not only to the trade of the Delaware, but also to the coastwise trade generally, assumed its support, and did so support it until the 30th of June, 1816, a period of two and a half years, at an outlay of $2,460 48, of which sum Congress, in the session of 1845-'46, reimbursed $1,600, leaving a balance of $860 48 still in advance by the board. From June 30, 1846, to the present time, the light has been sustained by the Treasury Department, the agent of this office having charge of the public property at the harbor being continued as light-keeper until the 21st of May last, when he was superseded by that department. Subsequently to this change, the possession of the dwelling on the break water proper, of which the light is a mere appendage, was yielded up to the agent of the Treasury Department, in compliance with the orders of the bureau of the 8th of June. During the past season, a new light has been erected on the break water proper. It is provided for in the general light-house bill of last session. The same bill makes appropriation for two light houses and one beacon, "to be expended under the direction of the Bureau of Topographical Engineers." It is a matter of regret that, as the harbor of the Delaware break water is still in course of construction, and in charge of the bureau, a like provision was not made in favor of this light also; and that, failing in this, a transfer was not directed by executive authority, as was done in the case of the light-houses for Flynn's Knoll and Brandywine shoal. In the absence of any such action, the erection of the new light, as a matter of course, devolved on the Treasury Department, which having deferred to the bureau on the subject of the proper site only, is responsible for the work, both in the plan and execution. It is proper to state here, with regard to the site selected, that the reports from this office, to which the subject had been referred, in consideration that the contractors were already on the ground, examined the question solely with reference to the present state of the works; whereas, had the entire matter been within its control, the extreme verge of the breakwater proper, though involving the time and cost of filling up the deep hole and finishing off the work at that point, would have been chosen. For these reports and the correspondence generally, which took place on the occasion of erecting the new light and of removing the agent of this office as the keeper of the old one, the bureau is referred to its own files.

$52,761 00

27,162 00

Estimate for completing the works on their present bases-the breakwater proper to 15 feet, and the ice-breaker to 12 feet above low water: 17,587 tons of stone, of pieces of two tons and upwards, for the breakwater proper, at $3 per ton 9,054 tons of stone, of pieces of two tons and upwards, for the ice breaker, at $3 per tou 15,827 tons of stone, of pieces less than one fourth of a ton, to raise the bottom at the ends of the breakwater proper, to the level of forty feet below lowest spring tides, at $1 75 per ton Renewal of machinery, &c., cranes, crabs, shears, boats, buoys and buoy-chains, rope, blocks, hand-spikes, waterbarrels, spikes, nails, &c., &c., necessary on resuming operations

Barracks on the works for men, including bunks, cambooses, mess furniture, &c.

27,697 25

7,750 00

2,000 00

Reimburse board of underwriters of Philadelphia, balance of sum advanced by them for support of light from January 1, 1844, to June 30, 1846

Amount

Contingencies, at 173 per ct.

Total amount

$860 48

118,230 73

20,690 38

138,921 11

The estimate differs slightly in the aggregate from the one which accompanied the report of 1843. Some items are stricken out, others changed, and a new one inserted. The quantities of stone under the first and second heads are now deduced from more accurate measurements, both of the breakwater proper and the ice-breaker; and the quantity for the latter is further modified by giving that work a height of 12 instead of 10 feet above low water. An increase, also, for "renewal and repair of machinery," &c., has become necessary, by the almost total destruction, since the close of operations-now ten years-of all property under this head. The balance of the sum advanced by the board of underwriters of Philadelphia in keeping up the light is likewise added as an actual arrearage. On the other hand, the items for "extraordinary emergencies, such as the destruction of the light house, the current expenses," and "probable arrearage" of the same, are omitted, as the light is no longer in charge of the War Department, and the probable arrearage gives place to an actual one. Again: the heavy item for iron "screw piles, and fixing the same,' as a "protection against ice," is also omitted, to conform the estimate to the recommendation that the operations be confined to completing the works on their present lengths.

True economy requires that, as the contingent expenses in such operations are nearly the same, whether the quantity of stone deposited be large or small, the whole amount of the estimate be appropriated at one time. No serious inconvenience, however, would arise, were the sum divided between two consecutive fiscal years. The remnant of the season of the first year may be profitably employed in building the barracks for the men, erecting cranes, &c.-measures necessary preparatory to receiving the vessels carrying the large-size stone required for the works above water, and in depositing the small-size stone provided for filling up the bottom, an operation which requires no such arrangements; and the next season, in receiving and bedding the large-size stone, the contracts for which may be so framed that no payments be made until after the commencement of the second fiscal year. Under this division of labor, the first year would require the aggregate of all the items in the estimate, with the exception of the first and second, amounting, with contingencies, to $45,011 58; and the second, the balance of the estimate, or $93,909 53.

1 desire, though not strictly within the province of superintendence, to call attention to the necessity of providing a hospital in connexion with this harbor.

The number of vessels which resort to the harbor, or, more properly, the number of days' shelter afforded to vessels by the harbor, is now very large. During last year, as shown by the table already given, there were 9,126 vessels, requiring 74,387 men to navigate, or an average of 25 vessels and 204 men for every day. For each of the previous two years the

number of vessels, or days' shelter to vessels, was even still greater. It is now a very rare occurrence that no vessels are seen in the harbor; 100 are frequently lying in it at the same time; and on the 27th of August, 1848, as many as 141, with crews numbering 1,149 men, were congregated in it. On one occasion, the 4th of July of the present year, it is said the fleet reached the extraordinary number of 240, requiring 1,956 men for their crews; but as the statement is not authenticated by the record, which, as stated, was discontinued because of the removal of the agent of this office from the works, it is not relied on in support of the present views. For this purpose, the facts established by the record are suficient. In estimating the number of men, the crews for the different classes of vessels are rated as follows: for ships, 16; for brigs, 11; for schooners, S; for sloops, 5; and for pilot-boats, 3. If passengers were taken into account, the results given would in every instance be very considerably increased. The record also shows that the number of vessels seeking the protection of the harbor has, with slight fluctuations, steadily increased from the first. In the early years of its existence, this was owing in a great measure to the extension, from time to time, of the works; but as they attained their present dimensions, in 1839, no part of this increase, the ratio of which is quite as great as it was previously, can be referred, since that year, to this cause, but it is properly attributable to the increase of trade, and the growing confidence of navigators. This fact, interesting generally in connexion with the harbor, is here put forth as evidence that a hospital for that most important roadstead is not likely hereafter to lose any of its usefulness.

The foregoing statements are of themselves sufficient to show how largely the class most interested, and which furnishes the means in whole or in part for the maintenance of marine hospitals, is likely to be benefited by the establishment of one of these provident resorts at the locality in question. But the subject has derived unusual interest from recent events of a most painful character. During the present year the harbor has received within its waters three vessels, on board of which disease and death were exhibited in the most appalling forms. The first was the British ship Cambria, bound to New York, with immigrants. She put into the breakwater in distress, after a voyage of 91 days, short of provisions and water, and with sickness among her passengers, 55 of whom died at sea, and 17 after her arrival. The second, the schooner Martha Collins, from Norfolk, bound also to New York, with cholera on board, two of the crew dying shortly after coming to anchor. And the third, and under by far the most distressing circumstances, the three-masted schooner Florida, from Chagres, destined for the same port. This vessel was boarded, apparently abandoned, by a Delaware pilot-boat, about twenty miles from the capes. Three of her people had already died of the yellow fever, and the master and remainder of the crew were found below, sick with the same disease, and so entirely helpless as to be unable to navigate the vessel. In this condition she was towed into the harbor. The scene on board, both as regards the dead and the sick, is described as revolting in the highest degree to every feeling of humanity. The first case may not properly, except as to the crew, come within the objects of a hospital of the character of the one proposed. Of the other two there can be no doubt. In every instance the inhabitants, including the physicians, of Lewes, as well as others, ministered with most commend

able assiduity to the wants of the sufferers; and yet it will not be doubted their condition, both the healthy as well as the diseased, would have been greatly ameliorated had there existed a suitable refuge on shore to receive the latter.

In suggesting a hospital at the Delaware breakwater, it is with no view to an establishment costly either in the first outlay or in the current expenses. As no chronic cases should be admitted, and those that became so might be removed, the accommodations of at most a dozen beds, in a plain building designed for the purpose, would be sufficient, except under very extraordinary circumstances, to meet the wants of the harbor. The cost of maintenance would also, for a large part of the year, be confined to the compensation of a physician and a matron, with (say) one nurse, to keep the house in order-a discretionary power being given to the former to obtain additional temporary assistance as occasion may require.

I have the honor to be, sir, very respectfully, your obedient servant, HARTMAN BACHE,

Major Topographical Engineers, Brevet Major.

APPENDIX F.

PHILADELPHIA, October 4, 1849.

SIR: Upon being assigned, early in April last, to the charge of the lighthouse to be erected on Carysfort reef, Florida, I found the various parts, as originally designed, in a satisfactory state of forwardness.

The cast iron work was being executed by Messrs. Merrick and Torone of this city, except the lantern, which was made in Boston. The lantern, and the lumber for platforms and for the house, had already been shipped to Key West. The illuminating apparatus, which is to be that of Fresnel, had been ordered from Paris.

My predecessor, Captain Stansbury, corps of topographical engineers, had wisely determined to erect at the foundry those parts of the work most complicated in structure, in order that any errors-the liability to which was very great in a work of such magnitude and numerous details-might be corrected there, thus avoiding the embarrassment which would be caused by the discovery of errors while erecting the light-house on its permanent site.

The general form of the light house, as you are aware, is a skeleton tower, composed of a frustum of an open octagonal pyramid resting upon an octagonal prism of equal base, with a vertical central post rising to the base of the lantern. In the experimental erection only the pyramidal part of the tower has been put together, the lower angle sockets, which connect it with the prismatic base, resting on discs placed on the ground. Upon reaching the elevation of the top of the dwelling, it was perceived that a moderate force would produce a considerable oscillation of the tower, with a tendency to torsion.

The entire tower, independently of the lantern, may be considered to have seven planes of perfect rigidity, as follows:

1. At the surface of the foundation rock.

2. At the lower series of radial and periphery ties, 15 feet 8 inches above the rock.

3. At the floor of the lower story of the dwelling, 21 feet 6 inches higher.

4. At the floor of the upper story of the dwelling, 7 feet 2 inches higher. 5. At the roof of the dwelling, 10 feet 6 inches higher.

6. At the upper series of radial and periphery ties, 22 feet 5 inches higher.

7. At the base of the lantern, 17 feet 8 inches higher.

The original plan of the light house did not include a system of diagonal bracing; the structure, it was supposed, would be rigid enough by means of its radial and periphery ties. The necessity for their introduc tion became apparent, as I have above stated, before we had attained to a great elevation in the experimental erection.

The dwelling is a conic frustum, sufficiently rigid between planes 3 and 5 to resist any tendency to change of form. The application of braces to oppose the movement of oscillation, and of torsion, was therefore only necessary between the planes 1 and 2, 2 and 3, 5 and 6, and 6 and 7. Accordingly, at the middle points of the angle posts between planes 2 and 3, 5 and 6, and 6 and 7, clamp collars were adjusted, and tension braces of one and a half inch iron, with turn-buckles, were carried therefrom to the intersections of the adjacent angle posts with the planes of rigidity above and below. Radial braces were also arranged to corresponding points of the central post from the same collars on the angle posts. Above the dwell. ing, the tubular casing of the spiral stairway made it necessary to attach the inner ends of two sets of radial tension braces to the upper radial hori. zontal ties. Between planes 1 and 2, the size of the tension braces was increased to two inches diameter, and such an arrangement made of the radial diagonals as to resist the thrust of the pyramidal frustum at its junction with the prismatic base.

The introduction of these braces has greatly increased the stiffness of the tower, which, it is now believed, will have very little motion during the most violent gales.

It was at first proposed to carry on the experimental erection no higher than the top of the dwelling; but upon reaching that altitude, the expediency of putting up all the parts that had not been shipped to Key West had become apparent; I therefore continued to erect the tower, which was completed by the close of July.

On the 20th of August, we commenced taking down the work for shipment to the Florida reef, the 10th of October being the time fixed for sailing from this port. . I have not thought it prudent to sail sooner, on account of the violent gales which blow in the southern latitudes during September and the early part of October.

The difficulties of this undertaking will in reality only commence when we shall begin to erect the light-house on its permanent site. These difficulties depend on the exposed character of the position selected, which is at all times covered with water; on the nature of the sand, which is calcareous, and has a specific gravity little greater than that of water; and on the distance, over shoal water, that it will be necessary to transport the large amount of heavy materials in boats and scows.

The first step to be taken after arriving at the reef, will be to discharge the vessels at the most convenient point to serve as a depot. This will be indispensable as a measure of safety for the materials, and in order that the two smaller vessels may be available as lighters and despatch boats.