“Odometer” comes from two Greek words put together which roughly mean “path-measure.” The modern-day odometer measures how much distance is traveled by a vehicle, machine, or any moving device. Here is a simple history of this equally simple but incredibly useful device.
The first suspected use of an odometer-like object came between 60 AD to 80 AD. Two authors, the Greek Strabo and the Roman Pliny, talk about how far Alexander the Great (356-323 BC) traveled throughout several journeys. Alexander the Great used bematists, literally “step-measurers,” who were trained to take steps of equal length and count them to get an idea of total distance traveled.
While bematists were renowned for their ability to walk with perfectly paced steps, some historians suspect they might have used devices for measurement particularly over long distances. In that case, they would have had the first known odometers. However, if they did not use the devices, humans themselves would be the very first odometers.
How advanced did mechanical devices have to be before the discovery of the odometer?
At the very least, mechanical devices should have advanced to the point where creators and inventors knew how to use gears and gearwheel coupling to create joint movement. The earliest known gears in use were in Chinese chariots in 2700 BC, and in the Western world, by mathematician and inventor Archimedes in 300 BC.
Despite China’s early knowledge of gears, its first suspected use of odometers was still around 100 BC. The device did not seem to be of widespread importance, and was simply one of the mechanisms in development at the time. In contrast, rulers in the European continent depended heavily on mechanical devices to win wars, therefore the development of devices like the odometer progressed much quicker.
Case in point, Roman architect and military engineer Vitruvius
Marcus Vitruvius Pollio (80-15 BC) is widely credited with the invention of the modern-day odometer, partly because he describes one in detail which he developed for the military. Vitruvius wrote De architectura, a ten-book series that talks about many military details. The odometer was one of them.
The odometer for land travel developed by Vitruvius worked as a device attached to one of the back wheels of a four-wheeled vehicle. It operated the same way that the movement of a clock’s second hand manipulates the minute hand and, in smaller degrees, the hour hand. With every revolution of the wheel, one tooth of a large gear would be moved. Every 400 teeth was one mile.
The large gear was also manipulating a mile counter at a much slower pace, much like an hour hand. The top of the mile counter was made of pebbles set into holes at 400-tooth intervals. The pebbles were blocked from falling by the bottom of the mile counter, which was a container with a single hole. Every 400 teeth, a pebble would be situated above the hole, and fall through. The military could tell the number of miles they had traveled by how many pebbles were in the container by the end of the journey.
There were some obvious limitations, including the need to replenish the pebbles as needed for the mile counter. However, it was a useful device in practical military use, and Vitruvius’s treatise ensured that future inventors would have a detailed guide for its development.
Is that it?
Once the basic principle of the odometer was discovered, the next steps for various inventors was to simplify the instrument, make it smaller, adapt it for more than land travel. Here are some honorable mentions named by most historians.
Leonardo da Vinci
The inventor Leonardo da Vinci (1452-1519 AD) was a great fan of Vitruvius, and recreated a number of his inventions as drawings. He also modified the original odometer, attempting to simplify it, make it smaller, and develop ways of counting miles that did not depend on the number of pebbles. While his design was never developed into an actual mechanical device, it does reflect how solid Vitruvius’s invention was in principle and practicality, since it had hardly been improved upon in the last 1500 years.
Blaise Pascal (1623-1662) was a French mathematician who specialized in calculating machines. He developed the Pascaline, considered one of the first calculators, which could add and subtract. It used the same principle of the odometer to move counters that reflected the answer of the problem presented. While not technically an odometer, it does reflect how the gear system of odometer-like devices were being refined and made much smaller and more precise.
Thomas Savery (1650-1715 AD) is better known for his work with steam and mine shafts, but he is also credited with making the first odometer for sailing ships. Not much is easily discoverable about this odometer besides the credit to the inventor.
Benjamin Franklin (1706-1790 AD) measured mileage with a simple, portable odometer that helped him plan mail and other routes more efficiently. He is specially mentioned as a known name and for his own skill as an inventor, and his use of the odometer shows how far it had come so that it could now be used by individuals for personal or business reasons.
The history of the odometer: simple but lasting
As a mechanical device, the odometer is deceptively simple. However, the principles of the original device were so sound that it took over 1500 years to simplify and refine its design until it looks like what we know it to be today.
Callegari, M., Brillarelli, S., & Scoccia, C. (2020). Archimedes, Vitruvius and Leonardo:
The Odometer Connection. Advances in Historical Studies, No. 9, pp. 330-343.