170 years ago today - Apr 19, 1847

William Clayton suggests to Orson Pratt "the idea of fixing a set of wooden cog wheels to the hub of a wagon wheel, in such order as to tell the exact number of miles we travel each day." Pratt agrees "that it could be easily done at a trifling expense" but the device isn't constructed and installed until May 12. In the mean time Clayton walks alongside Heber C. Kimball's wagon counting each revolution of a wagon wheel.