HORTICULTURE BY IRRIGATION. 



demonstrating.* That it almost uniformly, when distributed to any 

 extent, increases the humidity of the climate ; that it avoids the occurrence 

 of the much dreaded drouth, with its accompanying record of failures, 

 discouragements and often appalling consequences ; and, finally, that 

 it makes possible a condition of agriculture so manifestly in advance of 

 the present status of things, that words seem inadequate to express these 

 possibilities. 



*NOTK. A very probable effect ot irrigation on a large scale " would be an 

 increase of precipitation in the region watered. Hitherto, scientific observation has 

 recorded no such increase, but, in a question of so purely a local character, we must 

 ascribe very great importance to a consideration which has frequently been over- 

 looked by meteorologists ; namely, that vapors exhaled in one district may probably 

 be condensed and precipitated in another, very distant from their source. If, then, 

 it were proved that an extension ot irrigated soil was not followed by an increase of 

 rain-fall in the same territory, the probability that the precipitation was augmented 

 somewhere would not be in the least diminished." (Man and Nature. Page 463.) 

 It is asserted that rain-fall on the Isthmus of Suez has increased since the opening 

 of that great water thoroughfare, and has enlarged the evaporable surface of the 

 country. Some leading cultivators of California assert positively that an increase 

 of rain-fall has followed extended irrigation in portions of that State. While this 

 belief is gaining ground, perhaps, in other sections of the country, the fact should 

 be kept in mind that questions of this character, that involve changes of climate, 

 can only be determined by tests extending through a series of years. 



