C. A. Steinheil Sohne, Mtlnchen. 119 



Terrestrial Telescopes. 



Hunting draw telescope 



in bronzed brass mounting, two draws and sun shade; 34 millimeter 

 (15'") aperture and 32 centimeter (12"). focus magnifying 15 times, 

 particularly bright field. 



Leather case and tree screw. 



Panorthic Monocular 



with object glass of 16 millimeter (7'") diameter and very large field. 

 Polished aluminium or nickeled brass mounts. Total length 

 28 millimeter, weight about 12 grammes and 21 grammes respectively; 

 for pocket or strap. They may be used with equal advantage by hy- 

 permetropic, myopic or normal sighted persons. The linear magnifi- 

 cation is about 1.6. These telescopes are not adjustable by draws 

 and have to be adjusted for each individual eye. For this purpose 

 the indication of the spectacle number required for correcting the eye 

 for distance is sufficient for the selection of the proper focus. 



Panorthic Double Telescopes 



(Jumelles) with double distance of lenses. (German patent No. 28787.) 



(Examplified by one of magnification 4.4 with object glass of 

 47 millimeter (21" / ) ( li ame ter and 12 glasses. Aluminium mount and Eussian 

 leather cover. Double draw,s and adaptable to width of user's eyes.) 

 This special form of Galileo's telescope is particularly distinguished 

 from all other existing forms in . that its achromatization is of a higher 

 order and that, consequently, the definition is greater. Even when the 

 instrument is placed at an angle to the normal direction brillantly 

 illuminated objects sharply set off by the back ground show hardly any 

 coloured fringes. 



The ratio of the magnification of the telescope to the size of the 

 field is, in spite of these points of excellence, not less, in many cases 

 even greater than with other types. There are, <as a rule, 8 glasses 

 in a double telescope of this kind. Of these, two cemented lenses form 

 the objectives, while the oculars consist of two lenses separated by a 

 short distance. Only in the case of relatively high magnifications 

 (4.4X) each of the ocular lenses consists of two cemented lenses; in 

 this case the double telescope contains 12 lenses. 



