THE TELEWRITER n 



graph engineer, Meyer, except that he used syn- 

 chronously revolving cylinders in place of the 

 curved metal plates. 



Although the transmission of writing cannot be 

 classed with the telegraphy of photographs, it will 

 be, nevertheless, of interest to describe the tele- 

 writer, which gives a facsimile reproduction at the 

 receiving station of anything written or sketched 

 at the sending station. In writing any letter on 

 paper, the movement of the pen can always be re- 

 solved into horizontal and vertical components ; 

 by making these resolved movements mechanically 

 vary two resistances, currents of two corresponding 

 strengths can be transmitted to a receiving instru- 

 ment ; but three lines are necessary, or two lines 

 and an earth. The two currents when received are 

 used to actuate a V-shaped nib filled with ink, both 

 vertically and horizontally, the resultant move- 

 ment causing the nib to trace over the paper a 

 replica of whatever the transmitter draws with his 

 mechanical " pen." In the telautograph of Grzanna, 

 the two currents corresponding to the vertical and 

 horizontal movements of the transmitting pen are 

 made to actuate a mirror galvanometer, the mirror 

 of which can turn about two axes, so that a spot 

 of light traces the letters or sketch over a sheet 

 of photographic paper. 



^These methods are only suitable for transmitting 

 sketches or designs that are drawn at the actual 



