system from the western part of the northern crest of Inarya, which separates the waters of the Blue from those of the White Nile. I have now given the reasons which have occurred to me for concluding, with M. d'Abbadie, that the White Nile owes its sources to Inarya and Kaffa rather than to a region S. of the equinoctial line. They are of course speculative to the extent that our knowledge of the facts connected with the geography of the White Nile is uncertain. Various, indeed, have been the aspects which this geography has been made to assume. The course of the White Nile stretched by Pomponius Mela and Pliny through the medium of the Niger to the very back of the Atlas, was by Ptolemy brought within more eastern and definite limits. By D'Anville, after a lapse of 16 centuries, the limits assigned by Ptolemy were again curtailed. By Browne and by Rennell a yet more distinct course was proposed: and while the latest writers, including MM. Jomard, D'Avezac, and Ritter, who, with Africa, have made the Nile their peculiar study, discover their opinions to be shaken on the side of the W., they withhold a precise destination for them towards the E.; thinking, perhaps, with the caution which so many changes have suggested, that the question for its final solution awaits the fuller research which shall fill up the gap subsisting between the observations of M. d'Abbadie and the termination of the journey of M. d'Arnaud. [The following Note is inserted for the purpose of correcting some inaccuracies in the Papers by the Messrs. Gregory and Lieut. Helpman.-ED.] NOTE on the identity of certain rivers and hills on the west coast of Australia, between the parallels of 28° and 30° south latitude, which have been differently laid down by Capts. King, Grey, Stokes; Lieuts. Roe and Helpman, and the Messrs. Gregory. THE names and positions of Mount Fairfax and Wizard Hill of Capt. King, admit of no change. The names of Mount Fairfax, Wizard Hill, and Mount Hill were misapplied by Capt. Grey, who travelled over many hills of very similar appearance. Capt. Stokes and Lieut. Helpman have, by sea and land, cleared up this discrepancy very satisfactorily. Capt. Grey's names of the rivers admit of no change, as he was the discoverer of the whole of those that flow into the sea between the above atitudes; his distances, only, require correction. Capt. Grey was shipwrecked in Gantheaume Bay in April, 1839,-he and his party travelled thence to Perth by land, and he named every river which he crossed, and the description which he has given of each is so clear, that no difficulty exists in identifying the whole of them with the more recent accounts of Stokes, Roe, Helpman, and the Gregorys. Latitudes of Rivers in W. Australia. 75 The difficulties and privations which Capt. Grey had to overcome (which will be seen by all who read his very interesting narrative) prevented his obtaining latitudes at the various rivers which he crossed, so that the map of his route, which was laid down by himself, from Gantheaume Bay to Water Peak, is too long by 14' or 15', and thence to Perth is too short the same number of miles; all, however, that is required is a simple correction of distances. In proceeding towards the south from Gantheaume Bay, the first river, the latitude of which Lieut. Roe has very recently observed, is the Hutt, which he finds 7' farther north than laid down by Captain Grey by estimation. The next river is the Bowes, the latitude of which has been observed both by Capt. Stokes and Lieut. Roe, and found to be 11' or 12' farther north than it is laid down by Capt. Grey by estimation; thence the error slightly increases till about the Irwin river and Water Peak, where the error is the greatest, viz., 14 or 15'. The names and identity of the hills and rivers are as under The Messrs. Gregory have sought to identify the rivers and hills of Capt. Grey by latitude only, which in the present instance is untenable, as Capt. Grey had no observations for latitude. To show that the Arrowsmith of Grey is not to be mistaken with his Irwin, or with any other river on that part of the coast, in size, fertility, &c., it only remains to quote Capt. Grey's own description, which is this : : "The Arrowsmith is in a rich, flat, fertile valley; it is a very large river; its bed is 200 yards wide, and 50 to 60 feet deep; the trunks of immense trees, washed down in the floods, lie scattered on the ground about its banks; no water in the river where we crossed, without digging a few inches in the sand-large pools immediately above and below us. It drains extensive valleys running north and south between the interior range and the sandy limestone range parallel to the coastit probably comes through the range; its mean course from the interior appeared to be from E.S.E.; many natives came to drink at it. From a range 1 mile south of the river is a fine view of the rich valleys which this important river drains." The misapplication by Messrs. Gregory of the name of Irwin to this river, is the cause of all the other misapplications of names to the northward, as far as the Bowes J. A. VIII.-Depression of the Dead Sea and of the Jordan Valley. By Dr. EDWARD ROBINSON, of New York. [Read November 22, 1847.] THE deep depression of the Dead Sea below the Mediterranean appears never to have been suspected, down to the time of its actual discovery; and no experiments were ever made to ascertain the true level until March, 1837. At that time Messrs. Moore and Beek, in attempting to survey the Dead Sea, were led to examine the question of its comparative elevation by means of some experiments on the boiling point of water. They were greatly surprised at the results, which indicated a depression of about 500 English feet.* A month later, in April of the same year, Schubert's observations with the barometer gave the depression at about 600 (598-5) Paris feet.† In the following year, 1838, two barometrical measurements were taken. That of Bertou, a French traveller, gave to the sea a depression of 406 metres, or 1332 feet English. The other, by Russegger, a German, indicated 1319 Paris feet, equal to 1400 feet English.§ The results of similar barometrical measurements for the level of the lakes of Tiberias and the Hûleh, by Schubert and Bertou, exhibited a still greater diversity. The former made the depression of the first lake to be 535 Paris feet, only 65 feet less than his estimate of that of the Dead Sea; yet he made the Jordan at the bridge, near the Hûleh, to be 350 Paris feet above the Mediterranean-a difference of 880 French feet in the distance of about 5 miles! || Bertou, on the other hand, gave the depression of the Lake of Tiberias at 230-3 metres, or 756 feet English, being 577 feet less than his estimate of that of the Dead Sea; while that of the Hûleh, according to him, is about 18 feet; implying a fall of 737 feet in the same 5 miles Such was the state of the question when the 'Biblical Researches in Palestine' were published, in 1841. The preceding results were so greatly at variance as to be utterly inconsistent with each other; and seemed in some respects to be equally so * Journ. of R. Geog. Soc. 1837, p. 456; Ib. 1839, p. lxiv. + Schubert's Reise, iii. p. 87. The proportion of the French foot to the English is as 16 to 15. Bulletin de la Soc. de Géog., Oct. 1839, p. 161. § Berghaus, Annalen, Feb. u. März, 1839, p. 432. Schubert's Reise, iii. pp. 231, 259. The distance is here reckoned from the bridge to the alluvial tract below. Bulletin de la Soc. de Géog., Oct. 1839, pp. 161, 146, 145. VOL. XVIII. H with the rapidity of the stream and the nature of the country. I therefore ventured in that work to suggest that "so great is the uncertainty of all such partial measurements and observations (as evinced in the like case of the Caspian Sea), that the question can never be solved with exactness until the intervening country shall have been surveyed and the relative level of the two seas trigonometrically ascertained."* Such a measurement was afterwards understood to have been accomplished during that very year, 1841, by Lieut. Symonds, of the British Royal Engineers. A very slight notice of his results was laid before the Royal Geographical Society of London, at their meeting, January 24th, 1842.† One of the earliest accounts was published in this country in July, 1842, in the following extract of a letter from the Rev. Eli Smith to the writer, dated at Beirût, February 7th, 1842:‡ I am happy to inform you that the altitude [depression] of the Dead Sea has been ascertained by exact trigonometrical measurement. Lieut. Symonds, of the British Royal Engineers, surveyed the greater part of Judea and the region around the plain of Esdraelon; and, while doing it, carried a double line of altitudes from the sea at Yâfa to Neby Samivîl, and thence another double line to the Dead Sea. He found the latter to be 1337 feet below the Mediterranean. By similar observations he ascertained the Lake of Tiberias to be 84 feet below the Mediterranean. These numbers he gave me himself, and at the same time showed me his calculations." The same statement of the ascertained depression of the two lakes (1337 feet and 84 feet) was communicated by M. von Wildenbruch, the Prussian Consul-General at Beirût, to the Royal Geographical Society of Berlin, during the same year, and published by them in their Monthly Report. § In May of the same year, 1842, the President of the Royal Geographical Society of London, William R. Hamilton, Esq., in his annual address delivered before the Society, and afterwards published in their Journal, || entered into some details respecting the manner in which the survey had been performed, to which we shall have occasion hereafter to recur. He also stated the results at 1311.9 English feet for the depression of the Dead Sea, and 328 feet for that of the Lake of Tiberias. The same distinguished gentleman, in his annual address of the following year (1843), and also in his address on delivering one of the gold medals of the Society to Lieut. Symonds, gives *Bibl. Res. ii. p. 222. Lond. Athenæum, Jan. 29, 1842. Bibl. Repository, June, 1842; also in Biblioth. Sac., Feb. 1843, p. 16. |