THE CLIMATE OF THE PLAINS. 481 



cess.' This explanation may be fanciful, but the fact remains 

 that near the mountains the rains seem to decrease north of the 

 great divide; fortunately, however, this occurs in a region 

 where irrigation may be applied extensively and where there is 

 sufficient moisture to nourish bountiful crops of grass. 



" The vegetation of the plains along wagon tracks and rail 

 road embankments shows a capability of production scarcely 

 suggested by the surface where undisturbed : wherever the 

 earth is broken up, the wild sunflower (Helianthus) , and others 

 of the taller-growing plants, though previously unknown in 

 the vicinity, at once spring up. 



" I have been on the plains all the time since early in May 

 till this date (22d of September). There has been much dry 

 weather, but I have not seen one cloudless day no day on 

 which the sun would rise clear and roll along a canopy of 

 brass to the west. There has always been humidity enough to 

 form clouds at the proper height; and on many days they 

 would be seen denning, by their flat bottoms, the exact line 

 where condensation became sufficient to render the vapor visi- 

 ble. I conclude, from all this, that abundant moisture has 

 floated over the plains to have given us a great deal more rain 

 than would be desirable if it had been precipitated. 



"Sometimes a storm would be seen to gather near the 

 horizon, and we could see the rain pending from the clouds 

 like a fringe, hanging apparently in mid-air, unable to reach 

 the expectant earth. The rain stage of condensation had been 

 reached above, but the descending shower was re-vaporized ap- 

 parently, and thus arrested. 



" These hot winds are not, so far as I have observed, apt to 

 be constant in one place for any considerable length of time ; 

 they strike your face suddenly, and perhaps in a minute are 



27 



