ASTRONOMICAL OBSERVATORIES. 271 



iron, and grooved. The circular iron rail attached to 

 the lower part of the building traverses the uppen 

 surface of the wheels one foot from the floor. The roof 

 is of tin, and conical ; the aperture is 16 inches wide, 

 and is covered by a door which opens in a single piece. 

 The pier upon which the telescope rests is built of stone 

 faced with brick, and rises two feet above the floor. 



The telescope is a refractor, made by Henry Fitz. 

 The object-glass has an aperture of six and a half inches, 

 and a focal length of eight feet; and it was mounted 

 on an equatorial stand by Phelps and Ghirley. The 

 declination circle has a diameter of ten inches, and 

 reads by verniers to one minute of arc ; the hour circle 

 has a diameter of seven inches, and reads by verniers 

 to six seconds of time. The telescope is driven by 

 clock-work, and cost $1,125. 



The object-glass of this telescope has given entire 

 satisfaction. Saturn is seen with a division in the outer 

 ring, the division being somewhat eccentrical and nearer 

 the outer edge. Occasionally there has been seen a sub- 

 division of the inner bright ring at the ansae, near the 

 inner edge. The interior dark ring is also seen. 



The planet Mars is well defined in a good atmos- 

 phere with a white circumference, both at the equatorial 

 and the polar regions, the interior space being varied 

 with dark shades. 



The comet-seeker was also made by Henry Fitz. 

 The object-glass has an aperture of four inches, and is 

 fitted to a section of tube which screws into the finder 



