BAIRD &.TXTLOCK (LONDON) LTD. 



Zeiss' Achromatic Objectives (continued). 



f These Objectives contain Fluorite Lenses. 



All these objectives are also supplied adjusted for the English 10-inch body (tube-length 250 

 mm. (about io-in.)). 



1109' Zeiss' Huyghenian Oculars for use with achromatic objectives, No. noS. 



Table of Magnifications of the Achromatic Objectives with Huyghenian Oculars 



(Nos. 1108 and 1109), calculated for a tube length of 160 millimetres (about 6-| in.) and 

 an image distance of 250 millimetres (about 10 in.). 



In employing nosepiece 01 sliding objective-changer, the length of the nosepiece, amounting 

 to 15 millimetres, and of the sliding objective-changer, 22 millimetres, must be taken into account, 



CROSS STREET HATTCHSr GARDEN, E-C 



228 



