32 THE IRRIGATION AGE 



of the soil, produced by simple mechanical work, will move the mois- 

 ture more rapidly through the soil, while another condition, produced 

 by a different line of mechanical work, will check the movement of 

 moisture in the soil ; in fact, almost stop its movement for a time. To 

 know that these facts are true is of great value to the farmer; and 

 when we are able to ascertain by some simple device just the proper 

 quantity of moisture to retain in the soil for be^t possible results, we 

 will then be able to grow the best possible crops each year. 



In a recent communication from one of the best posted men in soil 

 physics, we were informed that by the aid of that most noble servant, 

 electricity, a mechanical device had been invented by which the per- 

 centage of moisture at any point from the surface for several feet 

 down could be quickly and easily ascertained. If it proves successful, 

 it will be of untold value to the farming interests in developing fur- 

 ther scientific truths. For all that, kind reader, don't foster for a 

 moment the idea that sience will ever develop a plan of growing crops 

 without labor. The edict that went forth at the fall of Adam and Eve 

 stands today: "Thou shalt live by the sweat of thy brow." 



When soil is made firm by any artificial or mechanical work a 

 greater amount of moisture is gathered there. This almost any farmer 

 has seen from the effect of "horse foot," or wheel tracks in his grain 

 fields. These invariably show in a dry season very remarkable growths. 

 The stock will be coarser, the number of stools very materially in- 

 creased, the heads longer and better filled, which is mainly due to the 

 very firm condition of the soil- Do not, however, loose sight of an- 

 other fact, and that is, the loose mulch that falls into these tracks, 

 putting the firm soil under loose soil. Thus you have increased mois- 

 ture by increased capillary attraction, protected by the loose, dry 

 mulch, which holds the moisture at the roots by checking evaporation. 



The effect of firmed soil may be explained in two or three ways. 

 It may not be well understood, but it is, however, a fact, that when soil 

 becomes the least moist close investigation demonstrates that each 

 little particle of soil, even if ever so minute, is enveloped in a thin film 

 or covering of water, and each of the little particles u ill carry a film 

 or covering up to a given thickness, when the soil will appear quite 

 moist. Beyond this thickness, providing the soil is not impervious, 

 the water will pass down by gravity; that remaining about the particles 

 is held there by capillary attraction. This capillary attraction is in- 

 creased as the soil becomes closer packed, for the reason that capillary 

 attraction is increased or diminished by the increase or decrease in the 

 surface tension. 



You can readily see that when you press soil together so 

 that two or three particles are contained in the same space that one 

 occupied, you have increased surface tension two or three times, be- 



