KEP0RT8 OF ASTRONOMICAL OliSKUVATORIKS. (185 



DriJLix, InUoul. 



1> lot si III: ObsvyraiDiij. 



Loiigitnde from (ireciiwicli, i*.")'" 21^ W. 



Latitude, 53^23' 13" N. 



Authority for latitn(l(> and loiiuitudc: Dr. Ukinnow. 



Directors: H. Fssinnj, 1774; 



.). Brinkley, 17!>2; 



W, E. Hamilton, 1827; 



r. BRtJNNOW, 1805 ; 



Prof. Robert S. Ball, LL.I)., F. li. S,, Astronomer lioyal 

 of Ireland^ 1875. 

 Assistant: J. L. E. Dreyer. 



Obserratory of Trinity College. 



Founded in 1774, by means of the legacy left for the purpose by F. 

 Andrews; built in the midst of a vast park at Dunsink, 3^ miles (6 

 kilometers) northwest of Dublin. It was not linished until 1792. A 

 structure of' three stories, surmounted by a revolving dome. 

 Instruments : 



{a) Meridian circle: makers, Pistor & Martins; diameter of circles, 

 36 inches; divided to 2'; read by 8 microscopes to 1"; aperture of ob- 

 jective, G.4 inches; magnifying power ordinarily employed, 1S(> diam- 

 eters. 



{h) Meridian transit instruments: one, made by Bamsden; aperture. 

 4 inches: not in use. {h') One with reversible circle by Bamsden cS: 

 Berge ; object-glass, 3 inches ; diameter of circle, 8 feet ; 3 micrometers: 

 not in use. 



{c) Equatorial _ instruments: one; makers, Cauciioix object-glass, 

 Grubb mounting; aperture of objective, llf inches; magnifying ])owers 

 of eye-pieces, 300: is generally used, (c') One of four inches aperture ; 

 English equatorial by Tulley. (!) Hardly e^•er used. 



{d) Spectroscopes: one of Browning's two-prism spectroscopes: and 

 one of Vogel's small-star spectroscopes. 



(/) Chronograph: maker, Grubb; two barrels and controlled clock. 



[g) Clocks: one mean time; maker, Booth of Dublin: one sidereal; 

 maker. Dent, London. 



(It) Chronometer : sidereal ; maker, M'Master. 



(t) Miscellaneous: The mean-time clock controls by electricity the 

 clocks in the port and docks board and Trinity College, the distance 

 being about five miles from Dunsink. 



Dunsink Observatory belongs to Trinity College, Dublin. An annual 

 visitation of the Observatory is held every summer by the board of 

 Trinity College. 



Observations during the past year (1880) : 



The meftdian observations of red stars (commenced by Dr. Cope- 



