REPORTS OF ASTROXO^nCAL OBSERVATORIES. GG9 



WiLLETS Point, Queens CounUj, Xtic Yorl:. 

 Field Observatory — Engineer School of Application. 



Longitude from WashingtoD, 13"' 04\57 E. ± OM-i. 



Latitude, 40^ 47' 21".59 X. ± 0".0S. 



Latitude determined by observations with zenith telescope. Longi- 

 tude determined by telegraphic time-signals from jSTaval Observatory, 

 Washington. 



Director : General ICenry L. Abeot. 



Assistant : Capt. J. C. Mallery. 

 Instruments : 



(h) Meridian transit instruments: {Four:) One, makers, Lingke & 

 Co., Silesia ; aperture, 2^ inches ; magnifying power, — diameters ; focal 

 length, 30 inches. One, Eussian transit, aperture, 2.0 inches ; Stackpole 

 & Bro., New York ; focal length, 30 inches. One, Troughton, ai)erture, 

 2 inches; Troughton, London; focal length, 30 inches. One, Stack- 

 pole, aperture, 2 inches ; Stackpole & Bro., New York ; focal length, 

 24 inches. 



(c) Equatorial instrument : makers, Fauth & Co., Washington ; 

 aperture of objective, 5J inches; magnifying x)owers of eyepieces, as- 

 sorted. 



(/) Ghronograplis : Hipp's; Negus-Morse register. 



{h) Chronometers : one mean time ; makers, Arnold & Dent : one 

 sidereal; makers, Lukens; Bond & Son. Both break-circuit. 



(i) Miscellaneous: One portable telescope, equatorially mounted; one 

 zenith telescope — William Wurdemann ; two sextants, Stackpole 

 & Bro. ; one personal equation machine ; one barometer, Green's 

 cistern. 



Observations during the past year : 



Observations for determining latitude and longitude, for instruction 

 of engineer officers at the school. 



Observations upon auroral disi^lays, extended through entire night, 

 and continued since 1870. 



Work proposed for the coming year (1881) : 



Similar to above. 



Principal publications of the observatory during the 



YEAR : 

 Annual battalion order announcing results of season's works. 



Additional information : 

 Observations on the Aurora Borealis — The regular series of records of 

 the displays of the Aurora Borealis, begun in 1870, has been continued, 

 as heretofore. Three sentinel posts, widely separated from each other, 

 are guarded nightly by soldiers of the Battalion of Engineers specially 

 selected as watchmen. Eight men are thus permanently detailed. 

 Three of them remain on duty from sunset to sunrise, and are required 



