.s/A' WILLIAM .S7AM/A.V.S, l-'.R.S. 355 



working might be suited for such places as Paris, Vienna, and 

 Berlin, it would never do for London, where speed was a principal 

 object. He should be very sorry to have put forward for London 

 a system that was not capable of the greatest development of 

 speed, knowing as he did the value of time. But Mr. Preece, in 

 describing the advantages of the radial system, seemed to forget 

 that the two principal distances worked by the Post Office at the 

 present time were worked on the continuous system, in exact 

 accordance with the principles laid down by himself. All that had 

 been done in the first circuit laid down by him was to take out 

 about 3 yards of pipe at the neutral point at Charing Cross. One 

 branch was worked by pressure, the other by a corresponding 

 vacuum, and at the extreme point the pressure was neutral, so that 

 the connecting link between the two sides might be taken out 

 with impunity without altering the system in the least. The only 

 difference would be that instead of bringing the same air back to 

 Telegraph Street or to the General Post Office, there would be air 

 which had travelled through the instrument room at Charing 

 Cross and which had taken up a good deal of vapour from the 

 numerous persons engaged there, giving rise, probably, in a 

 measure to the inconvenience of rust in the iron tubes ; an 

 inconvenience which had not made itself felt in Paris, Vienna, or 

 Berlin, where iron tubes were used. He thought that with proper 

 care that might be completely prevented in London. He admitted 

 that it would have been expedient indeed, he proposed it at the 

 time to have the inside of the iron tubes tinned, which would 

 have given all the advantages of the lead tube coupled with the 

 comparative cheapness of iron tubes. Mr. Preece seemed to imply 

 that a circuit system of iron tubes was a roundabout system by 

 which, in order to get from Charing Cross to Telegraph Street, it 

 would be necessary to go round by Islington. That was not the 

 case, nor had he proposed any such thing in laying down the first 

 circuit between those places. The continuous system, if worked 

 in circuits, could be so arranged that the distances between the 

 two principal points on the circuit would be minimum distances, 

 even though the intermediate stations might be a considerable 

 distance apart. If a tube were established on the circuit system 

 between Great George Street and the City, one branch might pass 

 by the Strand, or the Embankment, and the other over the bridges 



A A 2 



