

» 



' 











1917] 



DENN I —PERMEA BILI T V 



385 



process, and (d) with a chemical process. These figures also 



em 



averaged for a large interval of temperature, but that the range 

 of the values of Q I0 for each temperature interval should be shown 

 for which experimental data are available. 



TABLE VII 



Rysselberghe's 



results with living 



protoplasm 



Results obtained with 



non-living plant 



membranes 



Vapor pressure 

 of water at various 



TEMPERATURES j 



Remsen and Reid's 



results with hydrolysis 



of nitro-benzamide* 



Tempera- 

 ture 



Qx* 



Tempera- 

 ture 



Q« 



Tempera- 

 ture 



Q» 



Tempera- 

 ture 



Q« 



o-6° 



6-12 



12-16 



16—20 



20-25 



25-30 



3-2 



3-8 



2.0 



1-5 

 I. I 



I. I 



5-2-i5?2 



15.2-25.2 

 25.2-35.0 



35.0-45.0 



1.628 



1-525 

 1-343 

 1-344 



5-15 



15-25 



25-35 

 40-50 



1 943 



I • 854 

 1.776 



i.°75 



60-70° 

 70-80 

 80-90 

 90-100 



I.84 

 1.72 

 1 65 



1 59 



























* From data given by Snyder (20, p. 169). 



itions of permeability of membranes to vapor pressure of wate\ 

 experiments of Brown and Worley (6) showed that Q 



10 



pproximated in numerical 

 rater at those temperatu: 



From table VII it will be noted 



that similar results were not obtained with the peanut membrane; 

 that while the coefficient of permeability rates and vapor pressure 

 are not equal, they both show the same tendency to fall in value 



temperatures 



may 



coefficient 



coefficient 

 flow through capillary 



According to the 



law of Poiseuille, as reported by Krabbe (19), the quantity of 



water flowing through a p-Irss tube increases from 1 to 1+0 0336703 



/-ho. 00022 

 grade (Kr, 



rabbe iq, p. 477). This would make the coefficient for 

 10 rise in temperature about i .358. Since this law applies only to 



minimum 



and since the temperature coefficients obtained in these experiments 

 are not constants but vary with the temperature, it is not believed 







