RECENT WONDERS OF ELECTRICITY. 6 77 



house I happened to be, she put her little instrument to "messenger," 

 sent the current by pulling clown the spring, and in two minutes a 

 messenger was at the door waiting to convey my message to the tele- 

 graph-office. Time passes terribly quick, and my energy is gradually 

 disappearing, so that I shall have to pass over some of the things I 

 wanted to show you, such as the process of engraving by the electro- 

 magnetic system ; how toys were moved, boats made to swim about, 

 and birds to sing. At the recent Paris Exhibition, the varied applica- 

 tions of electricity were simply wonderful and amusing. I have no 

 doubt we shall have a great many of them exhibited, shortly, at the 

 Crystal Palace, where I hope some of you may be able to go before 

 your return to school. I will now show you how this system of pro- 

 ducing electro-magnetism can be utilized for telegraphic purposes. 

 On the table are fixed two complete sets of telegraph-instruments, 

 very close to each other, but the set on the right hand belongs to one 

 station, and that on the left hand to another station. You may fancy 

 that the instrument which I touch, on the left, is in London, and that 

 which Mr. Cordeaux touches, on the right, is in Liverpool. For every 

 current of electricity I send from London, I do a little work in Liver- 

 pool, and that results in motion, producing sound. The mere depres- 

 sion of my "key" produces electro-magnetism in Liverpool, which 

 attracts a piece of iron and produces a sound. [Illustrated by work- 

 ing the instrument.] The battery attached to my key is in London, 

 and the depression of my key sends on a current which arrives at 

 Liverpool, produces magnetism and sound. By depressing the key 

 rapidly or slowly the sounds may be made correspondingly short or 

 long. [Illustrated.] By an arrangement of dots and dashes, the 

 letters of the alphabet are represented, and experienced clerks can 

 read off the sounds and translate them with astonishing rapidity. 

 To illustrate this to you, I will ask your secretary to write down a 

 short sentence, unknown to my assistants, which shall be sent by 

 one of them, Mr. Cordeaux, on one instrument (supposed to be in 

 Liverpool), and read off by Mr. Cooper on the other instrument (sup- 

 jjosed to be in London). [The secretary then handed in a slip of 

 paper to Mr. Preece, and the message it contained was read off by 

 Mr. Cooper, "A merry Christmas to the juveniles."] That is the 

 operation of telegraphy. The sounds are read off as clearly as ordi- 

 nary spoken language, though mistakes are sometimes made. For 

 instance, a party of young school-girls, out for an excursion once, 

 wished to advise their schoolmistress of their safe arrival at a certain 

 point, and sent the message, " Arrived all right " ; but the schoolmis- 

 tress was horror-stricken to read the message as delivered to her, which 

 read " Arrived all tight." Telegraphically, the difference between the 

 two messages is not great, for the letter R is represented by two dots 

 and a dash, while T is represented by a dash. Another error in trans- 

 mission was where a message, " Five fathoms and four feet is ample 



