The invention of the circular dividing engine was an important moment for surveying. The measurement inscriptions on instruments such as the compass had previously been made by hand, which meant their accuracy varied considerably. The dividing engine eliminated the problem of human error and paved the way for instruments with a consistently high degree of accuracy to be produced.
Exactly when and by whom the first dividing engine was made remains unclear, but one of its first creators was undoubtedly clockmaker Henry Hindley, in around 1739. His instrument was based on a gear-cutting machine for clockworks, and used a worm-gear and toothed index gear-plate to operate the mechanism.
Sometime between 1765 and 1768, Duc de Chaulnes produced a pair of dividing engines for dividing circular arcs and linear scales, which were also inspired by clockmaking. Chaulnes’ goal was to improve the accuracy of instruments by removing the danger of human error wherever possible.
In 1773, Jesse Ramsden produced a dividing engine with a screw-cutting lathe which was a significant improvement on previous designs. Ramsden received funding for his dividing engine from the Board of Longitude, on the condition that his design would not be patented, and he would teach others to create their own.
Following the invention of the dividing engine, the UK had a near-monopoly on the precision instrument industry, as other countries failed to produce anything as accurate as the instruments based on Ramsden’s creation. In the early 1800s, American surveying instrument specialist William J Young created a larger dividing engine, which he claimed allowed an even greater degree of precision. He modified his dividing engine so it could be operated automatically. Later, he produced a circular dividing engine with a 48-inch radius, which was used in the graduation of scales for engineers’ transits and other instruments.
The instruments produced with Young’s automatic dividing engine played a key role in the exploration and colonisation of the American West. The dividing engine made it possible to produce more accurate surveyors’ compasses, and a number of other valuable instruments, including the railroad compass, which was widely used as railway lines were laid across the U.S. Later, the surveyor’s transit was developed by replacing its sighting bars with a telescope which could be revolved on its horizontal axis. Young’s transit achieved widespread popularity among surveyors shortly after the launch of its commercial production, in the mid-1800s.
Christian Louis Berger also played an important role in the development of the dividing engine. In 1871, after a number of years working with some of the world’s best instrument makers, he and George L Buff established Buff and Berger, producing instruments for surveying, engineering, mining and science. The pair developed a reputation for producing high-quality precision instruments, until the firm was dissolved in 1898, following a dispute. After acquiring the company’s assets, Berger and his sons moved the business to Roxbury, Massachusetts, where they produced instruments for geodetic, civil, geological and petroleum surveyors internationally. With their highly accurate dividing engines, this was perhaps the company’s most productive period, and the company remained influential until it was eventually sold, in 1948.