170 RECORD OF SCIENCE FOR 1887 AND 1888. 



leiigtli of the building east and west is 80 feet, north and south 100 

 feet. The clock -room is on the first floor of the main building, and is 

 27 feet in diameter. The large circular pier for the 1(1 inch equatorial 

 (to be constructed by Brashear) is in the middle of this room, suitably 

 cased to a height of 7^ feet, and provided with shelving. The mean- 

 time and sidereal clocks, both by Howard, are mounted in recesses in 

 the east and west faces of this pier. In the west wing, upon the same 

 floor, is the library with about 1,400 bound volumes, a small study or 

 class-room, and a jaintor's room; to the north is the prime vertical of 

 3-inch aperture (Fauth), and beyond this a class and lecture room. A 

 small dome over the north wing covers the 8^ inch Clark refractor. In 

 tlie east wing is mounted a fine Repsold meridian circle of 4.8 inches 

 aperture, which is under the charge of Dr. H. 0, Wilson. The chrono- 

 gr;iph, chronometer, and time-distributing apparatus are in the clock- 

 room. A time-service over more than 12,000 miles of railway is under 

 the immediate care of Miss C. R. Willard. 



The co-ordinates of the observatory provisionally adopted are ( Astron. 

 Nachr. 120:85): latitude +44° 27' 41"; longitude 0"' 12"' 3G^0 west of 

 Greenwich. 



Cincinnati. — A zone catalogue of 4,050 stars observed with the 3-inch 

 transit was i)ublished in 1887. In September, 1888, a new meridian cir- 

 cle, by Fauth & Co., was mounted, one of the first large instruments of 

 this class made, in the United States. The clear aperture of the object- 

 glass is 5J inches, and the focal length 70 inches; object-glass and mi- 

 crometer are inter-changeable. The piers are of masonry to the floor- 

 level, and from there up an iron frame work bricked inside to within a 

 foot of the top. The i)ivots are of steel, glass hard. There are two solid 

 circles, 24 inches in diameter; one is divided ver^' coarsely to half de- 

 grees only : the other has tAvo sets of graduation upon a silver baud, 

 both of them to 5'. The inner one is somewhat heavier than the other, 

 and does not pretend to great accuracy, being used merely for setting. 

 The outer graduation alone is visible in the reading miscroscopes; as far 

 as Professor Porter has carried his investigation the errors of this grad- 

 uation are very small. Electric illumination has been used throughout 

 and has been found practically i)erfect, A detailed description of the 

 instrument will be found in the Sidereal Messenger for January, 1889. 



Coinie {Liege). — Observations of Titan and lapetus have furnished a 

 determination of the mass of Saturn. The meridian circle has been used 

 for zone observations. 



Copenhagen. — Mr. Nielsen has recently erected a private observatory 

 with a 6^ inch refractor by Reinfelder & Hertel, intended principally 

 for selenographical work. 



Cordoba. — Volumes 6 and 0, containing the zone observations made in 

 1875 and 187G, have been published. 



Dearhorn. — The report for 1885 and 188G, which has not previously 

 been noticed, contains a list of nebulae discovered by Professor Safford 



