That baffled me for a minute until looking at it. I had forgotten that slide rules
could be circular. Sure beats for size the large German-made one inherited
from my engineer brother that I carted around in the
early 50's at University.
It was too big to fit properly in my zipper binder.
I eventually bought a
cheaper one that was only 10-12" long. I was aghast when much later my
son was allowed to bring an electronic calculator with him into exams.
IIRC slide rules were strictly verbotten in my time.
Lawrence
Digital?
How about analog, incl. an analog calculator?
"Selectron slide rule wristwatch"
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=948218019
FYI
John A.
lgwalker(a)mts.net
bigwalk_ca(a)yahoo.com