An eighteenth or early nineteenth century waywiser or odometer.
This extremely rare blacksmith made artefact is made from ebonised wood with an iron bound wheel and turned spokes. To the centre is a box containing the mechanism comprised of a threaded axle which turns three wooden gears which are engineered to accurately measure miles, furlongs and yards. These are measured by means of a superb eighteenth century handwritten paper dial and three decorative iron pointers.
The odometer (also variously known as a sureyor’s wheel, a waywiser and perambulator) was used prolifically by surveyors and mapmakers during the period. One was certainly used by Major James Rennell (Surveyor General to the Honorable East India Company) during his surveying of Bengal. He is noted in “The Cyclopedia; or Universal Dictionary of Arts, Sciences & Literature” in 1819 as saying that, “he measured a meridian line of three degrees with this instrument; and found it to agree minutely with the observations of latitude. An Allowance however, was made for the irregularities of the ground whenever they occurred”.
Their history of course is much longer than that. It is supposed that Archimedes was the inventor of the odometer and it was further developed by Vitruvius. In the seventeenth century, waywisers were put to use in John Ogliby’s surveying of the British Isles, a slightly different model can often be seen pictured in the cartouches present on his maps.
A very similar example to this one currently forms part of the historical maps collection of Princeton University. These examples were used by the first surveyors of the United States.
A fantastically rare museum piece from the days of early surveying and map making.