132 Ludwig Tesdorpf, Stuttgart. 



The arithmetical mean of both readings on the rod gives 

 the true horizon. 



On the same principle also larger instruments are made magnifying 

 30, 36 and 60 times. 



No. 10. Levelling Instrument with fixed telescope mounted on 

 long vertical axis horizontal fine adjustment; telescope of astronomical 

 magnification 30 ; level of sensibility of 13" per interval of 2 millimeter. 

 Mounted on stand with Patent horizontal adjustment. English model stand. 



No. 11. The same without fine adjustment; terrestrial magni- 

 fication 20. 



No. 12. Levelling Instrument with fixed telescope mounted upon 

 long vertical axic. Horizontal fine adjustment.* A Telescope with 

 astronomical magnification 21. Patent horizontal stand adjustment. 



No. 13. The same without clamp and fine adjustment ; astronomical 

 ocular 21. 



Note: If a terrestrial ocular be used the magnification, the tube 

 length being the same, will be 14. 



No. 14. Universal Levelling Instrument with elevation screw; 

 telescope magnifying 21 times; horizontal circle of 8 centimeter diameter, 

 divided in 1/2, reading to 1'; on light stand, Canvass case. 



No. 15. The same, without circle, on a lighter stand, in case. 

 See Fig. 14. 



No. 16. Patent Pocket Levelling Instrument (Wagner's). 

 Telescope magnifying 18 times; reversion -level encased and protected 

 from external influences; bubble directly visible in field of ocular; mounted 

 upon light stand. In leather case. See Fig. 7, 9, 10, 11. 



No. 17a. The same, with telescope magnifying 12 times; on 

 light stand. 0.5 centimeter can be conveniently read off at a 

 distance of 100 meters. Degree of accuracy: ^QO f the distance. 



No. 17 b. The same, with telescope magnifying 12 times, in case. 



No. 18. Universal Instrument, for general plans. Patent 

 Schmalkalden Compass with prism, lens and folding - sights, circle 

 divided in 400, reading to single grades or 20' by estimation: telescope 

 magnifying 12 times; surveying level of sensibility of 20" fitted 

 with hinged mirror for convenient reading; altitude arc divided in 1/2 

 grades, reading to 1', besides / divisions. Degree of accuracy: 5 milli- 

 meter per 100 meter distance. In polished walnut case. See Fig. 15. 



No. 19. Instrument for Chain and Compass Survey. 



Small handy instrument for limited areas, The instrument is fixed 

 upon a rod; it is fitted with patent Schmalkalden compass; circle 

 divided in 360 reading to 1, by estimation to 12'. 



For measuring rise and fall in terms of % the diopter instrument 

 No. 20 will be found useful. 



No. 20. Diopter instrument. Type I. Hand instrument with 

 handle; in case, sail-cloth or leather, as preferred. 



Altitude arc divided in %, viz. 050% "reading 1%, 50100% 2%. 



