THE ROMANCE OF NATURAL HISTORY. 



of the sandy soil by the weak support of a single 

 wiry root, and are fed rather by the dews of 

 heaven than by the moisture of the soil. During 

 the rainless months of the dry seasons, these 

 plains are scarcely less arid than the sandy deserts 

 of the north; yet even then there are reservoirs 

 beneath the surface. Livingstone speaks of a cer- 

 tain plant, named leroshna, which is a blessing to 

 the inhabitants of this desert. "We see a small 

 plant with linear leaves, and a stalk not thicker 

 than a crow's quill; on digging down a foot or 

 eighteen inches beneath, we come to a tuber, often 

 as large as the head of a young child ; when the 

 rind is removed, we find it to be a mass of cellular 

 tissue, filled with fluid much like that in a young 

 turnip. Owing to the depth beneath the soil at 

 which it is found, it is generally deliciously cool 

 and refreshing. Another kind, named mokiiii, is 

 seen in other parts of the country, where long- 

 continued heat parches the soil. This plant is a 

 herbaceous creeper, and deposits underground a 

 number of tubers, some as large as a man's head, 

 at spots in a circle a yard or more, horizontally, 

 from the stem. The natives strike the ground on 

 the circumference of the circle with stones, till, by 

 hearing a difference of sound, they know the 

 water-bearing tuber to be beneath. They then 

 dig down a foot or so, and find it."* 



There are deserts on the Pacific coast of South 

 America as horribly barren as any in Africa or 

 Asia, if not so extensive. One of these is described 

 by Mr. Darwin, who was all day riding across it, 

 as a "complete and utter desert." 



"The road," he says, "was strewed with the 

 bones and dried skins of the many beasts of bur- 

 den which had perished on it from fatigue. Ex- 

 * Livingstone's " Travels," p. 47. 

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