52 



WILTING COEFFICIENT FOE DIFFERENT PLANTS. 



Reference to the weighings in Table XV will show a continuous 

 loss of water, decreasing somewhat at the time the system reverses 

 its direction of motion. While this loss of water is taking place the soil 

 end of the system at first rises continuously; then the system remains 

 balanced for a short time, and finally the plant end of the system 

 rises. It will be noted that the wilting of the lemon plant followed 

 immediately after the change of direction of motion of the system. 



In Table XV is given a series of observations on three balanced 

 systems (PL I, fig. 1) , two plants being grown in each system, as fol- 

 lows: (1) Cactus and squash, (2) cactus and wheat, and (3) olive and 

 wheat. The cactus is capable of losing a relatively large amount of 

 water without giving visible evidence of loss, while the leaves of the 

 olive will dry and become brittle without wilting or rolling. These 

 two plants form typical examples of cases where it is necessary to 

 resort to a balancing method in order to determine the wilting 

 coefficient. 



Table 



XVI. — Observations with three balanced systems containing three pairs of plants. 



Plants and time of observation. 



Weight. 



Notes. 



Cactus and squash, plants: 



Oct. 1, 9 a. m 



Grams. 



Balanced and adjusted to zero. 

 Plant down; readjusted to zero. 

 Plant up; squash wilted. Rewatered October 4; the squash 



growing and in good condition. 

 Balanced and adjusted to zero. 

 Plants down; readjusted to zero. 

 Do. 



Oct. 1, 12.30 p. m 



Oct. 3, 9 a. m 



523.6 

 518.2 



528.9 

 525.7 

 523.0 

 520.9 

 519.3 

 518.0 

 516.8 



516.3 

 516.0 

 515.9 



772.2 



768.9 



763.5 



762. 7 



758.8 



754.3 



750.0 



744.95 



743.1 



742.5 



741.1 



520.2 



517. 62 



511. 15 



507.9 



501.6 



499.5 



494.6 



491.25 



490.4 



488.0 



487.0 



486.5 



485.8 



Oct. 11, 5.30 p. m 



Oct. 12, 5.30 p. m 



Oct. 13, 5 p. m 



Oct, 14, 5.30 p. m 



Oct. 15, 5.30 p. m 



Do. 



Balanced. 



Oct. 16, 12 m 



Plants up; squash wilting; readjusted. 

 Plants up; squash wilted. Squash cut off, resealed, and cor- 

 rections made for change in weight. 

 Plants up; readjusted to zero. 

 Do. 



Oct. 17, 12 m 



Oct, 17, 5 p. m 



Oct. 18, 9 a. m 



Oct. 19, 9 a. m 



Do. 



Cactus and Kubanka wheat 

 plants: 

 Feb. 18, 5 p. m 



Svstem balanced. 



Feb. 20, 5 p. m 



Plants down; readjusted to zero. 

 Do. 



Feb. 21, 4 p. m 



Feb. 22, 4 p. m 



Do. 



Feb. 23, 4 p. m 



Do. 



Feb. 24, 5.30 p. m 



Feb. 25, 4 p. m 



Do. 

 Do. 



Feb. 27, 4 p. m 





Feb. 28, 4.30 p. m 



Mar. 1, 9.30 a. m 



Plants up; wheat rolled and wilted. 

 Do. 



Mar. 2, 9.30 a. m 



Olive and Kubanka wheat 

 plants: 

 Feb. 28, 5 p. m 



Do. 



Balanced and adjusted to zero. 

 Plants down; readjusted to zero. 

 Do. . 



Mar. 1, 9.30 a. m 



Mar. 1, 4.30 p. m 



Mar. 2, 9.30 a. m 



Do. 

 Do. 



Mar. 3, 10 a. m 



Do. 



Mar. 3, 5.30 p. m 



Do. 





Do. 



Mar. 5, 12 m 



Balanced. 



Mar. 6, 10 a. m 



Balanced; wheat wilting. 



Do. 

 Plant up; wheat wilting. 



Do. 



Mar. 6, 4.30 p. m 



Mar. 7, 9.30 a. m 



Mar. 8, 10 a, m 







Keferring to the record of observations with the cactus and the 

 squash, it will be seen that the reversal of the direction of the motion 



230 



