10 



will be no leakage into the bridge ; so that the pumps may be 

 of the centrifugal type, and will be required only in case of 

 accident or repairs to the structure. 



The motive power for trains is to be electricity, or compressed 

 air heated when being used ; the heat is to be stored in a mixture 

 of water and glycerine, in order to dispense with the elaborate 

 and enormously expensive ventilating appliances necessary for a 

 tunnel of such a length, if ordinary locomotives were used. If 

 necessary, ventilating shafts may be provided at intervals to 

 come above water level in the channel, having the necessary 

 lights, etc., fitted to warn vessels when in their vicinity. 



The front and rear carriages of the train are to be fitted with 

 shutter- doors, actuated either automatically or by the persons in 

 charge of the train. These shutters will practically close the 

 space between the carriages and the inner shell of the bridge, and 

 in case of flooding convert the train into a piston, in order that 

 the trains may be driven out in safety by the inrush of water. 



The ventilation will be induced by the motion of the trains 

 themselves. If, however, that is not sufficient, the idle pumping 

 engines at the shore ends may be utilized. 



The foregoing is a general outline of the proposed bridge, 

 and a few of the more important features may now be touched 

 upon which may commend themselves to engineers, promoters, 

 or probable proprietors and the travelling public. 



Should the outer shell get pierced, this would have the effect 

 of flooding a short length of the cellular space round the inner 

 shell only, and would in no way interfere with ordinary traffic 

 through the bridge. Should both shells be pierced, the outer 

 space for a short distance would be flooded, and the inner shell be- 

 tween the automatic flood-gates, D {Fig. i), only. Should, by 

 any conceivable means, the whole of the passage-way get 

 flooded, the design is such that the bridge would still float. 

 Should a train be in the bridge when any inrush of water 

 takes place, the expanding shutters at the front or rear of the 

 train would prevent the water from passing, and, instead, the 

 water would drive the train out, as a carrier is driven through a 

 pneumatic tube. 



