"On Christmas morning, about 8 o'clock, the bed of the river of Air was perceived to be quite dry, from near the ships to the Dam-back, which is a large half-mile. Several gentlemen walked backward and forward in the channel where the water used to run, and the boys catched fishes on dry ground. When the tide began to make, the river returned to its usual bigness, and has continued so ever since." -- Scots Magazine, Dec 1764.
Reprinted in the Scottish Journal of Topography, Antiquities, Traditions, etc.etc.etc. September 4th, 1847.