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seems to be the first time that the designation of "Nyanza" has been applied, without any qualification, to the separate Lake Tanganyika. I perceive that "F.R.G.S." associates Captain Burton with this "Nyanza;" but such a name was never given to it by its discoverer, neither is it generally known by any other designation than that of "Lake Tanganyika;" whether or not it should properly be called the "Lake of Tanganyika" is of no moment.

I come now to the consideration of Dr. Livingstone's claim to the discovery of the sources of the Nile, which will be best given in his own words: "I think that I may safely assert that the chief sources of the Nile rise between 10° and 12° south latitude, or nearly in the position attributed to them by Ptolemy, whose river Rhaptus is probably the Rovuma." On this "F.R.G.S." acutely remarks: "Here two different problems are attempted to be solved at once—the one touching the sources of the White Nile, and the other those of Ptolemy's Nile;" in which remark he is no doubt substantially correct. Into the question of Ptolemy's sources of the Nile, on which subject "F.R.G.S." and I differ widely, I need not now enter; what I have here to do with, is the question of the chief sources of the Nile. And in order to decide whether Dr. Livingstone has really discovered these sources, it is, in the first instance, requisite to define the limits of the basin of the Nile, so as absolutely to determine where the sources of the river can or can not be situated. As those limits were approximatively determined in a paper "On the Nile and its Tributaries," communicated to the Royal Geographical Society in 1846, and published in the seventeenth volume of the Society's Journal, I cannot do better than reproduce the portion of it relating to this particular subject.

After describing the physical character of the table-land of Eastern Africa, of which Abyssinia forms the northern extremity, and its rivers as far as they were then known,—on which subject I need not dilate, as the substantial correctness of my views is now established,—I proceeded in these terms:—

"All the streams of the plateau or western counter-slope of the Abyssinian chain are affluents of the Nile, and their easternmost branches take their rise at the extreme eastern edge of the table-land, which is the limit of the basin of the Nile, and the watershed between its tributaries and the rivers flowing E. and S.E. towards the Indian Ocean. On the seaward side of this watershed, the declivity being much more abrupt and its extent much more limited, the rivers must necessarily be of secondary importance. Thus, proceeding from the N., we do not meet with a stream deserving of name until we come to the Hawash; and even that river is, near Aussa, lost in Lake Abhebbad before reaching the ocean. The river Haines of Lieutenant Christopher, which is the next in succession, appears, in like manner, not to have sufficient power to reach the sea, at least not at all times of the year. Further to the S. we find the river Gowin (i.e. Wabbi-Giweyna) or Jubb, possessing a substantive character as an ocean stream; but this river, during the dry season, has at its mouth a depth of only two feet. At a short distance to the S. of the equator is the Ozay, which river, though said to be of great extent, has very little water at the entrance. Further S. the same law appears to prevail, as is exemplified in the Lufiji or Kwavi (Quavi), the Livuma [Rovuma] and the Kwama (Quama) or Kilimane (Quilimane), which rivers rise on the eastern edge of the elevated plain in which Lake Zambre or N'yassi is situate, and flow into the Indian Ocean. Here, however, the southern extremity of the basins of the Nile having been passed, the larger streams of the counter-slope no longer join that river, but take their course westwards into the Atlantic, belonging in fact to a distinct hydrographical basin."

What I thus wrote three-and-twenty years ago requires now but little modification. The erroneous identification of Lake Zambre with N'yassi was simply adopted from Mr. Cooley's learned and valuable paper in the fifteenth volume of the Society's Journal, which was then our only authority on the subject. I also followed him in his alteration of the spelling of the name "Zambre," which in my paper was printed "Zambeze," with the explanatory note, "This name is usually printed Zembere, Zembre, or Zambre. It is the Lake Maravi of the maps." Though even this was wrong; for Nyassa is properly Lake Maravi, and Tanganyika is the Great Lake, or Zambre. The blending of the two together by Delille and D'Anville was the primary cause of the long-existing misapprehension of the subject.

In my paper from which the foregoing extract is taken, when speaking of the lakes and swamps of the Upper Nile as then known, I added in a note, "May not Lake Zambre ('Zambeze'), or Nyassi, be the continuation of this series of lakes? In this case it would be simply the upper course of the Nile."

Acting on this suggestion, Professor Berghaus, in 1850, laid down Mr. Cooley's "Nyassi, or the Sea" as the head of the Nile; but, as I pointed out to him, he had under any circumstances carried the river too far south, because the Chevalier Bunsen and I had in the jirevious year come to the positive conclusion, on the reports of the Church missionaries at Mombas, that Zambre (now Tanganyika) and Nyassa were two separate lakes, a conclusion which every fresh discovery only tended to confirm.

The Cuama and Quilimane mentioned by me were all that we then well knew of the Zambesi, the great western extent of which river only became revealed to us through the former explorations of Livingstone. He thus absolutely closed the basin of the Nile in that direction though the fact of his having done so was not then demonstrable. When he wrote to Lord Clarendon in February 1867, as he says in his present letter, he "had the impression that he was then on the watershed between the Zambesi and either the Congo or the Nile." His present determination of the want of connection between the Chambeze and the Zambesi, and of the western and northwestern course of the former river, has proved the soundness of his impression of February 1867.

The question is therefore now narrowed to this:—Do the united streams of the Chambeze and the Lufira, under the name first of Luapula, and then of Lualaba, flow into the Nile or into the Congo? I am of opinion that they join the former river, and that the explorations of Dr. Livingstone have established the correctness of the views I have long entertained, and especially those enunciated in the Athenaeum, No. 1,969, of July 22, 1865, on the first announcement by Sir Samuel Baker of his (unconscious) discovery of the main stream of the Nile under the name of "Albert Nyanza," and consequently I believe we are at length enabled to strip the veil from the Nile Mystery.

Bekesbourne, December 1

Under the above head, in a note which appeared in Nature of the 16th Dec. p. 192, Mr. Gwyn Jeffreys "calls the attention of physiologists to the fact that plant-life appears to be absent in the ocean, with the exception of a comparatively narrow fringe, known as the littoral and laminarian zones, which girds the coasts, and of the 'Sargasso' tract in the Gulf of Mexico." He then proceeds to say that, "during the recent exploration in H.M.S. Porcupine of part of the North Atlantic, he could not detect the slightest trace of any vegetable organism at a greater depth than fifteen fathoms. Animal organisms of all kinds and sizes, living and dead, were everywhere abundant, from the surface to the bottom... some of them being zoophagous, others sarcophagous, none phytophagous." And, lastly, after asking "whence do oceanic animals get that supply of carbon which terrestrial and littoral or shallow-water animals derive, directly or indirectly, from plants?" and "can any class of marine animals assimilate the carbon contained in the sea, as plants assimilate the carbon contained in the air?" Mr. Jeffreys sums up his conclusions on the subject in the following words:—"At all events, the usual theory, that all animals ultimately depend for their nourishment on vegetable life, seems not to be applicable to the main ocean, and consequently not to one-half (sic) of the earth's surface."

As Mr. Jeffreys has been constituted an authority on deep-sea exploration, and now claims the view above cited as original, I must be permitted to point out that he has either forgotten what, at one period, he professed to have read and acquiesced in, in one of my writings; or that, for some unaccountable reason, he now repudiates both my opinions and those which were once his own. As the entire absence of plant-life, even in its primitive phases, in the deeper abysses of the ocean, and the process whereby the nutrition of the lowest animal forms is secured in the absence of even the rudimentary digestive apparatus which is observable amongst the higher Rhizopods, were fully discussed by me in my "Notes on the Presence of Animal Life at great depths in the Ocean" (p. 27), published in 1860; in my work on "The North Sea-bed" (pp. 131–2), published in 1862; in a note which appeared in the Annals and Magazine of Natural History for August 1863 (p. 166) and more recently in two papers contributed by me to the Monthly Journal of Microscopical