XI. APPLICATIONS. 30? 



' 1551. Bain's Perforator for double dot or Steinheil 

 Alphabet, 1846. 



The perforations are made by circular punches on a band of paper, the 

 right handle making the perforations on the right hand, and the left handle 

 those on the left. The third key on the right is for advancing the paper 

 without punching, for spacing between letters and words. 



1552. Bain's Chemical Telegraph. (Incomplete.) First 

 form of recording Instrument used in England, 1846. 



The chemically -prepared paper is wrapped round the cylinder. An iron 

 style presses on the paper and writes dots and dashes in a spiral line as the 

 cylinder moves endwise while revolving. 



The signals, are formed manually by pressing a key, or automatically by a 

 spring, making contact through perforations previously punched in a paper 

 ribbon. 



1553. Early form of " Chronopher," or time-current 

 sending apparatus, used in London about 1852. (Incomplete.) 



1554. Early form of Wheatstone's Resistance Coils. 



1555. Wheatstone's Perforator for punching the paper in 

 the automatic system, 1867. 



The right-hand key when depressed perforates the paper thus : 



Which corresponds to a dash- in the Morse alphabet. 

 The left-hand key perforates the paper thus : 



Which corresponds to the dot in that alphabet. The middle key besides 

 being used for spacing, perforates the centre row of holes and moves the 

 paper forward. The centre row of holes acts as a rack in which a star- wheel 

 engages for advancing the ribbon. 



1556. Wheatstone's Automatic Transmitter, 1867. 



This instrument is used for transmitting automatically the signals punched 

 on the paper ribbon. When no paper is in the instrument reversals are con- 

 tinually sent out to the line by a reversing arrangement actuated by the wheel- 

 work. When the punched paper ribbon is placed in the instrument, it is 

 carried forward uniformly by a star- wheel which engages in the centre row of 

 holes in the ribbon. The reversals are controlled, that is, allowed to pass out 

 to the line or not by the following means : 



Two vertical rods or pins are in connexion with the reversing arrangement ; 

 these move up and down in readiness to pass through the perforations. 



When a marking reversal is sent, the back pin rises and the front one 

 ialls. 



When a spacing current is sent (that is, the current which moves the 

 marking disc away from the paper at the receiving station) the front pin rises 

 and the back one falls. 



When no hole is opposite a rising pin, the current which would have been 

 sent is prevented by the battery being disconnected ; tttus the lengths of the 



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