6. The absence of injurious effect, from said sewage discharge, upon the property of the United States situated in the harbor of New York.

7. The absence of reduction in the dissolved oxygen contents of the waters of New York Bay, resulting from the discharge of Passaic Valley sewage, to such an extent as to interfere with major fish life.

Third. The State of New Jersey and said Passaic Valley Sewerage Commissioners further agree with the United States that so long as said sewer system, or any part thereof, is operated, the United States shall have, through such representatives as may be designated by the Secretary of War at any time for such purpose, full opportunity to inspect the condition and working of the sewer system, with a view to determining whether this contract is being in all respects performed, and that the said Passaic Valley Sewerage Commissioners will render such expert or other assistance as the United States may desire in the course and in aid of such inspection and determination.

EARLY DREDGING APPLIANCES AND STEAM
DREDGES*

The object of these works was to increase the depth of water on Van Buren Bar by the corroding force of the increased quantity of water thrown into that channel, but, in that, the works have not been successful. In 1825, dredging was begun on the bar. The depth of water in which the excavation was commenced was 4 feet, and it is now 8 feet. The top digging for about 1 or 11⁄2 feet was a hard cemented gravel and sand; it then became loose and easy to be removed. The depth of water since the dredging, which was confined in a narrow channel, has been lessened by deposits brought from the upper parts of the stream. The dams are very much dilapidated; they were built about thirty years ago, and Mr. MeCoun says, that when they were in perfect order they increased the depth of water at Troy 1 foot. Captain Reed, of Troy, in speaking of the Washington Bar, told me that the channel which has been dredged through it does not fill up much, which, he says, is owing to the hard bottom, and the raising of the water by the dams before alluded to. The corporation of Troy have expended, since 1829, about $5,000 in dredging between that city and Albany.

Below the foot of Patroons Island, a pier runs from the west shore for 540 feet into the stream; it was built in 1799 with a view to remove the Fish House Shoal, but has not fully answered the purpose intended. In 1826, excavation of that shoal was commenced by a dredge worked by horse power, and continued to operate until 1830. In 1831, the steam dredge was employed for the same purpose. The channel opened was, however, injured by an ice flood in 1831.

In a subsequent part of his report, he says: "if the navigation of the river was to be improved by dams, I am of opinion, that, to avoid any public trespasses of such a repulsive nature, and effectually to improve the navigation, without depending on system and casualties, the plan executed in Scotland, on the River Green

* Extracts from Report of De Witt Clinton, United States Civil Engineer, to Lieut. Col. John J. Abert, Topographical Engineer, upon the survey and improvement of the Hudson River. Document No. 189, House of Representatives, 22d Congress, 1st Session; March 30, 1832.

ock, below Glasgow, by Mr. Gouldbourne, a civil engineer of great repute, would be the most eligible, inasmuch as it has a tendency to straighten the channel of a river by the alternative concentration of low dams, and to deepen the bed by local excavations performed by mud turtle injurious to no one, but, on the contrary, reclaiming on each side of the river lands covered up by water, inasmuch as the stuff withdrawn from the bottom is lodged behind projecting piers by men constantly in that business.

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DREDGING

The changes, which occur in the beds of all streams, are of such a nature as would require more or less labor to remedy the injuries the channels might sustain. It would therefore be necessary that we should always have at command a power which we could apply to that purpose. That power is the dredge, and we can rely with confidence on its ability to perform such labor as we may require.

By the application of steam, the power and practical utility of the dredge has been much increased. It has also lessened the expense of excavations in a ratio corresponding with the improvements of its machinery and its strength; and, at this time, it may truly be considered as so important an agent as to have rendered many river improvements attainable, which before were considered impracticable.

To obtain full information on the subject of the Albany steamdredge, I addressed a letter to General Gansevoort, of Albany, who had the kindness to procure for me the following information :

The expense of the dredge, and its appendages, was about $14,000, The annual expense of repairs about $250. The daily expense of fuel and labor about $20, and the durability of the machine, if used every season, about seven years; and it can perform work between seven and eight months in the year.

The power of the machine is about 15 horses, working under high pressure, with boilers on each side. The buckets are 2 feet wide and 1 foot deep, and oval form. A moderate and even power applied effects the best operation. Her present clearing is in 10 feet water, but it can be made to operate in 14 feet water if necessary.

The machine can remove from 50 to 60 cubic yards an hour in good digging. From hard bottoms and deep water, from 30 to 40 cubic yards in an hour, and has removed from the overslough bar 600 cubic yards in a day.

The expense of the dredge, therefore, for seven months, or say 182 days, at $20 daily, would amount to $3,640; and to which add $250 for the repairs of the machinery, making $3,890. If we suppose that the dredge could only work two-thirds of the time, the other one-third being interrupted by high water, and breaking of the machinery, and that the averaged excavation was 40 cubic yards per hour, and the time in which it operates ten hours, it gives 400 cubic yards as the daily labor of the machine, or 48,000 cubic yards

is its total amount of work yearly.

We have seen that the daily performance of the dredge, and the repairs of the machine, amount to $3,890. If to this we add the annual decay, and the loss of interest on the capital, it would give, in seven years' average, $2,400. But, even after the machine was useless, some parts of it would be salable. If we assume this as one-eighth of its original cost, it leaves $2,100, or $5,990 as the total annual expense of the dredge, and the loss of interest, decay, and repairs of the machine, or nearly 12 cents per cubic yard for the cost of excavation, on the amount of work which the machine is capable of performing to meet that sum.

Without entering into a minute calculation, we will assume, as the soil is now placed in scows to be taken away, that each craft will contain 20 cubic yards, or it will require twenty scow loads to carry away the soil which the dredge would excavate, or two in each hour; consequently, one gang of men, comprising four persons, would be sufficient to attend to this part of the duty, at $1 each; it gives the expense of transportation of earth to the place of deposit, at one cent per cubic yard, or making 13 cents per cubic yard for all expenses of digging and removing the soil.

This calculation may appear high, and is probably so. It is therefore safe. But it will be seen that I have supposed the work to be done by contract, and that the machines are owned by individuals. But if done directly by the Government, the work might be done lower than I have calculated it.

Richard Delafield

Richard Delafield (see frontispiece) was born in New York City, September 1, 1798. He entered the U. S. Military Academy May 4, 1814, and was graduated and commissioned Second Lieutenant, Corps of Engineers, July 24, 1818. He served as astronomical and topographical draftsman to the American commission under the treaty of Ghent for running the northern boundary of the United States in 1818, and was assistant engineer on the construction of the defenses of Hampton Roads, Virginia, from 1819 to 1824. He was promoted First Lieutenant, Corps of Engineers, August 29, 1820, and Captain May 24, 1828, and served as superintending engineer of the fortifications at Plaquemine Bend on the Mississippi River from 1824 to 1832, part of which time he was also in charge of the survey of the mouths of the Mississippi River and was engineer of the New Orleans Canal and Banking Company.

In 1831-1832 he was in general charge of the improvement of the Ohio and Mississippi rivers. From 1832 to 1838 he was at various times superintending engineer of the Cumberland Road east of the Ohio, of the fortifications of Fort Delaware, Del., repairs at Fort Miffin, Pa., and of the improvements of the harbors in Delaware River, and of the breakwater at the mouth of that river.

He was promoted Major, Corps of Engineers, August 7, 1838, and from September 1, 1838, to August 15, 1845, was Superintendent of the United States Military Academy. From 1846 to 1855 he was superintending engineer of the defenses of New York Harbor, and during the same period was in charge of the Hudson River improvement, 1852-1855; Light-house Inspector of the New York District, 1853; Chief Engineer of the Department of Texas, 18531854; member of the Board of Engineers for the Atlantic Coast Defenses of the United States, 1845-1855, and for River and Harbor Improvements, 1854-1855. In 1855-1856 he was a member of the Military Commission to the Crimea and the theater of war in Europe, and his report and observations, entitled "Report on the Art of War in Europe in 1854-1856," was published by order of