ROYAL OBSERVATORY, Greenwich. England, the famous observatory established by order of Charles II, who appointed John astronomical observer 4 March 1675 at a salary of f100 ($500), for which he was also to instruct two boys from Christ's Hos pital. The first observation was made 19 Sept 1675. The observatory was established to meet the requirements of navigation and not only has amply fulfilled its object, but under the distinguished successors to Flamsteed has con tributed to the higher branches of science, some of the most important of the astronomical and physical discoveries of modern history. Among the directors of the observatory have been Ed mund Halley (1720-42); James Bradley (1742 62) ; Nathaniel Bliss (1762-65) ; Nevii Maske lyne (1765-1811) • John Pond (1811-36) ; Sir George Airy (1836-81) ; Sir William Ch tie (1881-1910) ; Dr. Frank Watson Dyson (1910). The director of the observatory is styled the astronomer royal, and is under the official control of the Admiralty, but receives his ap pointment directly from the Prime Minister, and holds office by warrant under the royal sign manual. The largest instrument is a 28 inch refractor, with spectroscope attached. An other fine instrument is the astrographic equa torial designed for work in connection with the *Photographic Chart of the Heavens.' It con sists of two telescope tubes rigidly connected and parallel, one carrying a 10-inch lens, the other a 13-inch photographic lees which the star. images are imprinted on the photographic plate. The Greenwich section of this important work was completed at the end of 1909. The Thompson equatorial, presented to the observatory by the late Sir Henry Thompson, has on one side of the declination axis a telescope with a lens corrected for photo graphic rays of 26 inches aperture, and on the other side a telescope with a mirror of 30 inches diameter. A photographic spectroscope
is mounted on the reflector. The refractor is being used to determine the distances of stars. Photographs of the sun are taken on every available day, and after being measured are carefully stored for reference, giving a daily record of sunspots for the last 35 years. The chronometers used in the navy are purchased after at the observatory. The average number being tested daily is about 600. Every hour during the day thee-signals are sent out from the standard clocks of the obser vatory through the postal telegraph service, giv ing Greenwich time to all parts of the United Kingdom. The true basis of accurate astron omy was laid by James Bradley's observations of 3,222 stars at Greenwich; the observatory has the 24-inch reflector by which the satellites of Uranus and Neptune were discovered by Lassell; and at Greenwich in 1908 the eighth satellite of Jupiter was photographically dis covered by Melotte. Astronomical Observa tions founded 1750 and published annually since 1838 contains a continuous record of the moon's position since 1750. At Greenwich in 1767 Nevil Maskelyne founded the Nautical Magaeine. The observatory staff consists of the director, two chief assistants, six assistants and a staff of computers. See OBSERVATORY.