ASTRONOMY. 



75 



circular, and is covered with a revolving dome twenty-nine feet in 

 diameter, which weighs but 4000 pounds, and can therefore be easily 

 revolved without machinery. The piers for the meridian instruments 

 are in the east wing. The central part of the roof of this wing is flat 

 and is surrounded by an iron railing ; it is directly accessible from 

 the Equatorial room, and forms a convenient place for the use of por- 

 table instruments. 



The following are the only instruments yet in the possession of the 

 observatory : 



Transit Instrument, by Kubel, of Washington, of 2^ inches aper- 

 ture and 31 inches focal length. It is so made as to admit of ready 

 reversal, and is provided with delicate Level and Micrometer, to adapt 

 it for use as a Zenith Telescope. 



Another Transit, of 2 inches aperture and 30 inches focal length, is 

 mounted in the prime vertical. 



Telescope, by Fitz, of 3 inches aperture, mounted on an equatorial 

 stand. 



For furnishing the time, there are two mean Solar Clocks and a Si- 

 dereal Chronometer. 



Washington, D. C. : U. S. Naval Observatory. 



Bear-Admiral John Rodgers, U.S.N. , Superintendent. 



The report of the Secretary of the Navy for 1878 contains that of 

 the Superintendent of the Naval Observatory, which gives an account 

 of the work of the past year. The 26-inch Equatorial continues to 

 be used in the observations of the faint satellites. The Transit Circle, 

 besides its regular work of observations of the sun, moon, and major 

 planets, has made a very large number of observations of asteroids, 

 and is also engaged in the formation of a catalogue of the B. A. C. 

 stars between 120 0' and 131 10' of N.P.D. 



The number of observations made with the Transit Circle during 

 the year is 3450. 



The sun was observed sixty-one times, the moon sixty times, and 

 there were made 110 observations of the major planets and 149 of 

 the minor planets. 



The Transit - of -Venus reductions are almost ready for publica- 

 tion. 



The work of reducing the observations for the chronometrical lon- 

 gitudes of five southern stations is now completed. From 23 to 35 

 Chronometers were used, and the corrections to each one have been 

 computed for every day from August 6, 1874, to January 30, 1875. 



The principal work of this observatory is described under its ap- 

 propriate heads as Saturn, Mars, Solar Eclipses, etc. 



