136 Sir Frederick Bramwell [May 19, 



working of the tunnel, still more than in the making of it, the question 

 of the purity of the air becomes of the first importance. In the making 

 of the tunnel, one is dealing with engineers and others accustomed to a 

 somewhat hard life, who, if they cannot get the best air to breathe, are 

 content to put up with something a little worse, and look upon it as 

 part of their business ; but when the tunnel is opened and has to be 

 worked, then one is dealing with the travelling public — people who 

 write letters to the Times, and whatever else may happen, the air they 

 breathe, wherever they are, must be of the very best quality, and must 

 be ample in quantity, and therefore it is that in the working of the 

 tunnel, still more than in the making of it, does the question of atmo- 

 spheric purity become one of paramount importance. This being so, 

 it is well to consider what modes there are available, in addition to the 

 ordinary locomotive, for moving the trains. 



Not excluding the ordinary locomotive from the list, we find these 

 modes are as follows : — 



1. Ordinary Locomotives. 



2. Fireless Locomotives. 



3. Tireless Locomotives as improved by Dr. Siemens. 



4. Ropes. 



5. Electricity. 



6. The Pneumatic System, where the head of the train is made as 



a loose-fitting piston in the tunnel, and the air being drawn 

 out in front, the train is propelled by the pressure of the air 

 at the back. 



7. Compressed air. 



With respect to No. 1, the ordinary locomotive, this, as you know, 

 is the mode of traction adopted in the Mont Cenis, and in the 

 St. Gothard tunnels. The Channel tunnel, provided with two roads, 

 one for the trains going one way, and the other for the trains going 

 in the reverse direction, would have the advantage over the Mont 

 Cenis and the St. Gothard, that currents uniformly flowing in one 

 and the same direction could be maintained in each roadway, and 

 calculations have been made by Mr. Low showing that with the full 

 allowance for the quantity of coke burnt per mile it would be possible 

 to effectually ventilate this tunnel, w'hich after all is only three 

 times as long as the Mont Cenis and a little more than twice as 

 long as the St. Gothard, and it is possible, that having regard to the 

 extreme convenience of using in the tunnel the same type of engine 

 as will be employed on either side of it, the ordinary locomotive will 

 be adopted. I have been through the Mont Cenis tunnel many times 

 and have never felt the slightest inconvenience. 



But however desirable it may be on various grounds that the 

 ordinary locomotive should be used, and however much one is justified 

 in that use by the example of the Mont Cenis and the St. Gothard, 

 where (unlike the plan proposed for the Channel tunnel) there is only 

 one opening for the trains running in both directions, and the currents 

 of air are thereby baffled, it appears to me we shall do well to consider 

 the other modes of train traction that I have enumerated. 



