34 ANNUAL OF SCIENTIFIC DISCOVERT. 



casings or fender?, such as those in use on the small rivers of Xorway and 

 elsewhere, would be an efficient protection for the piers. The proposal most 

 forcibly impressed on Mr. Stephenson was to protect his piers by what is 

 called a " crib-work; " that is to say, by large masses of timber in front of 

 the piers, crossed and weighted, and as thick, or thicker, than the ice itself. 

 It was evident from the first, that this extensive crib-work must be an addi- 

 tional obstacle and impediment to the free navigation of the river, and to 

 the passage of the ice. But, beyond this, Mr. Stephenson's calculations con- 

 vinced him that such a work would be entirely inadequate to protect such a 

 structure as he contemplated, in such a river as the River St. Lawrence; and 

 that, even if the crib-work stood, it would be subject to such abrasion and 

 wear and tear, from its conflicts with the ice, that it would require to be rein- 

 stated at least every two or three years. It was more than doubtful, to his 

 mind, if such an arrangement would be capable of resisting the ice at all; 

 and if it did not, the capital of the company would be wasted. Mr. Stephen- 

 son, therefore, at once determined that such a work was undesirable; and 

 that such enormous stakes as those at issue could not be left dependent upon 

 the uncertainty of such an expedient. 



The abstract methods he had taken to ascertain if any bridge would with- 

 stand the almost irresistible pressure of the ice, had not alone convinced Mr. 

 Stephenson that no such projects would avail as those proposed in Canada. 

 They had equally satisfied his mind as to the amount of resistance requisite 

 to encounter the pressure against which it was needful to provide. Know- 

 ing what timber would not resist, he equally knew what resistance could be 

 afforded by substantial masonry. "Cribs" he felt were useless; but there 

 were methods by which the pressure could be resisted, independently of 

 "cribs." Mr. Stephenson decided on the adoption of stone piers, to carry 

 the tubes at wide intervals, each pier having, on the side opposed to the 

 course of the stream, large cut-waters of solid stone work, inclined against 

 the current, up which, as it were, the ice would creep, and break itself to 

 pieces by its own weight and pressure. He arranged that these wedge- 

 shaped cut-waters should present angles to the ice sufficient to separate and 

 fracture it as it rose up upon the piers, but at the same time so obtuse as not 

 to be liable themselves to fracture. These piers, therefore, were devised to 

 answer the double purpose of piers and ice-breakers. They exhibit, as now 

 constructed, every indication of massiveness and power to resist pressure, as 

 well as of stability to support the superstructure. Experience, indeed, has 

 proved the piers suited for all the purposes for which they were designed. 

 During the four years the structure has been in progress, it has entirely ful- 

 filled all the conditions its originator anticipated ; and it has withstood, in 

 the most satisfactory manner, the most violent pressures Avhich have followed 

 the break-up of the ice. 



Whilst the piers of this bridge are thus peculiar in their design, in order to 

 meet the peculiar circumstances of the country and the climate of Canada, 

 the superstructure is an elongated repetition only of the design for the Bri- 

 tannia Bridge. The Victoria Bridge is indeed remarkable for its extreme 

 length, but its several tubes are not so long as those of the Britannia Bridge, 

 and are only otherwise distinguishable, inasmuch as that they are the longest 

 tubes yet constructed without the adaptation of the cellular principle. It 

 deserves notice, however, that these tubes, in all their details, were designed, 

 plate by plate and rivet by rivet, in the office of Mr. Stephenson, and were 

 calculated for every strength and strain, and prepared and arranged in all 



