250 



NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G. 



857 



FIG. 857. 



Achromatic Astronomical Telescope (Fig. 857), same as No. 856, but with 

 Tangent Screw and Hook's Universal Joint for horizontal adjustment, and 

 extra Steadying Rods to Telescope ; fitted in polished mahogany case, with 

 lock and key. 



Power. 

 With Terres. Eye-piece. With Astro. Eye-pieces. 



. 50 diameters 

 . 55 



. 60 

 70 



75 & 90 diameters 



80 & 95 

 85 & 105 

 90 & 110 



Price. 



36 



42 



48 



66 



EDUCATIONAL 



ASTRONOMICAL TELESCOPES ON IMPROVED 

 TRIPOD STANDS. 



858 Astronomical Telescope, on Taper Iron Tripod Stand, object glass 3 inches 



diameter, 3-ft. 9-in. focal length, one Terrestrial eye-piece magnifying 20 

 diameters, and two Astronomical eye-pieces, magnifying 60 and 125 

 diameters, vertical rack motion and Achromatic finder, fitted in stout case, 

 with lock and key 25 



859 Ditto ditto, on improved Tripod Stand, with object glass 3-in. diameter, 



4-ft. 9-in. focal length, one Terrestrial eye-piece, magnifying 25 diameters, 

 and three Astronomical eye-pieces magnifying 80, 155 and 230 diameters. 

 Fig. 859 45 



860 Ditto ditto, but with object glass 4^-in diameter, 5 -ft. 3-in. focal length, 



one Terrestrial eye -piece, magnifying 30 diameters, and three Astronomical 

 eye-pieces magnifying 85, 170 and 255 diameters . . . 60 



861 Telescope Stand, similar to Fig. 861, for large instruments, complete, with 



Vertical rack, Steadying rod and Horizontal tangent rack . 15 15 



