April the question was submitted to the electors with the following

1836. In July the Common Council ordered pipe to be laid preparatory to the introduction of the water, and in October Mr. Douglass was superseded by the appointment of John B. Jervis as Chief Engineer.

1837. Work on the Aqueduct commenced in the early part of this year.

Great Fires and Epidemics

In the course of the events heretofore described, several great fires and epidemics had occurred, greatly influencing public opinion in favor of a more copious water supply.

On September 21, 1776, six days after the British captured the City, a fire broke out at the foot of Whitehall street and spread to Broadway, burning up on the east side as far as Mr. Harrison's brick house and on the west side to St. Paul's chapel. Trinity Church and 493 houses were destroyed.

On August 7, 1778, a fire originating on Cruger's Wharf (in the block now bounded by Water and Front streets, Old Slip and Coenties slip) consumed about 50 houses in that vicinity. This was during the British occupation and the military took exclusive control of the situation.

On December 18, 1804, a fire broke out on Front street south of Wall street and burned the whole block in Water street from Coffee House Slip at the foot of Wall street to the next door to Gouverneur's Lane, including all the buildings in Front street to the water; and also some buildings on the northeast side of Coffee House Slip. The famous old Merchants Coffee House, built in 1737, on the southeast corner of Wall and Water streets, was burned.

On May 19, 1811, a fire began near the northwest corner of Duane and Chatham street (now Park Row), and spread rapidly with a wind from the northeast. Between 80 and 100 buildings were burned. The steeple of the old Brick Church, in the block bounded by Beekman street, Park Row, Printing House Square and Nassau street, and the cupola of the old jail in City Hall Park, caught fire, but were not seriously damaged.

The "Great Fire" broke out on the night of December 16, 1835, in the premises of Comstock & Andrews, at No. 25 Merchant (now Beaver) street and burned over the area bounded approximately by the south side of Wall street from William street to the East river, by William and South William street to Coenties. Lane; by Coenties lane and slip to the river; and by the river from Coenties slip to Wall street. In this area, 674 stores and other buildings were destroyed, causing a loss stated at $17,000,000. The Merchants Exchange (site of the National City Bank) and the old Dutch Church in Garden street (now Exchange Place) were among the structures destroyed.

In this connection, we may anticipate our story somewhat and mention that a notable fire which happened in the early years of the Croton system occurred on July 19, 1845, when 345 buildings were destroyed and about $5,000,000 loss was caused in lower Broadway, Whitehall street, New street, Broad street, and in Exchange Place and other cross streets to the southward.

There were epidemics of yellow fever in 1795, 1798, 1805, 1819 and 1822, and of cholera in 1832, 1834, 1849 and 1855. The epidemic of 1805 was particularly severe. John Lambert's diary says that in that year 26,000 persons moved from the interior of the City to escape the plague. Those who could not go far went to Greenwich village on the west side of the island "about two or three miles from town" where merchants and bankers had other offices for the transaction of business.

VI

THE CROTON AQUEDUCTS

The Old Croton Dam

The work on the old Croton Aqueduct which was commenced in 1837 began at a point on the Croton river about six miles from its mouth with the construction of a dam. This dam was designed to raise the water 40 feet above the level of the head of the aqueduct and 166 feet above mean tide.

The rock formation at the site is Fordham gneiss, and the rock bottom of the river was so deep as to give the engineers trouble at the very start. Even after shifting their plans, it was necessary to make an artificial foundation for part of the dam where they could not build it on the living rock. The southern abutment was of natural rock, and the aqueduct being on the southern side of the river, the water was conducted to its head by a tunnel cut 180 feet through the rock. The gateway was also located in the solid rock, unexposed to the floods of the river. A waste culvert was built in the north abutment, with suitable gates for drawing down the reservoir for repairs and to discharge the river at ordinary times during the course of construction. From this abutment the old channel of the river was filled by an embankment, with a heavy protection wall on the lower side which was raised fifteen feet above the waste-weir of the dam and designed to be fifty feet wide on top. While this was in course of construction in January, 1841, the water rose until, when near the surface, it began to pass between the frozen and unfrozen earth about 20 inches from the top. Then, after the breach was made, heavy masses of ice came down from the reservoir and broke down the unfinished protection wall, with the result that the whole embankment was carried away. The masonry of the dam and abutment, however, suffered little damage. It was then decided to fill the breach thus made, about 200 feet long, by a structure of hydraulic stone masonry, adapting 180 feet of it for a waste weir. This was effected with great difficulty in those days, it being necessary to lay an artificial foundation. The greatest height of the dam was 40 feet above low water level and 55 feet above the bed of the river. The masonry at low water line of the river was 61 feet long.

Three hundred feet below the main dam a second dam, 9 feet high, was built for the purpose of setting the water back over the apron of the main dam to form a pool of water which should receive the impact of the water passing over the main dam.

The Croton dam impounded the water of the river in a reservoir five miles long and covering about 400 acres.

High Bridge

From the Croton dam a masonry aqueduct was built through the country and the villages of Sing Sing, Tarrytown, Dobbs Ferry, Hastings and Yonkers to the Harlem river opposite 174th street, a distance of 32.88 miles. At this point, the next monumental structure of the aqueduct, namely High Bridge, was erected. The valley of the Harlem river here, at the aqueduct level, is 1450 feet wide, and it required a structure of that length to conduct the water across the river to the Island of Manhattan. The width of the river at ordinary high water mark was then 620 feet, but at low ebb tides was reduced to about 300 feet. The southeastern shore is bold and rocky, rising from the water's edge at an angle of about 30° to a height of 220 feet. On the northwestern shore, a strip of table land extends back from the water about 400 feet to the foot of a rocky hill which rises at an angle of about 20° to a considerable height above the level of the aqueduct.

Across this interval was constructed a picturesque masonry bridge, supported in the Roman style, by piers connected by half round arches. There are fifteen of these arches. Eight of them, over the river proper, have a span of 80 feet each. The others are of 50 feet span. Across the structure, above the arches and below the roadbed, were originally laid two 36-inch cast iron pipes. The Chief Engineer, John B. Jervis, explained that the object of using pipes in this case is more effectually to secure the conduit from leakage that might eventually injure the masonry of the bridge, and it incidentally allows the bridge to be constructed of less height."

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The whole length of High Bridge is 1450 feet; the height of the river piers above high water mark is 60 feet to the spring of the arches; the height from high water mark to the under side of the arches at their crown 100 feet. The height to the top of the

cornice was originally 114 feet above high water and 149 feet above the lowest foundation of the piers, but it was raised about six feet in 1860-63. The width across the top is 21 feet.

High Bridge was not completed until about six years after the other parts of the aqueduct had been finished, and water did not pass over it until May, 1848. Meanwhile the water had been carried through an inverted siphon under the IIarlem river so that it was introduced into the City in 1842, as stated hereafter. The cost of High Bridge was stated in 1849 to have been $963,427.80. The following inscription is on the southern face of one of the eastern piers of the bridge:

On the south face of the westernmost pier is the following