Odometer by J. D. Roberts
The odometer produced by J. D. Robert of Oakmont, Pennsylvania, measures distance traveled. Three concentric circles are marked in regular increments, but the unit of measurement is not specified. Three color-coded hands point to marks on the dial: the red hand corresponds to outer circled divided into single digit increments from 0 to 100, the yellow hand corresponds to the middle circle divided into increments of 100 from 500 to 4500, and the blue dial corresponds to the inner circled divided into increments of 4000 from 20,000 to 180,000. Two wing-nuts help fasten the device to a vehicle, and a piece of leather cushions the odometer. A star-shaped knob turns the hands of the dial and rests the device.
The Post Office Department equipped route agents with odometers to establish rural free delivery routes at the turn of the twentieth century. Using odometer readings and maps, officials worked to optimize the routes in new areas. They sought to use the minimum number of carriers and to portion the routes into equal distances. Some carriers used odometers to argue for changes to their routes, recording their miles covered and hoping to prove that an alternate road could save time.