LIQUIDS AND ALLIED EXPERIMENTS. 



23 



by the flow of hydrogen into them, so that they finally break oflf or may be 

 shaken off. After the first few days such bubbles no longer occur. This is 

 additional confirmation to the effect that hydrogen here diffuses from 

 apparent low pressure to apparent high pressure, so far as water levels are 

 concerned, in cases where it enters a medium of air, however small; i. e.,the 

 gradients due to mixture imply that pa>h"p^g, p,,<B~T, since pa+P),— 

 B-\-h"p^g — Tr is constant. Wherever the water is continuous or in actual 

 contact with the glass, no bubbles are produced. Neither do they ever 

 occur for the diffusions of air into air. 



Table 4. — Diffusion of hydrogen through water into hydrogen. 



^=0.005823; Af= 18.09; Pm=i3-6; /j' = o.8cm.; ;j"=ii.ocm.; /j"' = 5.5 cm.; /=22.ocm.; 



i/pj = o.3486*; water-head 0.06 cm. Hg. 

 Areas: 12.6 cm.^; 24.6 cm.'. Diameters: 4.0 cm.; 5.6 cm. 



*Cf. §24. 



After March 9, however, the regular decrease of weight begins, again 

 abruptly, due to the transpiration of hydrogen in accordance with the 

 pressure gradient (water-heads) alone. After March 20 it progresses with 

 satisfactory uniformity until April 14, when the experim.ents were broken 

 off, as it seemed improbable that further characteristic changes would occur. 



