WAVE, in physics, a volume of water elevated by the action of the wind, &c. upon its surface, into a state of fluctua tion, and accompanied by a cavity. The extent from the bottom or lowest point of one cavity, and across the elevation, to the bottom of the next cavity, is the breadth of the wave. Waves are consi dered as of two kinds, which may be dis tinguished from one another by the names of natural and accidental waves. The na tural waves are those which are regular ly proportioned in size to the strength of the wind which produces them. The acci dental waves are those occasioned by the wind's reacting upon itself by repurcuss sion from hills or high shores, and by the dashing of the waves themselves, otherwise of the natural kind, against rocks and shoals ; by which oneans these waves acquire an elevation much above what they can have in their natural state.
Mr. Boyle proved, by numerous expe riments, that the most violent wind never penetrates deeper than six feet into the water; and it seems a natural conse quence of this, that the water moved by it can only be elevated to the same height of six feet from the level of the surface in a calm ; and these six feet of elevation being added to the six of excavation, in the part from whence that water so ele vated was raised, should give twelve feet for the utmost elevation of a wave, This is a calculation that does great ho nour to its author ; as many experiments and observations have proved that it is very nearly true in deep seas, where the waves are purely natural, and have no ac cidental causes to render them larger than their just proportion.
It is not to be understood, however, that no wave of the sea can rise more than six feet above its natural level in open and deep water ; fbr Waves vastly higher than these are formed in violent tempests in the great seas. These however are not to be accounted waves in their natural state, but as compound waves formed by the union of many others ; for in these wide plains of water, when one wave is raised by the wind, and would elevate it self up to the exact height of six feet, and no more, the motion of the' water is so great, and the succession of waves so quick, that while this is rising, it receives into it several other waves, each of Which would have been at the same height with itself; these run into the first wave one after another, as it is rising; by which means its rise is continued much longer than it naturally would have been, and it becomes accumulated to an enormous size. A number of these complicated waves rising together, and being conti nued in a long succession by the conti nuation of the storm, make the waves so dangerous to ships, which the sailors in their phrase cull mountains high.
• "The Motion of the Waves" makes an article in the Newtonian philosophy ; the author having explained their mo tions, and calculated their velocity from mathematical principles, similar to the motion of a pendulum, and to the reci procation of water in the two legs of a bent and inverted syphon or tube. See