Thinned

Suddenly as we looked at the ship we saw a dense black cloud of smoke shoot up from her, which hung like a monstrous tree upon the sky line. A few seconds later a roar like thunder burst upon our ears, and as the smoke thinned away there was no sign left of the Gloria Scott.

No sooner had Acates finished speaking than the cloud suddenly parted and, in the serene sky, thinned out and vanished.