65 
of Edinburgh, Session 1869-70. 
density to resist the process, it is probable it would be too slow to 
show any results unless in very long continued experiments. But 
if the air be removed as perfectly as can be done by well-known 
practical methods, it is probable that the process will be very 
rapid: it would, indeed, be instantaneous, were it not for the cold 
of evaporation in one vessel and the beat of condensation in the 
other. Practically, then, the rapidity of the process towards 
hydrostatic equilibrium through vapour between detached liquids, 
depends on the rate of the conduction of beat between the several 
surfaces through intervening solids and liquids. Without having- 
made either the experiment, or any calculations on the rate of con- 
duction of beat in the circumstances, I feel convinced that in a 
very short time water would visibly rise in the capillary tube indi- 
cated in the diagram, and that, provided care is taken to maintain 
equality of temperature all over the surface of the hermetically 
sealed vessel, the liquid in the capillary tube would soon take very 
nearly the same level as it would have were its lower end open ; 
sinking to this level if the capillary tube were in the beginning filled 
too full, or rising to it if (as indicated in the diagram) there is not 
enough of liquid in it at first to fulfil the condition of equilibrium. 
