Orson Pratt - Migration West

Migration West

Pratt was a member of Young's initial pioneer company, the "Vanguard Company", that crossed the plains to select a western site for Mormon colonization. His journals of this trip are an important Mormon history resource. As the group made their way from Missouri to Utah, Pratt acted as the company's scientific observer. He made regular readings with the company's scientific instruments, took notes on geological formations and mineral resources, and recorded information on plants and animals. He described snow on Laramie Peak on June 7, and noted that rock found on June 10, ...would make excellent grindstones, being of fine grit sandstone. (May, p. 57)

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.

With Erastus Snow, Pratt entered the Salt Lake Valley on July 21, 1847, three days ahead of the main body of the Vanguard company. Several days later, he preached the first sermon in the Salt Lake Valley and formally dedicated the valley to the Lord.