124 ' Ludwig Tesdorpf, Stuttgart. 



No. 2795. 



Ludwig TeSdOrpf, Stuttgart. (Wuerttemberg.) 

 Maker of Scientific Precision Instruments. 



Adress for. letters: L. Tesdorpf, 81 Augustenstrasse, Stuttgart. 

 Telegraphic address: ,,Tesdorpf, Stuttgart." 



SPECIALITY: 



Astronomical Surveying Instruments of the most advanced 

 type and highest degree of excellence. 



The firm was established in 1881. > Flighest references. Export 

 to all countries. Instrument maker to many home and foreign govern- 

 ments. Now exhibiting at International Exhibition for the first time. 



For want of space only surveying instruments are being exhibited. 

 But also portable anfl stationary transit instruments, universal astrono- 

 mical instruments, refractors with and without parallactic mounting., 

 telemeters (for measuring distances for coast defence) are made in 

 the works. 



The firm undertakes the manufacture of scientific instruments of 

 precision according to drawings and sketches. 



Catalogues in German and french of all the instruments made in 

 the works may be had gratis and post-free on application. 



No. 1. Tachygraphometer , Wagner and Tesdorpf's latest 

 type. This instrument, which is intended for speedily working out 

 general and detailed plans, is particularly adapted for land-surveying, 

 rail-way, canal, road and military surveying. The apparatus is 

 only apparently complicated; in actual use it is extremely simple as 

 regards its manipulation. (See Fig. 1.) 



Theory of the instrument: The instrument described in the following 

 paragraphs solves all problems, with which other tachymetrical theodolites 

 have to be worked out by calculation, automatically by purely graphical means. 

 It dispenses with the calculation of the coordinates of the positions of the 

 staves (by the tachymetrical formula E D . cos 2 a from the oblique distance 

 measured with the telescope and the divisions sighted on the staff). The hori- 

 zontal distances from the center of the instrument to the position of the 

 staff and also the absolute elevation above the sea-level are directly 

 projected without the assistance of tables or slide-rules. (By slightly 

 pressing upon the needle apparatus the readings are instantaneously transferred 

 to the paper, in any desired scale 1 : 500, 1 : 1000, 1 : 2000 etc.) 



/ Description of the principal parts: 



1. The upper body. The tachymeter itself, which is mounted upon a 

 metal base-plate P opened in the center, rests upon three ivory wheels, 

 which can be adjusted vertically and run in accurate guides. The pillar in the 

 center supports the telescope and the distance scale A. 



2. The telescope mounted on horizontal trunnions, clamp and vertical 

 micrometer adjustment; adjusted for central transit, fitted with new distance 



