lOO Charles Darwin. 



and parts of the flesh of the beasts which had perished 

 on the road. To the same cause we must attribute 

 the singular faciHty with which electricity is excited. 

 My flannel waistcoat, when rubbed in the dark, ap- 

 peared as if it had been washed with phosphorus ; 

 every hair on a dog's back crackled ; even the linen 

 sheets, and leathern straps of the saddle, when 

 handled, emitted sparks." 



The descent was made on the east side of the 

 Cordilleras, where a magnificent view of the pampas 

 was obtained. An immediate difference between 

 the vegetation was apparent, though the soil and 

 climate were materially like that of the country re- 

 cently passed. The same was true of the fauna, 

 many Patagonian forms being seen, among them 

 the Agouti, Biscacha, three species of armadillo, and 

 ostrich. 



As they descended into the valley Darwin had his 

 first experience with the locust. He was near the 

 village of Luxan, when he noticed a large ragged 

 cloud, reddish brown in colour. It was at first sup- 

 posed to be smoke from a pampas fire, but soon 

 developed into a swarm of locusts. The vast con- 

 gregation was moving to the north at a rate of 

 fifteen miles an hour. They completely filled the 

 air from a height of twenty feet from the ground to 

 nearly half a mile above it, and made a noise as they 

 flew like the rustling of a mighty wind, or, as Dar- 

 win said, of a breeze through the rigging of a ship. 

 Where they were the thickest the sky was wholly 

 obscured. They occasionally alighted upon the 

 ground, so completely covering it that it changed 



I 



