Kccesslfy of Watering, 21 



will drink half a barrelful of water in three days' 

 time, and, having done so, will begin languishing for 

 lack of moisture, and die in a week. According to Dr. 

 J. H. Gilbert, for every ton of dry substance grown, in an 

 average crop, an amount of water equivalent to three 

 inches of rain is exhaled in the process; which amounts 

 to about two hundred times the weight of the vegeta- 

 ble product. And Sir J. B. Lawes arrived at substan- 

 tially the same result by his own researches, separately 

 prosecuted. Hence it will be readily seen that, unless 

 there is moisture enough when the crop requires it, 

 there will be a shortage in the harvest. 



What is commonly called an '" impoverished soil," 

 or one considered naturally unfertile, may be in fact 

 good enough in itself, its only deficiency being in the 

 matter of moisture. We often see a poor piece of 

 land yielding a good crop in a wet season ; and artifi- 

 cial watering on the grand scale has, in many well 

 known instances in Colorado, California, and else- 

 where, both at home and abroad, converted absolute 

 deserts into productive grain farms and fruit and cattle 

 ranches. 



Although the rainfall during each year averages 

 about the same now as in former periods, the seasons 

 are changing in this respect : that the rainfall is not so 

 evenly divided, and we get longer and more protracted 

 droughts; not relieved by the fact that the rainfalls, 

 when they do come, are heavier. For this reason the 

 subject of irrigation is constantly gaining in impor- 

 tance. It involves questions, both in regard to the 

 supply of water and the manner of applying it. Of 



