472 REVIEWS— DEPORT ON VICTORIA. BRIDGE. 



The=e consideration* lead me therefore to the conclusion that the present de- 

 sign for the foundation is a3 economical as i9 compatible with complete security." 



A legitimate conclusion, which we apprehend will not he gain- 

 saved. 



Air. Bom gives a graphic description of the difficulty of putting 

 in these foundations : 



" Any diminution in these piers (referring to a proposal to reduce the dimen- 

 sions of the centre pier?) which I might according to my own views of the case 

 be induced t i ad >pt, I should treat as some compensation, as far as it went, for 

 the increased depth of the foundations generally, which are found greatly to 

 exceed our anticipations : although every pains had been taken to ascertain what 

 these would be, we fi id in the progress of the works that the bed of the river in 

 most parts is formed of large boulders heaped together in large masses, the inter- 

 stices being filled up with gravel, Band and mud, in many instances forming a 

 hard concreted mass, and in others the reverse; bed3 of quick sand and mud 

 being as frequent a? any other. Three thousand tons of such material we had to 

 clear out of the foundation of No. 5 pier, a3 you will see indicated on the dia- 

 gram already referred to, below the level at which our previous examination 

 would lead us to expect the foundation we sought. One of the boulders taken 

 out, by admeasurement would weigh about eleven tons; masses of three and four 

 tons are strewed as thickly as pebbles on the sea shore. The shallows in the 

 river are evidently formed by these deposits, and I have no doubt in every in- 

 stance where these shallows appear we slnll have to encounter similar difficul- 

 ties. In pirr No 3 we founl a depth of four feet at one end, and nine feet at the 

 other, to clear out ere we reached the rock. These unlooked for contingents have 

 materially retarded our season's operations, otherwise we should by this time 

 have Nos. 3, 5 and 6 nearly completed, as it turns out we require another season 

 to accomplish this. And here I think it well to observe that up to No. 6 inclu- 

 sive, the expensive outlays have already been incurred; the dams have been 

 completed, and in all except No. 4 the water has been pumped out and the ma- 

 chinery erected for eetting the stone, but No. 5 is the only one where we have 

 been able to complete any masonry, owing to the unlooked for causes I have 

 already described. These contingents render it impossible to complete one pier 

 in less thin two seasons, though, a3 in the case of No. 1 pier, where no such 

 unlooked for difficulty arose, the whole was begun and completely finished in one 

 season, thus saving the removal and re-erection of all the machinery and appli- 

 ances neces-ary, besides the reparation of such damages as the winter operations 

 may produce." 



Of the spans, and the considerations which led to their adoption, 

 Mr. Stephenson sa; 



" These considerations lead me therefore to the conclusion, that the present 

 design for the foundation is as economical as is compatible with complete security. 



We are now brought to the question, as to whether the upper masonry is of a 

 more expensive description than necessary, or whether it can be reduced in 

 quality. This question is exceedingly important, since the cost of the masonry 

 constitutes upwards of 50 per cent, of the total estimated cost of the bridge and 

 approaches. The amount of the item of expenditure for the masonry is clearly 



