Wondering what this device is?
Surprisingly, it is a pioneer era odometer.
According to pioneer historian O. Ned Eddins, "The first wagon train to use an odometer was Brigham Young's Party in 1847. Based on William Clayton's suggestion, Orson Pratt designed a device to fit on the axle of one of Heber C. Kimball’s wagons. A wheel odometer measured rotation of the wagon wheel, and from this the distance traveled could be determined. The odometer was not unique to the Mormons, but they were the first to use one on the Oregon-Mormon trail."
Pretty cool for something made more than 150 years ago.
Of course, on our trek we will be pulling handcarts not guiding wagons, but those miles will still roll by and it is fun to know that even back then pioneers might have been counting the distance they had traveled as they went. Maybe their children even quipped, "Are we there yet?"