40 Wild Life in a Southern County. 
itself was dark, and the dark grey vapour harmonised 
precisely with its hue ; so that the real hill and the 
cloud merged into each other. Either the barn and. 
clump of trees were reproduced or perhaps enlarged 
and distorted by the refraction: the seeming column 
of smoke was a fragment of a blacker colour which 
chanced: to be in a nearly perpendicular position. 
Even when recognised as such, the illusion was still 
perfect ; nor could the eye separate the hill from the 
unsubstantial vapour. 
As I watched it, the apparent column of smoke 
bent, and its upper part floated away, enlarging just 
as smoke, its upward motion overcome by the wind, 
slowly yields to the current. Soon afterwards the 
light breeze stretched out one end of the mass of cloud, 
began to roll up the other, and presently lifted it, 
revealing the real ridge beneath, which grew momen- 
tarily more distinctly defined. Finally, the misty 
bank hung suspended over the down, and slowly sailed 
eastwards with the wind. Some time afterwards I 
saw a similar mirage-like enlargement of the down by 
cloudy vapour resting on it and assuming its contour ; 
but the illusion was not so perfect, because seen from 
a more open spot, allowing an extended view of the 
range, and because the cloud was lighter in colour than 
the hill to which it clung. 
These clouds were, of course, passing at a very low 
elevation above the earth: in rainy weather, although 
but a few hundred feet high, the ridges are frequently 
