SIX IV1I. I.I AM SIEMENS, F.R.S. 77 



needle instrument seemed to suffice for all practical purposes. It 

 was only when the exigencies of the traffic demanded a change, 

 that instruments of this nature proved to be valuable inventions. 



In like manner the long underground lines that were established 

 on the Continent at an early date had to give way to suspended 

 line-wire, whereas the present practice and necessities undoubtedly 

 tend toward a reversion to the former, as being less liable to in- 

 terruption by accident or by atmospheric influences, and because 

 an unlimited number of underground wires may be established 

 between any two stations without encumbering the public thorough- 

 fares. The best mode of insulating and protecting these under- 

 ground wires with a view to reducing the inductive influence of 

 the one upon the other, and of facilitating access to the one, 

 for the purposes of repairs, without disturbing the others, are 

 questions j>f practical interest for the present day. 



The Electric Telegraph is applicable with the greatest positive 

 advantage for the intercommunication between two points a great 

 distance apart ; through its agency New York and Calcutta are as 

 near to us in point of time as are the suburbs of our metropolis 

 from one another. It is probable indeed that in telegraphing from 

 one suburb to another the message has to be oftener retransmitted 

 than in going from the City of London to India or America, 

 because a direct transmission from any one part of London to 

 another would involve almost an infinite number of line-wires in 

 all directions. For this reason there must be a limit to the ap- 

 plicability of the Electric Telegraph in populous districts, and it 

 behoves us to examine whether another agent may not be preferable 

 in dealing with a traffic of this description. The pneumatic tube 

 seems to be well adapted to these circumstances, and having been 

 first applied for short distances by Latimer Clark, and subsequently 

 modified and extended by others, it will fall within the province 

 of our Society to examine fully into this and kindred methods that 

 may be devised for effecting rapid interchange of intelligence in 

 towns. 



The questions of field telegraphs and torpedo connections are 

 other branches of inquiry to which we shall have to give our at- 

 tention, and to these may be added the art of combining secret 

 codes and semaphore signals. 



These remarks may suffice to show how great is the field for our 



