Ida, on the 18th Sept. in Lat. 40° 20' South Long. 26° 00' East

"The last mentioned vessel, which was announced yesterday, reports the iceberg seen on the 22nd, to have been about 1,000 feet in length and 400 in height :that passed on the following day was about 300 feet high and 400 feet long."

I should recommend the thermometer used when in near the above situations which I always found give me plenty of warning to escape them, and that in very foggy weather indeed.

I am, Sir, &c.

J. CORNFORTH, Commander Majestic of Liverpool.

PILOT STATION OFF POINT PALMYRAS, AND LIGHT OF FALSE POINT,-Bengal. Fort William, April 21st, 1840. ORDERS having lately been received from the Honourable the Court of Directors, that the old station off Point Palmyras shall be resumed by their pilot vessels, during the south-west monsoon. Notice is hereby given, that from the 15th of March to the 15th of September, pilot vessels will cruize as formerly, during the day off Point Palmyras, in latitude 20° 42′ to 20° 48' north, with the point bearing from west to W.b.S., and anchor usually during the night in a line east and west of each other, when the vessel having on board the first turn pilot, will burn a blue light and maroon alternately every hour, commencing with the former at eight o'clock and continuing till daylight.

Commanders of vessels are hereby informed, that the former light-house on Point Palmyras has been undermined by the sea, and is now in so ruinous a state, that no dependence must be placed on seeing any part of it.

Commanders are further informed, that the new light-house at False Point stands in latitude 20° 19′ 25′′ north, and longitude 86° 48' 8", rising 120 feet above high water mark, and being coloured dark red, or reddish brown, with a large white star in the centre. The building may be seen in clear weather by day, and the light (formed of Argand lamps with reflectors) by night, from eighteen to twenty miles, at a height of twelve or fifteen feet from the level of the sea.

Commanders are recommended not to come under eight fathoms at the lowest for the purpose of making the light-house, or light at False Point, and having made it, to deepen their water again,-say from thirteen to eighteen fathoms according to circumstances, on steering to the north-eastward for the purpose of getting a pilot off Point Palmyras. They are also recommended, whenever the weather assumes a threatening appearance, and the wind inclines to the eastward to keep a still larger offing, particularly late in the season, as they may expect the pilot vessels to do the same, and that the latter will then be found nearer the tails of the reefs than Point Palmyras.

From the 15th of September to the 15th of March, the pilot vessels will cruize as before, between Saugre Sand and the Western Sea Reef, according to the old regulation.

(Signed)

COMPASS DEFLECTION.

T. T. HARINGTON.

THE variation of the magnetic needle, by local influence in the ship, may be produced in two ways:-1st, by two compasses being placed so

near each other as to cause variation, by the attractions or repulsions of their respective poles upon each other, a cause of variation which is obviated in merchant vessels by having only one compass to steer by instead of two, as in ships of war. 2nd, by the action of the ship's iron formerly attributed to induction, but now well ascertained to proceed from all masses of iron in a quiescent state in the ship, being rendered magnetic by the earth's induction, even to the guns, the upper parts being of course the reverse poles of the under. If all the masses of iron in a ship were so situated that a straight line drawn from stem to stern could be made to intersect their centres, than by placing a compass in this centre line, (which, of course, is one in which the poles of the needle would neither be attracted nor repelled), no deflection would be produced as long as the ship remained on an even keel; but, as this is impossible, from the iron being scattered in all directions through the ship, then the best securing method of preventing deflection is, to suspend the compass at a sufficient height above the centre of the deck, to withdraw it altogether from the influence of the magnetic iron in the hull; or, at all events, to insure only the upper poles of the hull iron influencing it, by which less irregularity in the deflections would be

secured.

Some six years ago it occured to me, that a needle might be constructed in the following way, less capable of being influenced by the attractions and repulsions of the magnetic iron in the ship than the present compass. Instead of a single bar two were made use of with their opposite poles in contact, in the centre of the card, the result of the experiment with it being as follows:-It pointed towards the magnetic north and south like the common needle: while on moving it upon a low pivot stand over, and from end to end of a long magnet, no perceptible dip took place, nor any perceptible deflection of either pole toward the magnet, on moving it in a parallel line along the edge of the latter— one magnet acting as a keeper to the other, consequently no loss of power was sustained by time, the only defect being its unsteadiness; that is, being much more easily agitated and much longer in returning to its magnetic bearing under such circumstances than the common needle. This defect might probably be diminished by future improvements; but, should it be found inapplicable, for the above reason, to sea purposes, none such can apply on shore.

Magnetizing by lightning and electricity, in vessels struck by lightning, the various steel articles on board have not only been frequently magnetized, but the compass poles reversed, in one, even the compass being made to point east and west. This latter could only have been caused by a transference of the magnetism from the ends to the sides of the needle, which, by magnetizing a steel bar laterally, I found to be the case, the whole of one side being a north pole and the whole of the other a south pole. The following experiment (frequently repeated with the same result) shewing the mode in which an electric mass passes along a conductor as well as the mode of magnetizing by electric agency, may not be unacceptable to some of your readers. Having charged a jar with vitreous electricity, a copper wire was twisted into two helixes, one from left to right and the other from right to left, in each of which a needle was placed and a spark from the jar passed

through, when the needles were found to be magnetized, in opposite directions as in similar helixes when operated on by galvanism, but with this difference-that the prob of the jar represented the negative end of a galvanic battery, and the outside coating the positive end.

From the above it would appear, that an electric mass has, like a galvanic current, a spiral motion around a conductor as well as a progress one along it; and that electric masses have a reverse spiral motion to galvanic currents, the motion of electric masses being from right to left; a curious coincidence with the similar motions of hurricanes, whirlwinds, and water-spouts. I failed to charge the jar on board ship with resinous electricity by all the various means recommended, and consequently, was unable to ascertain whether the negative spark had a reverse magnetizing power to the positive spark, which must naturally be the case. Should this latter turn out as I surmise, then a ready way of ascertaining the species of electricity that strikes a ship, may be arrived at by soldering the ends of a horizontal wire helix to Harris's conductor, at some inches distant from each other, in a perpendicular line, and placing a non-magnetized needle in it. As no vessel fitted with Harris's conductor has ever been struck with lightning, the inference has naturally been drawn, that they carry off the atmospheric electricity slowly and silently; and this the helixes would not only ascertain, but also, as I am led to hope, the species of electricity prevailing in different parts of the earth, as I am inclined to believe that the prevailing electricity in the northern magnetic hemisphere is the reverse of that in the southern. Securing needles across the lightning conductor by some adhesive substance, would, no doubt, answer equally well in the helix when strong electric discharges took place, the helix having simply the property of multiplying the revolutions of the electric mass, and thereby increasing its magnetic action upon the needle exposed to its influence.

NAVAL RENDezvous.

THERE is so much importance in the following remarks which appeared in the Standard lately, that we are induced to transfer them to our own pages. But it is in the light of a safe rendezvous for our men-ofwar, or even merchantmen in any future continental war that we attribute so much importance to these remarks. Such a rendezvous as would afford protection from weather and sea, and at the same time allow of a numerous fleet of all sizes of vessels to have a ready access and departure at all times, and in all seasons, from it, is what is wanted, and not a paltry refuge harbour just big enough to contain a few merchant vessels. The insufficiency of Dover even as a packet harbour is notorious; and any work carried on outside of it would be costly. The Downs has been alluded to.-Query.—Would our Dutch neighbours have allowed the Goodwin Sands to have remained a prey to the sea as many centuries as we have? We repeat again there is much for grave consideration in the following extract:"Friday Evening, March 19th.-It is most desirable to direct the attention of the country to that which was the subject of the conversation ENLARGED SERIES.-NO. 5.-VOL. FOR 1841.

2 Y

upon Mr. Rice's unsuccessful motion last night,-the necessity of providing a capacious harbour of refuge for merchantmen, and of rendezvous for ships-of-war, at some place in the Channel. This great commercial and naval state has at present but three harbours in England suited for ships-of-war, Plymouth, Portsmouth, and Sheerness, and none of these is in a position adapted for military purposes. The immense commerce of London too has to be conducted through a labyrinth of banks which the boldest and most skilful seaman does not encounter without anxiety in the darkness of night, or in foggy or tempestuous weather, but which, nevertheless, he must encounter at present, if at night he arrives near the mouth of the river. The Downs, it is true, affords protection in some winds; but in a wind from the south or S.S.E., or any point between, the Downs is without shelter. Is it right that there should be no harbour of rendezvous for ships-of-war between Portsmouth and Sheerness, exactly the most accessible part of the coast to an invading enemy, and exactly that part of the coast from which we could most effectually molest an enemy in turn? Is it right that the commerce of London with the whole world, and what we may therefore call the commerce of the world, should remain in its present state of exposure to danger? Nearly forty years ago the subject engaged the attention of Mr. Pitt, and all that has occurred within the interval gives reason to regret deeply that the exigency of the times disabled that great man from realising the design of defending England by a capacious deep-water harbour at the narrowest part of the Channel, which it is known he entertained.

"The introduction of steam navigation, which must in future bring every contest of naval powers to close quarters and to a short issue, however, leaves us now, if we see our interest or our danger, almost without a choice.

"It is not because we have any ill feeling towards France, or because there is naturally an opposition of interests between France and England, but because of our equality with France in Europe, and because of our proximity to that power, that we must always look to a French war as the most probable, and as that from which we have most to apprehend; and therefore with reference to France most of our defensive measures must be taken. But we are on the coast of Kent within eighteen miles of the French coast, and within less than thirty miles of ports from which France, if we neglect to guard against the danger, might send out war-steamers of considerable power to attack not merely our trade, but our towns and villages. A rendezvous harbour, however, in the narrow part of the Channel, would render such insults impossible— would be the more than adequate substitute for 20,000 men garrisoning the exposed positions on our shores. The proper site for such a harbour is a question for professional and scientific men; but many considerations, to which we shall advert presently, seem to recommend Dover. Now, let us suppose a rendezvous harbour at Dover, with a fleet of warsteamers and line-of-battle ships. Would not such a harbour and such a fleet keep, as it were, so effectually the key of the Channel, that no hostile vessel could show itself between Havre and Flushing,-need we say, dare show itself at the mouth of the river, as, even in the late war, some hostile vessels have done? But this is not all. War, though its

objects be strictly defensive-and we hope England will never have any but a strictly defensive war-must be carried on by offensive operations, or it will be interminable. Now, what an aid would the harbour of which we speak be in an offensive war. A steam fleet in such a harbour would have the whole of the coast of the continent from Rotterdam to Brest at its mercy for a day's run. This is an advantage which would more than double, treble, or quadruple the military power of Great Britain. Let men only look back to the weeks, nay, months, lost in the embarking and transporting expeditions to the Helder, to Walcheren, &c., and they will feel that we do not overrate this prodigious augmentation of power which Providence has given us, if we will only secure the means of exercising it. It is not too much to say, that a rendezvous harbour in the narrow part of the Channel would render necessary an army of at least 200,000 men to protect the opposite coast from invasion by less than a tenth part of the number,— would enable Great Britain to clear out in succession every port from Rotterdam to Brest.

"Sir Robert Peel plainly sees this, though he considers that in his peculiar circumstances it better becomes him to recommend the capacious harbour, which he approves of as a harbour of refuge than as a military post. It is quite true, as Sir Robert said, that a harbour of refuge upon a great scale is what is wanted--and that one such harbour is worth fifty small harbours, and is proved to be worth fifty small harbours by the demands made for the improvement of the latter. Why are such demands made? Because in certain winds or states of the tide these small harbours are of difficult, or dangerous, or impossible access; but give them a capacious refuge harbour in the neighbourhood, and vessels entering such a harbour under all circumstances of wind, weather, or tide, can choose their own opportunity, whether of wind, weather, or tide, to approach the smaller harbour. The question of expense ought not to be weighed for a single moment when such an object as that under consideration is to be obtained-call it 2,000,000 (1,500,000%. has been named)—call it two millions, three millions, four millions. Why, as regards the safety of trading vessels, to say nothing of the lives of their crews, the harbours would repay the whole in ten years. The advantages in war would repay it in half ten months. As to the value of the harbour, we have the honour of concurring in the opinion of Sir Robert Peel; but we must respectfully differ from the right honourable baronet as to the time of commencing to provide what is so valuable. Sir Robert hesitates to press it now, in consideration of the expense and the state of the public finances. We think that no consideration ought to delay the pursuit of an object so all important.

"Whatever may be the state of the public finances, the multitude of our railroads proves that the private finances of the country are not in a state of exhaustion. We are not sure that a refuge harbour scheme in shares might not turn out a better speculation than most of the railroads, more particularly if the government would engage itself to pay liberally for the use of such a harbour whenever its use might be required as a rendezvous harbour for her Majesty' vessels. In this way the whole cost might be raised in a few days without imposing any burthen upon the finances of the country. But, however provided, the