78 C. J. MERFIELD. 



ment 2 is given in "Astronomical Results, Sydney Obser- 

 vatory 1879-80-81. 



The instrument does not conform to modern ideas of 

 construction, nevertheless it is a remarkably good one, and 

 built on a secure foundation, the instrumental corrections 

 remain normal during long intervals of time, in this con- 

 nection it has given no trouble. 



3. The Observing Room. 



The observing room for the meridian circle is situated in 

 the central part of the main building. The observing slit 

 measures only fifteen inches in width, and is provided with 

 shutters on the roof of the building, a door and sliding 

 windows are used for closing the opening in the northern 

 and southern walls respectively. The general arrange- 

 ment, originally very defective, is now much better, but 

 the room is too small and badly situated for the funda- 

 mental instrument of the Observatory. 



4. Meteorology. 



The standard thermometer is exposed in a louvred shed 

 12 feet by 12 feet, with walls about 12 feet 6 inches high ; 

 the cover is in the form of a pyramid, the base of which 

 rests on the four walls, the apex being 13 feet from the 

 floor level. This shed is some 50 feet due south of the 

 meridian circle. The barometer is in the main building, 

 suspended on brackets attached to the southern face of the 

 equatorial instrument pier on the ground floor. The read- 

 ings of the barometer and attached thermometer were 

 obtained from the records of the meteorological branch of 

 the Observatory, as well as that of the standard ther- 

 mometer. The variations of these were obtained from the 

 self recording instruments. A thermometer was also read 



2 A reproduction of a photograph of this instrument is given in the 

 volume noted, over the title " Sydney Transit Instrument and Reverser." 



