HISTORY AND PROGRESS. 125 



found by the French Administration of Telegraphs to work 

 so well, that they have adopted it for use on the Government 

 lines in France and the colonies. This success is in a great 

 measure due to the nice discrimination between the sizes of 

 the movable and fixed portions of the apparatus having 

 reduced the vis inertia of levers, armatures, &c., to a mini- 

 mum, whilst amply sufficient strength is insured to effect 

 the complete marking of the paper. 



M. Guillemin, in 1862, made a series of interesting expe- 

 riments with this apparatus to determine the maximum 

 number of elementary signals, and, consequently, how many 

 words it was capable of recording in a given time. The 

 transmitting apparatus he employed consisted of four wheels 

 of twenty-five centimetres diameter on a common axis : one 

 of them made dots, the second dashes, whilst the two others 

 served to discharge the line after every elementary signal. 

 The words France and Paris, which in the Morse alphabet 

 represent a mean of the French words, were repeated on a 

 line of 750 kilometres, in fine weather, thirty times per 

 minute, and in wet weather he easily attained the rate of 

 forty words. On a line of 450 kilometres, passing by Le 

 Havre, the reception was augmented to seventy-five words 

 per minute six times that which the employes are able to 

 attain with the hand. 



79. Direct Working Ink- Writers of Siemens and Halske. 

 An important modification of Digney's instrument is made 

 by Siemens and Halske, who substitute a small inverted 

 bottle containing ink, and secured by a felt stopper, for the 

 inking roller of felt, described in the preceding paragraph. 



This arrangement is represented in Fig. 68. B B is a small 

 inverted glass bottle containing the printing fluid ; its neck 

 is cemented into a brass ring, c, fitting into a collar, D. At 

 the back of the collar is a horizontal hollow axis, E, supported 

 by a pin fixed in the side of the apparatus, on which the 

 whole thing turns, and from which it may be removed in the 

 same way as Digney's felt roller. A stopper of thick felt, //, 

 is put into the mouth of the bottle to allow the colouring 

 fluid to come through very gradually. The bottle presses, 



