Mormon History, May 16, 1847. Sunday.

[William Clayton Journal] ...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. We are now prepared to tell accurately the distance we travel from day to day, which will supercede the idea of guessing, and be a satisfaction not only to this Camp, but to all who hereafter travel this way. I have prepared another board to put up here, on which the distance from winter quarters is marked at 356 3/4 miles. I have also wrote on it that the last 70 miles are measured, and we shall continue to measure and put up guide posts as often as circumstances will permit through the journey. The whole machinery consists of a shaft about 18 inches long placed on gudgeons, one in the axle tree of the wagon near which are 6 arms placed at equal distances around it, and in which a cog works which is fastened on the hub of the wagon wheel turning the shaft once round at every 6 revolutions of the wagon wheel. The upper gudgeon plays in a piece of wood nailed to the wagon box and near this gudgeon on the shaft a screw is cut. The shaft lays at an angle of about 45 degrees. In this screw a wheel of 60 cogs works on an axle fixed in the side of the wagon and which makes one revolution each mile. In the shaft on which this wheel runs 4 cogs are cut on the fore part which plays in another wheel of 40 cogs which shows the miles and quarters to 10 miles. The whole is cased over and occupies a space of about 18 inches long 15 inches high and 3 inches thick.
. . . After supper Elder Whipple made me a present of half a candle made from buffalo tallow by the light of which I continue this journal. Although as may be expected the buffalo are generally poorer at this season of the year yet Brother Whipple has obtained sufficient to make 2 candles from his portion of meat received yesterday morning. The candle burns very clear and pleasant. The tallow smells sweet and rich. I imagine it has a more pleasant smell than the tallow of domestic cattle.

[source: George D. Smith, An Intimate Chronicle; The Journals of William Clayton, Signature Books in association with Smith Research Associates, Salt Lake City, 1995, http://amzn.to/william-clayton]
[George D. Smith, An Intimate Chronicle; The Journals of William Clayton, Signature Books in association with Smith Research Associates, Salt Lake City, 1995, http://amzn.to/william-clayton]