Odometer
An odometer is a device used for indicating distance traveled by an automobile or other vehicle. It may be electronic or mechanical.
Mechanical odometers usually appear as a row of wheels with the edge of the wheels towards the person viewing it. There are digits written on the edge of these wheels. A mask obscures these wheels from view, except for one row of digits which can be seen through a window in the mask.
In the U.S., odometers on older cars could only indicate miles up to 99,999 miles. At 100,000 miles, the odometer would restart from zero. This is known as odometer rollover. Newer cars usually have odometers that can indicate up to 999,999 miles.
A common form of fraud is to tamper with the reading on an odometer. This is done to make a car appear to have been used less than it actually has been, to get a higher price for the car.
History
An odometer for meauring distance is described by Vitruvius around 27 and 23 BC. The actual invention may have been by Archimedes during the First Punic War. Hero of Alexandria describes a similar device in chapter 34 of his Dioptra.
Chariot wheels of 4 feet diameter turn exactly 400 times in one Roman mile (about 1400m). On each revolution a pin on the axle engaged a 400 tooth cogwheel thus turning it one complete revolution per mile. This engaged another gear with holes along the circumference, where pebbles (calculus) are located, that drop one by one into a box. The number of miles travelled is given simply by counting the number of pebbles. Whether this instrument was actually built is disputed. Leonardo da Vinci tried to build it according to the description but failed, however, Andre Sleeswyk was able to make a working model.
References
- Sleeswyk, André Wegener "Vitruvius' Odometer", Scientific American 245.4 (October, 1981), pp. 188-200
- Sleeswyk, Andre W. "Vitruvius' Waywiser", Archives internationales d'histoire des sciences Vol. 29 (1979), pp. 11-22.
External links
Referenced By
Famous Canadians | List of Canadians | List of famous Canadian people | List of famous Canadians
|
