14 BURNING OFF THE GRASS. Chap. I. 



goods up to Shupanga and Senna. The country was in a 

 state of war, our luggage was in danger, and several of 

 our party were exposed to disease from inactivity in the 

 malaria of the delta. Here some had their first intro- 

 duction to African life, and African fever. Those alone 

 were safe who were actively employed with the vessels, 

 and of course, remembering the perilous position of their 

 fellows, they strained every nerve to finish the work and 

 take them away. 



Large columns of smoke rose daily from different points 

 of the horizon, showing that the natives were burning off 

 the immense crops of tall grass, here a nuisance, however 

 valuable elsewhere. A white cloud was often observed to 

 rest on the head of the column, as if a current of hot 

 damp air was sent up by the heat of the flames and its 

 moisture was condensed at the top. Eain did not follow, 

 though theorists have imagined that in such cases it 

 ought. 



Large game, buffaloes, and zebras, were abundant 

 abreast the island, but no men could be seen. On the 

 mainland, over on the right bank of the river, we were 

 amused by the eccentric gyrations and evolutions of flocks 

 of small seed-eating birds, who in their flight wheeled 

 into compact columns with such military precision as to 

 give us the impression that they must be guided by a 

 leader, and all directed by the same signal. Several other 

 kinds of small birds now go in flocks, and among others 

 the large Senegal swallow. The presence of this bird, 

 being clearly in a state of migration from the north, while 

 the common swallow of the country, and the brown kite 

 are away beyond the equator, leads to the conjecture that 

 there may be a double migration, namely, of birds from 

 torrid climates to the more temperate, as this now is, as 

 well as from severe winters to sunny regions; but this 

 could not be verified by such birds of passage as ourselves. 



