566 



MIRAGE. 



ground is not supplied in the path of the shad- 

 ows they do not appear. The specters of the 

 Brocken disappear by seeming to sink down 

 into the earth, because they are cast by the 

 rising sun; those of Ben Lomond disappear 

 by ascending into the air, because the sun is 

 sinking to the horizon. 



On the south coast of England a windmill 

 stands on a point of rocks that projects into 

 the sea, and at sunrise its shadow is seen west- 

 ward, and it always disappears by ascending into 

 the air, as represented by illustration 3. This 

 shadow also moves northward as the sun 

 moves southward in its morning declination, 



FIG. 3. WINDMILL AT NOON. 



