628 SEC. 15. GEOGRAPHY. 



3083. Quadrant, of boxwood. One side engraved as usual, 

 :>n the other are numerous figures and a movable index. 



William Sykes Ward. 



3084. Gunter's Quadrant, of boxwood. 



William Sykes Ward. 



3085. Quadrant, of brass ; one side divided as .a geometrical 

 square, the other with movable circle and index, signs of the 

 zodiac, and various figures. William Sykes Ward. 



3086. Levelling Instrument with telescope to lie down. 



Meissner, Berlin (ff. Miiller and F. Reinecke). 



This levelling instrument is distinguished by its simple and especially 

 unchangeable arrangements for correction. 



3087. Reflecting Frism Circle, 10 in. diameter. 



Meissncr, Berlin (77. Miiller and F. Reinecke). 



3088. Reflecting Prism Circle, 6 in. diameter. 



Meissner, Berlin (ff. Miiller and F. Reinecke). 

 Tha reflecting prism-circles can be recommended on account of their 

 excellent execution, in optical as well as in mechanical respects, and also on 

 account of their cheapness. 



3089. New Levelling Instrument, constructed by A. 

 Oeppert, completed by F. Miller. F. Miller, Innsbruck. 



This instrument is adapted especially for geometricians and engineers at 

 work in mountainous countries. The arrangement is as follows : The 

 vertical revolving axis is placed perpendicularly by means of 4 screws. The 

 horizontal circle is removable by means of a vernier giving two minutes, and 

 by adding a sail may be changed into .a sailing carriage. The astronomical 

 telescope will magnify 15 times with 14 degrees of depression or elevation. 

 The inclination of the telescope is measured by a mici'ometer screw. When 

 placed in proper contact the instrument is very suitable for tracing. Its uses 

 are : Direct and indirect levelling, measuring height and distance, horizontal 

 angles, &c., marking down the above on paper. 



3090. Land Surveying Apparatus, of simple construction, 

 by A. Geppert, completed by F. Miller. F. Miller, Innsbruck. 



This apparatus, chiefly designed for work requiring no particular exactitude, 

 and which a beginner with little experience in surveying may be trusted to 

 execute, consists of a " Nativ," in which around plank is screwed, and serves 

 as a leaf. On the edge of this leaf are put 4 brass plates, with a deviation 

 scale at distances of 90, for forming right angles. The distance of the two 

 dioptra is 30 cm. ; one bears two horizontal cords, in the other a little 

 sledge with movable sight, which can be moved in a vertical direction. If 

 the index of this slide stands at zero on the division fastened to the dioptra, 

 the line of sight is horizontal when the tablet of the instrument is put in 

 action. By moving the slide, and measuring the way which has been passed, 

 the instrument can be used for indirect levelling distance and mensuration of 

 heights and tracing. A chord drawn over both dioptra allows the formation 

 "of perpendicular lines. 



