Dr Traill read an account of dust falling from the atmosphere on the 2d and 3d of September last, in the islands of Orkney.

This dust was observed by a gentleman in the island of Rousay, falling from the air in the morning of the 2d. It was collected by another at Skaill, on the western shores of Pomona, on the morning of the 3d; and by two other gentlemen in Kirkwall on the same day. It appears also to have fallen in several other parts of Orkney, probably over all the islands; and was observed also to reach the northern coasts of Caithness, within an area of which the radius cannot be less than 30 or 40 miles.