ELECTRIC TELEGRAPHS. 411 



tion of chemical materials, and so by decomposing the chemical material 

 in which the paper is steeped, it recorded in a bright colour marks upon 

 the paper. It has a special merit of its own, which in some respects 

 renders it superior to any other form of instrument, and that is, that it 

 is quite independent of magnetism or electro-magnetism. An electro- 

 magnet always means certain force expended, certain time consumed 

 what we call magnetic inertia ; and we find where speed is essential a 

 considerable advantage is to be found by the use of Bains's Chemical 

 Recorder, and so an instrument which had a fitful existence between 

 1853, '54 and '56, is now coming again into use, and probably, in 

 England at least, will receive very general acceptance. 



Now in all these instruments you will see we require skilled labour. 

 A clerk who has to send the Morse alphabet of dots and dashes has to 

 spend many months in acquiring the art of sending by his hand those 

 intervals of time which require to be recorded. But it very early 

 appeared that advantage would accrue if we could produce an instru- 

 ment which would indicate directly before the eye of the receiver the 

 simple letters of the alphabet, and in the year 1816 Francis Ronalds 

 designed an instrument which was never tried except in his own 

 house. That was an A B C instrument. In 1841, when telegraphs 

 had become a matter of fact, Cooke and Wheatstone directed their 

 thoughts to the production of an A B C instrument. We have here 

 the original instruments made at that period. Here is one of the first 

 dial instruments. It contains a dial upon which the letters of the 

 alphabet were once depicted. Age has gradually removed them, so 

 that even an opera-glass can scarcely read them. Now here you have 

 this dial with the letters of the alphabet, and here you have an indi- 

 cator that rotates and stops or hesitates at every letter that it wants 

 to indicate. Here we have the apparatus that was used to send these 

 letters. This instrument itself is not quite complete ; the outer case 

 has disappeared, but there was at the top an index or fiducial spot 

 which always brought the hand up as it were, so that when you 

 wanted to send the letter ' K," for instance, " K" would be brought 

 there, and so with any other letter. We have here two dials of the 

 same character, but in one we have a little opening through which 

 the letters appear ; the brass window, as it were, has disappeared 

 from it, but the letter to be indicated was simply shown in front of 



