GRASS IN THE BAYUDA DESERT. 427 



pressed was Sir Charles Wilson, the D.A.G. to the Nile 

 Expedition, with this circumstance, and with the abun- 

 dance of the water supply at certain points, that he 

 states "the country between Korti and Matammeh is 



NOT A DESERT, IN THE TRUE SENSE OF THE TERM,"* yet 



it is marked as such on all the maps, and numerous 

 travellers report the existence of exceedingly barren 

 deserts considerably to the southward of this point. 



This, therefore, may be cited as a good example of 

 the difficulty met with in fixing the southern limits 

 of the Desert Zone in Northern Africa: it is 

 probable, however, that in January 1885 the Bayuda 

 desert was then in a fairly favourable condition as 

 regards vegetation occasional transitions, according to 

 the seasons, having already been noticed as being 

 common to nearly all deserts. 



After a long continued drought, however, all the 

 dwarfer herbage, and less woody fibred grasses, become 

 so dry and brittle, that the sudden storms peculiar to 

 these regions cause them to break off like bits of 

 stick, or tinder; and the debris are then blown away 

 by the wind and finally reduced to powder. Among 

 others, Sir Samuel Baker calls attention to this fact, 

 which came under his notice while travelling in the 

 Nubian Desert, at a point considerably to the south- 

 ward of the Bayuda region, spoken of by Sir Charles 

 Wilson, f This phenomenon is of so striking a character 

 in dry regions that it has been selected as the Scriptural 

 emblem of mortality. 



* See pp. xxvi and xxvii of the Introduction to Sir Charles Wilson's 

 book From Korti to Khartoum, A Journal of the Desert March from 

 Korti to Gubat, 3rd Edit, 1886. 



f See The Nile Tributaries of Abyssinia, by Sir Samuel W. Baker, 

 1867, p. 61. 



