bone projecting above high water, and caught vessels swept upon it by the ebb currents, which passed directly over the rock. Hallet's Point and the Middle Reef may be said to have been alternate in mischievous functions; vessels which escaped one ran a great risk of falling upon the other. What added considerably to the danger from these reefs was the bend at right angles of the river at this spot.

The originally adopted project for the improvement was the least extensive of three projects discussed by the engineer in charge.

That one now being carried out was judged by the authorities in 1867 to be too extensive and costly. The project first adopted was the removal of Pot Rock, Frying Pan, Way's Reef, Shelldrake, the rock off Negro Point, the rocks near Wolsley's Bath-house, Blackwell's Rock, portions of Hallet's Point, and Scaly Rock. Sea-walls were designed for the Middle Reef, Hogsback, the Bread and Cheese, and a beacon for Rylander's Reef.

The project most favored by the engineer in charge, which included. likewise the total removal of Hallet's Point and of the Middle Reef, has, as time passed, received the approval of the authorities.

The project first intended solely for Hell Gate has also been modified by incorporating with it rocky obstructions in the East River, Diamond Reef, Coenties Reef, a reef near the North Brothers, and Pilgrim Rock, East River.

The amount expended thereon to the close of the fiscal year ending June 30, 1884, was $3,162,043.31.

The condition of the improvement was the removal of Diamond, Coenties, and Way's reefs and Shelldrake to a depth of 26 feet at mean low water; the breaking up of Heel Tap Rock; the tunneling and explosion of Hallet's Point, and removal of the débris to the depth of 26 feet at mean low water; the tunneling of the Middle Reef (Flood Rock) to the extent of 23,180.9 linear feet, and removal therefrom of 70,347.9 cubic yards of stone measured in place; and the removal of the reef off the North Brother's Island to a depth of 26 feet at mean low water.

The amount expended during the year ending June 30, 1885, was $99,232.75, and has been for extending the galleries of Flood Rock over an area of three quarters of an acre and drilling 43,784.4 feet of 3-inch holes for the final blast; and removing Pilgrim Rock to 24 feet at mean low water.

The work done under the project for this improvement exceeds that which was originally projected, Diamond and Coenties reefs, and a reef near the North Brothers Island, and the Pilgrim Rock having been added to it; the removal of these, together with that of Hallet's Point, Way's Reef, and Shelldrake to the named depths, the partial removal of Heel Tap, Frying Pan, and Pot Rock, and the work already done on Flood Rock, constitute about four-fifths of the whole project. The work already done has been a great relief to navigation. The removal of Middle Reef (Flood Rock now in hand), will nearly double the width of the east and most used channel in Hell Gate. During the year ending June 30, 1886, the available balance, $267,949.74, will be applied to the exploding of the mine in Flood Rock and the removal of a portion of the broken stone after the explosion.

The amount that could be profitably expended in the fiscal year ending June 30, 1887, is $500,000, which should be expended as follows: For grappling and removing the broken stone after explosion of Flood Rock, $250,000; for completing removal of Pot Rock, Frying Pan and Heel Tap, at Hell Gate, and for beginning the removal of a reef near Diamond Reef, in East River, $180,000; and for commencing work in

Negro Point, $70,000. The estimated amount required for the entire and permanent completion of the work of improvement in accordance with the approved and adopted project is $1,601,340.67.

This work is in the collection district of New York. The nearest port of entry is New York City. The amount of revenue collected during the year ending June 30, 1885, $126,183,873.57. The amount of commerce and navigation benefited by the completion of this work about $4,000,000 daily.

ORIGINAL ESTIMATE.

Removing reefs at Hell Gate and Diamond and Coenties reefs, $5,139,120.

AMOUNTS EXPENDED DURING THE YEAR ENDING JUNE 30, 1885.

July 1, 1884, amonnt available

Amount appropriated by act approved July 5, 1884.
Received from sale of fuel to Lieutenant Derby..

Received from sale of property to Raritan River, New Jersey

$11,978 87 360, 000 00

66.00 1,557 00

July 1, 1885, outstanding liabilities..

July 1, 1885, amount expended during fiscal year, exclusive of outstanding liabilities July 1, 1884.

July 1, 1885, amount available.....

267,949 74

harbor acts of 1866 and 1867.

(Amount (estimated) required for completion of existing project.... Amount that can be profitably expended in fiscal year ending June 30, 1887 500, 000 00 Submitted in compliance with requirements of section 2 of river and

1,601,340

67

1881.

1882.

1883.

1834.

1882 1883. 1884.

Number.

Abstract of proposals for furnishing copper cartridge cases for final blast of Flood Rock, Hell Gate, New York, opened June 20, 1885, under circular letter of June 8, 1885.

Contract will be made with the Rendrock Powder Company for the furnishing of the copper cartridge cases.

Abstract of proposals for furnishing explosives for final blast of Flood Rock, Hell Gate, New York, opened June 20, 1885, under circular letter of June 8, 1885.

Bidders.

Contract made with the Rendrock Powder Company for 225,000 pounds of rackarock, and with R. W. Warren for 50,000 pounds of dynamite.

COMMERCIAL STATISTICS.

Value of imports, exports, and duties collected at port of New York.

Tabulated statement of the commerce of the port of New York.

Tabulated statement of the commerce of the port of New York-Continued.

Number and tonnage of steam and sailing vessels, barges, and canal-boats belonging to the port of New York.

OPERATIONS AT FLOOD ROCK, EAST RIVER, NEW YORK.

REPORT OF LIEUTENANT GEORGE M'C. DERBY, CORPS OF ENGINEERS.

ENGINEER Office, United STATES ARMY,
FLOOD ROCK, HELL GATE IMPROVEMENT,
Astoria, N. Y., July 1, 1885.

GENERAL: I have the honor to submit the following report of operations at Flood Rock for the fiscal year ending June 30, 1885.

The beginning of the year found the works closed, no work having been done since May 31, 1883, the appropriation having failed. The new appropriation did not become available until too late for the work to be finished in time to blast the fall of 1884, necessitating the postponement of the blast until the fall of 1885, this being the only season of the year at which it was deemed expedient to fire the final blast. It being desirable to keep the men occupied until the end so as not to employ new hands for the loading, the force employed has been regulated with that view; the amount of work done during the year being only about five months' work for the plant.

Operations were commenced on a small scale August 1, 1884; the last shot was fired ¦ May 29, 1885, and the last 3-inch hole drilled June 25, 1885. The mine has been cleaned up and all preparations made to commence loading about July 15. This latter operation should be done slowly and cautiously, and will require about two months and a half.

CONSTRUCTION OF DAM.

The difficulties encountered during the year have been exceptional. All attempts to pass around the large seam at the north end having failed, it became necessary to cross it. In order not to endanger the rest of the mine, a heavy timber dam set into the rock with Portland cement was built, across heading K, between 38 and 39. The seam was cut just beyond this dam, and all the rock excavated during the year was brought through a door in the latter that could be closed in case of accident by means of a rope leading to high ground. A second door of smaller size, arranged to close itself in case of a rush of water, afforded means of extracting the foul air from the galleries. Progress was much delayed by the large amount of water encountered, and work in the different galleries was frequently suspended on account of large and dangerous seams. One of the latter was a foot wide and filled with round grained sand and gravel from the river. In all cases these seams were sealed with Portland cement as fast as opened, the water being carried off through pipes while the cement was setting.

DRILLING.

All of the 3-inch holes drilled during the year were done with the tubular drill, the description of which I have already reported. This machine shows a saving to the Government of $28, 246.31.

The total length of 3-inch holes drilled is 113,102.15 feet, and the number of holes 13,243.

BLASTING.

The new explosive, rackarock, has been used throughout the year with satisfac tory results. There have been no accidents. Little or no stoping has been done the headings having been carried through the full height required. All blasting was suspended during my absence in Florida from April 11 to May 18.

HAULING, HOISTING, AND DUMPING

have been carried on as heretofore, the loading of the stone into cars being much retarded by the large amount of water in the headings.

PUMPING.

The leakage is now about 1,200 gallons per minute, all the increase coming from the seams in the north end.

VENTILATION.

There being only one longitudinal gallery through the new work, ventilation was secured with a horizontal brattice, the foul air being carried out overhead.

TIMBERING.

As heretofore, but little has been required.

TRANSPORTATION.

The tug Humphreys and the dump-scow were both docked and overhauled before work was resumed.

SURVEYING.

Mr. G. W. Kuehule has dope the surveying in the new work, and, with Mr. J. M. Gore, has been employed throughout the year numbering and measuring the drillholes for the final blast, and locating them in plan and elevation, and in making the computations necessary for the proper distribution of the charge.

PREPARATIONS FOR THE FINAL BLAST.

After the completion of the galleries and drilling much work remained to be done, cleaning up the mine, removing the rubbish that has accumulated during the past ten years. The timbers require extra wedging to make sure of their not floating out when the mine is flooded; and all the mud in the sump and ditches must be cleaned out, lest it may cover sticks that might afterwards foul the wires. All the railroads and air-pipes must be taken up and stored, as well as all the plant on the surface. An elaborate set of pipes is required, to provide means of escape for the air when the water is let into the mine. Buildings have to be provided on Mill Rock for the use of the powder contractors, and suitable scaffolds erected in the mine for charging the holes that are too high to reach from the floor. Under this head is also charged the cost of extensive experiments made in Florida during the early spring to determine the most efficient way of firing the mine, and to test a new method of firing inert explosives, such as rackarock, so as to make them available for the final blast. These experiments have already been reported in full.

I inclose herewith a tabular statement of amount and cost of work done for fiscal year.

Respectfully submitted.

General JOHN NEWTON,

Chief of Engineers, U. S. A.

GEO. MCC. DERBY,
Lieutenant of Engineers.

(Through Col. Walter McFarland, Corps of Engineers, U. S. A.)