But perhaps the largest bridge ever built, will be, when completed, that now erecting over the St. Lawrence, called the Victoria (railroad) bridge, which is to be an immense iron tube, ten thousand, two hundred and eighty-four feet, or nearly two miles long. It is to be set on twenty-four piers, from two hundred and twenty to three hundred feet apart. At the highest point it will be some sixty feet from the water; and it is estimated that it will take at least five years to finish it. These are some of the largest bridges, (in addition to those already particularly mentioned,) ever erected in any part of the world.
THE HIGH BRIDGE AT HARLEM.
The High bridge at Harlem, a view of which is given in the cut below, forms part of the immense works erected to bring the water of the Croton river into the city of New York. The dam at the river, which is seventy feet wide at the bottom, seven feet wide at the top, and two hundred and fifty feet long and forty feet high, creates a pond five miles long, covering a surface of four hundred acres, and containing five hundred million gallons of water. From this the aqueduct proceeds, sometimes tunneling through solid rocks, crossing valleys by embankments, and brooks by culverts, till it reaches the Harlem river, a distance of thirty-three miles. It is built of stone, brick and cement, arched over and under, and is made large enough to discharge sixty millions of gallons every twenty-four hours. It crosses the Harlem river on a magnificent bridge of stone, fourteen hundred and fifty feet long, having fourteen piers, eight of them bearing arches of eighty feet span, and seven others of fifty feet span, one hundred and fourteen feet above tide-water at the top. The aqueduct then passes on to a first, or receiving reservoir, which covers thirty-five acres and will hold one hundred and fifty million gallons, and thence to the second, or distributing reservoir, which holds twenty million gallons, whence it is distributed by pipes through the city. The entire cost of the work has been fifteen million dollars.
THE HIGH BRIDGE AT HARLEM.
THE BOSTON RESERVOIR.
The mention of the High bridge at Harlem, and its connection with the aqueduct which brings the Croton water to the city of New York, suggests some notice of the aqueduct by which water is brought to the city of Boston, Massachusetts. So early as 1795, an association was formed in Boston for supplying the inhabitants with pure water; and for years it was brought from Jamaica pond, in Roxbury, some four miles distant, in logs which were bored for the purpose. These logs were capable of supplying some fifty thousand gallons daily, which could be raised to the hight of forty-nine feet above tide-water. This supply, however, was soon found inadequate to the wants of the city, though in 1845, some fifteen miles of pipes had been laid, and some three thousand houses were regularly supplied with water. A plan was therefore formed in 1845, to supply the city with water from Lake Cochituate, or Long pond, as it was formerly called, about twenty miles west of Boston. This lake covers a surface of some six hundred and fifty acres, is seventy feet deep, and drains the springs, it is supposed, of some eleven thousand acres. Its elevation is one hundred and twenty-four feet above spring-tide, so that the descent is such as to make the conveyance of water to the city both easy and sure. The water is carried in a brick conduit or tunnel, high enough for a man to walk upright in, as far as the receiving reservoir in Brookline, and from there is taken in thirty and thirty-six inch pipes to the distributing reservoir on Beacon hill, in Boston. It is this reservoir, a view of which is given in the cut beyond, from which the water is distributed in pipes throughout the city. The average daily supply of water needed for the present population of Boston, is about five million gallons. The water-works are capable of supplying twenty million gallons daily; and the Cochituate lake is capable, (by laying down another main pipe,) of supplying forty million gallons daily. The supply of the lake is fully equal to the wants of half a million of people.
THE BOSTON RESERVOIR.