Page:Popular Science Monthly Volume 64.djvu/231

Rh shimmered like silk and the colors changed to brown and gray, and even white on the edges of the folds, and these changes spread through the whole face of the cloud. The base became darker, and the paler summits soared obliquely upwards and forwards; this was believed due to sinking dust and separated steam.

The steam cloud, with a velocity of twenty miles an hour, came overhead, gray and tongue-shaped, with a blunt rounded apex, and convolutions still forming. The lightnings, reduced in number and frequency, threaded the dark mass in every direction. "A low rumbling noise was given out as the cloud worked its way across the clear, starry sky." It spread across the vault, producing darkness; when it reached the zenith, pebbles fell about the size of a chestnut, cold, and these

became a rattling hail diminishing to the size of peas. Fine gray ash followed in little moist and adherent globules, noiselessly sinking through the air and sticking to everything on which they landed. They were not warm, and there was a slight smell of sulphurous acid. After a few minutes the ash took the form of a gritty dry powder. The layer which fell on deck had a total thickness of one sixteenth of an inch.

The southerly wind rose to a fresh breeze and the naturalists took their sloop into Fort de France harbor safely. They noticed a thunderstorm to the northeast, as heretofore described.