hundred feet from the works, until the hour stated, five o'clock in the morning, when her cable parted, and she was driven into Raritan bay, at the distance of several miles from the works, before she was brought to anchor again. The gale abated in the course of the day. On examining the works the next day, they were found to be nearly destroyed; but, what was very extraordinary, the greatest injury was sustained by the portions of the work that by their positions should have been sheltered; they being on the leeward and landward side of the works, while comparatively little injury was experienced by the portion of the work on the windward and seaward side, where it had to encounter the first shock of the sea. It was also perceived that the tripod benches were generally in the positions they had occupied before the gale. These tripod, benches are of a very fragile structure; they are formed of three scaffold poles, having the larger ends, which are to rest on the bottom, loaded with kentledge, and kept at proper distances by iron braces, and the three smaller ends bolted together, and forming the top of the bench. They are easily moved, and are found to be convenient in forming temporary platforms. It was somewhat remarkable that these benches, with but little strength, and less stability, withstood the gale, as though they had been scarcely disturbed, while parts of the work that had much strength and stability were entirely destroyed. The facts just stated gave rise to doubs as to whether the injury sustained by the works had been caused by the violence of the gale solely, or in connexion with other circumstances that had not transpired; and as to the circumstances that might have operated to produce the injury, there were two conjectures, either of which being established, would have removed all further doubt upon the subject. One of these conjectures was, that a vessel might have been driven through the works during the gale; the other conjecture was, that the brush which formed a part of the structure, and which had been laid between the piles, from the bottom nearly to low-water mark, throughout a large portion of the work, night have floated to the surface, in consequence of having been insufficiently ballasted, or in consequence of the ballast, which consisted of loose stones of moderate size, having by constant and violent agitation gradually slipped through the interstices. of the brush, and thus left it free to float to the surface. If a large portion of the brush had floated to the surface, and become entangled with the frame work that connected the heads of the piles together, forming a mass more or less compact, the power of the wave acting upon such a mass, during a gale, would be sufficient to draw out the piles or break them off in a very short time. The effect most likely to happen would be, to draw out the piles, as the force of the lateral pressure of the wave would be but limited in comparison with that of its upward pressure, when acting upon the under side of the mass; and this action would, moreover, constantly weaken the resistance, by the vibration of the piles, that would be produced by it, the tendency of which would be to lessen their adhesion to the sand into which they had been driven. If the adhesion should not be overcome in this way, then it is possible the piles might be broken by the force of the lateral pressure, which, although weaker than the upward pressure, would still be very great, as it would have the advantage of leverage, by its acting against the heads of the piles. The part of the piles at which the fracture would occur, if they were broken by lateral pressure, would probably be at the surface of the sand into

which they were driven, as that would be the fulcrum or point of resistance; supposing, as was the case, that the brush which had been laid between the piles had not been in that position long enough to acquire the compactness and solidity it usually attains, in the course of time, by the gradual filling of its interstices with deposites of sand.

If the injury had been occasioned by a vessel, or other floating mass, being impelled against the works by the force of the waves, as referred to in the conjecture first stated, the effect would have been precisely that which was produced. Except a few straggling piles that remained, all the piles that belonged to the parts of the works that were injured were carried away; and when recovered, as nearly all were, it was perceived that, except one of them, which had been drawn out, they were all broken off at their point of contact with the bottom. It was evident from this fact that the injury had been occasioned by lateral pressure; and as the tripod benches, together with the piles belonging to the parts of the work that were not injured, received but comparatively little injury, as has been stated, although they were at the windward, and therefore most exposed side of the works, and some of the piles had brush laid between then, in the same manner as the piles that were carried away, it was also evident that the injury produced had not been occasioned by the force of the waves alone. The prevalent impression, in the first instance, seemed to be that the injury had been occasioned by a vessel having been driven through the works. This impression was strengthened by the recollection of an event of that kind that had occurred the year before. A temporary platform, composed of nine tripod benches placed near to each other in three rows, so as to form a square, and having their tops secured to each other by beams hung to them with chains, with other beams crossing these, and lashed to them, was established upon or very near to the site occupied by the works for the light-house on Flynn's Knoll. It was intended to establish a more substantial platform with piles, to be driven from this; and a pile engine, provided for that purpose, was lashed to the beams, in an upright position. In this state, it encountered, on the 12th and 13th of September, 1838, a gale of violence equal to if not greater than that of the gale of the 16th of August, 1839, and of longer duration, and, to the surprise of every one, without having experienced the slightest injury. In less than three weeks after the gale it was destroyed, as was some time after ascertained, by being run through by a schooner during a dark night; and so slight was the shock it occasioned to the schooner, that the persons on board of her supposed they had been passing through a collection of drift wood. Al the benches had been displaced, and one of them, that had probably become entangled with the stock of the anchor, was found at the distance of a quarter of a mile from the others.

But there were circumstances that seemed to render it altogether improbable that the injury to the works had been caused by a vessel running through them. It must have occurred in daylight, as the works were known to have been uninjured at 5 o'clock in the morning, and the gale had abated in the afternoon; and, if it had happened, it is hardly probable it would have escaped the notice of every one on board the vessel. If it had been observed, it would have become public, or, at all events, would have been known by the pilots, who would have mentioned it.

There were circumstances, also, that rendered it improbable that the injuries had been occasioned by the brush escaping from the ballast that was intended to keep it at the bottom, and becoming entangled with the ram

ing of the heads of the piles, so as to form a raft or mass more or less compact at the surface. In such a case, it would appear to be almost certain that the upward pressure of the force of the waves, aided by the buoyancy of the piles, would be more likely to draw them out of the land, than that the lateral pressure would cause them to break off; and, especially, as the upward pressure would have far less resistance to overcome, since it would be effective upon single piles, or row of piles, in succession, while the lateral pressure could be effective only after it had overcome the collective resistance of the whole mass. As long as the bracing of the heads of the piles remained firm, the escape of the brush would be but to a limited extent, and the force of the waves, either by upward or lateral pressure, would be most effective. But although this would be favorable to the effect of the upward pressure in drawing out the piles, it would be unfavorable to the effect of the lateral pressure in breaking them. The bending of the piles before breaking would be resisted by the framing or bracing while it remained firm; and when this resistance should be overcome by the destruction of the framing, the effect would be the escape of the brush which had been retained by the framing, and the consequent reduction of the power of the lateral pressure by the absence of the greater portion of the means whereby its effect was to be produced.

The facts relative to the injury sustained by the works of Flynn's Knoll during the gale of the 16th of August of last year, and the remarks upon them, which are set forth in the foregoing statement, being matters connected with the subject of the light-house, and such as it may be proper to preserve in the files of the Engineer department, are introduced in this report, as they were not included in the annual report of last year, where the record of them would have been more appropriate.

The works remained in this shattered state, in which they had been left by the gale, until the beginning of October. The repairing of them, with some slight additional work deemed necessary to afford further security, were completed in November. The parts of the work carried away by the gale were not renewed-the repairs being confined to the parts that remained after the gale, and the additional work being what was required to connect those parts.

In making these repairs, no pains or expenses were spared to render the work capable of resisting during the approaching winter the shocks of violent gales and of drifting ice that were to be expected. Notwithstanding these precautions, the work was nearly destroyed by a violent gale that happened near the close of December, during which the general level of the sea was said to have been higher than had been known for a number of years. In a subsequent gale, about the close of last January, all that remained of the work above the water line was destroyed. On examining the site in March last, it was discovered, by means of a sounding rod, that there was brush at the bottom, covered with ballast, and apparently at the same level as that at which it had been laid in the preceding November. It was also discovered that the soundings in the vicinity of the site indicated less depths than those that had been taken at the same places in November; and it was therefore judged that there had been an accumulation of sand in those places. The site has not been examined since March last. Respectfully submitted.

Colonel J. G. TOTTEN, Chief Engineer, &c.

JNO. L. SMITH, Major Corps Engineers.

2d Session.

War Dept.

ERECTION OF A LIGHT-HOUSE ON FLYNN'S KNOLL.

MAY 12, 1842.

Referred to the Committee on Commerce.

WAR DEPARTMENT, April 22, 1842.

SIR: On the 15th instant I had the honor to transmit to you so much of the information required by the resolution of the House of Representatives of the 12th instant as had been prepared by the Colonel of the Corps of Topographical Engineers, relative to the erection of a light-house on Flynn's Knoll. I now transmit, here with, the report of the Third Auditor, "giving the items of expenditure" required by the resolution.

With great respect, your obedient servant,

Hon. JOHN WHITE,

Speaker of the House of Representatives.

J. C. SPENCER.

TREASURY DEPARTMENT,

Third Auditor's Office, April 21, 1842.

SIR: I have the honor to return the resolution of the House of Representatives of the 12th instant, in relation to the expenditures of the appropriation made for the erection of a light-house on Flynn's Knoll, which was referred by you to me on the 14th instant, to furnish a statement in regard to that part of the resolution which requires "giving the items of expenditure."

In compliance with your directions, I have the honor to hand you enclosed a statement taken from the vouchers on file in this office, showing the purposes and actual amount of expenditures made between the second quarter of 1837 and third quarter of 1841, inclusive; to which latter period accounts have been received at this office, amounting to $51,541 54. With great respect, your most obedient servant,

Hon. J. C. SPENCER,

PETER HAGNER, Auditor.

Secretary of War.