TJO BENJ. PIKE'S, JR., DESCRIPTIVE CATALOGUE. 



the sliding pipe, which contains the two first glasses, and in 

 its place substitute the higher power, 2. Observe, the 

 highest power, 1, is screwed into the adjusting tube, C, 

 without the long eye-tube, and is preferred for astronomical 

 uses. 



The legs of the brass stand are jointed and fold together, 

 and the whole instrument neatly packed in a mahogany 

 case. 



Price, the main tube 20 inches long, $42.00. 



" 30 " 60.00. 



" " " 36 " 90.00. 



" 42 " 150.00 and $200. 



" 30 inch, without box and ast. eye-piece, 48.00. 



Astronomical Telescope. (Fig. 131, next page.) Figure 

 1 in the plate represents the telescope, supported in the 

 centre of gravity, with its rack- work motions, and mounted 

 on its mahogany stand, the three legs of which are made fo 

 close up together by means of the brass frame, a a a, which 

 is composed of three bars, connected together in the centre 

 piece by three joints, and also to the three legs of the 

 mahogany stand by three other joints, so that the three 

 bars of this frame may lie close against the insides of the 

 legs of the mahogany stand when they are pressed together 

 for convenience of carriage. 



The brass pin, under the rack-work, is made to move 

 round in the brass socket, b, and may be tightened by 

 means of the finger-screw, d, when the telescope is directed 

 nearly to the object intended to be observed. This socket 

 turns on two centres, by which means it may be set perpen- 

 dicular to the horizon, or to any angle required in respect to 

 the horizon ; the angle may be ascertained by the divided 

 arc, and then made fast by the screw, e. If this socket be 

 set to the latitude of the place at which the telescope is 

 used, and the plane of this arc be turned on the top of the 

 mahogany stand, so as to be in the plane of the meridian, 

 the socket, b, being fixed to the inclination of the pole of 

 the earth, the telescope, when turned in this socket, will 

 have an equatorial motion, which is always very convenient 

 in making astronomical observations. 



Figure 2 in the plate represents a stand to be used on a 

 table, which may be more convenient for many situations 

 than the large mahogany stand. The telescope, with its 



