Gestation (was re: mathematics etc.)

[Satyanad Kichenassamy]

With reference to Jonathan Silk's interesting reference, one may add that
ChAndOgya V.9.1 gives the length of gestation as `ten or nine months' more
or less (das'a vA nava mAsAn antaH s'ayitvA yAvad vA 'tha jAyatE...). In
this particular case, the duration is therefore given in terms of months
rather than weeks. 

By the way, the initial issue on arithmetic modulo nine and `casting out
nines' has been addressed by many people already. It may be interesting to
note that its use in checking operations is found in India (apparently
before it is found anywhere else).  The use of bases other than nine in
this connection has, if memory serves, been noted by NArAyaNa. (I'll be
happy to look up the actual reference if anyone is interested).

                            Satyanad Kichenassamy
                            kichenas at math.umn.edu