30 
THE OCEAN WORLD. 
Fogs are frequently formed over sand-banks, because the cold water 
which covers them produces a local precipitation of atmospheric vapour. 
The contour of these fogs are perfectly defined when seen from a 
distance : they reproduce the form and accidents due to the sub- 
marine soil. Moreover, we often see clouds arrested over these points, 
which look from afar like the peaks of mountains. 
