The splendid Washington Bridge, built of steel at a cost of $2,700,000, carries one of the Boulevards across the Harlem at a height of one hundred and fifty feet; but the great landmark is the High Bridge which brings the Croton Aqueduct over, its tall granite piers and graceful arches displaying singular beauty from every point of view. This aqueduct is forty miles long, and has been well described as "a structure worthy of the Roman Empire." It originally cost $12,500,000, subsequent improvements absorbing millions more. The Croton River, coming down through Westchester County, falls into the Hudson about twenty-five miles above the city, and its headwaters are dammed, making artificial lakes gathering the supply. The Aqueduct was finished in 1842, and, going through tunnels and rock-cuttings, has a cross-section of about fifty-four feet and an inclination of one foot to the mile, or thirty-three feet in the distance to the Harlem River. About one hundred and fifteen millions of gallons go through it daily, moving at the rate of a mile and a half per hour. Three huge pipes carry the water across the High Bridge at one hundred and sixteen feet elevation. There are eight arches in the river crossing, their openings being eighty feet wide and one hundred feet high, to allow the passage of vessels, and seven narrower arches of fifty feet span on the banks. At the New York end of this picturesque bridge is the tall tower, rising two hundred and sixty-five feet, which has water pumped into its surmounting tank to supply the highest parts of the island. New York, however, long since outgrew the capacity of this famous aqueduct, so that a new one of much greater size was tunnelled underground and finished in 1890, which is fourteen feet high, and bored at an average depth of one hundred and fifty feet below the surface, and is carried three hundred feet under the Harlem River bed, its estimated daily capacity being three hundred millions of gallons. The receiving reservoirs in Central Park hold over a thousand millions of gallons. An imposing gate-house at One Hundred and Thirty-fifth Street admits this supply into the northern city mains. The great Quaker Bridge dam across the Croton is two hundred and seventy-seven feet high and thirteen hundred and fifty feet long, making the most enormous artificial reservoir in the world, holding forty thousand millions of gallons. It has cost New York over $70,000,000 to thus insure an ample water supply, free of all risk from drought. THE BRONX AND THE NEW PARKS.