200 Proceedings of the Royal Physical Society. 
coast region ; we then come to the slopes leading up to the 
plateau, while the bottom of the soup-plate represents quite 
conveniently the Central African plateau. We have only to 
imagine upon this plateau three or four mountainous masses, 
and four rivers which rise in the Central African lakes, 
cutting their way through the rock-bound borders of the 
plateau to find their way through gorges, and over rocky 
beds, to the sea and ocean surrounding the continent. 
Now it is due to these facts, thus briefly stated, that the 
entity of Central Africa has been maintained for centuries. 
The low-lying coasts, with pestiferous marshes and wide 
tracts of malaria, have prevented much intercourse between 
the highlands and the coast; and the fact that the navigation 
of the Nile, the Congo, and the Zambesi is impeded by 
cataracts of no slight magnitude, has prevented more highly 
civilised nations overrunning the country as they have done 
in North America and elsewhere. It may be objected that 
Central Africa might have been reached from the Cape in the 
south, and from the Mediterranean in the north. Here, 
however, climatology again shows us that this 1s impossible, 
for we have the great Sahara barring the entrance from the 
Mediterranean littoral in the north towards the centre, while 
easy access from the Cape is rendered almost impossible on 
account of the tzetse fly and the malarious regions south of 
the Zambesi. 
A few brief details may not be out of place with regard to 
Africa as a whole. The vast country was known as the 
“world’s end” in mythological writings, the term being a 
practical prophecy, it being the last continent to be explored. 
It has an area of 12 million square miles; it is 5000 miles 
long and almost 5000 miles at its greatest breadth. It is 
three times as large as all Europe, four times as large as 
Australia, and has a remarkable coast-line of only 17,700 
miles in length, this being out of all proportion to its vast 
area, owing to the absence of bays, inlets, or estuaries, and in 
consequence there is no easy access to the interior of the 
continent. 
Africa has been likened to a shapeless mass, but this is 
hardly accurate. As you may see upon the map, the eastern 
