In all of them you seem to feel the interposition of the air between you and the distant horizon at which you are looking.

What else is there?
At each point in the picture the air modifies the distinctness with which you can see the objects.

This consciousness of air in a picture of low horizon is a very difficult thing to describe and explain.

We know when it is there and when it is not.

It has to be seen, to be enjoyed, and recorded.