MENAI BRIDGE. [By Percival Skelton, after his original Drawing.]
The floating and raising of the remaining tubes need not be described in detail. The second was floated on the 3d of December, and set in its permanent place on the 7th of January, 1850. The others[102] were floated and raised in due course; on the 5th of March Mr. Stephenson put the last rivet in the tube, and passed through the completed bridge, accompanied by about a thousand persons, drawn by three locomotives. The bridge was found almost entirely rigid, scarcely showing the slightest deflection. When, in the course of the day, a train of 200 tons of coal was allowed to rest with all its weight, for two hours, in the centre of the eastern land tube, the deflection was only four tenths of an inch, or less than that produced upon the structure by half an hour's sunshine;[103] while the whole bridge might with safety, and without injury to itself, be deflected to the extent of 13 inches. The bridge was opened for public traffic on the 18th of March. The cost of the whole work was £234,450.
The Britannia Bridge is one of the most remarkable monuments of the enterprise and skill of the present century. Robert Stephenson was the master spirit of the undertaking. To him belongs the merit of first seizing the ideal conception of the structure best adapted to meet the necessities of the case, and of selecting the best men to work out his idea, himself watching, controlling, and testing every result by independent check and counter-check. And, finally, he organized and directed, through his assistants, the vast band of skilled workmen and laborers who were for so many years occupied in carrying his magnificent original conception to a successful practical issue.
But it was not accomplished without the greatest anxiety and mental pressure. Mr. Clark has well observed that few persons who merely witness the results of the engineer's labors can form any conception of the real difficulties overcome, and the intense anxiety involved in their elaboration. "If the stranger," he says, "who contemplates the finished reality, requires so much thought to appreciate its principles and comprehend its detail, what weary hours must he have undergone who first conceived its bold proportions—who, combating, almost alone, every prejudice that assailed him, and with untiring labor discussing every objection, listening to every opinion, and embodying every inquiry, at length matured, step by step, this noble monument?" On the occasion of raising the last tube into its place, Mr. Stephenson declared, in reply to the felicitations of a large company who had witnessed the proceedings with intense interest, that not all the triumph which attended this great work, and the solution of the difficult problem of carrying a rigid roadway across an arm of the sea at such a height as to allow the largest vessels to pass with all their sails set beneath it, could repay him for the anxieties he had gone through, the friendships he had compromised, and the unworthy motives which had been attributed to him; and that, were another work of the same magnitude offered to him with like consequences, he would not for worlds undertake it!
The Britannia Bridge was indeed the result of a vast combination of skill and industry. But for the perfection of our tools, and the ability of our mechanics to use them to the greatest advantage—but for the matured powers of the steam-engine—but for the improvements in the iron manufacture, which enabled blooms to be puddled of sizes before deemed impracticable, and plates and bars of immense size to be rolled and forged—but for these, the Britannia Bridge would have been designed in vain. Thus it was not the product of the genius of the railway engineer alone, but of the collective mechanical genius of the English nation.
CONWAY BRIDGE—FLOATING THE FIRST TUBE.
