Posted 6 years ago
Irishcolle…
(137 items)
The wheel has a notch which is lined up with the pointed piece and as it rolls along a section of map the wheel moves on a threaded axle. The wheel can then be rolled backwards along a ruler or scale until the notch gets back to the starting point. This makes it very easy to measure windy roads and routes. 5 inches long. Brass with wooden handle.
