202 FROM NORTH POLE TO EQUATOR. 



the power of growth comes to an end, and heat and drought de- 

 stroy what the rains have produced. Therefore only those plants 

 can flourish in the steppe the course of whose life is run within a 

 few weeks; those which are capable of outlasting centuries never 

 attain to full development. Only in the low grounds, traversed by 

 streams which never dry up, and watered by these as well as by 

 the rains, where sunlight and water, warmth and moisture, work 

 together, does the magic wealth of tropical lands develop and en- 

 dure. Here have arisen forests which, in magnificence and beauty, 

 grandeur and luxuriance, are scarce inferior to those of the most 

 favoured lands of lower latitudes. They are primeval forests in the 

 true sense of the v^ord, for they grow and disappear, become old 

 and renew their youth without help of man; even to this day they 

 are sufficient unto themselves, and they support an extraordinary 

 wealth of animal life. 



The storms of spring carry the rain-laden clouds from the south 

 over the African countries lying north of the equator. Accordingly, 

 these forests do not burst suddenly on the eye of the traveller 

 journeying from the north, but become gradually more characteris- 

 tic the farther south he penetrates. The nearer he approaches to 

 the equator the more brilliantly the lightning flashes, the louder 

 and more continuously the thunder rolls, the more noisily the rain- 

 torrents fall, so much the more luxuriantly do all plants thrive, so 

 much the richer in forms does the fauna become; the earlier the 

 rainy season sets in the longer it lasts, and so much the greater 

 is the charm it works. In exact proportion to the increase of 

 moisture, the forest becomes denser, loftier, and more extensive. 

 From the banks of the streams the plant-growth spreads into the 

 interior, and takes possession of every available space, from the 

 thickly-covered ground to the tops of the highest trees. Trees 

 which are only dwarfs elsewhere, become giants here; known species 

 become the hosts of still unknown parasites, and between them a 

 plant- world hitherto unseen struggles towards the light. Even here, 

 however, at least in the northern belt of the forest, the heat and 

 drought of winter have still so strong an influence that they periodi- 

 cally destroy the foliage of the trees and condemn at least most of 



