46 MOZAMBIQUE 



that suggests itself as particularly suitable for 

 this character of land. Plants, other than those 

 especially adapted by nature, will not flourish in 

 soil that is waterlogged ; hence land liable to 

 be inundated for a period longer than a few 

 days at a time is of little value for agriculture 

 unless it is embanked. A large quantity of the 

 sugar of South America is produced upon low 

 land protected by embankments, and this alluvial 

 plain of the Incomati could no doubt be simi- 

 larly reclaimed, but the constructing of embank- 

 ments being expensive work, the reclaiming of 

 swamps is not likely to be seriously considered 

 so long as accessible sugar land is available 

 elsewhere. It is characteristic of the Incomati 

 plain, as of other rivers that have helped to build 

 up their own beds, that the land slopes away 

 from the banks. The reason for this is quite 

 well understood. In a freshet the river becomes 

 charged with alluvium in suspension. So long 

 as the stream is confined within the banks the 

 current is too swift to permit of this alluvium 

 settling, and it is swept along. When the river 

 overflows, the flood-water by reason of the 

 greatly increased friction it encounters is checked 

 in its velocity, and being no longer able to 

 carry its sediment the latter begins to sink to 

 the bottom. Hence the land in the immediate 





