Back in the 1930s my grandmother had a beau who would take her flying in an open cockpit plane. She said it was the most amazing experience flying through clouds, reaching out expecting something tangible, perhaps silky gossamer threads, but, surprisingly, feeling only moist nothingness instead.

Clouds can have a real solidity. They form shapes and move with a purpose, sentient beings of air. This morning when I arrived at work, two big balls of clouds hung over the trees across the river. They seemed to possess a heft: cloud breasts, perhaps, or giant fluffy footballs. But really, they carried no more weight than their accumulated volume of water vapor. Very large illusions. You can't touch this:


They oppress the trees
with their weight that is no weight--
great balls of water.