By the condition of their courses, all the four magnates are broken into cataracts and rapids at the gates where they burst through the lateral chains; the Mosi-wa-tunya (smoke that thunders) of the Zambeze, and the Ripon Falls discovered by Captains Speke and Grant upon the higher Nile, are the latest acquisitions to geography, whilst the “Mai waterfall,” reported to break the Upper Congo, still awaits exploration.  This accident of form suggests a division of navigation on the maritime section and on the plateau-bed which, in due time, will be connected, like the St. Lawrence, by canals and railways.  All but the Nzadi, and perhaps even this, have deltas, where the divided stream, deficient in water-shed, finds its sluggish way to the sea.

The largest delta at present known is the Nigerian, whose base measures 155 direct geographical miles between the Rivers Kontoro east, and Benin west.  Pliny (v. 9) makes the Nile delta extend 170 Roman miles, from the Canopic or African to the Pelusiac or Asiatic mouth, respectively distant from the apex 146 and 166 miles; the modern feature has been reduced to 80 miles from east to west, and a maximum of 90 from north to south.  The Zambeze extends 58 miles between the Kilimani or northern and the west Luabo, Cuama or southern outlet-at least, if these mouths are not to be detached.  The Nzadi is the smallest, measuring a maximum of only 12 to 15 miles from the Malela or Bananal Creek to the mangrove ditches of the southern shore.

In these depressed regions the comparatively salubrious climates of the uplands become dangerous to the European; the people also are degraded, mostly pirates and water-thieves, as the Nigerian Ibos, the Congoese Musulungus, and the Landim (Amalandi) Kafirs about the lower Zambeze.  There is a notable similarity in their productions, partly known to Pliny (v. 8), who notices “the calamus, the papyrus, and the animals” of the Nigris and the Nile.  The black-maned lion and the leopard rule the wold; the gorilla, the chimpanzee, and other troglodytes affect the thinner forests; the giraffe, the zebra, and vast hosts of antelopes scour the plains; the turtle swims the seas; and the hippopotamus, the crocodile, and various siluridae, some of gigantic size, haunt the lakes and rivers.  The nymphaea, lotus or water-lily, forms rafts of verdure; and the stream-banks bear the calabash, the palmyra, the oil-palm, and the papyrus.  Until late years it was supposed that the water-lily, sacred to Isis, had been introduced into Egypt from India, where it is also a venerated vegetable, and that it had died out with the form of Fetishism which fostered it.  It has simply disappeared like the crocodile from the Lower Nile.  Finally, to conclude this rapidly outlined sketch, all at the present moment happily share the same fate; they are being robbed of their last mysteries; the veil of Isis is fast yielding to the white man’s grasp.