214 



Journal of Agricultural Research 



Vol. X, No. s 



tory proper. A Hoff recording gage (i6) was installed in connection 

 with tank 4, making it possible to keep a continuous record of the low- 

 ering of the water surface of that tank. The Weather Bureau type of 



IMkrdurroudMoirJ ibrClos3'A'Sfnffon5 



U5. 6. 6. Siundanj Hooting 









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IfiildrpckeM Sand or Sal Tank 

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Pig. 3. — Sketch showing types of evaporation tanks in use at the Irrigation Field Laboratory, 



Still well (17) was used in tank 8, but with the Hoff gage. During the 

 early spring months a special portable still well (fig. 3, B) was used 

 when observations were taken at the other tanks. Later in the season 



