22 ANNUAL OF SCIENTIFIC DISCOVERY. 



The tube as proposed is large enough for the passage of car- 

 riages of the present ordinary construction, and to avoid the ol)- 

 jcclions to the use of locomotives in a tube of so great a length, 

 it is proposed to work the traffic by pneumatic pressure. Tlie 

 air will be exhausted on one side of the train and forced in on the 

 other, and so the required difference of pressure will be given for 

 carrying the train tln-ough at any determined speed. Powerful 

 steam-i'ngines, for exhausting and Torcing the air into the tube, 

 will be erected on shore at each end. This system of working 

 the traffic will secure a constant supply of the purest air. By this 

 system of working there would scarcely exist the chance of acci- 

 dent — no collision could take place. There would never be foul 

 air within the tube. The pnc^umatic system can be as cheaply 

 Morked, and be in every way preferai)le to locomotive power. 

 Combined goods and passenger trains might be sent through the 

 tube at 20 miles an hour, with occasional express trains at .'30 

 miles an hour. The estimated cost of the whole undertaking is 

 8,000,000 pounds. Mr. Chalmers estimates the total annual revenue 

 at 1,300,000 pounds. The working expenses would be amply cov- 

 ered by ir)0,000 pounds,' leaving about 14 or 15 per cent, dividend. 



Mr. Bidder remarked that this subject had not been without 

 interest to him, as it would be recollected that he made a few 

 remarks on it when presiding over the section at Norwich last 

 year. The atmospheric system, which was a very old subject, 

 and which had Ijeen tried to a very great extent in this neighI)or- 

 hood, failed on account of using a small tube with a large pres- 

 sure, but it was dillerent with a large tube. He believed the 

 pneumatic principle was the only one that could be adopted to 

 work the tunnel. lie thought there would be a difficulty in get- 

 ting: the united actions of the two "governments to carry out the 

 work. Uidess the tunnel was worked pneumatically, he would 

 rather cross in the present boats. Until an experiment had been 

 made to test this plan, and the probable cost, it would be more 

 reasonable to construct a huge breakwater, and i)uikl vessels that 

 should be adapted to cross, except on special occasions, with cer- 

 tainty and dispatch. 



Mr. C. Viiruoles believed that if ever there was to be a tunnel 

 to Calais it must be on this })rinciple. The real cause of the fail- 

 ure of the atmospheric system was not as ^Ir. Bidder pnt it, l)Ut 

 from an accumulation of heat in the air-pumps. It would never 

 pay as a commercial undertaking, as there was not suffieient traf- 

 fic ; but it might be done by the governments. The}-, as engi- 

 neers, considered the scheme a })ractical one ; but he was afraid it 

 must be left to the next jreneration to carry out. 



Mr. Bateman, in reply, contended that the cost would not ex- 

 ceed his estimate. 



MT. WASHINGTON RAILWAY. 



The depot is 2,G85 feet above the level of the sea, or 1,117 feet 

 above the White Mountain House. This leaves a gra(h> of 15,000 

 feet to be overcome, as the height of the mountain is 0,285 feet 



