdays every four years--both
on the 24th and 25th every leap year.