30 



NA rURE 



{May 13. 1875 



THE PROGRESS OF THE TELEGRAPH* 



WE now continue our description of Wheats tone's 

 electrical " Jacquard." 

 The rapid sequence of currents passed into the line- 

 wire by the " Transmitter " are automatically recorded 

 at the distant station by means of an apparatus called the 

 " Receiver," or printer, which marks upon a continuous 

 paper ribbon, as it passes through the instrument, the 

 "dot" and "dash" code of the Morse alphabet, corre- 

 sponding to the holes in the perforated Jacquard ribbon, 

 as rapidly as the sequence of currents can be passed into 

 the line. Two forms of this receiving instrument may be 

 noticed : one shown in Fig. 22, in which the " dot " and 



" dash " code is represented by dots upon the paper ribbon 

 upon either side of a central line, the lower line of dots 

 being read as "dashes" and the upper line as "dots." 

 The paper ribbon, mechanically advanced forward through 

 the machine in a continuous manner, is passed under a 

 shallow dish containing ink or other marking fluid. Two 

 fine small holes are made through the bottom of this 

 reservoir, in a position to correspond with the dots to be 

 printed upon the ribbon as it passes underneath the 

 reservoir. By reason of capillary attraction, the ink is 

 prevented from passing through these apertures. Two 

 electro-magnets, one on either side of the ink-reservoir, 

 actuate two needles, which are adjusted so as to be 

 depressed by the action of the current, and, dipping into 

 the reservoir, pass into the holes, and carry a small dot 



Fig. 22. — Wheatstone': 



of ink through on to the paper ribbon ; thus the mark is 

 printed as a " dot " or " dash," according as the respective 

 needle is depressed without any friction or mechanical 

 resistance beyond that of the needle dipping into the ink 

 held in the capillary tubes. The electro-magnet coils 

 are so arranged that only the respective needles are acted 



upon by the currents as they flow from the positive or 

 negative poles of the battery. The " dot " printing is 

 shown at Fig. 23. 



In the other form of '• Printer " the Morse code is printed 

 in "dot" and " dash " characters, the groups and sequence 

 of groups forming fthe letters and words exactly corre- 



N 



N 



V 



o ooo\ 

 000 I 



i 



W H EATS T.a N. £. 



Fig. 23. — Perforated Jacquard ribbon and printing by the 



_automatic_systein. 



sponding with the dot and dash perforations in the Jac- 

 quard ribbon. Y'\g. 24 is the automatic printing upon 

 this system from the perforated ribbon shown at Fig. 20. 

 Capillary attraction is here again made use of, only in a 



different manner. A small inking disc of metal mounted 

 upon a delicately poised axle capable of a slight 

 angular oscillation in a lateral direction, according as it is 

 influenced by the to-and-fro motion of a permanent mag- 



R E S S 



THE TEL EG RA P H 



Fig. 24. — An " electric loom," or automatic telegraph printed message from the perforated paper ribbon (Fig.20.) 



netic armature when acted upon by the alternate currents 

 passed into the line from the " Transmitter," is made to 

 rotate rapidly by the same mechanical means that ad- 



* Continued from vol. xi. p. 512,;' 



vances the paper ribbon. This little rotating inker \z 

 placed close to the surface of the paper ribbon, so that on 

 receiving a lateral motion in one direction its edge is 

 pressed against the paper and removed from it by an 



