Keim's illustrated hand-bookWashington and its environs: a descriptive and historical hand-book to the capital of the United States of America . ch obsejvations are made. NAVAL OBSERVATORY. 165 XL Prime Vertical Transit, made by Pistor & Martins, Berlin, was erect-ed in 1S44. Object-glass, 4,86 in., clear aperture; focal length, 6 ft. 5 in. Is usedonly for declinations. XII. Machine Shop. XIII. Room of Officer in Charge of thh GreatEquatorial. XIV. Sleeping Apartment of Officer in Charge of theGreat Equatorial. XV. Great Equatorial,mounted in 1873, made by Al-van Clark & Sons, Cambridge-port,
Keim's illustrated hand-bookWashington and its environs: a descriptive and historical hand-book to the capital of the United States of America . ch obsejvations are made. NAVAL OBSERVATORY. 165 XL Prime Vertical Transit, made by Pistor & Martins, Berlin, was erect-ed in 1S44. Object-glass, 4,86 in., clear aperture; focal length, 6 ft. 5 in. Is usedonly for declinations. XII. Machine Shop. XIII. Room of Officer in Charge of thh GreatEquatorial. XIV. Sleeping Apartment of Officer in Charge of theGreat Equatorial. XV. Great Equatorial,mounted in 1873, made by Al-van Clark & Sons, Cambridge-port, Mass. Object-glass, 26in., clear aperture; focallength, J2i-^ ft., cost ;f47, rough lump of glass wascast by Chance & Co., Birm-ingham, England. The in-strument rests upon a doublepier of masonry, imbedded 17ft. in the earth. The pierabove the floor is of brick,arched, and has a cap consist-ing of asolid block of red sand-stone, 8 ft. long by z ft. wideand high. On top of this is aniron support weighing 1,100lbs., to receive the axis uponwhich the telescope is mount-ed. The instrument with itsbase weighs 6 toas. The in-. strument IS equatoriallymounted, the general planbeing that devised by Fraun-hofer, modified by and Prof. S. Newcomb,and is run by a reaction waterwheel. It is fitted with mi-chrometers., spectroscopes^ & tube is of sheet steel,rolled in Pittsburgh. Thereis also a chronograph con-nected with the great equatorial is plac-ed in an iron dome 41 ft. indiameter and 40 ft. in height,erected at a cost of $14, superstructure rests ona stone foundation. The roofis supplied with a slip, re-volves on conical wheels,and is easily moved horizdnt-ally in either direction by
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Keywords: ., bookauthorkeimdebr, bookcentury1800, bookdecade1870, bookyear1874
