OF THE RATES OF LETTER POSTAGE.

POST-OFFICE DEPARTMENT, Contract Office, Sept. 7, 1849. SIR: The practice you have adopted (as appears by your letter of the 31st ult.) under the recent act of Congress, changing the scale of progression in the rating of letters, is correct. That law adopts a rule for this country, uniform with the one that prevails in Great Britain and Germany, to wit: to count the half ounce in rating postage, that is, when the letter does not exceed the weight of half an ounce. When the letter exceeds the weight of half an ounce, it is required to be rated by the ounce. For instance, if weighing less than an ounce, but more than half an ounce, it is to be charged with two rates of postage; if weighing over an ounce, but less than two ounces, with four rates of postage, [no matter how little the excess, it is to be charged the same as if it weighed two ounces;] if over two ounces, but less than three, six rates of postage, and so on.

This law is general, embracing inland as well as foreign letters; for in seeking uniformity with other countries with which we have Postal Treaties, it was not intended to make a complicated and conflicting regulation for ourselves.

Respectfully, your obedient servant,

S. R. HOBBIE, First Assistant Post-master General.

J. E. WHARTON, Esq. Post-master, Wheeling.

NAUTICAL INTELLIGENCE.

NOTICE TO THE SHIPPING OF BOSTON.

BOSTON, September 10, 1849.

The city government have placed a lead pipe across the channel from Boston to East Boston, nearly in the track of the ferry boats, for the purpose of supplying East Boston with Cochituate water, and, for the better preservation of said pipe, I caution all persons from anchoring vessels in the vicinity of said ferry track, under the following penalty:

Be it enacted by the Senate and House of Representatives, in general court assembled, and by the authority of the same, as follows:

SEC. 1. The harbor-master, authorized to be appointed by the fifth section of the act to which this is in addition, shall have authority to regulate the anchorage of all vessels in the upper harbor of Boston, and, when necessary, to order the removal of such vessels, and to cause the same to be removed, in obedience to such order, at the expense of the master or owners thereof; and if any person shall obstruct said harbormaster in the discharge of his duties, as prescribed by this act, or by the act to which this is in addition, or shall neglect or refuse to obey any lawful order made by said harbor-master, he shall be liable to a penalty, not exceeding fifty dollars, for each offence, to be recovered by indictment, for the use of the city of Boston.

G. P. TEWKSBURY, Harbor-master.

LIGHT-HOUSE ON GIBB'S HILL.

This light-house is the second only on a large scale that has ever been constructed of iron. Both it and the former one-on Morant Point, Jamaica-are the design and contrivance of Alexander Gordon, Esq., Civil Engineer, of London. The tower is 24 feet in diameter at the base, and 14 feet at the neck, under the hollow conodial capital which supports the gallery-the gallery itself is 20 feet in diameter, and the footway is 105 feet 9 inches from the level of the foundation. The carcase of the tower is of cast iron plates, joined by wrought iron bolts and by iron cement. There are in all 135 concentrick plates, 10 in the circle, carrying in weight from 1 tons, to 15 cwt. The necessary stability is given to the building by a mass of concrete nearly 500 tons in weight, contained between the outside plates of the tower, and the walls of a central circular well, 8 feet in diameter; through which well, ascent is gained to the upper rooms of the tower. This mass of concrete reaches to a height of 22 feet in the light-house, and at this height is the first floor; above this there are 7 rooms, each 12 feet in height, divided from each other by iron floors, supported on the outer plates,

and on the central hollow column, which runs from top to bottom of the light-house, and serves for a passage for the weight of the revolving machine of the light. The ascent through the rooms is by winding stairs of perfectly easy gradation. The two rooms next above the concrete, are cased with brick work, to serve as oil and store rooms-the rest are lined with sheet iron, disposed in large panels, with oaken pilasters and cornices, and are large enough for comfortable dwelling rooms.

The light is a "revolving dioptrick lens light, of the first order, with mirrors," with one central lamp of four concentrick wicks; it will be one of the largest and most powerful in the world. The light by calculation should be seen from the deck of a ship of the ordinary run of vessels 26 or 27 miles, but as the atmosphere makes the greatest difference in the distance at which objects are discerned at sea, it may often be seen at a distance of 32 or 34 miles. The light for this light-house was manufactured by Messrs. Wilkins, of Long Acre, London.

Height of Gibb's Hill from high water level, 245 feet; of light-house to gallery 105 feet 9 inches; from gallery to center of lamp, 11 feet; from center of light to top of vane 17 feet; total height from high water level to extreme top of vane, 378 feet 9 inches. The first plate was erected in its place on the 19th December, 1844, and the last plate of the tower on the 9th October, 1845.

NEW HARBOR OF REFUGE NEAR CAPE HATTERAS.

COAST SURVEY STATION,

(Near North Deerfield, N. H.,) July 25, 1849.

}

SIR-In consequence of the information received from Lieutenant Commanding Maffit, and already reported to you, in regard to the importance of the inlet opened in 1846, south of Cape Hatteras, I have had a reconnisance made of it by Lieutenant Commanding James Alden, U. S. N. Assistant in the Coast Survey, which confirms the previous statement of the value of this inlet as a harbor of refuge. The report of Lieutenant Alden contains the following statements of interest to navigators:

"This opening bears from Hatteras Light S. 70° W., distant about twelve miles. It will be easily recognized by the remarkably round hammock covered with trees on the East side of the entrance. The least depth at low water on the bar is 14 feet. It should be approached from the Northward, and Eastward, and as the brakers seldom extend entirely across the entrance, it can be readily discovered by the smoothness of the water between them; at that point steer N. W. by W., keeping along the breakers on the starboard hand until well in, then haul more to the northward, and anchor soon after inside the sand pits, which form the entrance, and which, together with the bar outside, afford sufficient protection against all winds from that quarter; the best an chorage, however, for a vessel drawing 10 feet of water, is where the schooner's first position is marked on the chart, and where the current will be felt much less than in mid channel; the currents and tides are influenced very much by the winds; the greatest velocity we found was three knots between the two sand pits; the mean rise and fall was 2.2 feet.

"There are two openings; the one to the westward is small, and has a very narrow and intricate channel, and must be considered of little or no importance, while so near a much finer and better one.

"Good pilots can be obtained for Hatteras Inlet at any time."

The sketch of Lieutenant Commanding Alden's reconnoisance has been reduced to publication, and will be at once placed in the hands of an engraver.

Very respectfully, yours,

A. D. BACHE, Superintendent U. S. Coast Survey.

WM. M MEREDITH, Secretary of the Treasury.

CEDAR POINT LIGHT.

John Young, Collector at the port of Sandusky, (Ohio,) gives notice “that one of Capt. Callard's Patent Signal Lanterns has been placed on Cedar Point, so as to range with the Cedar Point Light, and the channel across the outer bar, which does away with the difficulty heretofore existing of entering this port in the night. Steamers or vessels bound up or down the lake, should get the two lights in range and steer directly for them. The lamp shows a red light on the east and west sides, and a white light on the north, or front side."

BANKS NEAR GRAHAM'S SHOAL DISCOVERED.

LLOYDS AGENCY, MALTA, August 22, 1849. SIR:-On the 17th inst. H. M. S. Terrible, Capt. Ramsay, was despatched by His Excellency, Sir W. Parker, to survey Graham's Shoal, from which service she returned on the 20th inst. The plans of the survey not having yet been received at the Admiral's office, we have only been able to learn that where soundings were thirty-five fathoms when the previous survey, in 1846, was taken, only thirty-two fathoms are now found; and a considerable bank has been discovered close to Graham's Shoal, with only nineteen fathoms of water upon it. This new shoal is stated to be between Graham's and the Sicily Coast. As soon as we can obtain more precise information, we will not fail to transmit it to you.

CAPT. G. AALSTED, R. N. Secretary, Lloyds.

R. DUCKWORTH & Co., Agents at Lloyds.

WING'S NECK AND PALMER'S ISLAND LIGHT-HOUSES.

William T. Russell, Collector of customs at New Bedford, (Massachusetts,) gives notice that the following light-houses have been erected in that District :

WING'S NECK LIGHT-HOUSE.

Situated on the point of Wing's Neck, near the head of Buzzard's Bay, and was lighted on the 17th of September, 1849.

PALMER'S ISLAND LIGHT-HOUSE.

Situated on the north-easterly point of Palmer's Island, in this harbor, and was lighted on Monday, the 1st day of October, 1849.

We shall publish the bearings and distances of these lights in the Merchants' Magazine, as soon as they are taken.

BUTTERMILK CHANNEL, NEW YORK HARBOR.

From a survey recently made by the Hydrographical party of the Coast Survey, under the direction and command of Lieutenant D. D. Porter, of the United States Navy:

The various soundings in the whole extent of the Channel are minutely and distinctly designated, and the Channel has been buoyed out by Lieutenant Woodhull with spar buoys, so that ships of the largest class can pass through it without difficulty or delay, by observing the sailing directions as indicated on the published chart. It has heretofore been held that there was not sufficient depth of water in the Channel for vessels of large draught, and, therefore, could not be used with safety. The survey shows that there are from thirty-one to forty-two feet of water in and about the main Channel at low tides. The buoys are painted and numbered, and moored in nineteen feet low water. The use of this Channel by vessels will often save much time going in

and out the East River at certain times.

LIGHT-VESSEL IN ATCHAFALAYA BAY.

CUSTOM-HOUSE NEW ORLEANS,
COLLECTOR'S OFFICE, July 24th, 1849.

There has been placed in Atchafalaya Bay a Floating Light-Vessel, for the guidance of vessels navigating said bay. The bearings from said Floating Light are as follows: Pointe-au-Fer, E. 22 S., distant 12 miles. Belle Isle, N. 33 E. Tucka Hammock, N 22 W. Turn Stake, N. 5 W., 1 miles. S. W. or outer Stake, S. 38 E.

DIRECTIONS.-Bring the Floating Light to bear N. W. W., and run directly for her. You will leave the outer or S. W. stake on your larboard hand; when up with the Light-Vessel, you must anchor near her on the N. E. side, as you cannot proceed further without a pilot, or until daylight. At full sea there is twelve feet water in the channel, The Light-Vessel bearing any way between S. S. E. and N. N. W., westward of you and near to, you are in safe anchorage.

SAMUEL J. PETERS. Collector.

APPROACH TO WESTERN BAR AT OAK ISLAND.

Col. Rankin, the Collector of this port, says the Wilmington, N. C. Commercial, has handed us the following, relative to the bearings of the ranging Lights. They are from Capt. I. B. Smith, of the steamer Gibraltar.

On approaching the Western Bar of Oak Island Channel, get the Light on Bald Head to bear E. or E. by N., and run for it until the Lights on Oak Island bear N. E. by N., and run for the Lights until the Light on Bald Head bears E. or E. N. E., and then the course is E. N. E., up to the Rip, or to the Point of Oak Island. When in over the Bar, Bald Head Light will bear E. S. E.

COMMERCIAL STATISTICS.

TRADE AND COMMERCE OF NEW ORLEANS.

The "New Orleans Price Current,” etc., one of the ablest and best conducted journals of its class in the United States, of September 8th, 1849, contains the usual annual statement of the commerce of that city. Agreeably to our custom, we give, in a condensed form, the substance of the tabular statements, which have been prepared with so much accuracy and skill by our New Orleans cotemporary. Similar accounts of the trade and commerce of New Orleans for previous years, from 1831 to the present time, derived from the same reliable sources, will be found in the "Merchants' Magazine,” vol. ii., p. 349; vol. v., p. 471; vol. vii., p. 390; vol. ix., p. 568; vol. xi., p. 415; vol. xiii., p. 369; vol. xv., p. 404; vol. xvii., p. 412, and vol. xix., p. 511 :—

EXPORTS OF COTTON AND TOBACCO FROM NEW ORLEANS FOR THREE LAST YEARS, COMMENCING On 1st of SEPTEMBER, AND ending on 31st of August.

EXPORTS OF Sugar from new orleans for thrEE YEARS, (UP THE RIVER EXCEPTED,) FROM 1ST OF SEPTEMBER TO 31ST OF AUGUST.

EXPORTS OF MOLASSES FROM NEW ORLEANS FOR THREE YEARS, (UP THE RIVER EXCEPTED,) FROM 1ST SEPTEMBER TO 31ST OF AUGUST.

50,113

5,451

EXPORTS OF FLOUR, PORK, BACON, LARD, BEEF, LEAD, WHISKY, AND CORN, FOR TWO YEARS' FROM 1ST SEPTEMBER TO 81st August.

Total...... 778,370 466,050 67,202 1,249,691 60,058 489,641 53,473 1,466,861