318 



cox. 



Table X. — The effect of capillary attraction on the height of the column of water 



in the piezometer. 



Observed height in 

 centimeters. 



Observed quantity of 



outflow per minute in 



cubic centimeters 



(grams). 



Height of 

 column in 

 centimeters 

 to be sub- 

 tracted due 

 to capillary 

 attraction. 



Hi 



Us 



Qi 



Q. 



C 



80 



90 



80. 



90 



80 



90 



80 



90 



1.8 

 1.8 

 1.9 

 1.9 

 2.0 

 2.0 

 2.1 

 2.1 



349. 90 

 370. 75 

 349. 90 

 • 370. 75 

 349. 90 

 370. 75 

 349. 90 

 370. 75 



17.96 

 17.96 

 21.94 

 21.94 

 25.36 

 25. 36 

 28.51 

 28. 51 



1.593 

 1.593 

 1.592 . 

 1.590 

 1.589 

 1.590 

 1.58 

 1.58 

 "1.59 



" Mean. 



When the quantity of water which leaves the outflow orifice j/ in a unit of 

 time has been measured, we know that the same quantity has simultaneously 

 passed over a cross section of each elutriating tube and we have therefore, 



4 

 v=Q — — centimeters. The velocity in each elutriating tube is directly propor- 

 tional to the quantity of water passing, hence 



V : v„=l/h-C : l/'h„-C 

 therefore v„=i/h„— C (^j^^q) 



]j Q 



and h„=v„^ — ^ \- G. 



I obtained the constant — ^ from the following data: 

 Table XI. — Derivation of the constant 



(1) 

 (2) 



(3) 

 h-C 







Corre- 







Observed 



sponding 





Observed 



quantity 



velocity in 



Constant 



height in 



of outflow 



tube B in 



h— C 



centime- 



in cubic 



centime- 





. ters. 



centime- 



ters per 







ters. 



minute. 





1.8 



17.96 



0. 9184 



•0.249 



1.9 



21.94 



1.122 



0.246 



2.0 



2.5.36 



1.297 



0.244 



2.1 



28.51 



1.458 



0.240 



80.0 



349. 90 



17.892 



0.245 



90.0 



370. 75 



18.957 



0.246 



>■ 0. 245 



■ When the unit of time is a second the constant will be multiplied by (60)^ 

 •> Mean. 



