This however can only be foretold to a certain extent, as the tidal height not only depends upon the attraction of the heavenly bodies, but also upon the casual influences of the wind, which defies all calculation, and of the pressure of the air. Thus Mr. Walker observed on the coasts of Cornwall and Devonshire that when the barometer falls an inch, the level of the sea rises sixteen inches higher than would otherwise have been the case. When a strong and continuous wind blows in an opposite direction to the tide-wave, and at the same time the barometer is high, the curious spectators will therefore be deceived in their expectations, however promising the position of the attracting luminaries may be; while an ordinary spring-tide, favoured by a low state of the barometer and chased by a violent storm against the coast, may attain more than double the usual height. When all favourable circumstances combine, an event which fortunately but rarely occurs, those dreadful _storm-tides_ take place, as menacing to the flat coasts of the Netherlands as an eruption of Etna to the towns and hamlets scattered along its base, for here also a vast elementary power is let loose which bids defiance to human weakness. It is then that the rebel sea affords a spectacle of appalling magnificence. The whole surface seethes and boils in endless confusion. Gigantic waves rear their monstrous heads like mighty Titans, and hurl their whole colossal power against the dunes and dykes, as if, impelled by a wild lust of conquest, they were burning to devour the rich alluvial plains which once belonged to their domain. Far inland, the terrified peasant hears the roar of the tumultuous waters, and well may he tremble when the mountain-waves come thundering against the artificial barriers, that separate his fields from the raging floods, for the annals of his country relate many sad examples of their fury, and tell him that numerous villages and extensive meads, once flourishing and fertile, now lie buried fathom-deep under the waters of the sea.