rate of a chronometer
21Escapement — redirects here. For the fisheries term for the stock surviving fishing pressures over a spawning cycle, see Spawn (biology). For other uses, see Escapement (disambiguation). A deadbeat escapement, used in many pendulum clocks. Click above to see… …
22Geschichte der Zeitmessgeräte — Die Geschichte der Zeitmessgeräte lässt sich bis vor 6000 Jahren zurückverfolgen, als die Sumerer auf Tontafeln von Sonnenuhren berichteten. Von dieser Erfindung, die als eine der größten der Menschheit bezeichnet werden kann, existierte in einer …
23Navigation — This article is about determination of position and direction on or above the surface of the earth. For other uses, see Navigation (disambiguation). Table of geography, hydrography, and navigation, from the 1728 Cyclopaedia. Navigation is the… …
24John Harrison — Infobox Scientist name = John Harrison |300px image width = 260px caption = P.L. Tassaert s half tone print of Thomas King s original 1767 portrait of John Harrison, located at the Science and Society Picture Library, London birth date = birth… …
25Watch — For other uses, see Watch (disambiguation). Early wrist watch by Waltham, worn by soldiers in World War I (Deutsches Uhrenmuseum, Inv. 47 3352) A watch is a small timepiece, typically worn either on the wrist or attached on a chain and carried in …
26Longitude — For Dava Sobel s book about John Harrison, see Longitude (book). For the adaptation of Sobel s book, see Longitude (TV series). Map of Earth Longitude (λ) Lines of longitude appear vertical with varying curvature in this projection, but are… …
27Time — This article is about the measurement. For the magazine, see Time (magazine). For other uses, see Time (disambiguation). The flow of sand in an hourglass can be used to keep track of elapsed time. It also concretely represents the present as… …
28Time dilation — This article is about a concept in physics. For the concept in sociology, see time displacement. In the theory of relativity, time dilation is an observed difference of elapsed time between two events as measured by observers either moving… …
29Celestial navigation — Celestial navigation, also known as astronavigation, is a position fixing technique that was devised to help sailors cross the featureless oceans without having to rely on dead reckoning to enable them to strike land. Celestial navigation uses… …
30History of longitude — The history of longitude is a record of the effort, by navigators and scientists over several centuries, to discover a means of determining longitude. The measurement of longitude is important to both cartography and navigation. Historically, the …
