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.