236 JOHN ERNST WEAVER 



seen that in all cases, except on July 6 and at a depth of 5 feet, 

 a higher water content was, maintained in the soils on the north- 

 east slope. 



In order to further check these deep soil water conditions 

 samples were again taken in duplicate on the northwest and 

 south slopes of another prairie-covered hill. These findings, 

 indicated in table 3, check very closely with the preceding, and 

 the striking difference between soil water content on the two 

 hillsides at all depths is well shown. 



It may also be noted that at each determination the soil at 

 any depth was much drier than at the same depth at the pre- 

 ceding determination. On the south slope, it is interesting to 

 note that without exception the soil moisture increased with 

 depth, and that the same condition maintains in most cases for 

 north-side soils. Thus, it may be seen that topography with 

 soil texture is the great middleman that distributes the soil 

 moisture to fill the gigantic earthen reservoir, which again is 

 largely emptied during the following growing season. The 

 common farm practice in the Palouse region of alternating season 

 after season the growing of wheat with summer fallow, is a method 

 of storing the moisture from one year for use in the growth of the 

 next year's crop. 



TEMPERATURE 



The observations on the temperature of the soil consist of 

 two series of readings, namely, of a continuous one by means of 

 a thermograph and of a very large number of readings of ther- 

 mometers. The thermograph records are at a depth of 4 inches 

 ' April 22 to June 9, 1913) and 3 inches (June 5 to August 15, 

 1914) respectively, on a southwest slope. Comparative tempera- 

 tures on the northeast slope were taken at frequent intervals. 

 The other thermometer readings are mostly for depths of 1 foot, 

 and a number of readings were made at each foot to depths of 8 

 feet. 



The thermograph records show an undulating line of which 

 the curve crests correspond to the warmest period of each day, and 

 the depressions to the coldest. The crests for any (7 day) 



