Why does "cal 9 1752" produce incorrect results?

[Jerry Gitomer]

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).

>-Ken

That is the month in which England switched calendars.  They
really did jump from the 2nd to the 14th.  The change was
needed to compensate for errors in the older calendar.
Incidentally in most of Europe the switch in calendars
occurred at a different time.

Jerry