XV SWARM OF LOCUSTS 351 



outer range of the Cordillera, we did not cross a single stream. 

 In many parts the ground was incrusted with a saline efflor- 

 escence ; hence we had the same salt-loving plants which are 

 common near Bahia Blanca. The landscape has a uniform 

 character from the Strait of Magellan, along the whole eastern 

 coast of Patagonia, to the Rio Colorado ; and it appears that 

 the same kind of country extends inland from this river, in a 

 sweeping line as far as San Luis, and perhaps even farther 

 north. To the eastward of this curved line lies the basin of 

 the comparatively damp and green plains of Buenos Ayres. 

 The sterile plains of Mendoza and Patagonia consist of a bed 

 of shingle, worn smooth and accumulated by the waves of the 

 sea ; while the Pampas, covered by thistles, clover, and grass, 

 have been formed by the ancient estuary mud of the Plata. 



After our two days' tedious journey, it was refreshing to see 

 in the distance the rows of poplars and willows growing round 

 the village and river of Luxan. Shortly before we arrived at 

 this place we observed to the south a ragged cloud of a dark 

 reddish-brown colour. At first we thought that it was smoke 

 from some great fire on the plains ; but we soon found that it 

 was a swarm of locusts. They were flying northward ; and with 

 the aid of a light breeze, they overtook us at a rate of ten or 

 fifteen miles an hour. The main body filled the air from a 

 height of twenty feet to that, as it appeared, of two or three 

 thousand above the ground ; " and the sound of their wings was 

 as the sound of chariots of many horses running to battle :" or 

 rather, I should say, like a strong breeze passing through the 

 rigging of a ship. The sky, seen through the advanced guard, 

 appeared like a mezzotint© engraving, but the main body was 

 impervious to sight ; they were not, however, so thick together, 

 but that they could escape a stick waved backwards and for- 

 wards. When they alighted, they were more numerous than 

 the leaves in the field, and the surface became reddish instead of 

 being green : the swarm having once alighted, the individuals 

 flew from side to side in all directions. Locusts are not an 

 uncommon pest in this country : already during this season 

 several smaller swarms had come up from the south, where, as 

 apparently in all other parts of the world, they are bred in the 

 deserts. The poor cottagers in vain attempted, by lighting fires, 

 by shouts, and by waving branches, to avert the attack. This 



