face of the bay; and hence, if it be considered important that the course of the ebb tide will make, with it, a very to prevent the blockade, a floating force must, in every oblique angle. From the western extremity of this line, case, be provided. 4th, and lastly, As the advantages we draw the line a b, (towards the shore,) at an angle of the harbour become more apparent, the commerce of 135 degrees, to which we give a length of 440 yards; benefitted by it more extensive, and the means of the and from the eastern end, we draw the line e d, at the country more ample, the harbour may be progressively same angle, of 580 yards in length. It will be seen by enlarged, and a battery erected upon the Shears, for its an inspection of the chart, that the ice which will strike protection. a Breakwater, made according to the above delineation will be deflected outwardly, while that which passes within the extremity b will course along near the shore, leaving a broad space entirely clear. It will be seen, too, that, while by the shore or the Breakwater, all winds will be entirely excluded, except the east-northeastwardly, that there will be a large space secure even

4th. On the extent and form of the Breakwater:

1st. As to the complete harbour at the position B. Going far enough from the shore to leave about half a mile in breadth, of good anchorage, we draw the line be, of 740 yards. The direction of this line must be such

Bottom.

from these. The area of this harbour will be about half the course of the tide, an angle of 120 degrees. This a mile square; the mean depth at low water being twen-line is so far up the roadstead, that a vessel anchored ty-eight feet: the whole length of the Breakwater will be behind it at the distance of 800 yards, will be protected one mile. The bases of the interior slopes of this work will be one-half the altitudes: but the exterior being exposed to a heavy sea, will require for the slopes bases of four times the altitudes. The side facing the north-east will be finished at high water mark, while the other two sides must be raised three feet higher, to keep the ice from being forced over into the harbour.

2d. As to the partial Breakwater at the position A. From the point c, which is in about twelve feet water, we draw the line eƒ, of 1100 feet, so as to form with

from east-south-east winds by the lower part of the Shears. And here it is proper to remark, that the winds blowing from between the east-south-east and south-east are neither violent nor of long continuance. It will be perceived on the chart, that, from the direction we have given to the Breakwater, the descending ice will be deflected towards the deepest water and strongest current, and that vessels, to the number of twelve, moored in two lines behind the Breakwater, will be protected either by the shoal or by the main land, from all winds, excepting those just mentioned.

It has frequently been remarked above, that the shoal itself is a good Breakwater, and that there is no doubt that vessels, provided with good ground tackle, could ride under its lee in safety; but it is proper to provide against deficiency in this respect, which may be often expected with merchant vessels; therefore, the commission propose to fix, in addition to the Breakwater, two lines of heavy anchors, connected with buoys, by strong chain cables. These buoys, cables, and anchors, will not only enable vessels to ride in safety, but the buoys will guide the vessels, as they arrive at their proper stations in the harbour, thereby insuring the greatest economy of space. The length of the line of Breakwater is just sufficient to cover the vessels from the passing ice, when they happen to be riding with a scope of sixty fathoms parallel to the Breakwater.

The mean depth in the harbour, at low water, will be twenty-one feet.

As this work will not be exposed to a violent sea from any direction, it is considered sufficient to make the base of each slope equal to twice the altitude.

5th. Estimate of the expense of a Breakwater. 1st. As to a complete harbour at the position B. In the left flank of the Breakwater there will be,

In the centre of ditto

In the right flank of ditto

Cubic feet

5,817,975 11,346,420 9,744,251

Total cubic feet 29,908,646 26,908,646 cubic feet, equal to 996,616.52 cubic yards.

One perch, or 24.75 cubic feet, at $2 00, is 2.1818 per cubic yard, 996,616-52 cubic yards of stone promiscuously thrown in to form the mass, each stone weighing from half a ton to four tons; for materials and labour, at $2.1818 per cubic yard 2,174,417 92

Add for unforeseen expenses, 7 per cent. 152;209 25
Total expense of complete Breakwater $2,326,627 17

2d. As to the expense of a partial harbour at the position A.

In the whole of the line of the Breakwater there will be 5,585;536 cubic feet, or 95,750.592 cubic yards.

One perch, or 24.75 cubic feet, at $2 00, is $2,1818 per cubic yard; 95,760.592 cubic yards of stone, promiscuously thrown in to form the mass, each stone weighing from half a ton to four tons; for materials and labour, at $2.1818 per cubic yard, 208,930 46 10,446 52

Add for unforeseen expenses, 5 per cent.

Add for moorings:

12 cast iron anchors, each of 30 cwt. at $70
dollars per ton,

12 chain cables, of 12 fathoms each, of an
inch and a half iron; at one end of each
chain a ring, of 12 inches diameter in the
clear, to be made of 2 inch iron, to receive
the end of the vessel's cable, which rings
should be puddened; equal to 144 fathoms,
at 10 dollars 50 cents per fathom,
12 buoys for the chains, say at 30 dolls.

Total expense of partial Breakwater and moorings

1,260 00

1,512 00
360 00

222,508 98

The light on this cape is elevated near 200 feet above the level of the ocean, and is at least one mile from the pitch of the cape. In connection with the circumstances of elevation and distance, it is difficult, in nights which are too dark for the very low margin of the Cape to be seen, to guard against an optical delusion, as to the distance of the vessel from the shore; and the error is most apt to be on the unsafe side; hence, vessels have often been suddenly run upon the Cape, which were supposed to be in mid-channel of the roadstead. The soundings give no intimation of proximity, as bold water is found at the very edge of the shore.

2d. The necessity of a permanent lighthouse on the lower end of the Brandywine Shoal.

The importance of a light on this position has been made evident to Congress, as appears by an appropriation for a floating light. But though this floating light will, doubtless, answer all purposes during the greater part of the year, it is certain that it will be destroyed, unless removed at the approach of each season of floating ice; and hence, as that is the season of most violent gales, and of greatest damage, it will be away when perhaps most necessary.

The commission do not hesitate, as to the practicability of fixing a permanent lighthouse, (which need be but twenty or twenty-five ft. high,) on the point indicated. It is essential to remark here, that at the period when the floating light will be removed from its station, all the buoys and other signals of sub-marine dangers, will also, for the same reasons, be wanting to direct the navigator. 3d. The importance of having, without delay, a correct hydrographic chart, made of the whole bay and river.

Of all the navigable communications from the sea to the interior, within the United States, that upon this bay and river is most intricate, and most beset with unseen dangers; and there is none, probably, more imperfectly known. The pilots, it is true, are acquainted with certain channels, well enough to conduct vessels at a favourable time with safety; but it is far from certain that they know these thoroughly, or that these are the only or the best.

The great distance and small elevation of the shore, and the similarity in the soundings and composition of the shoals, make it very difficult, at times, to hit or keep in the best water, even to the pilots. A chart of the bay and river, which would exhibit a true outline of the shores, with all the landmarks; the courses and widths of the several channels; the set of the tides; the influence of the moon and of winds upon the rise of the tide in different parts of the bay; the place, extent, and form, of all ledges, banks, and shoals; the soundings and nature of the bottom, both on the shoals and in the channels; the harbours and anchorages; exact and perspicuous sailing directions, &c. &c. Such a chart would not only greatly add to the knowledge and utility of the pilots, but with the help of proper signals, buoys, &c. would enable intelligent masters of vessels to enter with confidence upon the navigation, when, as sometimes happens in stress of weather, they could neither obtain pilots, nor keep the sea with safety.

It will not be out of place here to advert to the facilities as to the pilotage of the bay, which will be afforded 3,132 00 by the partial harbour. The pilots of Cape Henlopen are provided with pilot-boats and whale-boats; with the former they cruise in fine weather, sometimes out of sight of land, though some have been lost by pursuing their cruises too long; in bad weather, they retire to LewisOn concluding this report on an artifical harbour, the town behind the Cape Henlopen, and depend on signals commission take the liberty of recommending to the at the lighthouse, to inform them of the approach of notice of government some other matters, which, though vessels. On these signals being made, they start in not within reach of their instructions, are not only impor- whale-boats; but the distance is so great, that vessels are tant in themselves, but strictly analogous in their ten-frequeutly in danger, and sometimes lost, before they dency to those they have been considering: these are, 1st. The necessity of a beacon-light near the extremity of Cape Henlopen.

can board them. Anchored under cover of the partial Breakwater, however, the pilots would be enabled to get to sea in time, with their largest class of boats; there.

FALLS IN THE DELAWARE.

by materially diminishing the risk to the arriving vessels ly quick to be called a rapid: it forms a semi-pool and is and to themselves.

Of the several Rapids or Falls in the DELAWARE Jersey side. The whole fall is smooth on Pennsylvania