Cauchoix to Mr. Lubbock, dated October 1831:-"I have just finished another object-glass, of the same di mensions as that which Sir James South is now mounting, and which appears to me as perfect. I used it for one of the three pieces of glass which were set apart for the first objectglass, and I have adapted to it a new disc of flint-glass. A trial of it with Jupiter, does not detect any flaw, either in the flint or crown-glass. I hope also to be able to make a third glass of similar dimensions, as well as another glass of the same size as that which Mr. Cooper has lately bought of me. I have likewise another kind of telescope, which I have made for these two or three years, where rockcrystal is substituted for the crownglass, by which means the focus is considerably shortened, and the brilliancy and clearness of the image greatly increased. But, at present, I have not been able to make them of larger diameter than about five and a quarter English inches."

VI. A Catalogue of Stars, observed with the Moon, from June to October 1831, at the Greenwich Observatory. From the Astronomer Royal.

VII. A paper on the Orbits of Binary Stars, by Sir J. F. W. Herschel, was commenced.

Dec. 9th.-The following communications were read:

1. On the proper motion of the Fixed Stars, by Francis Baily, Esq.

II. The reading of Mr. Herschel's paper on the Orbits of Binary Stars was continued.

After the meeting, Mr. Bate exhibited a machine for the illustration of the precession of the equinoxes. It consists of a pair of flexible hoops or rings, about nine inches in diameter, representing a globe mounted on an axis, which forms its poles, and to which a rapid motion is given (being the same construction as is usually employed to show the enlargement of the equatorial diameter by the centrifugal force). The axis of these hoops centres in a brass meridian, which is also mounted in delicate vertical centres in a wooden frame, to which the axis of the hoops is inclined at an angle of 2340; a clock-spring movement is attached to the axis of the hoops,

and the whole is carefully balanced' and stripped of friction as far as possible.

The clock-movement being wound up and restrained from action by a small click or trigger, on the removal of this click a very rapid motion, from west to east, is given to the inclined axis and flexible hoops, the upper hole of which becomes gradually depressed, by which depression the flexible hoops assume the figure of an oblate spheroid, in the usual manner. When this is acquired, the brass meridian receives a very slow movement from east to west, and it is the retrograde motion of this meridian which is charged with representing the precession of the equinoxes.

Baron de Drais also exhibited two instruments; one for converting mechanically the area of any figure of a regular form into the corresponding area of a triangle, square, or parallelogram: and the other for clearing the distance in lunar observations, without the aid of computation.

ROYAL GEOGRAPHICAL SOCIETY.Jan. 9th. G. B. Greenough, Esq. V.P. in the chair.-A paper, entitled Notes on Guiana, South America, communicated by Capt. J. E. Alexander, H.P. late 16th Lancers, was read. Of the natives, Capt. Alexander says, they are of short stature, but well proportioned; they walk about in a state of nudity, with a strip of blue salampore about their loins; their skins are beautifully clear, and of a light mahogany colour; the expression of their faces is apathetic good-nature. Capt. Alexander proceeded a hundred miles up the river Essequibo in a small country schooner, and then embarked and proceeded higher in canoes. All vestiges of the Dutch settlements are gone, and all is solitude and silence on either hand; occasionally, says Capt. Alexander, one stumbles in the entangled brushwood on the tombstone of some Dutchman, from the shores of the Zuyder Zee. Captain Alexander's very interesting paper was accompanied by a map illustrative of his route through a part of Guiana before entirely unknown.

A paper was also communicated, by Captain Horsburgh, on the Maldiva Islands, in the Indian Ocean; and a letter from the Royal Asiatic Society

was read. By this, it appears that apprehensions of the cholera being introduced from Egypt had subsided. The Bashaw was on the eve of an engagement with the Arabs of various places, who had refused to pay tribute for some time past, and had intercepted all communication between Soudan and Bornou. The Bashaw had 30,000 men in the field when the intelligence left Tripoli in November last.

In the course of the evening a great many candidates were proposed and balloted for; and notice was given, that, in consequence of the valuable papers to be read at the Society's meetings having accumulated, an extra-ordinary meeting would take place on the following Monday at the usual hour.

Jan. 16th. C. Lyell, Esq. in the chair. Some extracts from the papers and journal of Capt. Bannister were read, respecting the country between the Swan River and King George's Sound. The object of this expedition was to ascertain the condition of the country with regard to settling it. Its report is favourable.

An extract of a letter also from Lieut. E. Day, of the Bengal Artillery, was read, dated from Chirra, in the Cossya country. In consequence of the favourable reports of this part of the country, a depôt was directed to be formed there by the East India Company in 1830, and a party of invalids sent to it under the charge of the writer.

A communication from Mr. Barrow, giving an account of Alexander's Cave, near Tabriz, in Persia, by Sir Henry Wallack, was then read, and excited much interest. The Cave of Iscendereea, about twenty miles from Tabriz, is supposed to be under the influence of a magic spell, contrived by Aristotle for the security of treasure which Alexander the Great left in this place while he proceeded to conquer Persia and Judea. The tradition is generally believed among modern Persians, who regard Alexander as a necromancer. In the vicinity of the cave is a considerable village, which takes its name from it. The enchanted spot is situated in an elevated position, near a quarry, from which millstones are cut. The natural arch,

which forms the entrance to the cave, is high and imposing. The approach is rather inviting than otherwise: vegetation flourishes, flowers, wild-rose bushes, long grass, grow even near its mouth; and there is nothing in the exterior to indicate the existence of pestilential vapours, nor would the general formation of the cave warrant such a supposition. As the visitor enters it, his presence disturbs the wild pigeons from nooks in the vault where they have taken up their abode, secure from molestation. The arch of the cave is about eighty feet high; and the whole extent of it is about one hundred yards. The guide conducts the visitor along the high sides of the interior of the cave, and, having placed him in safety, proceeds cautiously to the lower ground, occasionally stooping down his head to ascertain the limits of life and death. The visitor, watching with intense interest the progress of the guide, discovers immediately the presence of pestiferous vapour-the sudden jerk of the head, and equally sudden halt, denotes the presence of danger. The guide now flings forward a fowl, which he carries with a string fastened to it; a convulsive gasp, and one or two flaps of the wings, bespeak approaching dissolution; and, having satisfied the visitor of the fetid nature of the vapour, the guide draws back the fowl, and, while it yet lives, cuts its throat in the name of God, in order that it may be lawfully eaten, being one of his perquisites. In the lower part of the cave were seen the skeleton of a fox, the body of a pigeon, or the remains of some other small bird, which had ventured within range of the destructive atmosphere. The extent of the vapour depends on the season of the year. In August, it was dry, and nearly clear of bad air. The guide declares, that the richest treasure would reward the man who had sufficient skill to dispel the enchantment. Many lives have been lost in it. A peasant disappointed in love, rushed into the infectious air, and met instantaneous death. On another occasion, a person seeking shelter in the cave from a storm, without being aware of his danger, was killed by its noxious vapours; and the guide has

ROYAL NAVAL COLLEGE.-The half yearly examination of the students of the Royal Naval College previous to their Christmas vacation having been completed, the first medal was awarded to Mr. Leopold George Heath, and the second to Mr. Frederick Thomas. On the 20th of December, the day on which the young gentlemen returned to their homes, the above medals were presented in the presence of Admiral Sir Thomas Foley, G.C.B. Commissioner; Sir Michael Seymour, Lieut. Governor; Capt. Loring and Capt. Rainer, of H.M.S. Britannia.

A reduction has taken place in this establishment, as follows:-One Lieutenant (Lieut. Ralph), one Assistant (Mr. Livesay), one serjeant, and eight students. The number of students hitherto admitted was eighty, it is now restricted to seventy-two. The salary hitherto specially given to the surgeon of the Dock-yard, for attendance on the students of the College, is henceforth to be withdrawn.

PRESENTATION OF A SNUFF-BOX TO CAPT. NEVILLE, LATE OF THE 13TH DRAGOONS.-The officers and men of the French Ship Bengalee, Capt. Feillet, on board of which Capt. Neville, late of the 13th Dragoons, had taken his passage from India to Europe, have presented that officer with a silver Snuff-box, in testimony of their respect and friendship formed during the long and disastrous voyage of that ship. He is also to receive a further mark of favour for his service on board, in assisting and cheering, by his example, the exhausted crew employed at the pumps, at a period of great danger, during a heavy gale of twelve days' continuance off the African coast, in August last.

SHOAL IN THE ARABIAN SEA, OFF CAPE RAS EL HAD.-A shoal has been discovered in the Arabian Sea, by H. M. S. Challenger, Capt. C. H. Freemantle, lying about forty miles distant from Cape Ras el Had. In the month of August, when the Challenger was on her way to the Persian Gulf from the southward, at 1° 30′ P.M. the water was observed to change colour suddenly, and soundings were immediately tried for. Two casts of thirteen fa

other, and at the next no bottom was found with twenty fathoms, and afterwards with sixty-five fathoms. The colour of the water resumed its usual appearance on crossing the bank, which, from the extent of the ripple, appeared to be about three miles long, and half a mile broad. The distance of the shoal from the Cape may be relied on, as it was run over in a direct course by the Challenger, and when five miles from the Cape, no bottom was found with a hundred fathoms of line. The shoal is not laid down in any chart, nor was it known at Muscat on the ship's arrival there. Vessels should be cautious of it, as there may be less water on it than that found by the Challenger. The latitude of the middle of it is 22° 9′ N. and longitude 60° 25′ E.

LIGHT-HOUSE AT THE ENTRANCE OF THE HARBOUR OF MARSEILLES:Chamber of Commerce, Marseilles, 23rd Nov. 1831. Notice from the Director-General of Light-houses, &c. Port of Cette, Dept. de l'Herault, France.

Navigators are hereby informed, in order to facilitate the north-east entrance of this port, (the only one which it is prudent to use during winter,) that in the month of October 1830, a sea-mark was established, having the form of a quadrangular pyramid near the foot of the mountain, which is a little to the south of Fort Richelieu, the height of which is about 60 metres (197 feet) above the level of the sea.

The eastern face of this pyramid is painted white, with a black lozenge in the middle of it, and two revolving lights have also been placed on this face, one above the other.

This temporary light may be seen from four leagues at sea, and the two lights which compose it, may be distinguished from each other at a mile and a half from the port.

In order to make the north-east passage, it will be necessary to bring the tower of the Light-house in Fort St. Louis, on with the pyramid in question, and following the same course from east to west, will preserve a vessel in the middle of the channel.

It will be equally easy to do the same at night, by bringing the light of

sum of money, is now extended to officers of the Militia, entitled to the disembodied allowance: and that allowance will not be granted to future appointments.

ROCKET SIGNALS-EXPERIMENTS AT BRIGHTON.-As we have inserted in our present Number an Article, on the subject of Rocket Lights, from Colonel Macerone, we think it but fair also to insert the following extract from the Hampshire Telegraph of the 2nd ult.:-" Experiments were made on Wednesday night on the Chain Pier at Brighton, in the presence of the Duke of Sussex, and many other persons of distinction, of a new code of rocket signals, invented by Lieut. Hughes, R N. and intended to supersede the lanterns at present used for that purpose in the Navy. No less than seven Admirals were present,Sir Robert Otway, Sir Pulteney Malcolm, Admiral Thomson, and four others. The signals were fired from two batteries, that on the pier being directed by Lieut. Hughes, and at Bear's Hide, near Newhaven, by Lieut. Crispo. Rockets of ten different colours are used; and it is supposed they will be equally available in

the most boisterous weather as in a perfect calm."

CHANGES IN THE STATIONS CORPS SINCE OUR LAST.

OF

2nd Dragoon Guards from York. 6th Ditto from Cahir to Kilkenny. 1st Foot, 2nd Battalion, from Chatham to Edinburgh.

7th Ditto, Reserve Companies, from Portsmouth to Bristol.

9th Ditto from Limerick to Cork for Gibraltar.

11th Ditto, Reserve Companies, from Swansea to Cardiff.

14th Ditto from Isle of Wight to Gosport.

30th Ditto from Belfast to Enniskillen.

33rd Ditto, Reserve Companies, from Barnsley to Dudley.

35th Ditto Ditto from Portsmouth to Gosport.

47th Ditto from Glasgow to Belfast. 50th Ditto from Dublin to Newbridge and to Naas.

58th Ditto, Reserve Companies, from Mullingar to Limerick.

Portsmouth-Dec. 25th. Arrived the

Wellesley, 74, Capt. Rowley; Curaçoa, 28, Capt. Dunn, and Teed, 20, Commander Bertram, from the Downs. Sailed the Isis, 52, Capt. Polkinghorne, bearing the flag of Rear-Admiral Warren; Charybdis, gun-brig, Lieut. Crawford; and Pluto, steamer, Lieut. Buchanan, to St. Helen's, and on the following morning proceeded to the coast of Africa.

Dec. 28th. Arrived the Pelorus, 18, Commander Meredith, from the Eastward, and Recruit, gun-brig, from the North Sea. Sailed the Etna, surveyingvessel, Commander Belcher, and Raven, cutter, tender, for the river Gambia; and the Wellesley, for Plymouth, to be paid off.

Dec. 30th. Arrived the Viper schooner, from the Eastward.

Jan. 3rd 1832. Sailed the Pelorus, 18, Commander Meredith, for the coast of Africa.

Jan. 4th. Arrived the Pearl, Capt. Broughton, from the Western Islands. Jan. 6th. Sailed the Tweed, 20, Commander Bertram, for Bermuda.

Jan. 7th. Sailed the Curaçoa, 28, Capt. Dunn, for the Cape of Good Hope.

Jan. 11th. Arrived the Dispatch, 18, Commander Frankland, from Lisbon.