154 
degree of warmth experienced in the locality is not always 
proportioned to the condensation of vapour as indicated by the 
fall of rain. This was admitted, but it was contended that 
the objection taken did not invalidate the general proposition. 
It was then shown that when vapour was condensed in 
abundance and the local atmosphere thereby much heated 
and expanded, the adjoining heavier air forced the lighter to 
ascend to upper regions, conveying the liberated heat of the 
condensation with it to warm those regions, and of course 
leaving the lower air unheated. But in the winter when the 
vapour was supplied from the ocean in more moderate quanti- 
ties, at the time that the surface of the earth was cold, the 
vapour was condensed by that cold, and gave out the heat of 
elasticity near the surface. In this way it was shown that 
ice was often formed on very cold ground ; and mist and fog 
produced, at moderate heights, over land not so cold, leaving 
the liberated heat of vapour to warm the lower regions. And 
this warmth remains near the surface when the condensation 
takes place during thick fogs and light drizzling rains, because 
there is not sufficient heat set free to produce an ascending 
aerial current. The western coasts of Ireland and Scotland 
in the winter are in this way enveloped in a warm mist, a 
thick fog, or a small drizzling rain, which gives out a con- 
siderable amount of heat that remains in the lower regions, 
thus raising their temperature. The same processes take 
place over England and the whole of the western coast of 
continental Europe, making them misty and warm in pro- 
portion to the extent to which vapour is condensed over them, 
as compared with parts farther east in the same latitudes. 
Instances wei’e quoted of this kind of heating in northern 
mountainous countries. 
In the course of the discussion which followed the reading 
of the Paper, the Rev. W. N. Moles worth supported the 
hypothesis that the favorable climate enjoyed by Great 
Britain was in a great measure owing to the influence ot 
