Critical Phenomena of Ether. 803 



tube VII. In every case the bubbles could be made to vanish 

 by gently warming the upper layers of ether and thus adding 

 the vapour pressure to the hydrostatic pressure, so that had 

 the vapour been tested under atmospheric pressure it would 

 probably have completely condensed in every case. 



Table I. 



No. of 

 Tube. 



Observations of condensation 

 of vapour. 



Fraction of 



tube occupied 



by liquid 



at 0° C. 



Critical Tem- 

 perature (of 

 reappearance 

 of meniscus). 



Bell filled 

 by inversion. 



Bell filled 

 by ebullition. 



VII 



§ remained 

 after 13 mts. 

 (f remained 

 after 90 mts.) 



Yapour con- 

 densed in 

 1 mt. 



0-335 



193°'59 C. 



XII 



| remained 

 after 13 mts. 



Vapour con- 

 densed in 

 2|mts. 



— 



— 



XIII 



T V remained 

 after 13 mts. 

 (^o remained 

 after 90 mts.) 



Vapour con- 

 densed in 

 1\ mts. 



0-385 



193°'58 C. 



XIV 



Condensation 

 complete in 

 1£ mts. 



Vapour con- 

 densed in 

 2^- mts. 



0345 



193°-59 C. 



The bell- tubes were then filled by ebullition. The bells 

 having been filled with liquid, the experimental tubes were 

 placed point downwards over a hot-water coil for five minutes. 

 They were then plunged, still point downwards, into the 

 water-tank. In this case the vapour in tube VII. condensed 

 more readily than that in the remaining tubes, the conden- 

 sation being probably assisted by the partial pressure of the 

 gaseous impurity. The distinctly greater persistence of the 

 vapour in tube XIV. may be accounted for by the additional 

 time required for the preliminary establishment of equilibrium 

 of temperature. The time required for the condensation of 

 the vapour in tube XIV. does not seem unduly great when it 

 is considered that to maintain the two menisci in equilibrium 

 at the average difference of level (about 6 cm.) a difference 

 in temperature of only 0°'2 C. between the menisci was 

 necessary, or a difference in temperature of o, l C. between 

 either meniscus and the water-bath. During the process 



