138 Proceedings of the Royal Society of Edinburgh. [Sess. 
This curve is typical in form for the northern or eastern sides of anti- 
cyclones, though the reversed gradient is less pronounced when the clouds 
are not continuous. The general form of the curve is probably similar in 
winter also, as the appearance of the cloud and haze layers is the same at 
all seasons. 
It therefore seems probable that two layers of air of different origin are 
responsible for the formation of anticyclonic stratus ; the upper layer is 
very clear, and undoubtedly of a lower relative humidity than the lower 
layer, though I made no actual observations of this. 
Descent of Air in Anticyclones. 
On a few occasions in Northern France I have observed clear evidence 
of descent in an anticyclone of warm air to a lower level, though not to the 
surface of the earth. A good example occurred during the passage of a 
