134 Ludwig Tesdorpf, Stuttgart, 



Fig. IT. 

 Cartometer No. 34. 



No. 35. Cartometer with 5 wheels, in case. 

 No. 36. The same, with 7 wheels, in case. 



These patent cartometers serve for computing the lengths of lines 

 of any form, curves, spirals, serpentines etc. 



Special features of the apparatus: (No. 3436.) 



1. Greatest simplicity of manipulation and great accuracy. 



2. Lines can be traced backwards and forwards without interruption, the 

 wheels being alternately thrown in and out of gear according to the direction 

 in which the apparatus is made to follow the lines. 



The absolute length L results immediately from the product of the 

 arithmetical mean (m) of the tracings made by the instrument with 3, 5 or 

 7 wheels and the constant K attached to each particular instrument. 



L = m. K. 

 Example : 



1st tracing Position of wheels before, N t after tracing, N 2 



II nd tracing N 3 N 4 



thenN 2 -N 1= ,n, and = ^_^ 



N 4 N3 = n n 

 No. 37. Pachymeter for measuring the thicknesses of me.tal, 



paper, card board, for workshop use. Reading directly to 0.005 mm; 

 measuring up to 5 mm. 



No. 38. Pachymeter, larger size. Divided wheel of 85 mm 

 diameter, with reversible jaw, suitable for cartridge manufacture. Reading 

 directly from 0.005 to 5.0 mm. 



No. 39. Protactor ruler, made of argentan, semicircle of 20 cm 

 diameter, divided in 360: l / 2 Q , reading to 2' with ruler 0.5 m long. 

 Clamp and fine adjustment. 



No. 40. Protractor for tachymetrical surveying (radial ruler 

 without centration), with special adjustment of the magnetic deviation. 



No. 41. Xylometer, apparatus for determining the specific gravity 

 of various species of wood; for scientific determination of the qualities 

 of woods. 



No. 42. Hand Compass, mounted upon staff, with ball and 

 socket joint, and vertical axis of rotation. 



No. 43. Bertram's Heliotrope, mounted upon wood base. 

 (Signalling apparatus for long distance surveying.) 



