40 MR. BARLOW'S ACCOUNT OF THE CONSTRUCTION OP 



In e Bootis the small star is well separated from the larger, and its blue 

 colour well marked with a power of 360. 



)} CoronjE Borealis is seen double with a power of 360 and 700 ; 62 Orionis, 

 ^ Orionis, and others of the same class, are also well defined with the same 

 powers. 



Still, however, it must be admitted that the telescope is not so competent 

 to the opening of the close stars, as it is powerful in bringing to light the 

 more minute luminous points. 



Of the planets, I have only had an opportunity of trying the telescope on 

 Venus, Satui'n, and Mars; and the latter is too low to furnish a good test. Venus 

 is beautifully white and well defined with a power of 120, but shows some 

 colour with 360. Saturn with the 120 power is a very brilliant object, the 

 double ring and belts being well and satisfactorily defined, and with the 360 

 power it is still very fine. The moon also is remarkably beautiful, the edges 

 and the shadows being well marked, while the quantity of light is such as to 

 bring to view every minute distinction of figure and shade. 



Description of the Telescope Stand. 



A correct representation of the stand, with the telescope upon it within the 

 building, is given in Plate III. The fixed base is a strong built oaken curb six 

 feet in diameter and six inches broad, imbedded on a circular brick founda- 

 tion : to this is screwed an interior fillet or ribband, projecting higher than the 

 other part of the curb, and sei-ving the double purpose of keeping the stand to 

 its centre and of receiving graduations to degrees and quarters, thus forming 

 an azimuth circle. The outer part of the curb is beveled to the centre, and 

 on this run three cast-iron rollers made to the same bevel : by these means 

 the principal azimuth motion of the instrament is effected. 



At the corners of the triangular base are three strong cast-iron sockets for 

 receiving the ends of three oaken bars four inches square, which form the 

 moveable base of the stand, the plate below each socket being a detached 

 casting, screw-bolted through the timber and upper side, admitting thereby 

 of being screwed up and tightened, in case any shrinkage takes place in the 

 wood. 



