INTRODUCTION INTO THE UNITED STATES. 181 



amount to twenty inches, elsewhere the precipita- 

 tion is from three to five, and in some localities 

 ten inches, for the year. In the northern division 

 the precipitation is ten inches for the centre, 

 twenty for the borders. 



In the eastern basin the winter is the driest 

 season, the sunimer in the western, and the 

 quantity of rain and snow appears, throughout 

 the whole extent of both, to be too small to 

 interfere seriously with the utility, or prejudice 

 the health, of the camel. 



Large tracts in both basins are deserts, not 

 indeed absolutely destitute of vegetation, but 

 yielding neither grass nor shrubbery suited to 

 the support of any quadruped but the camel, 

 though there seems to be good cause to believe 

 that this animal, in reasonable numbers, would 

 find sufficient and appropriate pasturage. The 

 deserts in their general character bear a con- 

 siderable resemblance to those of Arabia, but 

 the deposits of sand appear to be less extensive 

 than the corresponding formations in the Libyan 

 desert. Water is only met with at long inter- 

 vals, and the rivers sometimes run at the bottom 

 of ravines so deep and with walls so precipitous, 

 that their beds are quite inaccessible from the 

 plateau above. There is, however, no evidence 

 of the existence of any American desert, where 

 water cannot be obtained as often as the animal 



