28 THE DIFFUSION OF GASES THROUGH 



Since the area of diffusion is a = 6.4 cm. 2 and 



//'=iocm. fc'"=5cm. l=h" + 2h"'=20 cm.-| = 490-^1 



<// cm. 



(apparent) i = o.6X io -12 . Thus the volume coefficient is 



k = 4 .qXio- 10 

 Hence comparing the coefficients per unit of volume it appears that for 

 air-air ^ = 0.91 Xio -10 ; for hydrogen-hydrogen, k = 2.I4Xio -10 ; for air- 

 hydrogen, k = 4.92Xio -10 . 



Thus the present coefficient is over 5 times as large as the corresponding 

 coefficient for air and over twice as large as the coefficient for hydrogen. 

 Hence the mixture transpiring can not be pure hydrogen. The reason for 

 this large k is difficult to ascertain. 



In fact (curve e to/) after April 30 till May 7 the rate abruptly diminishes 

 again to 



— m = 5 1 X io~ 6 g/day = 5.9 X io~ 10 g/sec. 



whence &=i.57Xio -10 which is now below the value for hydrogen, as it 

 should be. 



On May 7, the upper atmosphere of hydrogen was accidentally forgotten 

 and replaced by air for but one day. The loss of weight thereafter is 

 enormous, showing that the contents must at least have approached pure 

 hydrogen. The artificial atmosphere of hydrogen was replaced on the 

 next day, but the recovery of the curve is slow (J to g in curve) and corre- 

 sponds to the initial behavior of hydrogen (§20) above. Thereafter to June 10, 

 the mean rate is — w = 26X1 o -6 g/day = 3.0X1 o -10 g/sec. From this coeffi- 

 cients are obtained as k = 0.97X10" 13 and k = 0.81 Xio -10 . Hence, as usual, 

 the influx of air has enormously reduced the final rate by diminishing the 

 partial pressure of hydrogen. 



22. Transpiration of Oxygen into Hydrogen Through Water. — These 

 results, which contain the first example of the behavior of two simple gases, 

 are given in table 6 and in fig. 9. One may note the enormously rapid rate 

 of efflux (a to b in curve), on the first day. The mean apparent rate (rela- 

 tive to mass) during this day was in fact 



— m = 8.2 X io -4 g/day = 9.5 X io~ 9 g/'sec. 



nearly 30 times as large as the final rate and about ten times as large as the 

 initial rate of the hydrogen-air system. This might seem to be due to the 

 solubility of oxygen in water, but it will probably be explained in terms of 

 the relatively high density of this gas. The rapid diffusion ceases after the 

 first day, when the greater part of the oxygen will have escaped. The case 

 is particularly remarkable, as the rate is necessarily the difference between 

 the influx of hydrogen and the efflux of oxygen, so that the actual rate of 

 loss of oxygen must have been relatively enormous. 



On the six succeeding days (curve, from b to c) the influx of hydrogen into 

 the swimmer about balances the efflux of oxvgen from the swimmer. There- 



