Tracking Road Mileage -- Then & Now -- Roadometer vs. Odometer

Most emigrant diaries record the number of miles covered each day.  How'd they do that?

An enterprising (or desperate) Mormon pioneer, William Pratt, figured it out during his 1847 vanguard wagon trip to Utah.  Given the responsibility to track trip mileage, he became restive counting the turns of a red ribbon tied to a wagon wheel: mileage =  # of turns x wheel circumference.  Easy to see how both exacting and incredibly tedious this task would be.  Together with a master carpenter and a mathematician, Pratt devised a toothed set of gears that attached to the hub of the wheel and called it a "Roadometer."  Add 1-3% to the total to adjust for rough terrain, and you have a pretty accurate mileage count.

Handy gadget, the "Roadometer".   Pioneers faced with the incessantly grueling journey in a largely unknown landscape, came to depend on the roadometer for a much needed sense of accomplishment and forward progress.

"When we halt at night we are usually too tired for games or sport of any kind.  We smoke our pipes, talk when we feel like it, and before we examine the Odometer, we do some guessing about the number of miles made during the day....if we have anything to bet, and there is sometimes a little extra tobacco, we back our opinons regarding the speed of the train with a wager.  This is about the extent of our gaiety." Wm Swain, June 12, 1849

My 2017 odometer reading, day before departure

1849 Roadometer at the Pioneer Museum, Omaha, Nebraska