Why does "cal 9 1752" produce incorrect results?

[Kenneth Herron]

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).  

Actually it's correct.  That month was shorted 13 days (or whatever)
due to calendar reform; the previous calendar was getting out of step
with the seasons, so in one fell swoop they caught up the calendar and
instituted a new leap-year strategy.

Kenneth Herron
-- 
Kenneth Herron                                            kherron at ms.uky.edu
University of Kentucky                                        (606) 257-2975
Department of Mathematics
                                "Never trust gimmicky gadgets" -- The Doctor