The bridge is to be constructed, on ways, in lengths of 400 ft. 

 to 1,000 ft., tested by hydraulic pressure, and rolled or launched 

 into the water, practically in a finished state. 



The lengths are to be jointed by ordinary bolted flanges, and 

 afterwards riveted from the inside, or the joints made on the 

 expansion principle. 



The space between the outer and inner shells is to be filled with 

 water, and temporary water-tight bulkheads, N {Fig. 5), to be 

 fitted a short distance back from each end. In this condition the 

 lengths are to have a minimum reserve buoyancy consistent with 

 safety. Each length is to be then towed out into the channel 

 separately, as nearly over its final position as possible. 



Here four or more temporary hydraulic hauling gears, pre- 

 viously placed, are to be attached to the length, so as to haul it 

 down to its proper level ; and it is in order to give these 

 hydraulic apparatus as little work to do as possible that the 

 reserve buoyancy of the lengths is proposed to be reduced to a 

 minimum. 



When the length under manipulation is to be hauled down 

 nearly into a line with the shore end, or the part of the bridge 

 assumed to be laid, another hydraulic gear is to be connected 

 from the one to the other, and the length being laid is to be 

 directed radially and centrally by conical and other guides fitted 

 temporarily on the ends for that purpose, and so drawn hard 

 against the fixed section. When the jointed faces come into 

 exact relative position, several automatic catches are to lock the 

 lengths together, and an india-rubber band, O (Fig. 5), is then 

 to be strapped round the joint in order to make it water-tight 

 for the time being. 



Should access to the length of bridge under manipulation 

 be required during laying operations, it may be obtained 

 by divers through manholes at M [Fig. 5) ; but with the 

 foregoing automatic arrangements this, under ordinary circum- 

 stances, would be quite unnecessary. It may be here stated 

 that the hydraulic apparatus will all be under the control of 

 one diver, who will go down with the length being laid and 



