On Sun, 17 Apr 2011 14:54:24 -0700, "Steve B"
wrote:

I need one of those pen contraptions that you roll over blueprints and
aerial photos that then give a numerical value to the distance traveled.
What are they called, and what's a good supplier of them?

The box for my K&E is labeled "MAP MEASURE, D1741". On the
back of the measure itself is impressed, "Hamilton Watch
Company". I bought it new, sometime around 1940, and paid
$4.50 for it. It has inch and cm scales.

--
croy