4 BOARD OF AGRICULTURE. [Jan., 



not fly off into space if a cloud intervenes. Hence, then, the 

 watery vapor becomes, during the early autumn months when 

 our crops are maturing, a sort of blanket for the earth. The 

 larger the area from which this evaporation can occur the 

 larger will be, other things being equal, the amount of watery 

 vapor in the air. The less we have of this vapor the greater 

 will be the chances of early and destructive frosts, and the 

 more likely will our crops be wilted, because the thirsty atmos- 

 phere will, so far as it can, take the moisture from the plants 

 themselves, and from the soil on which they grow. What- 

 ever, then, tends to preserve the areas of evaporation tends to 

 that extent to preserve our crops. The quantity of water- 

 evaporated in a summer month from a mile square of water 

 surface is enormous. It has been estimated to be in our 

 climate 3,339,304 gallons. To make a practical application of 

 this statement: sum up the area which, in your State, should 

 normally be covered by water. Reduce it to miles, then 

 multiply the number of gallons which I have given you above, 

 for the month of July, by the number of miles of water surface 

 which your State represents. You will be astounded at the 

 result. If you have fifty square miles of such surface you 

 would have the atmosphere receiving in a single month 166,- 

 965,200 gallons of water. 



Suppose we change the picture and imagine, what is not 

 improbable, that just at the season when your crops most re- 

 quire water vapor in the atmosphere that your evaporating sur- 

 face has been reduced one-half because of the low stage of 

 water; that would mean that the atmosphere over your State 

 had been deprived of 83,482,600 gallons of water in a single 

 month. I am as fully aware as you that it is still an open ques- 

 tion whether or not the moisture which comes as dew upon the 

 plants can be absorbed by them. That is a purely scientific 

 question. You and I know, however, that corn leaves which 

 were hanging limp, or were curled up to reduce their evaporat- 

 ing surface, when the sun's rays were pouring down upon 

 them, will be refreshed after a night of heavy dew. During a 

 prolonged drought you may endeavor to maintain capillary at- 

 traction from the depths of the earth by keeping the soil well 

 tilled. The stubborn fact remains that there is only a given 

 quantity of moisture there, and that while cultivation may 

 render more moisture available to the plants for a time, it is 



