CLIMATIC CHANGES ON THE PLAINS. 483 



pears as the "frontier" extends westward, and its place is taken 

 by grasses and other herbage of taller growth. That this 

 change of the clothing of the plains, if sufficiently extensive , 

 might have a modifying influence on the climate, I do not 

 doubt; but whether the change has been already spread over a 

 large enough area, and whether our apparently or really wetter 

 seasons may not be part of a cycle, are unsettled questions. 



"The civil engineers of the railways believe that the rains 

 and humidity of the plains have increased during the ex- 

 tension of railroads and telegraphs across them. If this is the 

 case, it may be that the mysterious electrical influence in which 

 they seem to have faith, but do not profess to explain, has exer- 

 cised a beneficial influence. What effect, if any, the digging 

 and grading, the iron rails, the tension of steam in locomotives, 

 the friction of metallic surfaces, the poles and wires, the action 

 of batteries, etc., could possibly or probably have on the 

 electrical conditions, as connected with the phenomena of pre- 

 cipitation, I do not, of course, undertake to say. It may be 

 that wet seasons have merely happened to coincide with rail- 

 roads and telegraphs. It is to be observed that the poles of the 

 telegraph are quite frequently destroyed by lightning; and it 

 is probable that the lightning thus strikes in many places 

 where before the erection of the telegraph it was not apt to 

 strike, and perhaps would not reach the earth at all. 



" It is certain that rains have increased ; this increase has 

 coincided with the extension of settlements, railroads, and tele- 

 graphs. If influenced by these, the change of climate will go 

 on ; if by extra mundane influences, the change may be perma- 

 nent, progressive, or retrograde. I think there are good 

 grounds to believe it will be progressive. Within the last 

 fifteen years, in Western Missouri and Iowa, and in Eastern 



