INCREASING SUPERSATURATION. 33 



Very soon, however, the effect of 8p ceases to increase the apertures. 

 All the ^-curves either pass through a maximum or reach a limiting 

 asymptote, as is particularly marked in case of table 15 (figs. 20 and 

 21). The fog limit lies a little lower in case of the large chamber (wood, 

 vlV=o.ii,) than in the case of the small chamber (glass, v\ F 0.063), 

 an anomalous result, since the latter condensation must be the swifter. 

 There does not seem to be any adequate effect for the relative sudden- 

 ness of condensation in the two cases. The last parts of table 13 con- 

 tain examples in which, with the same apparatus and apparently 

 under identical conditions (dew on one side of the glass), a steady and 

 thereafter an oscillating aperture is encountered. The last series gives 

 an instance of oscillations which vanish when the water in the fog 

 chamber is shaken from side to side. 



TABLE 13. Effect of pressure difference. Long condensation chamber. ^ = 55X12 

 X2O = i3,2oo cm. 3 , for fog chamber; V= 106,000 cm. 3 , for vacuum chamber 



v\V= ' = 0.125. Instantaneous valve. Goniometer 85 cm. from fog chamber. 



106,000 



TABLE 14. Cylindrical condensation chamber. t//F=o.o6. 



Goniometer 85 cm. from fog chamber. 



Instantaneous valve. 



* Initial excess. 



