Hilger & Watts Clinometer in wooden box. Serial number: 89183 Made in England. Unfortunately, I don't have specific information about the exact date when the Hilger & Watts clinometer was produced, but the company was active for many years during the 19th and 20th centuries, so the instrument would have been produced somewhere within that period. The Hilger & Watts clinometer, an instrument used to measure the angle of a slope or incline, was produced by Hilger & Watts Limited, a renowned British company specializing in precision instruments. The company was founded in 1853 by William Johnstone Hilger and Thomas Watts in London, England. They specialized in manufacturing a wide range of precision instruments, including theodolites, level meters, and clinometers.