The study of timekeeping is known as horology. In horology, the anchor escapement is a type of escapement used in pendulum clocks. Its portfolio of courses includes jewellery, silversmithing, horology, and gemmology. The Swiss Lever escapement has been the standard in horology for hundreds of years. It is Huygens' major work on pendulums and horology. Gem City College is a school that specializes in horology and cosmetology. Burgess coined the term "sculptural horology" in the 1960s. It is a group of collectors and enthusiasts interested in the history of horology. Hans Wilsdorf's legacy and contribution is unparalleled in the world of Horology. There are many horology museums and several specialized libraries devoted to the subject. It is considered to be one of the preeminent works on the history of horology. Many honours recognised his enormous contribution to horology. From studying horology at night classes, he became a Fellow of the British Horological Institute. People interested in horology are called "horologists". Thys calls his version a snek drive (after the Dutch term for Fusee (horology)).