Wave

Collier's New Encyclopedia (1921)

one of a series of undulating inequalities on a surface; an undulation; a swelling outline. The undulating streak or line of luster on cloth, watered and calendered. Anything which advances and recedes, rises and falls, comes and goes, or increases and diminishes with some degree of regular recurrence, like a wave; as, a wave of prejudice, a wave of popularity, etc. A waving or undulating motion; a signal made by waving the hand , a flag, or the like. In physics, an undulation; a movement which, though it seems progressive, is in reality only up and down, or, to a certain extent, to and fro, though it is transmitted to a distance by the fact that at each successive point the otherwise similar motion of a single particle takes place a little later in time = the time which it takes for the motion to be communicated from the preceding moving particle. Waves exist in water, in air (sound waves), in ether (light waves), etc. A wave on the ocean alternately rises into a ridge and sinks into a depression (the trough of the sea). Anything floating, say a quantity of sargasso seaweed, rises on a billow and sinks again as the wave falls, without otherwise changing its place. Even the undulatory movement affects the water only to a few feet in depth, where, unless there are submarine currents, all is still. When a wave comes inshore and enters a narrow gulf, it becomes affected both by the return of the reflex waves from its sides and the friction of the bottom, if the water be shallow, so that instead of a movement mainly up and down, it now becomes progressive, and breaks in a series of billows on the sands or rocks. In the former case the water runs up the sand, and then recedes considerably before the next wave comes in. Sea waves are mainly caused by the wind. If a breeze blowing off the shore cause ripples near the land, these will rise higher the farther they are from the shore if the cause which brought them into being continues to operate. Out on the open ocean they rise to some feet in elevation, but it is a great exaggeration to call them " mountains high"; they have, however, been witnessed approximately 60 feet from trough to summit in the Atlantic. When they rise into a sharp ridge, and the wind is strong, they crest over, break, and fall on the leeward side with abundant spray; but this does not occur on the ocean to the same extent as near shore. The force of waves is so great that, geologically viewed, they are a potent force in altering the conformation of coasts. When in a storm they break with transcendent force on a shore they scoop out soft shales into the harder rocks above in time to fall in, caves, allowing or they break off portions of those rocks themselves, beside grinding against harder each other any fallen slabs which may already be lying on the beach.