Streams less important than the Weaver are treated in a less dignified way. Thus, a little farther on we come upon two small rivers which are carried under the canal in huge cast-iron pipes. At the busy town of Runcorn we reach the first railway bridge, and the canal is narrowed to ninety-two feet, flowing in a graceful curve between concrete walls. The railway bridge, as it stands to-day, was built by the Canal Company, for the old one was too low for ships to pass beneath. It is now seventy-five feet above the surface of the water, and all other fixed bridges that cross the canal must be equally high.
Ten long straight miles beyond Runcorn a vessel comes to a halt in front of the first lock on the canal proper. It is at a place called Latchford. We are twenty-one miles from Eastham, and at the end of the tidal course. Fourteen and a half more miles to Manchester—and in that distance we have sixty feet and six inches to climb! As we move slowly into the lock the hydraulic machinery is set in motion; the gate behind us is closed, and the one in front slowly opens. In rushes the foaming water, lifting our vessel as it rises in the lock, and in a few more minutes we are steaming on our way—sixteen feet above the level of the waters just left behind. We have mounted the first step in the watery stairway leading to Manchester's front door.
Some seven miles further on another lock is reached, and passing through this we shortly come in sight of what is, perhaps, the most interesting engineering feat performed in this great enterprise. It is the Barton swing bridge, and was constructed to carry the Bridgewater Canal across the one upon which we are travelling in imagination. About the year 1756 the young Duke of Bridgewater employed an engineering genius named James Brindley to make a canal from his coal-mines near Manchester to the town of Runcorn. With astounding skill, James Brindley carried out the work, finding his greatest difficulty at the point of which we are speaking. The river Irwell flowed directly across the course of his canal and at a considerably lower level. Friends advised him to lead his canal down to the river by a large number of small locks, and lift it again on the other side by similar means. 'That is the usual thing to do,' they said.
But Brindley preferred the best way to the usual way, and boldly carried his canal over the river on a stone bridge or aqueduct. It was the first time such a thing had been done in England, and it served its purpose for nearly one hundred and fifty years. Then the Manchester Ship Canal comes along the Irwell, and the stone aqueduct must be turned into a swing bridge, or how is any ship to pass?
'Very well,' said the owners of the Bridgewater Canal, 'but you must not let much of our water be lost, for we have little to spare.'
And this is how Mr. Leader Williams, the engineer, got over the difficulty. He built an island in the middle of the Ship Canal for the iron bridge to turn upon, leaving the two ends free. The bridge itself he made in the form of a long tank, nineteen feet wide and seven feet deep, the two ends being hinged so that they would open and close like doors. Strengthening iron girders, rising to a height of some twenty feet, form the sides of the bridge, while cross-girders close in the top. The two ends of the canal proper where it reaches the entrance to the bridge, are also provided with watertight doors. When the bridge is in position there is a narrow gap between its two ends and the canal. This is filled up and made watertight by a ponderous wedge, weighing twelve tons and shaped like a U, its sides and lower part thus corresponding in outline with those of the tank and canal. The wedge is further padded on each side with indiarubber which, when squeezed into place, effectually prevents any leakage. As soon as a ship is signalled on the Manchester canal, the doors at each end of the tank-bridge are closed, together with those at the ends of the canal. Then the U wedge is lifted from between them, and the bridge (weighing, with the water it contains, sixteen hundred tons) is swung round on its island pivot till the channels are open on either side. The ship passes by and the bridge is swung back to its original position. The towing-path (for all craft on the Duke of Bridgewater's canal are drawn by horses) is carried across the bridge on an iron shelf, nine feet above the water.
Beyond Barton the Salford docks are reached, and after passing one more lock, we sail triumphantly into the magnificent docks of Manchester to which this thread of silver leads.
| Barton Swing Bridge and Aqueduct. A huge Crane at Work. | The Barton Aqueduct. Coming through the Aqueduct. |
When first the canal was opened Manchester seemed to be taken by surprise, and hardly knew how to perform the part of a seaport; but that is all changed now. The docks are growing fast, and only in 1905 their Majesties the King and Queen opened a new dock two thousand seven hundred feet long, two hundred and fifty feet wide, making an area of fifteen and a half acres, and capable of accommodating ten of the largest steamships entering the canal.