Before the age of GPS,
or handheld calculators,
or cell phones--
there was the
If you were taking a trip (car, plane, bus, it didn't really matter)
and you wanted to know exactly how many miles it would be to get from one place to another,
you could grab your large table map, get out your compass (the MATH kind) and do some calculations
to come up with an idea how many miles and how long it might take.
Enter the Dist-O-Map.
Easy to use. Quick
Almost Google like in its simplicity.
Pick a city nearest to you on the map, pick your destination, set up the movable map to the correct arrow positions, and Bob's your Uncle! You've got your info.
Pretty darned useful items, these.
Ah, the days before technology...