Upwards of three years ago the author laid a paper before two members of the Scottish Meteorological Society. The question taken up was, why horizontal movement takes off vertical pressure; and the conclusion arrived at was, that every such horizontal current, owing to its passage over a resisting surface, and by means of rapid upper currents, caused removal of air and lifting, and thereby diminished pressure. It was inferred that the barometer which represented this was consequently an “effect” and not a cause of wind.