XI. APPLICATIONS. 369 



1659. Three ABC Telegraph Sending Instruments, 



showing gradual improvements. 



The Council of King's College, London. 



1660. Horizontal Sending and Receiving ABC 

 Telegraph Instrument. 



The Council of King's College, London. 



1661. Two ABC Telegraph Receiving Instruments. 



The Council of King's College, London. 



1662. Punching Instrument, for preparing the paper for 

 the transmitter. The Council of King's College, London. 



1663. Transmitter. 



The Council of King's College, London. 



1664. First Electric Key, constructed by Sir Charles 

 Wheatstone. The Council of King's College, London. 



1665. Wheatstone's First Relay Instrument. 



The Council of King's College, London. 



1666. Printing Telegraph. 



The Council of King's College, London. 



1666a. Charge and Discharge Key. 



Warden, Muirhead, and Clark. 



1666b. Reversing Key. Warden, Muirhcad, and Clarh. 

 1666c. Short Circuit Key. Warden, Muirhcad, and Clarh. 



1666d. Testing Key, for testing copper resistance. The 

 battery circuit is completed first, then the galvanometer circuit 

 by one movement of the finger. Warden, Muirhead, and Clark. 



1666e. Perforated vitreous chamber, for interior of 

 cell No. 1666d. Warden, Muirhead, and Clark. 



1666f. Pair of Brequet Crossley ABC Telegraph 

 Instruments. Louis John Crossley. 



1558a. Model of a Morse Printing Telegraph (blue 

 writer), with key, galvanometer, and paper stands. 



A. Herbst, Berlin. 



1667. Apparatus specially intended to illustrate the 

 Morse System of Telegraphy in primary and secondary 

 schools. J. Cauderay, Lausanne. 



For the clockwork is substituted a small crank, which can be turned by hand. 

 This apparatus works by means of a single Bunseii cell, of small size. Its 

 low price, 40 frs., places it within the reach of every school. 



40075. A a 



