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eastern coast of Florida, and to transmit for details a report of Lieutenant Commanding John Rodgers, United States navy, assistant in the coast survey, by whom an examination of the inlet was made. I send herewith a copy of the sketch of the reconnaissance.

I concur in recommending the placing of these buoys as stated by Lieutenant Commanding Rodgers, with the precautions which he suggests for their maintenance in the right positions, and for the change of place of the bar buoys according to the change of the bar itself.

I would further recommend that Lieutenant Commanding Rodgers be intrusted with the placing of these buoys in the first instance-a duty which can be performed as he returns to Section VI, the coast of Florida.

Important suggestions of local signals for pilotage of barred harbors are given in Lieutenant Commanding Rodgers's report, and are hereto appended for the examination of the department.

Very respectfully, yours,

Hon. THOMAS CORWIN,

A. D. BACHE,
Superintendent.

Secretary of the Treasury.

UNITED STATES COAST SURVEY OFFICE,

Washington, August 29, 1851.

DEAR SIR: The position of the proposed buoys at Mosquito inlet, Florida, cannot be usefully marked on the sketch.

As the bar shifts with every gale, the best water is not now, in all probability, where it was when the examination was made.

I think three buoys would be ample. I venture to propose a secondclass buoy outside of the bar; a third-class buoy inside; and a thirdclass buoy at the bar.

To be useful, or rather that it may not become a nuisance, the bar buoy must be carefully attended, and its place changed with every alteration in the position of the channel. For this buoy spare moorings should be furnished, as it is probable that after every change of bar the shifting sand will so have covered the anchor that every attempt to weigh it will be fruitless; in which case, to unshackle the buoy and expend new moorings will be the only resource.

The collector is allowed boat hands. These men might be required to keep the buoy in the best water, and the collector be held responsible in his office for the faithful discharge of this duty. To this end a log or frame house should be erected on the beach for the men to live in. The beach washes away so fast that it is scarcely desirable to use more durable materials.

There is now no regular pilot for Mosquito, because there is not enough commerce to support one. The boat hands employed to keep the buoy in the best water would necessarily know the state of the bar, and be competent to point out the channel. Living on the spot, they would always be ready to pilot vessels. Mount Pleasant is the

nearest habitation to the inlet; and at present, since no look-out is kept, it is only by chance a vessel is seen.

On account of the breakers it is often impossible for a row-boat to cross the bar; the pilot must then wave the vessel in by means of a flag. In such harbors conventional telegraphs are established, as at St. Augustine, Florida, and Rio Grande de San Pedro, in Brazil, by which the vessel indicates her draught of water, and the pilot gives directions to her for keeping in the channel.

It is desirable that this telegraph should be general to all the barred harbors of the United States, and not varied in different localities, and at the pilot's discretion.

I have ventured to propose the annexed table as perhaps sufficient. It is simpler than the Brazilian telegraph, and fuller than the St. Augustine one.

Such modifications as may be deemed necessary can easily be made

on it.

Very respectfully, your obedient servant,
JOHN RODGERS,

Lieut. Commanding, and Asst. Coast Survey.

To A. D. BACHE, LL. D.,
Superintendent Coast Survey.

Table of signals for piloting vessels into barred harbors.

The pilot's flag to be seven feet by six in size, and to consist of two triangular red pieces of red muslin, or bunting, enclosing a white triangle of the same materials, fastened to a staff twelve feet long and one inch in diameter. The end of the staff to have a barrel hoop firmly lashed to it, and to have stretched over the hoop a piece of muslin, the upper half white and the lower half black.

The

The pilot boat to approach the bar as nearly as she safely can. pilot lays on his oars, or anchors his boat. The boat should be fitted with an awning stanchion aft, and a strap around it, for the pilot to make himself fast to, that he may stand steadily while signalizing.

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*The bar is not always the best place for beaching a vessel while the breakers are very heavy on it; there may be a comparatively smooth place on the sea-beach.

Table of signals-Continued.

Sentences to be communicated to the vessel by the pilot.

Signals for the sentences opposite.

1. Pilot cannot come out; what water does the vessel draw.

Wave the flag to right and left.

2. Not water enough on the bar until high | Pilot raises the flag over his head, and dips it tide. towards the vessel once for every hour she must wait.

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Report of the Superintendent of the Coast Survey to the Secretary of the Treasury, upon the necessity for a light-house, or permanent beacon, on the Rebecca shoal, between the Tortugas and Marquesas, Coast of Florida.

COAST SURVEY OFFICE,
November 22, 1851.

SIR: I would respectfully call the attention of the department to the necessity for a light-house, or at least for a permanent beacon, on the Rebecca shoal, between the Tortugas and Marquesas, in the Gulf of Mexico. The position of the shoal is shown in the annexed sketch. It lies in an important thoroughfare for vessels bound into the Gulf, and is not now marked. My attention has been called to this subject by Assistant F. H. Gerdes, of the Coast Survey, who made the reconnaissance of the Florida keys and reefs, and who has presented two drawings-one for a beacon to serve as a light-house, and the other for a simple beacon-which are at the disposal of the department, if their communication is desired. I send herewith a letter of Lieutenant Commanding John Rodgers, United States navy, assistant in the Coast Survey, in charge of the hydrographic party on the coast of Florida,

to Mr. Gerdes, in reply to his inquiries relative to the necessity for a light on the Rebecca shoal, and to the plan for a structure to contain it. Very respectfully, yours,

A. D. BACHE,

Superintendent United States Coast Survey.

Hon. THOMAS CORWIN,

Secretary of the Treasury.

COAST SURVEY OFFICE, Washington October 21, 1851.

DEAR SIR: In reply to your letter of this morning, I beg leave to say that I think no doubt can exist in the mind of any person acquainted with the facts of the case, as to the great necessity to commerce of a beacon on the Rebecca shoals.

The passage between the Marquesas keys and the Tortugas is a great thoroughfare for vessels bound into the Gulf of Mexico. By taking this passage the time to ports in the gulf is shortened more than the mere distance cut off, since the current is thereby avoided sooner. To sail vessels this is, in light or head winds, of the greatest impor

tance.

The shoals which lie in this passage are very dangerous, and there is now no mark for them. For want of some such mark, scarcely a day passes without many vessels running a great risk of injury or loss. The beacon of which I saw a draught in your room would undoubtedly stand; the plan combining great strength with little surface.

Any beacon put on the Rebecca shoals should be built, as the one you propose, with reference to its ultimate conversion into a light-house. I would prefer, however, that the whole structure should be of iron, rather than part wood.

With a given strength, iron offers so much less surface to the wind or sea, and it is of so much greater durability, that the increased cost of iron is by no means commensurate with its advantages.

Very respectfully, your obedient servant,

JOHN RODGERS,

Lieutenant U. S. N., and Assistant Coast Survey.

F. H. Gerdes, Esq.,

United States Coast Survey.

APPENDIX No. 35.

Report of Lieutenant Commanding C. P. Patterson, United States navy, to the Superintendent of the Coast Survey, on buoys and beacons for entrance to Mobile bay.

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SIR: The following report upon the location, &c., for buoys and beacons for the entrance to Mobile bay is respectfully submitted:

Buoys.

1. A buoy, or, far better, a boat-buoy, with a heavy bell, just outside the bar, in eight and three-quarters fathoms, soft bottom, with Sand Island light-house bearing north 22° west, and distant from the bar one mile. A buoy is necessary at this place at all times, but much more so during the thick, hazy, and foggy weather, prevailing nearly through the most active season, when a bell would be of great benefit.

2. A buoy off the south end of West Bank, in twenty-five feet water, with Sand Island light-house bearing south 11° 30' west, distant 1.78 mile, on a range of Mobile light-house, on West Umbrella Tree.

3. A buoy off the north end of West Bank, in forty-eight feet water, with buoy 2 bearing south 11° 30' west, in range with Sand Island light-house, distant 1.68 mile, and Mobile light-house bearing south 55° 30' east, distant 1 mile. The line joining buoys Nos. 2 and 3 will clear West Bank.

4. A buoy off the southwest end of Middle Ground, in twenty-five feet water, with Mobile light-house bearing south 28° 30' east, distant 1.66 mile.

5. A buoy on the northeast edge of West Bank, opposite to the southeast end of the Middle Ground, with buoy 4 bearing south 42° 30' east, distant 1.82 mile. The line joining buoys Nos. 3 and 5 will clear the northeast edge of West Bank.

6. A buoy on the twelve-feet spot (northeast end) of the Middle Ground.

7. A buoy on the southwest point of the spit, in nine feet water. These buoys should be large, and of such construction as to be seen some distance; and of such form, and so colored, as to be known when seen in foggy weather, and to point out on which side they are to be passed. The system adopted for this purpose should be based upon the principles proposed by the late Lieutenant G. M. Bache, United States navy, in a report upon the buoys of Long Island sound.

Beacons Entrance to Mobile Bay.

1. A beacon on Sand island, with the light-house bearing north 22° west, distant 245 feet. To cross the bar with beacon on the lighthouse.

2. A beacon on Sand island, with light-house bearing south 83° west, distant 145 feet, and beacon 1 bearing south 11° west, distant 250 feet, so that beacon 2, in range of beacon 1, shall clear the west bank.

3. A beacon on Revenue point, the south end of east bank. This beacon would bear nearly the same relation to this entrance that the "Rower beacon" bears to that of New York.

4. A beacon on Mobile point, with the light-house bearing south 34° east, distant 140 feet, near the water, and on the range of the black barrel over the chimney of the frame-house on middle of light-house; to lead through the channel between the southwest point of the Middle Ground and northeast edge of West Bank.

5. A beacon on Mobile point, with the light-house bearing north 46°

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