Engineering Wonders of the World
Volume I

212 ENGINEERING WONDERS OF THE WORLD. A Descrip- tion of Working Operations. central span would have found a resting-place in the bed of the river. Thus ended a very exciting episode in the history of engineering. Another cause of apprehension presently ap- peared in the form of huge rafts sweeping down-stream at such a pace as to be prac- tically unsteerable. Large numbers of them, massed together, struck the dam surrounding the site of pier No. 11. Several men were upset into the seething waters among the logs and swept away ; but, in spite of their ap- parently hopeless position, all the victims of this accident escaped with a good ducking. The crib, however, somewhat shaken by the collision, had to be repaired. Then things went ahead rapidly. To use the words of the engineer-in-charge : “ The works pre- sented a small island of crib- work surrounded by barges laden with stone, timber, steam engines, puddle clay, traveller stagings, and pumping ma- chinery, in the midst of which were crowds of men apparently in the greatest confusion. This, added to the shoutings of the workmen, the noise of the pile engines, the ‘ yeo-heave- yeo ’ of the British boatmen unloading ma- terials on one side, enlivened by a chorus of French Canadians chanting their boat- songs to the time of their work on the other, amidst a torrent of waters rushing past, with the surging and creaking of the barges as they tugged and tried to break adrift, formed, at first sight, such a bewildering scene of ap- parent disorder and confusion as can scarcely be described. “ A careful survey, however, must have satisfied the observer that, instead of con- fusion, everything was order. Observing the gang of men driving piles with a steam engine at one place, he would not fail to notice that they were as indifferent to what was going on around them as if not a soul was there but themselves. So with a body of mechanics putting up pumping apparatus ; or with the divers, the men working the air-pumps as unconcernedly and with as much confidence as a philosopher would prosecute experiments in a closet. At another place the dredging machine, worked by a steam engine, would be seen scooping every bit of loose material from the puddle chamber ; while in the rear were men wheeling puddle into the cleared space, each, side of which was lined with men armed with rammers, puddling and working the clay into every hole and corner so that there might be no leakage.” On August 2 the river-bed at the site of this, the last, pier was pumped dry, while out- side the dam the river ran past at the rate of eight or nine miles an hour. The masonry was laid at such a pace that by September 26, 1859, the masonry of the bridge was com- pleted. Before the end of the year the first train passed through the bridge. This event occurred simultaneously with a powerful ice- shove, which loosened the temporary staging that had carried the span and swept it bodily down-stream. The chief operations remaining to be done were to roof over the tubes with wood and sheet iron, and to provide rails on which should run the travellers used in the painting of the tubes. From each end of the trav- eller hung platforms which could be swung outwards for the passage of a pier. The need for a proper provision of this kind will be understood when it is stated that the surface to be covered by each coating was no less than 32 acres—that is, the painters had to cover 128 acres, the area of a fair-sized farm, before the four coatings were on. The stiffness of the bridge was tested by running over it trains averaging one ton per foot in weight. Under full load the deflection of the central span was found to be little more than one inch, and, in the case of the shorter tubes, only about three-quarters of an inch. In all cases the tubes returned to their Painting the Tubes.