22. New Alkali.

We understand that Professor Berzelius has sent an account to this country of a new alkali having been discovered in Sweden.

The discoverer has also ascertained the existence of a new inflammable body.

23.

A work containing coloured figures of the six known spe、 cies of Strelitzia is preparing for publication from the admirable drawings by Mr. Francis Bauer. The work is to consist of sixteen plates in large folio, and they are coloured with the greatest care, and as nearly as possible resemble the original designs which have been so long admired in the splendid collection of Mr. Bauer's Drawings in the possession of Sir Joseph Banks. The work is to consist of four numbers, each containing four plates. We have seen three of the plates which are already executed, and have no hesitation in pronouncing them superior to any coloured figures of flowers in any published work.

Some omissions in the List of Wines given in the last Number will be found rectified in the following Table, exhibiting the average Quantity of Spirit (alcohol) in different Kinds of Wine. By W. T. BRANDE, Esq. Sec. R.S. &c.

ART. XVII. Narrative of an Expedition to explore the River Zaire, usually called the Congo, in 1816, under the direction of Captain Tuckey, published by permission of the Lords Commissioners of the Admiralty.-Murray,

1918.

OUR knowledge of the continent of Africa has in nowise kept pace with our increased and increasing knowledge of the other parts of the globe, and although we may have obtained more precise information respecting the outline of its coasts than the ancients, it may be doubted whether their knowledge of the interior did not surpass ours. The object of the voyage, the narrative of which has been just published, was planned and undertaken with the view, and in the hope,

of solving the great geographical problem respecting the Niger, which has for a considerable time excited the attention of the scientific world. We are indebted for the greater part of what is known respecting the interior regions of Africa to the Arabian writers of the middle ages, and the information of Arabian travellers of our own times; after these the Portuguese were the first Europeans who penetrated beyond the coast into the interior, and they probably collected much information; but it was the policy of that nation to conceal what they discovered till it has been lost even to themselves. The Portuguese followed the Arabian writers in describing the course of the Niger as flowing from east to west, which Herodotus had learned nearly 20 centuries before to flow in a contrary direction, but this question was at last completely set at rest by Mr. Park; but another question respecting this great river remains to be solved,-where is its termination? As ancient authorites had pointed out the true direction of the stream, it was but fair to allow them credit for a knowledge of its termination. In the examination of this part of the question, by Major Rennell, the authorities of the Arabian writers are weighed and compared with the geography of Ptolemy; and after a close and accurate investigation of the various statements of ancient and modern authorities, and a train of reasoning clear and argumentative, the result of the inquiry appears to be, that the Niger loses itself in the extensive lakes or swamps of Wangara; an hypothesis, which was supposed to have the merit of falling in pretty nearly with the termination of that river, as assigned to it by Ptolemy, in what he called the Libya Palus, which lake, however, Ptolemy only says, is formed by the Niger. In addition to this coincidence, there were also negative proofs of the disappearance of the Niger in the interior regions of Africa. It could not, for instance, be a branch of the Egyptian Nile, as the Arabs generally contend, for the two reasons adduced by Major Rennell; first, because of the difference of level; the Nile, according to Bruce's measurement by the barometer, passing over a country whose surface is very considerably higher than the sink of

North Africa, through which the Niger is stated to flow. Secondly, because the Nile of Egypt, in this case, must necessarily be kept up at the highest pitch of its inundation for a long time after that of the Niger, which is well known to be contrary to the fact. Neither was it probable, that its waters were discharged into the sea on any part of the eastern coast, there being no river of magnitude on the whole extent of that coast, from Cape Guardafui to Cape Corientes. The hypothesis, therefore, of the dispersion and evaporation of the waters of the Niger, in lakes of an extended surface, was the most plausible, and perhaps the more readily adopted, as it fell in with ancient opinion.

The stream of this mysterious river being now traced with certainty from west to east as far as Tombuctoo, so little suspicion seems to have been entertained of the probability of its making a circuitous course to the sea on the western coast, near to which it has its source, that the examination of this side of Africa seems entirely to have been left out of the question. But when Park was preparing for his second expedition to explore the further course of this river, it was suggested, that the Congo or Zaire, which flows into the Southern Atlantic about the sixth degree of south latitude, might be the outlet of the Niger; and as this suggestion came from Mr. Maxwell, who, in the capacity of an African trader, had not only become well acquainted with the lower part of the river, but had actually made a survey of it, the idea was warmly espoused by Park, who, in a memoir addressed to Lord Camden, previous to his departure from England, assigns his reasons for becoming a convert to this hypothesis; and adds, that if this should turn out to be the fact, "considering it in a commercial point of view, it is second only to the discovery of the Cape of Good Hope; and in a geographical point of view, it

* Mons. Malte le Brun (Geograp. Universelle) states this conjecture to have originally been made by M. Seetzen more than sixteen years since, but was afterward abandoned by him. Corresp. Geo. et Astron. de Mons. Zach, p. 260.