24 THE DIFFUSION OF GASES THROUGH 



To compute the constants for the diffusion of hydrogen into hydrogen 

 through water, data from March 17 to April 14 were treated by the method 

 of least squares, as shown in table 4. If 



m = m — ml 



(time in days) the constants are 



w = 8i4.i Xio -6 grams w = 9.734Xio -6 grams/day 



From these the rate per second follows as 



m= i.i266Xio _10 g/sec. 



The constants of the apparatus are 



1 = 22 cm. 



a =12 cm. 2 



h" = 1 1 cm. 



2h'"=u cn 



Thus 









dp h" Pw g 



dl h" + 2h'" 



= 489 dyne /cm 



and therefore 









b- ™ 



T ***** V/ » S^ 14 





, , 



„ — 1.92 X 10 



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 -6 is 



k = 2.I4Xio~ 10 



or the velocity of transpiration is 2.14X10 -10 cm. /sec. This is, therefore, 

 more than twice as large as in case of air, where k = o.9i X io~ 10 . 



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

 through which the hydrogen molecule supposedly transpires, if iV=6oX io 18 , 

 2r = 2Xio -8 cm. (O. K- Meyer), is 



r t = i /6n Nrv = 0.0004 T 3 



The viscosity of hydrogen at ordinary temperatures is normally 91 .5 X io -6 . 

 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, 



A T = 2.64Xio 19 2r = 2.28Xio~ 8 cm. 



the datum 2AV = 6.03X io 11 replaces 2A T r= 12.0X10 11 , whence 



77 = 826Xio~ 6 



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 



77= 1240X10"" 6 



