On May 11, 1847, at a location three-fourths of a mile north of the confluence of the North and South Platte Rivers, members of Brigham Young’s vanguard company attached an odometer (or roadometer) to the wheel of a wagon owned by Heber C. Kimball and driven by Philo Johnson. The company first used the instrument on the morning of May 12, 1847, and they used it for the rest of their journey to the Salt Lake Valley. The 1847 pioneers did not invent the roadometer, but the version they created was accurate enough for William Clayton to later use the recorded mileage in his famous The Latter-day Saints’ Emigrants’ Guide.
May 11, 1847
"Brother Appleton Harmon is working at the machinery for the wagon to tell the distance we travel and expects to have it in operation tomorrow, which will save me the trouble of counting, as I have done, during the last four days."
12 May 1847
"Morning cool, weather fine. Brother Appleton Harmon has completed the machinery on the wagon so far that I shall only have to count the number of miles, instead of the revolution of the wagon wheel."
16 May 1847
"About noon today Brother Appleton Harmon completed the machinery on the wagon called a 'roadometer' by adding a wheel to revolve once in ten miles, showing each mile and also each quarter mile we travel, and then casing the whole over so as to secure it from the weather" (William Clayton's Journal, , 143,152).
“Arose in the morning as usual at the blast of the winding horn. got up our teams & started on our way and crossed the Looking glass crick about one mile from whare we ware camped and travled about 3 miles when we seen a lone indian approaching toward us from [a] narrow skirt of timber. . . . Soon after several more Indians immerged from the same wood & on coming up to us seemed to extend the hand of fellowship & say how de do.” (Journal of Appleton Milo Harmon, typescript, 21 Apr. 1847, Family and Church History Department Archives, The Church of Jesus Christ of Latter-day Saints [microfilm], 4–5).
May 8, 1847
“All the sights of Buffalo that our eyes beheld [this] was enough to astonish man. . . . The face of the earth was alive & moving like the waves of the sea.”
Wilford Woodruff’s Journal: 1833–1898, Typescript, ed. Scott G. Kenney, 9 vols. (Midvale, Utah: Signature Books, 1983–95), 3:171.