The impalpable dust was thick upon its floor.

About them rose the impalpable dust of ages.

An enormous mushroom of impalpable dust, settling very slowly in even this thin air.

There was the faintest possible residue, like a coating of impalpable dust.

The dry air smells of sage and salt and impalpable dust.

Remember the explosion in our laboratory, that blew an entire mountain into I impalpable dust?

But all we could find was a sort of ridge of impalpable dust, which gave out a strange dead odour.

The brown gas in the air already had changed to an impalpable dust that was settling slowly to the floor.

For a quarter of an hour I trod on this sand, sown with the impalpable dust of shells.