Other accounts state, that the waters of the Congo may be distinguished at sea more than thirty leagues from the coast, and that the water is fresh at the distance of thirty miles.

[Footnote: Lopez, Merulla, and Dapper, referred to in Phillips's Voyages, vol. iii. p. 236.]

These, perhaps, are exaggerations; but they may be received, in confirmation of the preceding testimonies, as sufficient proofs of a general opinion among navigators with regard to the size and force of this prodigious river. It is mentioned by Major Rennell in his very interesting account of the Ganges, that the sea in the bay of Bengal ceases to be affected by the waters of that river, and recovers its transparency, only at the distance of about twenty leagues from the coast. (Phil. Transactions, vol. lxxi.) But the Ganges being obstructed by its Delta, and passing through eight channels into the sea, is probably much less rapid and impetuous than the Congo.

To this it must be added, that all the accounts concur in representing, that the stream of the Congo is of a more uniform height, and subject to much less variation from the dry and rainy seasons, than any tropical river which is known; and that on a comparison with such rivers, it may be considered to be in a perpetual state of flood. The average rising of the Ganges in the rainy season is stated by Major Rennell to be 31 feet, being about the same with that of the Nile; whereas, the difference between the highest point of the Congo about February, and the lowest in September, is only about nine feet; and the river, at the latter period, has all the appearance to a stranger of being in full flood.

[Footnote: MS. Letter of Mr. Maxwell to Mr. Park, Oct. 12, 1804.]

It is this remarkable peculiarity, which distinguishes the Congo from other great rivers of a similar description, and which leads to important conclusions with regard to its origin and course.

In support, then, of the hypothesis which identifies the Congo with the Niger, the following arguments, deduced from the preceding facts and observations, may be alleged:—1. The great magnitude of the Congo. 2. The probability that this river is derived from very remote sources, perhaps considerably north of the equator. 3. The fact, that there exists a great river north of the equator, (the Niger,) of which the termination is unknown, and which may, perhaps, form the principal branch of the Congo. These, in truth, are the only grounds upon which the present supposition can be fairly said to rest. Arguments founded upon etymological conjectures, supposed resemblances of names, or affinity of languages, &c. &c., are, for the most part, too arbitrary and fanciful, and liable to too much uncertainty to be entitled to any place in disquisitions of this nature. The same remark is applicable to the narratives and descriptions given by native travellers and merchants, and, in general, to all African evidence whatever, except when supported by collateral proof from other less exceptionable sources.

Such being the evidence in favour of the hypothesis respecting the Congo, the objections against this theory must be admitted to be weighty and formidable. The principal of these are, 1. That it supposes the course of the Niger to lie through the vast chain of the Kong Mountains (anciently Montes Lunæ), the great central belt of Africa. Of the existence of these mountains there appears to be no doubt; and from their situation in the midst of a great continent, they may reasonably be supposed to be of vast size and extent; in which case it is difficult to understand, how the Niger could penetrate this barrier, and force a passage southwards. 2. The course of the Niger, estimated from its source in the mountains of Senegal (supposing it to be the same river with the Congo, and to flow by Wangara and Cashna through the centre of Africa into the Atlantic), would be considerably more than 4000 miles. But the course of the Amazon, the greatest river in the old or new world with which we are acquainted, is only about 3500 miles; and, although the existence of a river considerably greater than any yet known, may be within the limits of physical possibility; yet, so improbable a supposition ought not to be adopted upon slight or conjectural reasoning, or upon any thing much short of distinct and positive proof. To give such a vast extension to the Congo upon the grounds stated by Mr. Maxwell, might justly be considered as one of those exaggerations, to which, according to a remark of D'Anville, geographical writers upon Africa have always been remarkably prone, 'en abusant, pour ainsi dire, du vaste carrière que l'intérieur de l'Afrique y laissoit prendre.' (Mém. de l'Academie des Inscriptions, Tom. xxvi p. 61.)

[Footnote: The following scale (taken from Major Rennell's Memoir of a Map of Hindostan, p. 337,) shewing the proportional length of some of the most considerable rivers already known, may be useful to the reader on the present occasion.

EUROPE.
Thames 1
Rhine 5-1/4
Danube 7
Wolga 9-1/2