300 Mr. W. H. Prcece [Feb. 13, 



the sending portion of the instrument opposite to the printed letters. 

 The whole apparatus is based on one of the most remarkable dis- 

 coveries of the century, that by which Faraday found it possible to 

 obtain electricity from a magnet. I have here the identical apjDaratus 

 that Faraday himself used in developing this beautiful idea. It was 

 not an accident (none of Faraday's discoveries were accidental), but it 

 was the result of continued self-education, scientific training, ex- 

 perience, and observation, and forms one of the most interesting 

 episodes in the scientific history of this country. Faraday, by taking 

 this magnet and placing over it a soft iron armature, around which 

 wire is wound, was able to produce electricity on moving the magnet 

 backwards and forwards. He thus caused currents to flow in the 

 wire round the armature, which produced sparks as you see I now do. 

 The following lines were written upon this experiment : — 



" Around tUe maojnet Faraday 

 Was siu-e that Volta's lightuings play. 

 But how to draw them from the wire ? 

 He took a lesson from the heart. 

 'Tis when we meet, 'tis when we joart, 

 Breaks forth the electric fire." 



Wheatstone applied this fact first of all to produce artificial 

 alarums. Here is an instrument (which old electricians call a 

 " thunderpump ") containing an arrangement similar to that used 

 by Faraday, the magnet being caused to move by the pressure of a 

 handle. The ends of a wire round the armature are joined to an 

 alarum, and on my pressing down the " pump " handle you hear the 

 bell ring, which is caused by the electricity produced, and sent along 

 the wire by the moving magnet. The bell might be fifty miles away, 

 but the effect would be the same. The same idea was adopted for an 

 ABC instrument, and a wheel (like a ship's steering wheel) was made 

 to send a current every revolution. A case is marked off with the 

 letters of the alphabet, and the wheel is made to stop opposite the 

 letter sent. This aj^paratus was used in 1840. It was too cumbrous 

 for practical adoption, and so fell out of use. From then to 1868 little 

 or nothing was done, but in that year Wheatstone introduced quite 

 a novel feature in the manufacture of his instruments in the way of 

 making them of the most perfect mechanism, and as accurate in their 

 fittings as chronometers ; and to enable this to be done he fortunately 

 succeeded in acquiring the assistance of perhaps one of the finest 

 mechanical geniuses and workmen that England has had for many a 

 long day ; and that is Mr. Stroh, whose name I need not say is well 

 known to this Institution. Here is a sj)ecimen of the improved 

 alphabetical transmitter. When the handle is turned, currents of 

 electricity are produced which when the keys opposite the letters are 

 pressed down, go to the other end of the wire, to which is attached 

 the receiver or indicator, the needle of which moves according to the 

 currents sent. (The method by which the indicating needle revolved 

 was explained by the use of a large model with toothed wheel and 



