412 SECTION MECHANICS. 



this window. The other is merely an index as in the first instance. 

 This ABC instrument was also very largely used ; it was the first 

 form of instrument that was used by Messrs. Siemens in Prussia 

 in the year 1846. Here is one of the identical instruments that were 

 very largely employed in that country, and they were only after 

 great difficulty and opposition replaced by the Morse apparatus ; 

 but these two forms, in England under the hands of Sir Charles 

 Wheatstone and in Prussia under the hands of Mr. Siemens, have 

 been so changed and altered and improved and shaped that probably 

 a more exquisite instrument can scarcely be conceived than the simple 

 ABC apparatus of the present day. This is the simplest form of 

 Wheatstone's ABC. It is so accurate in its working and so simple, 

 that I have known a case at a post-office where an old lady over 

 seventy acquired the art of working this instrument with an hour's 

 practice, and the very next day the office was open to the public, the 

 messages were sent that is now six years ago and from that day to 

 this I have not heard a complaint from that office. Children work it, 

 private people work it, and it has really become one of the most 

 valuable instruments for telegraphic purposes. It is rather slow in 

 its operation, so that for the ordinary commercial requirements of the 

 country it is not adapted. The idea of an A B C instrument which 

 indicates the letters of the alphabet to the eye very speedily led to the 

 conception of an instrument which should permanently record the 

 letters of the alphabet upon paper in fact, that it should print from 

 ordinary type the messages that were sent. The first recorded form 

 of type instrument was made by Mr. Vail in America ; and it is a 

 matter of great regret, as far as this collection is concerned, that the 

 Exhibition at Philadelphia should occur at this particular time, for 

 there is no doubt that in America they have many exceedingly inte_ 

 resting historical apparatuses that would have added considerably to 

 the interest of this Exhibition. Amongst the rest, this original type 

 printer, which did not take root in England until the year 1841, when 

 Sir Charles Wheatstone produced this type printing instrument that 

 you see there. It was not successful. It is very pretty as a philo- 

 sophical toy, but as a practical instrument it never acted, and after 

 having passed through the mill in every electrician's studio in England, 

 on the continent of Europe, and in America, the instrument which has 



