Air-Pockets in Shore Sands and Winter Packing of the Sea-Bottom

Abstract

WHILST crossing the Lancaster sands last summer from the village of Flookborough, my attention was attracted by a succession of curious sounds all around me, resembling either profound sighs or the strong flat expirations made through pursed lips by a sleeping person. These sounds were first heard in daylight; but they may have been heard at night in the past by others and given rise to tales of legendary monsters. On searching for the cause I was at once shown it by my companion, Mr. Thomas Wilson; the sounds were due to the escape of air from small pockets below the surface of the wet sand, and could be produced by perforating with one's finger the drying and slightly elevated areas of sand overlying the pockets. The vibration produced in the ground by a pedestrian or a passing cockle-cart appears to increase the air pressure sufficiently to blow off the sandy caps of the pockets.