NEGEETTI AND ZAMHRA, HOLBOEN YIADUCT, E.C. 255 



Each 

 s d 



871 Telescope Eye-Pieces, Huyghenian .... 16s. to 1 5 



872 Dawe's Solar 800 



873 Transit 300 



874 Terrestrial . . . ... 1 15 



875 Comet 1 10 



876 Diagonal 4 10 



877 Sunshade and Brass Cap fitted to eye-piece 060 



878 Micrometer, Double Image, with Eye Pieces, &c., in Box . . 20 



879 Micrometer, with Position Circle, &c 15 



880 Reflecting Telescopes, for Students' use, mounted on improved 



stand, with endless screw motion to follow the stars with 

 Equatorial Motion, Silvered Glass Speculum, 5 in. diameter, 

 with two eye-pieces 25 



881 Ditto, Ditto on Equatorial stand, with 6^ in. speculum . 80 

 82 Ditto, Ditto with 85 in. Speculum and three eye-pieces . 110 

 883 Silvered Glass Specula (unmounted) best quality. 



5J inch diameter 7 10 



63 ..900 



8* 17 10 



10 . 38 



Prices of larger sizes may be had on application. 



884 Foucault's Reflecting Telescope, for Terrestrial or Astronomical observations. 

 The improvements of this telescope are principally in the use of a Glass 

 Speculum coated upon the surface with pure Silver. The eye-piece is 

 an achromatic microscopic arrangement of lenses mounted on the side 

 of the telescope, the image being received from the large speculum by 

 a prism, and the reflected image examined by the Microscope Eye-Piece, 

 which is fitted with rack-work adjustment. With these arrangements, high 

 powers can be used, and large field of view, combined with light, obtained. 

 Mounted on a table stand, with simple adjustments (fig. 884). 



Supplied to order . . 20 



With simple instructions for re-silvering the speculum. 



Gregorian or Newtonian Reflecting Telescopes constructed to order. 



