Why does "cal 9 1752" produce incorrect results?

[Gerben 'P' Vos]

khenry at umaxc.weeg.uiowa.edu (Ken Henry) writes:

>Does anybody know why "cal 9 1752" produce incorrect
>results?  It seems to be in the Unix systems I
>checked (BSD 4.3, AIX 3.1).  

$ cal 9 1752
   September 1752
 S  M Tu  W Th  F  S
       1  2 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30

Actually, these are the correct results, at least in some
parts of the world. Up till 1752, a different calendar
was in use, which was more incorrect than the one we now use.
Because of that, the dates had gotten eleven days out of sync
with reality. When the change occurred, there were many protests
from people, complaining they lost eleven days of their life!

In many countries, however, this calendar is indeed wrong.
Obviously, this is what you meant in the first place :-) :-).
I seem to remember that most parts of Europe (excluding, of
course, England :-)) changed in 1593, and losed only ten days
instead of eleven in the process.

-					Gerben.
--
--- Gerben Vos - Aconet: BIGBEN!Gerben Vos - Internet: gpvos at cs.vu.nl
---- Definition of intelligence: Anything a human does better than a computer