Page:The New International Encyclopædia 1st ed. v. 20.djvu/448

* WAVES. 374 WAXES. are less attenuated than short ones in general. Consequently, as a complex train of waves ad- vances, its diti'erent component trains are at- tenuated to different degrees, and the 'shape' of the wave changes. Tliis is called 'distortion.' If the inertia of the medium is very great, the at- tenuation is diminished, and the distortion al- most vanishes. Waves along stretched cords are special cases of elastic waves. See Acoustics. Stationart Waves are the particular kind of vibration observed in stretched cords, the air in organ-pipes, etc. (See Acoustics.) It is evi- dent that, if waves are sent down a stretclied rope toward the end which is fastened to some rigid support, they will be reflected when they reacli the end. Consequently, if waves are con- tinued to be produced, there will be in the rope at any instant two trains of waves of the same wave-length, velocity, and amplitude, but ad- vancing in opposite directions. It must happen at certain points in the rope that one train of waves neutralizes the action of the other; and it is evident that these points must lie at a dis- tance of half a wave-length apart. These posi- tions of no motion are called 'nodes;' and the fixed end of the rope is one. In between two nodes the rope vibrates exactly like a short rope of a length equal to the distance from node to node and fastened at its two ends. A point mid- way between two nodes is called a 'loop.' If a long rope is hanging vertically from a balcony, with its lower end free, waves sent down it will be reflected ; and there will be nodes and loops as before, only in this ease the free end is a loop. Such a vibration is called a 'stationary wave,' an extremely poor name, because it is not a wave-motion at all. The vibrations of the air in an organ-pipe are of this kind; the nodes are points where there is the least motion but the greatest fluctuation in pressure, while the loops are the points of greatest motion but the least change in pressure. The open end of an organ- pipe is a loop. The effect of opening a bole in a flute is to make that point a loop and thus alter the vibration of the column of air. Stationaiy waves may be produced by the ether-waves, as has been shown by Wiener and others. See Light; for electrical waves, see Electricity, paragraphs on AUernutiiiy Currents and Electri- cal Wat;es Along Conductors. WAVRE, v-i'vr'. A town of the Province of Brabant, Belgium, on the Dyle, 15 miles south- east of Brussels (Jlap: Belgium, C 4). There are breweries, tanneries, paper mills, and cotton manufactures. Population, in 1809. 8200. Here on June 18, ISl.i, after their defeat at I.igny (q.v. ), the Prussians under Thielniann repulsed a greatly superior force of the French under Grouchy, and thereby prevented the latter from bringing timely assistance to Napoleon at Water- loo (q.v.). WAVRIN, va'vraN' (or Waurin), .Jehan DE, Seigneur du Forestel (e. 1.304-0.1474). A French chronicler of England, whose work covers the history of Great Britain, both real and fabled, from the earliest time to 1471. It has been edited by Sir W. Hardy and translated by E. L. C. P. Hardy, under the title "Recucil des Cro- nJques ct ancicnnes Tstories de la Grant Bre- taigne a prC-sent nonime Engleterre" ("Master of Rolls Series," 1864-91). Consult Anciennes cro- niques d'Engleterre, choix de chapitres inedits, edited by Mile. Dupont (publications Soei^te de I'Histoire de France, Paris, 1S58-G3). WAX, iMiNERAL. See Ozocerite. WAXAHACHIE, waks'a-hach'e. The county- seat of Ellis County, Tex., 30 miles south of Dallas. OB the llissouri, Kansas and Texas and the Houston and Texas Central railroads (Map: Texas, F 3). It is the shipping point of one of the richest farming sections in the State, a dis- trict which produces cotton, wheat, oats, corn, etc. Cotton gins, a cottonseed-oil mill, a flour mill, and lumber yards are among the more im- portant industrial establishments. The water- works are owned by the munici|)ality. Popula- tion, in 1890, 3076;" in 1900, 4215. WAXBILL. One of several weaver-birds (q.v.) liavinig a coral-red, waxy beak; especially the astrild (Estrilda astrilda), a near relative of the aniidavad (q.v.) — a common cage-bird. WAX CLUSTER. See Gaultheria. WAXES. A class of substances of animal or vegetable origin containing mainly one or more esters (q.v.) composed of higher monatomic or diatomic alcohols and higher fatty acids. Waxes have a somewhat characteristic consistence, simi- lar to that of their prototyiie, beeswax, although some (e.g. the so-called sperm oil) are liquid, and others (e.g. carnauba wax) are so hard that they can be readily pulverized in a mortar. The principal difference, chemically, between waxes and fats consists in the f'act that the alcohol found combined in the latter is ordinary glycerin (a tri-atomic alcohol). The term waxes, how- ever, as used commercially, is often extended to substances having a 'waxy' consistence, but con- taining no ester of a monatomic or diatomic alcohol at all. Thus the so-called 'Japan wax' is really a fat, almost entirely composed of gly- cerin and palmitic acid; the so-called 'myrtle wax' consists of about 20 per cent, of tri-palmitin (i.e. the fat composed of glycerin and palmitic acid) and about 80 per cent, of free palmitic acid. On the other hand, the term 'oil.' which is gen- erally applied to the true liquid fats, is in com- mercial usage extended also to liquid waxes, like the spei'm oil already msntioned. Free fatty acids (as well as free monatomic or diatomic alcohols and hydrocarbons) are found also, in limited quantities, in the true waxes. But if waxes are at all to be classed separately from the fats, the term waxes should not be a])plied to materials containing glyeerides, and the term oils should not be applied to materials contain- ing no glyeerides and composed chiefly of the substances that characterize the true waxes. Of course, since the true waxes contain no gly- cerin, the latter does not appear among their saponification products, nor can acroli'in be pro- duced during their combustion. (See Fats.) Another tliffercnce between waxes and fats be- comes apparent when they are subjected to proc- esses of saponification. Thus, while any fat may be more or less readily saponified by alkalies dissolved in water, waxes can hardly be thus saponified at all, so that it is necessary to use potash or soda dissolved in alcohol when it is required to effect the saponification of a true wax. The following paragraphs contain ac-