Layton, Utah: Eborn, 1990. Octavo. Item #027958
Originally published in 1879. 118 pages. As a mathematician, Pratt assisted company scribe William Clayton in the design and invention of a version of the modern odometer. Intended to compute the distance traveled per day, the design consisted of a set of wooden cog wheels attached to the hub of a wagon wheel, with the mechanism "counting" the revolutions of the wheel. The apparatus, called the "roadometer", was built by carpenter Appleton Milo Harmon, and was first used on the morning of May 12, 1847. Bound in black cloth lettered and decorated in gilt, spine gilt. A fine copy in a very good dust jacket with small area to rear panel nicked apparently from a sticker removal.