ducing annually a perfected survey of several millions of acres, the success of General Colby must appear most complete and most wonderful. To secure the undisturbed and uniform movement of so complicated a machine, it was necessary to form an equally perfect office establishment, and this was done in the Survey Office at Mountjoy, in the Phoenix-park, Dublin, the arrangements of which (including those of the Engraving Establishment) were carried by Colonel Colby to the utmost perfection, under the personal superintendence of Captain (now Major) Larcom; and the final excellence of that establishment may be studied in that of the Map Office, at Southampton, which is, in fact, no more than its reflected image. Having thus grasped in his mind the requirements of the survey in its mere practical character, Major Colby felt, as a man of science, that so great a national work ought not to fall short of the excellence of continental works in any of its operations, and that some scientific advance should be made in the mode of measuring its first base line. With the beautiful differential rods of the French philosophers he was not perfectly satisfied, nor would he adopt the mode, proposed by the late Captain Drummond, of measuring with broad bands, or ribands formed of mica; but feeling a preference to the principle of compensation, he gave it a new application, by inventing those admirable compensation bars, which stamped on the Irish Survey a character of novelty, and inseparably connected the name of their author with the history of geodetic science. It is not to be supposed that so great a work could have been carried on successfully without the co-operation of many most able and zealous officers; but when it is considered that their efforts were all directed and regulated on the system planned by General Colby, it must be felt that the Irish Survey, in its beginning and in its end, was eminently his own work. Were this narrative now to end, it would still fail to do full justice to the comprehensive mind of General Colby. When asked by Sir Henry Hardinge, then Clerk of the Ordnance, to state the advantages of a survey, he did not content himself by describing its ordinary usefulness, but nobly represented it as the proper basis for geological, statistical, and antiquarian surveys. These views were acted upon at the commencement of the survey, and to General Colby must therefore be ascribed the merit of having first originated a national geological survey, and connected with it a museum of economic geology. He did indeed more, as his scheme comprised natural history and antiquities, and the museum at Mountjoy contained not only a most valuable collection of minerals and fossils, but also an equally important one of the plants and animals of Ireland. It is true that subsequently General Colby shrank from that responsibility which at first had seemed so light to him; that the Ordnance abandoned these collateral works; and that the geological survey passed into the hands of the Woods and Forests, there to acquire a full development, under the able guidance of that prince of geologists, Sir Henry de la Beche; but let us recognise in the Memoir of Londonderry, published in 1835, in the Report of the Geology of Londonderry and Tyrone, published in 1843, and in the Statistical Papers of the Census Commission, drawn up by Major Larcom, and founded on the Statistical Section of the Memoir of Londonderry, to which that officer had so largely contributed, proofs that the scheme proposed by General Colby in 1824 would, if it had been followed up, have led to the publication of a national work, which, both in the grandeur of its conception and the importance of its results, would have been unrivalled by any such national work in Europe. No one can now regret that the geological survey should have been placed in the hands of Sir Henry de la Beche, Professors Phillips, Forbes, Ramsay, Lyon, Playfair, Percy, Jukes, Hooker, and other most able men; but at the same time let us do justice to him who first officially suggested so noble an undertaking.-Liverpool Paper. NAUTICAL NOTICES. PORT OF LIVERPOOL.-C 1 Red Can will be altered to C 2 Red, and moved 200 fathoms E.S.E. into 32 feet at low water.-Formby Lightship bearing N.N.W. W. 14 miles; Crosby Lightship S.E. E. nearly a mile. A Red Can Buoy, marked C 1, will be placed off the S.E. Spit of the West Middle in 18 feet at low water.-Formby Lightship bearing N.6W. W. † of a mile; C 2 Red Can S.E. S. § of a mile V 4 Red Can will be moved 430 fathoms N.N.W. W. into 20 feet at low water. Formby Lightship bearing N. E.bN. 130 fathoms; C 1 Red Can S. E.BS. S. of a mile. V 3 Red Can, with Perch, will be moved 150 fathoms N.W.bW. into 12 feet at low water.-Formby Lightship bearing E. S. 400 fathoms; V 4 Red Can S.E.BE. E. of a mile. 1 V 3 Black Nun will be moved 300 fathoms W. S. into 14 feet at low water. Formby Lightship bearing E.S.E. † E. & of a mile; V 3 Red Can, with Perch, S. E.bE. E. of a mile. V 2 Black Nun will be moved 100 fathoms W.bN. into 12 feet at low water. Formby Lightship bearing E.bS. S. 1 of a mile; V 2 Red Can S.bE. E. 300 fathoms. VI Black Nun will be moved 120 fathoms N. W. W. into 12 feet at low water.-V 2 Blak Nun bearing S.E.bE. E. of a mile; V 1 Red Can S. E. of a mile. N 1 Black Nun will be removed and discontinued. HFFY White and Black Nun, striped vertically, will be moved 200 fathoms N.E. E. into 14 feet at low water, and the lettering altered to ZFY, in consequence of the name having been altered to Zebra Channel.-Formby Lightship bearing S.S.E. E. nearly two miles; Z White and Black Nun, striped vertically, S.E. 1 mile. HF 1 White and Black Nun, striped horizontally, will be moved 170 fathoms N. E. into 7 feet at low water, and the lettering altered to Z 1.-Formby Lightship bearing S.E.bS., a little southerly, 1 mile; ZFY White and Black Nuu, striped vertically, N.N.W. W. of a mile. The lettering of HF 1 White and Black Nun, striped vertically, will be altered to Z 1. K 1 Black Nun will be moved 320 fathoms S.E. into 16 feet at low water, -N.W. Lightship bearing W. N, 24 miles; Bell Beacon N.bE. 2 miles. R 2 Red Can will be moved 100 fathoms N.bW. W. into feet at low water.-Leasowe Lighthouse bearing S. W. of a mile; Leasowe Castle S.E. S. 1 mile. The Numbers of C 3 and 4 Red Can will be altered io 4 and 5. SARDINIA.-FIXED Light at Port TORRES, GULF OF ASINARA.-The Sardinian Government has given notice that on the 1st of last month a Fixed Light was established on the extremity of the Eastern mole of Port Torres in the Gulf of Asinara. The Lighthouse stands in latitude 40° 50′ 13′′ N. and longitude 8° 24′ 25′′ E. of Greenwich; and the light being 49 feet above the sea level is visible at the distance of 12 miles. SOUTH AUSTRALIA.-Revolving Light On the East End of Kangaroo ISLAND.-Mariners are hereby informed, that on the 10th of last January, a Revolving Light was established on Cape Willoughby, the eastern extremity of Kangaroo Island, in 35° 49′ 20 South, and 138° 12′ 30′′ East of Greenwich. The Light appears at intervals of a minute and a half, and being elevated 241 feet above the level of the sea, may be seen at the distancs of 24 miles, from the deck of a moderate sized vessel, and on all bearings, from N.E.ьE. E. round to S.bE. E. SOUTH AMERICA.-REVOLVING LIGHT AT MONTE VIDEO.-Her Majesty's Government has received official information, that the new lighthouse on the summit of Monte Video was completed and lighted on the 16th of July last; that the light is on the revolving principle, and is visible for an interval of thirty seconds once in every three minutes, and that it is 486 feet above the level of the sea, and is therefore visible from a distance of about ten leagues. FLOATING LIGHT IN THE LESOE CHANNEL, (KATTEGAT.)-Her Majesty's Government has been officially informed, that it is the intention of the Danish Government to place a light vessel in the course of this month. in the Læsoe Channel of the Kattegat. The vessel is to be painted red with a white cross, carrying two masts, schooner rigged, and will be moored in ten fathoms water in a direction E.bS. (true) three cables' length from the middle buoy (with two brooms on it) on the eastern edge of the Dvale Ground. The light will be fixed and appear at an elevation of 30 feet above the level of the sea, being visible in all directions from it at the distance of about 3 leagues. The position of the vessel will be lat. 57° 123 North, long. 10° 41′ East. from Greenwich. NOTICE TO MARINERS.-Information has been received at the Department of State (Washington), from B. Everett Smith, Esq., U. S. Consul at Grand Turk (Turk's Island), of the erection at that place of a new lighthouse, to be completed and in operation by the 1st of October next.-Shipping and Mercantile Gazette, Sept. 8, 1852. THE HORSBURGH Light. [We have already recorded the establishment of this Light, but not having before seen so complete an account of it as in the following paper, we are induced to preserve this also.-ED.] The Lighthouse was designed in 1848, and the plans sent home for submission to the Court of Directors. It was after careful consideration of the effects of the waves during the North East monsoon that I advised the Government that it should be entirely constructed of granite externally. I found that brick wasted rapidly under the effects of the spray. The estimate for the building amounted to 15,928.04 dollars Span sh, and the lantern machinery and apparatus to £1,500 sterling; the work was sanctioned under the impression of the honourable court that it would cost double the amount. Orders came out in December, 1849, to commence operations, but these were necessarily delayed until the monsoon changed in March. A party landed on the 31st of the month, but were got off again with great difficulty, as the monsoon came down again, and drove the gunboat in attendance to Pt. Romania. A perma nent landing was not effected till the 11th of April, when I landed with 46 men and commenced operations. The works were put a stop to on the 21st October, by a heavy swell coming in from North East, and we did not land again till April following, for the purpose of building. I came close to the rock several times during the North East monsoon, but was never able to land till the beginning of March. 688 NAUTICAL NOTICES. Pedra Branca is a rock 150 feet long, and 100 broad, at high water spring tides; rugged in aspect, and intersected by fissures. The highest point is 24 feet above high water spring tides, and the Lighthouse is built on the only stable rock that belongs to the group; all the rest are mere boulders, being intersected by fissures underneath. The rock on which the Lighthouse stands could only afford room for a house of 22 feet in diameter; the base at the level of the first entire course is consequently confined to that dimension. The walls at the first entire course are 7 feet thick, and at the 59th course 2); the interior of the walls are bricks, being faced with square granite in one foot courses, alternating 12 and 14 inches in breadth, every third stone being a header reaching through entire thickness of the wall. The house contains rooms 11 feet diameter for the light-keepers, 3 in number, 1 visitors' room, 1 store room for provisions, store room for light room articles, and 1 vault for water; each room is vaulted with bricks set in cement. Rings of iron two inches square are set in the walls at the level of each vault. The light-room on the top of the The doors and windows are of building is entirely constructed of granite. ma bow; all exposed metals are either of brass or copper. It is produced by a The light is 95 feet above high water spring tides. combination of reflectore and refractors, the invention of Mr. Thomas Stevenson, of Edinburgh. There are 3 planes of reflectors, and 3 in each group; each group attain their brightest state once every minute, and are seen as a star of the first magnitude, when they sink under the horizon, as seen from a ship's deck at the distance of 15 nautical miles. From the mast-head the light might be seen 22 miles The glass frames are triangular, by which great lightness is gained, and are of cast iron; the dome is of copper; the machinery is contained in a cast iron case, and the wheel work is of gun metal. Though the light only proceeds from 3 reflectors, yet by the new combination of refractors, they are equal to the power of 5 of the common kind. The lantern, apparatus, and lightning conductor were designed by Mr. Alan Stevenson, the engineer to the northern Lighthouse board, well known as the engineer of the Skerryvore Lighthouse, situated on the west coast of Scotland, in a position of more difficult access than either the Eddystone or Bell Rock. The Horsburgh Lighthouse is 10 English miles from the nearest point of land, which is Pt. Romania, and 40 English miles from Singapore, where provisions alone can be procured, a barren coast intervening. The stone work was completed in June, 1851, and the light ready to show on the 20th September, 22 days after the lantern and apparatus was landed on the rock. Thus the work from commencing till finishing took only 18 months. There were 40, 50, and even 60 men employed at the rock during the working season, most of whom were Chinese. The other natives were Malays, Klings, and Bengalese, and one or two Javanese, Boyans, &c., and natives of other As there were three classes of Chinese, viz., Canton, parts of the archipelago. Aya, and Kay, there was no less than eleven languages spoken; most could speak no Malay, so that they had to be directed by signs. It is not surprising that we found great difficulty at first in inducing men to engage to come; when brought out to the rock, they used to rush to the boats, and cling to the seats till driven back by main force. One of the two gunboats mutinied, and the commander and whole crew refused to remain, principally owing to the risks This was at a time we were dependent on them for which they said they ran. water, and then had only three days supply, when there were 40 men on the rock. They were of course all discharged, and the gunboats' crews have behaved exceedingly well ever since. The cost will be within 1,000 dollars Spanish of the original estimates. The accounts are not yet made up, but the cost of the building stands nearly 16,500 dollars Spanish, and the lantern apparatus, &c., £1,370 sterling; additions to the original designs were sanctioned to the amount of about 1,000 i dollars Spanish. I believe this will he satisfactory to the Government, as a much higher outlay was anticipated. Singapore, 30th September, 1851. J. T. THOMSON, Government Surveyor. PHAROS EGO. Cui nomen præbuit In maribus Indo-Sinicis præter omnes præclarus A.D. MDCCCLI. W. J. BUTTERWORTH, C.B. Prov. Malacc. Præt. J. T. THOMSON, Architect. A.D. MDCCCLI. The Horsburgh Lighthouse Is raised by the enterprise of British merchants So long as it shall last COLONEL W. J. BUITERWORTH, C.B. Hong Kong Register, Nov. 25. WALTER ISLAND AND ROCKS IN THE PACIFIC.-Captain Drescher, "of the Hamburg barque Walter, from China, at San Francisco, gives the following particulars of the discovery of a new island and rocks in the Pacific. On the the 18th August, 1852, at noon, by observation, was lat. 32° 9, long. 139° 18′ East of Greenwich, saw an island N.E.bE.; we steered East 26′ until 5 P.M., whence we took the position of the island, about 20 miles distant, which was lat. 32° 39′, long. 139° 49′ East of Greenwich. 5.30 P.M. saw from masthead, S.E.bS., several rocks, lying close together, rising 10 to 15 feet from the water; they were scarcely four miles distant from us, and a heavy surf was rolling over them. Neither island or 1ocks are marked on the newest charts in their above positions.—Shipping and Mercantile Gazette, Nov. 23rd, 1852. [They appear to be among the Japan Islands in the Pacific, of which we as - yet know very little.-ED N. M.] STEAM NAVIGATION BETWEEN BAHIA, MACEIO, AND CARAVELLAS.—AN exclusive twenty years' privilege has been granted by the Brazilian government to Senhor Pedrona de Albuquerque, a wealthy proprietor of Bahia, for establishing steam navigation between that city and Maceio, by a northern line, and Caravellas by a southern line of steam-packets. A privilege for thirty years has also been conceded to Senhor Irenen Evagalista de Soura for the navigation of the river Amazon by steamers. In one day the 3,000 shares of this company, representing a capital of 1,200 contos, were subscribed for. NO. 12.-VOL. XXI. 4 T |