A further motive was to test the value of the different watches. Capt. Owen has fixed the longitude of the North Battery at Sierra Leone, in 13° 14' 2" west, and as our passage out occupied a period of time exceeding six weeks, during which we underwent great change of temperature, from the winter of England to the oppressive heat at Sierra Leone, from 50° to 84° of Fahrenheit, by which the rates of the chronometers were materially affected. I did not venture to make any alteration in this longitude, but adopted it as the true meridian. The rates of the chronometers were determined from equal altitudes of the sun at the North Battery, at Sierra Leone, between the 3rd and 11th of February, and from thence the meridian distance was measured to. Cape Mesurada, by ten chronometers in five days To Cape Palmas in eleven days To Accoodah Cove, Cape Three Points, in sixteen days 2° 25' 59" E. 5 30 24 11 12 37 18 21 1 To Titway flag-staff, near Cape St. Paul, in nineteen days 14 13 64 22 01 79 The interval between the last observations at Sierra Leone, and the first at Fernando Po, amounting to a month, it was thought hazardous to the accuracy of the measurements to extend it further, before submitting the rates of the chronometers to a fresh examination. They were accordingly rated at Adelaide Islet, between the 13th and 20th of March, and thence the meridian distance was measured to the Crown Sand, in Corisco Bay, in an interval of eleven days 38° 4' east, which completed the proposed series of chronometric stations. Returning from Fernando Po to Sierra Leone, in May and June, on our way back to the Canary Islands, the meridian distance between those two places was again measured by the same ten chronometers 22° 01' 8" west, which agrees perfectly with that first obtained. interval between the observations on each occasion was exactly thirty days. The By the above measurements, in combination with the latitudes at the same points, all the headlands along our whole line of operations became fixed, and our next duty was, to complete the survey of the coast between them by the following method. The Etna and Raven, or the decked barge were anchored off one of these primary stations, at a sufficient distance from each other to form with it, or some remarkable object upon it, an equilateral or nearly equilateral triangle, the length of the side formed by the two vessels was then measured by the velocity of sound. To obviate any errors which might arise from the relative positions of the vessels with respect to the wind, three guns were fired alternately on board of each at intervals of three minutes. The time elapsed between the flash and the report was measured by the beats of a pocket chronometer, and the mean result of these six intervals was used to calculate the distance. The side of the triangle constituting the base thus determined, usually measured from four to five nautic miles. At a given signal, previously concerted by the officers conducting the work, simultaneous angles were taken between the vessels, and all such prominent objects as the land presented, and their true bearings were obtained. From this base, and these angles, the points, trees, forts, and other conspicuous objects were laid down on the plan, the vessels remaining in their respective positions, until the accuracy of the whole work, depending on them, was verified. The outline and representation of the coast in all its details, was confided to one particular officer, whose attention was exclusively directed to this important portion of the survey. It was performed in a light boat, in which he proceeded close alongshore, following the sinuosities of the coast, and sketching its peculiar features. His position, whenever required on this track was determined by measuring the angles subtended by the vessels and other fixed objects around him; and while he was thus employed other boats were despatched to take the soundings, their places being fixed in a similar manner by angles between the known points. Each boat besides being furnished with a general set of signals had - her own distinguishing flag, which she hoisted whenever a line of direction to her from the ship was considered necessary to fix her place; a circumstance of frequent occurrence on a low, monotonous, and thickly wooded coast. When the boats were sufficiently advanced to render the Etna at her first station no longer useful, she weighed and moved on to her next station ahead No. 3, which she took up on a previously arranged bearing from the Raven, at anchor in station No. 2; and at a certain distance from her, determined by a given angle, subtended by that vessel and one of the fixed objects on the land, so calculated as to form when practicable, an equilateral triangle as before. So soon as the Etna anchored in her next station No. 3, and was secure, a signal was made to that effect, and on its being answered by the Raven, the angles to all objects around were again simultaneously taken, and then that vessel weighed in her turn, and proceeded to station No. 4, which she took up in the same manner as that described for the Etna. This mode of operation was employed along the entire coast from Cape Mesurada to Quitta, and as the prevailing winds were from the south-westward, the work was carried on from west to east, or from windward to the leeward stations, which enabled the ship to pick up her boats at close of day. From the masthead of the ship as she lay at anchor in her station, the shore was carefully examined through a telescope, and angles taken to every rocky point, detached rocks, extremes of sandy bays, peaks, forts, or any other remarkable objects that could be seen, which might assist the officer charged with the coast survey, and act also as a check upon his work. It may be well to mention that it was our invariable practice to project the station of the vessels in advance with reference to the true meridian, and that the same practice extended to all long lines of direction to distant peaks, or other objects. Intermediate stations were determined at distances varying from forty to seventy miles of each other by carefully observed latitudes and meridian distances; the latter being measured from the nearest primary station. The triangulation between these minor points, was then adjusted to them, and the work continued from a fresh base. From Cape Mesurada to Cape Three Points, the coast was traced and laid down by the late Mr. Willson. For the delincation of it, from thence to Cape Paul, I am indebted to the taste and talents of Mr. Church. There is a bank of soundings along the whole of this coast, varying considerably in its distance from the shore. The extent and general character of it was determined by running out lines of soundings from shoal water near the land to its outer edge, until no bottom could be found with 200 fathoms of line, and thence continuing them in again to the coast. The inner parts of these lines are fixed by the land objects so long as they continue sufficiently distinct; the outer extremities depend generally on latitudes and meridian distances, the latter having reference to the stations of the survey near it; but in some instances they are laid down from courses, (corrected for various influences, including the effect of currents,) and from distances measured by the patent log. From Cape Mesurada to Cape Three Points, this bank was traced by Lieut. Bedford, in the Raven. From Cape Three Points to Quitta is ́ principally by the Etna. The currents were regulary registered at the several anchorages, to the depth of three fathoms, and numerous observations were made under other circumstances with a view to its determination. The times of high water, and the rise of tide were ascertained by tide poles erected at most of the principal stations, but the high surf which prevails so generally on the greater part of this coast was very unfavorable for such observations. The magnetic variation was found by theodolite on shore, whenever it could be done conveniently, and the ship was swung at several places for the local attraction, by which to correct the variations obtained afloat. The magnetic dip and horizontal intensity, were also observed at all the primary stations. The heights of many objects, both inland and on the coast, were found approximately from their angles of elevation above the horizon, measured by sextants at numerous stations of the vessels. The whole coast comprised between Cape St. Aun and St. Paul as represented in the charts and plans, now delivered into the office, is as completely original as if we had been its first discoverers: and I may make the same observations on those of the Canary Islands. In no instance have the works of others been copied, or in any way introduced into the survey. THE VARIATION OF THE COMPASS. (Continued from p. 765.) Royal Observatory, Oct. 24th, 1841, MEAN MAGNETIC VARIATION FOR SEPTEMBER 1841-23° 24′ 17′′. At 9 A.M. 1841-68° 43' At 3 P.M. G. B. AIRY, Astronomer-Royal Erratum in p. 765, in “Mean Magnetic dip "-for “ July " read “ August. " ACCOUCHEMENT OF HER MAJESTY. BIRTH OF THE PRINCE OF Wales. Buckingham Palace, November 9th, 1841. This morning, at twelve minutes before eleven, the Queen was happily delivered of a Prince. His Royal Highness Prince Albert, her Royal Highness the Duchess of Kent, several Lords of her Majesty's Most Honourable Privy Council, and the Ladies of her Majesty's Bedchamber, being present. This great and important news was immediately made known to the town by the firing of the Park and Tower Guns: and the Privy Council being assembled, as soon as possible thereupon, at the Council-Chamber, Whitehall, it was ordered, that a Form of Thanksgiving for the Queen's safe delivery of a Prince be prepared by his Grace the Archbishop of Canterbury, to be used in all Churches and Chapels throughout England and Wales, and the town of Berwick-upon-Tweed, on Sunday the 14th of November, or the Sunday after the respective minister shall receive the same. Her Majesty and the Infant Prince are, God be praised, both doing well. It is rather a remarkable circumstance that the Infant Prince of Wales should have been born on the morning of Lord Mayor's Day, only a few hours after Mr. Alderman Pirie had been sworn into office, and who is now in consequence entitled to a Baronetcy. It is however generally supposed, that that honour will be conferred both on the present Lord Mayor, and his predecessor Mr. Alderman Johnson. In the course of the day government messengers were despatched to Foreign Courts, with the important and gratifying intelligence of the Birth of a HEIR to the THRONE of the BRITISH REALMS. THE PRINCE OF WALES. The important event of yesterday produced a far greater degree of joyous excitement, than has been exhibited on any occasion within the memory of the oldest inhabitant of the metropolis. The 9th of November-Lord Mayor's Day, as it is familiarly termed, is ever held, amongst the citizens at least, as a day of jubilee. It was yesterday converted into one universal holiday by all classes and conditions of her Majesty's subjects. The auspicious event, although daily anticipated for the last fortnight, has come upon the country with a pleasurable sudden surprise; and those grateful emotions are considerably enhanced by the official announcement with which the Gazette Extraordinary concludes:-Her Majesty and the infant prince are, God be praised, both doing well. Although not generally known to the public until half-past eleven, there were certain indications in the immediate vicinity of Buckingham Palace which prepared those who take early exercise in St. James's Park for an event of the happy issue of which all felt more or less anxiety. During the whole of Monday her Majesty continued in full enjoyment of her usual health and spirits, and even, as stated in the Court Circular, took her accustomed walk in the palace gardens, accompanied only by her Royal Consort Prince Albert. There were no commands to the royal table on that evening, three covers only being laid, for the Queen, Prince Albert, and the Duchess of Kent, the latter illustrious personage having been a constant inmate of the palace since her Royal Highness's return from the Continent. Soon after dinner was served her Majesty complained of fatigue, and evinced such other symptoms as induced the Duchess of Kent to direct the immediate attendance of Sir James Clark and Dr. Locock in the ante-room.-The result of the conference was, that a special messenger was despatched at a quarter past 10 o'clock that night to the residence of Sir Robert Peel, in Whitehall Gardens, to apprise the Right Hon. Baronet that the accouchement of her Majesty might possibly take place before the next morning. On receipt of this intelligence, expresses were sent off to the Archbishop of Canterbury, the Bishop of London, and to the several Cabinet Ministers, in order that they might hold themselves in readiness should their presence be required during the night. Her Majesty, however, becoming more composed towards midnight, Sir James Clark and Dr. Locock judged that her Majesty's accouchement would not, in all probability, take place for several hours, and this opinion they communicated to Prince Albert, through the Lord Steward and the Lord Chamberlain. The medical officers, already named, however, deemed it right to send for Dr. Ferguson and Mr. Blagden, both of whom promptly attended the summons, and remained at the palace during the whole night. Between six and seven o'clock yesterday morning her Majesty's symptoms assuming the distinctive character peculiar to her critical situation, the several Cabinet Ministers and great officers of state were summoned by special messengers, whose departure from Pimlico Gate attracted, even at that early hour of the morning, the notice of the inhabitants of the neighbouring streets, and the intelligence soon spread to more remote quarters of the Westend. Sir Robert Peel arrived at the palace a few minutes before eight o'clock, and was received by the Lord Steward. The Right Hon. Baronet had an immediate interview of the medical gentlemen, and was assured that her Majesty was going on most favorably. The Archbishop of Canterbury, the Lord Chancellor, and the Bishop of London, arrived at 10 o'clock, and were speedily followed by the Duke of Wellington, the Duke of Buckingham, the Earl of Aberdeen, Sir James Graham, the Marquis of Exeter, and several other noblemen and commoners, members of the Cabinet or Privy Council. Her Majesty's accouchement took place (as stated in the Gazette Extraordinary,) at 12 minutes before 11 o'clock. In the room with her Majesty were Prince Albert, the Duchess of Kent, Dr. Locock, and the other medical attendants, Sir James Clark, Dr. Ferguson, and Mr. Blagden; and Mrs. Lilly, the nurse. The royal infant was immediately after birth taken into the room where the Cabinet Ministers and great officers of state were waiting, and the safety of her Majesty and that of the infant prince having been ascertained, the various persons summoned to witness the interesting event quitted the palace, with the exception of Sir Robert Peel, who remained until 12 o'clock, when the Right Hon. Baronet proceeded to Whitehall, to attend a Privy Council, specially summoned, at which the Gazette Extraordinary was ordered to be issued, announcing her Majesty's safe accouchement, and the birth of a prince. The council rose at two o'clock, and as the several ministers departed, the populace cheered loudly for "the Queen and Prince of Wales," the intelligence having by that time spread all over the western extremity of the metropolis. The Union Jack was hoisted from the steeples of the several parish churches, and the Park and Tower guns fired royal salutes, half minute time, at two o'clock, the ships and steamers below bridge displaying the gayest ensigns. This, together with the gorgeous pageant exhibited on the river, during the aquatic procession of the new Lord Mayor to and from Westminster. rendered "Old Father Thames" a most attractive feature in the combined festivities of the day. The Duke of Wellington looked in better health and in higher spirits than for many years past. After the Council broke up, his Grace, who went on horseback to the Palace, entered the park through the Horse Guards-gate, and meeting with the Earl of Liverpool, who was on foot, his Grace alighted, and giving his horse to the groom, took the Earl of Liverpool's arm, and walked across the park, followed by an immense concourse of persons, who cheered his Grace most vehemently all the way up Constitution-hill, and until he entered Apsley House. The Duke frequently acknowledged the congratulations of the multitude, and seemed pleased with the spontaneous fervour of their enthusiasm. Several parties were given in commemoration of the auspicious event. |