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WAUSAU 323 WAVE LENGTH tice in Mississippi; removed to Gonzales CO., Tex., in 1850; was a member of the Provisional Congress of the Confederate States in 1861. During that year he re- cruited 2,000 troops, known as Waul's Legion; was commissioned colonel of this body; and remained with it throughout the war. He rendered the Confederates important services as commander of the defenses at Tallahatchie and Yazoo rivers, Miss., and during the seige of Vicksburg; was promoted Brigadier-Gen- eral and later took a conspicuous part in the battles of Pleasant Hill and Mans- field, La. He was subsequently seriously wounded while leading a division in the battle of Saline. In 1865 he was a mem- ber of the Texas Reconstruction Conven- tion ; resumed the practice of law in Gal- veston, Tex.; and retired in 1896. He died in 1906. WAtrSAU, a city and county-seat of Marathon co., Wis.; on the Wisconsin river; and on the Chicago and North- western, and the Chicago, Milwaukee and St. Paul railroads; 42 miles N. E. of Grand Rapids, Wis. Here are nu- merous churches, court house, County Insane Asylum, waterworks, electric lights. National banks, and daily and weekly newspapers. Large quantities of lumber are here shipped dovra the river in rafts. The chief industries are those connected with the lumber trade. Be- sides the lumber industry the city has granite quarries, mills, etc. Pop. (1910) 16,560; (1920) 18,661. WAVE, 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 undulat- ing 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 cer- tain extent, to and fro, though it is trans- mitted to a distance by the fact that at each successive point the otherwise simi- lar 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 move- ment affects the water only to a few feet in depth, where, unless there are sub- marine currents, all is still. When a wave comes inshore and enters a narrow gulf, it becomes affected both by the re- turn 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 be- fore 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 abund- ant 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 po- tent 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 caves, allowing the harder rocks above in time to fall in, or they break off portions of those harder rocks themselves, beside grinding against each other any fallen slabs which may already be lying on the beach. WAVE LENGTH, the distance, in all kinds of wave motion, from crest to crest of successive waves. In the wave mo- tion of light these distances are almost inconceivably minute. The wave in the visible part of the spectrum ranges from about ^ihm inches in the red end to about ^hn inches in the violet. In the yellow part of the spectrum, where it is brightest (in sunlight) the wave is about rFBOT inches. When we remem- ber that light travels through space with a velocity of about 186,000 miles per sec- ond, if we wish to get some faint idea of the almost inconceivable frequency of the vibrations, multiply the denomina- tors of the above fractions by the num- ber of inches in 186,000 miles. We shall find that the extreme red light vibrates about 400,000,000,000,000 times, the yel- low light about 510,000,000,000,000 times and the extreme violet light about 800,- 000,000,000,000 times per second. The