March 13. S. Lat. 33° 41', E. Long. 29° 16'. Wind and Weather. heavy swell. At night, when the lead was heaved, no bottom was discovered at 95 fathoms. According to our reckoning we were off Algoa Bay, and at 8h P, M, at the edge of the bank, which the temperature of the water seemed to indicate. Between 8 and 9 o'clock we steered more to the south, and consequently came into deeper water, which was also indicated by the rise of the thermometer. The night was squally and the wind contrary. In the evening, and during the night, there was a good deal of lightning, but no thunder was heard. Had the atmosphere been clear, we expected to have seen land in the evening. March 14. S. Lat. D.R. 34° 34′, E. Long, 27° 20′, The night was cloudy and the wind moderate. March 15. S. Lat. 35° 41', E. Long. 24° 13′, The night was unpleasant, with some rain. The current, during the last two days, has been strong, and has set about S.SW. Though the thermometer is not below 68°, we feel so disagreeably cold that I am obliged to write wrapped up in a boat cloak, and yet do not feel warm. The remarkable change in the temperature of the sea between 6 and 10 P. M. seems to show that we are on the bank of Lagullas, and confirms the accuracy of our reckoning. It is in situations of this kind that the thermometer promises to be particularly useful in navigation. It will, no doubt, indicate a bank, even when the bottom is too deep to be ascertained by sounding, and it is far from improbable that it may become an excellent substitute for the lead, the use of which is attended with so many inconveniences at sea. If the temperature of the water, for instance, on different parts of the bank, and at different seasons, were once well ascertained, a ship on her voyage to or from India, and not intending to touch at the Cape, would not require to use the lead when supposed to be on the bank of the Lagullas, but might ascertain the fact without delay or trouble, by the thermometer, and make a fresh departure from the bank with confidence. The sea was very luminous, and the swell heavy. Many porpoises and many birds were seen in the course of the after noon. March 16, S. Lat. 35° 27', E. Long. 20° 20. The night was fine, the air very cold, and the horizon hazy, 4.5 Do. do. do. At 6h P, M. the water was greenish, and the Lagullas about 10 miles off. At 12h P. M. the lead was thrown out, and the bottom found at about 70 fathoms. The current has carried us a good deal to the SW. and I suspect it must have acted most powerfully between 12 and 6 P. M. We are now steering for Point Lagullas. Many albatrosses and several gannets were seen this morning. The appearance of the latter bird is considered as a proof of being on the bank. March 17. S. Lat. E. Long. Air. Water. Hygr. 60° 14h A. M. 63°.5 2o 6 65 60 2.5 8 63 52.5 2 10 65 51 4 12 72 54 9 Wind and Weather. E. moderate, clear overhead. SE. do. do. Cape of Good Hope about 3 miles off. Do. moderate, about 3 miles from land. Do. about 3 miles from Chapman's Point. About 5h P. M. the ship anchored in Table Bay, about 1 mile from land, and in about seven fathoms of water. ART. X.Account of a Map of Upper Laos, or the Territory of the Lowa Shan. By FRANCIS HAMILTON, M. D. F. R. S. and F. A. S. London and Edinburgh. Communicated by the Author. THE accompanying map (PLATE II.) has been reduced from the original drawing given to me by the slave of the heir-apparent of the kingdom of Ava, who has been mentioned, (Phil. Journ. ii. 89.) It represents the territory, which, in 1795, was in the possession of the Prince of Upper Laos, or of the Lowa Shan, but by no means the whole territory which at times has belonged to that people or its princes, and which is represented in the general map by the same person, (Phil. Journ. .) as I have endeavoured to show in treating of Zænmæ, (Phil. Journ. x. 65.) I then stated, that probably 16,000 square British miles, which at one time had belonged to Upper Laos, had been separated from it; and this alienated portion comprehended all the country on both sides of the Mækhaun, Mækhoup, and Mæpræn rivers. Nothing, therefore, remained then to the Prince of Upper Laos, but the territory on the Mæghue, and from thence to the Saluæn river. This accordingly forms the western boundary of Upper Laos, although Mr. Arrowsmith has brought it through the centre of the country. The principality of Upper Laos, therefore, in 1795, extended from about Lat. 24° 05′ N. where the Saluæn leaves China, to about 21° 50′ N. where I suppose the Maghue joins the Mæpræn, or principal branch of the river of Siam. In Arrowsmith's map, this is represented by a small branch joining the Maygue (as he writes it) on the east, and the name Maygue is extended down to Siam, in place of ending at the junction, as it ought to have done. The junction, besides, he brings too far south; as from the maps of Zænmæ, as well as the accompanying one, it is evidently at or near the frontier; the Maghue not appearing in the maps of Zænmæ, nor the Mæpræn in that of the Lowa Shan. The principality, in its reduced state, extends about 135 geographical milés (60 to a degree) from north to south; and at the capital may be 75 miles wide, but towards the north it is much contracted, and its area does not probably exceed 3000 square British miles, or one-third of its original extent. Such a great diminution of territory was probably owing to the Lowa Shan having given provisions to the Chinese army, in the dispute with the Mranmas about the mines at Boduæn, and to their having refused to pay tribute in the reign of Zhænbrushæn. ་ The northern boundary of Upper Laos is formed by the territory of the Independent, or Wild Lowas, probably the Lolos of the Chinese; and this tribe in all probability occupies all the adjacent parts of the Chinese empire, which extends also along the eastern boundary, until we reach those parts of Laos which have been given to Zænmæ. The southern boundary is Zænmæ, and the western is the Saluæn. Kiaintoun, the present capital, is about 30 or 40 miles from the southern end of the territory; and in place of being on the Saluæn, as represented by Mr. Arrowsmith, is about half-way between the eastern and western boundaries. In the sacred dialect, it is called Kemalatain. Leng, the former capital of the principality, was situated in the territory which has been alienated. There still, however, remain, besides the capital, twelve governments or cities marked in the map by squares; while the places marked by circles are Ruas or dependent towns. All these governments seem placed near the frontier, which is very mountainous; but there would appear to be an extensive plain around the capital, and towards the Mæghue on the north-east, and on the Mrænlo towards the north and west. This last small river runs through the centre of the country; but no connexion between it and any other is mentioned: it seems to rise in one cluster of hills, and to terminate in another. There are, in warm climates especially, many similar rivers; but from such a rude draught, it would not be safe to conclude that the Mræulo is lost either by evaporation, which is not likely in a country so well supplied with rain, or by sinking into a cavern. It may very possibly be a branch of the Saluæn. Mr. Arrowsmith, indeed, seems to have confounded it with that river, and therefore brought the Saluan through the middle of Upper Laos, as I have already mentioned. Even among the northern mountains an extensive flat of rice ground is laid down between Læhlu and M. Lue; so that, on the whole, the country is probably fertile, which will account for so many towns in so small an extent. With respect to the scale, we have seven days' journey for the distance between the extreme towns; and allowing each of these to be 10 miles from the frontier, and the whole length to be 135 geographical miles, we shall have about 16 of these miles direct distance for a day's journey on lines of a considerable length. This, however, is probably too much, and could not be applied to the lateral distances. ART. XI.-Notice of Experiments on a Variation in the Rates of Chronometers, with the Density of the Medium in which they are placed. By GEORGE HARVEY, Esq. F.R.S.E. Plymouth. In a serics of interesting experiments on chronometers, Mr. Harvey has lately been led to the important discovery, that the |