in Thoreau’s Journal:
They are the flitting sails in that ocean whose bounds no man has visited. They are like all great themes, always at hand to be considered, or they float over us unregarded….
What could a man learn by watching the clouds? These objects which go over our heads unobserved are vast and indefinite…..They are among the most glorious objects in Nature. A sky without clouds is a meadow without flowers, a sea without sails.