bridges from the most ancient to the great cantilever Forth 

 bridge, recently opened, and I am enabled to show these on 

 the screen, together with those having direct reference to the 

 submerged bridge, through the very kind assistance of Mr. 

 J. Brown, who has likewise generously lent the necessary 

 apparatus. 



[At this part of the proceedings a number of lime light views 

 of aerial bridges, etc., were thrown on the screen, and their 

 particular features explained ; likewise sections and diagrams 

 illustrating the proposed bridge, some of which are shown in 

 figs, i, 2, 3, 4, and 5 attached.] 



The scheme which it is my wish to bring before your notice, 

 and to submit for your criticism, is a proposed buoyant structure 

 to carry a roadway through the water at any pre-arranged 

 depth (which in this instance is 6o ft.) below the surface, held 

 in position vertically and transversely by dead weight and 

 other anchors attached to the bridge through steel or other 

 metal wire rope cables placed at intervals. 



The bridge is to lead from Donaghadee to Portpatrick. 



The structure is to consist of a circular or elliptical outer shell 

 Of steel, A (see fig. i, which represents a longitudinal and a 

 transverse section), and an inner rectangular shell, B, both 

 made water-tight and attached to each other through diaphragm 

 plates, C, placed transversely about 24 in. apart, and riveted to 

 the shells through double angles. These diaphragms are to be 

 lightened by manholes punched out of them, except at intervals 

 where they are to be solid, in order to make the cellular 

 construction water-tight at certain intervals in its length. 



The outer shell is to be coated with a layer of Portland cement, 

 then bound with metal wire, tape, or netting, and these in turn 

 covered with another layer of cement ; the shell is to have pro- 

 jections so that the cement may adhere more firmly. Japan 

 lacquer or bituminous cement could be substituted for the 

 Portland cement, or the steel treated by Barff's,or other approved 

 process, to afford a perfect protection to the steel against the 

 corrosive action of sea water. 



