MECHANICS AND USEFUL ARTS. 39 



wheels to the locomotive. Going down hill they act as a brake, 

 and the force the}' gather will carry the train up an equal ascent, 

 less the friction. A mocfel train loaded with water ran down a 

 sharp incline, the water ran off, and the force of the fly-wheel 

 carried the train back to the starting-point. In this way a short 

 railway, taking coal down an incline from the mouth of the pit, 

 could be worked without any other power than that gained by 

 each descent of the train. 



THE CHANNEL RAILWAY. 



In the volume of the " Annual of Scientific Discovery" for 1866- 

 67, p. 31, the plans of Messrs. Hawkshaw and Remington for 

 tunnelling the English Channel are alluded to. Mr. James Chal- 

 mers has recently published the second edition of a book on the 

 same subject. Mr. Chalmers provides in his plan for an unbroken 

 double line connecting the railways of England and France b} T 

 easy gradients ; by its means through trains could be run, obviat- 

 ing any change of carriage or locomotive. It offers no obstruc- 

 tion to navigation, and he computes the work might be completed 

 in three years. 



The principal feature of the work is new : 260 strong iron tubes, 

 each 15 feet in diameter and 400 feet long, cased with timber and 

 lined with brick in parallel series, each containing a single lino 

 of railway from shore to shore on the bottom of the channel. The 

 displacement and weight of these tubes can be so nearly balanced, 

 that both in submerging and in position they will not be subjected 

 to any injurious lateral strains. The process for joining the tubes, 

 at a depth of from 100 to 180 feet, is as follows : Each tube has a 

 strong temporary bulkhead at each end, fixed a few feet inward, 

 and provided with a valve, a man-hole, and a window of heavy 

 glass. The first tube having been sunk empty, connected to the 

 ventilator, and loaded down with anchor boxes, a sufficiently 

 powerful wire cable, welded to a bolt through the outward end of 

 the sunken tube, is now passed through a projecting ear upon the 

 inward end of the next following tube, and serves to guide that 

 end as sunk, into match with that to which it is to be joined. A 

 ball-and-socket joint, it has been suggested, may be applied to 

 guide the two ends, into exact coincidence, and the fixed end is to 

 be faced with an India-rubber packing. When the two ends are 

 fairly in contact all around, which is ascertained by inspection 

 through the window of the fixed tube, by the aid of an electric 

 light, the valve in the inward end of the tube just lowered is to be 

 opened, and the issue of the water from the chamber formed be- 

 tween the bulkheads, it is claimed, will leave a vacuum and secure 

 the instant compression of the two ends together with immense 

 force. The chamber may then be entered through the man-hole, 

 and the joint perfected and secured permanently. The estimated 

 cost is 12,000,000 of pounds sterling, and the time required for 

 construction, from two to three years, allowing 120 days in a year 

 to be placid enough for tube-laying. The tubes will be banked 

 over, and when the rise and fall of the tide have silted up the em- 



