rotating mechanism
71Lock (water transport) — Canal lock and lock keeper s cottage on the Aylesbury Arm of the Grand Union Canal at Marsworth in Hertfordshire, England …
72Preselector gearbox — For other uses, see Preselector (disambiguation). Transmission types Manual Sequential manual Non synchronous Preselector Automatic Manumatic Semi automatic …
73star — starless, adj. /stahr/, n., adj., v., starred, starring. n. 1. any of the heavenly bodies, except the moon, appearing as fixed luminous points in the sky at night. 2. Astron. any of the large, self luminous, heavenly bodies, as the sun, Polaris,… …
74photography, technology of — Introduction equipment, techniques, and processes used in the production of photographs. The most widely used photographic process is the black and white negative–positive system (Figure 1 >). In the camera the lens projects an image of… …
75Course Setting Bomb Sight — The CSBS Mk. IX mounted in a Fairey Battle. The bomb aimer is sighting through the white ring shaped backsights to the pin shaped foresights (just visible against the armoured cable) and holding the bomb release switch in his right hand. The… …
76Clock — For other uses, see Clock (disambiguation). Timepiece redirects here. For the Kenny Rogers album, see Timepiece (album). Platform clock at King s Cross railway station, London …
77Magnetic field — This article is about a scientific description of the magnetic influence of an electric current or magnetic material. For the physics of magnetic materials, see magnetism. For information about objects that create magnetic fields, see magnet. For …
78Su Song — 蘇頌 (Sū Sòng) Born 1020 near Quanzhou Died 1101 (aged 80–81) Nationality Chinese …
79History of science and technology in China — Inventions …
80History of timekeeping devices — For thousands of years, devices have been used to measure and keep track of time. The current sexagesimal system of time measurement dates to approximately 2000 BC, in Sumer. The Ancient Egyptians divided the day into two 12 hour periods, and… …
