PLATE II 



Fig. I. — Pot planted with sugar beets, showing the wax seal around the plants and 

 also the sealed holes where stand was not perfect. 



Fig. 2. — Weighing pots, showing spring balance, weighing support, and general pro- 

 cedure. Two men operate the weighing support, one of whom lifts the pot by means 

 of a windlass, while a third reads the balance and records the weight. By this method 

 weighings can be made at the rate of two per minute. 



Fig. 3. — Grindelia squarrosa (gumweed) at left (pot 164), and Artemisia frigida 

 (moxmtain sage) at right (pot 167), illustrating the growth of native plants used in the 

 water-requirement measurements. Photographed on July 29, 1912. Water require- 

 ment of Grindelia, 468±i8; of Artemisia, 474±i4. 

 60300°— 14 5 , 



