Ludwig Tesdorpf, Stuttgart. 133 



The levelling bubble a, (fig. 16) being projected by reflection into the 

 diopter tube may in a moment be brought into its horizontal position during 

 the sighting operation without changing the position of the eye; the level is 

 during this process brought into play by the milled head e. 



Bubble a and the pointer are rigidly connected and may be rotated to- 

 gether by means of the milled head. 



During each sighting operation this milled head is turned until the bubble 

 appears upon the metal mirror fixed at 45 inside the diopter tube in a sym- 

 metrical position with respect to the horizontal cross web. The corresponding 

 altitude can be read directly off the altitude arc. 



h = scale of percentages reading to 1/ , 



i scale divided in 1/1 reading, by vernier to 10 minutes. 



No. 21. The same. Type II, to fix on staff, with horizontal axis 

 and vertical trunnions, extremely serviceable for general preliminary work 

 or subordinate cross sectional measurements. 2 divisions, for direct reading 

 of rise and fall in percentage. In case with rod. 



No. 22. The same. Type III, combined with small horizontal 

 circle of 7 centimeter diameter, divided in single degrees, reading to 2', 

 sights as in No. 20. In polished walnut case. 



No. 23. Percentage Clinometer and Hand Levelling Instrument. 

 Combination of No. 20 with telescope magnifying 12 times. This 

 instrument has, like Nos. 9 and 17, the front of the ocular fitted with 

 a second lens for viewing the reflected image of the bubble, whereby it 

 is possible to sight the bubble and object simultaneously. See Fig. 16. 



No. 24. Patent "Schmalkalden" Compass for holding in band 

 or for screwing upon staff: in leather case. 



No. 25. Hypsometer. Handy instrument for general forest survey, 

 in particular for forest valuation. This instrument may be used for simple 

 levelling, measurements of heights and distances. Degree of accuracy: 5/ . 



.No. 26. Pantometer for limited areas. Horizontal circle reading 

 to 2', with compass and adjustable sights; in polished walnut case. 



Note : Instead of the usual hairs the instrument is provided with 

 metallic sight webs. See Fig. 13. 



No. 27. Optical Square, simple form. Large size. 

 No. 28. . Small 



No. 29. ,, , with three mirrors for setting off angles 



90 and for ranging lines. 



No. 30. Prismatic Square, in case. 



No. 31. ,, , watch form, in case. 



No. 32. Box bubble for screwing to levelling rod; accessory 

 to. Nos. 1. 



No. 33. Box compass; declination compass; accessory to No. 1. 



No. 34. Cartometer with three wheels, in case, This instrument 

 serves, like the planimeter, for computing boundaries. See Fig. 17. 



