1-630-324 - The Print Collector/Heritage Images

Elevation of Troughton's dividing engine, 18th century, (1886). Until the 1770s, scales on scientific instruments had been marked out by skilled craftsmen in a process called 'dividing', this was partly mechanized from the 1770s when dividing engines were introduced. Originally used on small instruments, by the 1850s they were used to graduate scales on large astronomical telescopes, making hand-dividing obsolete. This particular example was completed by John Troughton, and is similar to the first successful dividing engine which was completed in about 1775 by Jesse Ramsden. Illustration from Cyclopaedia of Useful Arts, Mechanical and Chemical, Manufactures, Mining, and Engineering, by Charles Tomlinson, Volume I, (James S Virtue, London, 1886).