758 KEPORT — 1891. 



■uniform, to stop tlie erosion of tlie banks, to reduce the rate of accretion, and to 

 aid the development of the left side of the river, regulation works have been pro- 

 posed at certain places -where the width of the river is excessive. By these 

 works, the Harbour Commissioners will give to Newport and the surrounding 

 mineral districts similar advantages to those which have been conferred, by more 

 extensive works, upon Other river ports less favoured by nature, will aid in pro- 

 moting that growth of trade which Newport has enjoyed during the last thirty 

 years, and will prevent the diversion of traffic which an irregular channel of 

 occasionally inadequate depth would sooner or later produce. 



4. On Mechanical Vmtilation and Heating of Buildings. By W. Key. 



FRIDAY, AUGUST 21. 



The following Papers were read : — 



1. On the Channel Tuhular Railway. 

 By Sir Edward Reed, K.C.B., M.P., F.B.S. 



After referring to former proposals for establishing railway communication 

 between England and France, and stating that the Channel Tunnel scheme of 

 Sir Edward "\^^atkiu provided for taking the traffic far below the bed of the 

 Channel at its deepest part, thus lengthening the underground route, and adding 

 to the working charges as compared with a tubular railway, the author said 

 that it was desirable in the first place to make plain the nature of the Channel 

 bed which it was designed to traverse. lie stated that for several miles out from 

 the English Coast the Channel, on the line selected by him, was only about 90 feet 

 deep, and, although it gradually sloped down to double that depth further on, 

 nowhere exceeded a depth of 186 feet, from which depth it gradually sloped up to 

 the French shore. In no place is the gradient even one-half that of the Severn 

 tunnel ; in fact the change of level is small and so gradual as to be almost imper- 

 ceptible upon any true-scale diagram of moderate dimensions. ' Here, then, we 

 have,' the author said, ' an almost level stretch of ground of over twenty miles in 

 length to be traversed by a railway, and, if it were dry, no mortal man would 

 ever dream of tunnelling underneath it in order to construct a railway, nor would 

 anyone be so insane as to propose to build a viaduct or series of bridges 500 feet 

 high across it.' The railway would in that case, of course, be laid along the 

 ground, as it is laid over any other stretch of level country. The presence of the 

 sea simply renders it necessary to make the railway a closed instead of an open 

 one, to secure it against being moved by the tidal waters, and to provide its proper 

 ventilation. To provide a closed railway, metallic tubes are employed — one for 

 each line of rails — and to make the structure durable, all the essential parts are 

 carefully imbedded in good Portland cement. The two tubes are set at a distance 

 apart, and connected by partial webs, so as to combine the two into a huge hori- 

 zontal girder of unprecedented strength. This device is adopted in order to make 

 each length of the tube structure (which is on the whole to be slightly buoyant) 

 strong enough to withstand the force of the tide when one end of it is carried to 

 the bottom, the other end being left emerging from the surface by vu'tue of the 

 surplus buoyancy. To this emerged end is brought and connected afloat another 

 floating structure which is to serve as a pier (when it is subsequently sunk to the 

 bottom), and beyond this floating pier the next length of the tube is brought and 

 connected by large cast-steel hinge-like joints. The pier is then sunk by suitable 

 appliances, carrying down with it the second end of the first of the tubes just men- 

 tioned, and also the first end of the second length of tube. In this manner the 

 tube is paid out length by length like the links of a huge cable, the junction of 



