24 THE DIFFUSION OF GASES THROUGH 



To compute the constants for the diffusion of hydrogen into hydrogen 

 through water, data from March 1 7 to April 1 4 were treated by the method 

 of least squares, as shown in table 4. If 



m = mo — mt 



(time in days) the constants are 



^0 = 814.1X10"^ grams w = 9.734X10"*' grams/day 



From these the rate per second follows as 



m= i.i266Xio~^''g/sec. 

 The constants of the apparatus are 



2//" =11 cm. / = 22cm. 



489 dyne /cm. 



involving, however, the change of gas constant. Hence the true coefficient 

 K, referred to unit of volume transpiring, if the density of hydrogen be 

 taken as 89.5 X io~^ is 



K = 2. 14X10"^'' 



or the velocity of transpiration is 2.14X lo"^*^ cm. /sec. This is, therefore, 

 more than twice as large as in case of air, where ^ = 0.91 X io~^°. 



If follows, finally, that the virtual viscosity, 77, of the intermolecular gas 

 through which the hydrogen molecule supposedly transpires, if iV=6oX 10'^, 

 2r = 2Xio"^cm. (O. E. Meyer), is 



r/ = I /67r Nrv = 0.0004 ^ 3 



The viscosity of hydrogen at ordinary temperatures is normally 91.5 X io~^. 

 Hence the virtual viscosity of the intermolecular hydrogen would be four 

 and a half times larger than its normal viscosity. 

 Using Millikan's data for N and r, viz, 



iV = 2.64Xio'' 2r = 2. 28X10"^ cm. 



the datum 2AV = 6.03Xio" replaces 2A>= 12.0X io^\ whence 



77 = 826X10"^ 



Here in turn the discrepancy of Stokes's equation is to be added. If it 

 is applied, the value of 77 will be further increased about 50 per cent or the 

 virtual viscosity of the intermolecular medium is finally 



17 = 1240X10"® 



