DECHEN. 42 DECK. that city, but soon devoted himself to practical mining, and subsequently held a number of im- portant Government posilious. In 1S34 he was made professor of mining engineering iu Berlin, and in 1841 director of mines at Bonn. Besides a mmiber of valuable geological maps, Deehen's published works include: Oeognostiiiclic Vnirisse der Rheinlaiidc zuiaclieii liascl und Mainz (2 ^ols., 1825) ; Gcofiiioslische Beschrcibtnig des Siebengebirgcs (1S52); and Die iiutzbarcn ili- neralien und Gebirgsarteu im Deutschen Reich, vebst cinvr phi/siographischen und gcognostischen Vebersicht des Gcbictes (1873). He was also for many years editor of the Archif fiir Mincralogie, Oeogtiosie, licrgbau- und Hiittenkunde. His in- vestigations of the geological structure of the Ehineland and Westphalia formed his chief contribution to science. DECID'TJOUS PLANTS (Lat. deciduus, fall- ing down or oil', from dc. away + cadere. to fall) . Plants which have organs that are shed periodi- cally. The term deciduous is applied in particu- lar to those trees and shrubs that shed their leaves at the approach of a season of cold or drought. See Duratiox: Forests; Trees. DECIDUOUS TEETH. See Teeth. DEC'IMA (Lat., fern, of decimus, tenth, from decern, Engl. Icn). In music, (1) an inten'al of ten diatonic degrees (for example, f rom C to E), or practically the third above the octave, as which it is treated in harmony. There are only two cases in which it is treated differently from the third: first, in double counterpoint, where a necessary difference nuist be made although the same harmonic rules apply: and second, in thorough-bass, where the figure 9 shall rise a degree to 10, instead of falling a degree to 8. (2) An organ stop, called also double tierce, pitched a tenth higher than the eight-foot stops. DECIMAL FRACTION, See Fr.^ction. DECIMAL NOTATION. See Xotation, DECIMAL SYSTEM (from Lat. decimus, tenth ) . A name applied to any system of weights, measures, mimey, etc.. in which the standard unit is divided into tenths, hundredths, etc., for the denominations below it. and multi- plied by 10, 100, etc., for those above it. An excellent example is that of the French or metric system of measures. The meter (approxi- mately 30.37 inches in length) is the unit of linear measure, and serves as a foundation for the measures of lengtli, surface, volume, capacity, and weight. For the higher denominations the Greek drl.n. liel.tn. Icilo. mi/ria. are prefixed to signify the multiples 10,' 100. 1000. 10.000, respectively. Thus 1 dekameter = 10 meters; 1 hektometer 100 meters, and so on. On the other hand, the T.atin prefixes dec!, cenfi. milli, are used to express divisions by 10, 100, etc., and thus furnish names for the lower denomina- tions; e.g. 1 decimet<>r =r y!^ of a meter: 1 centi- meter =: y^ "^ '"'■ '"cter. Similarly with money; the franc being the unit, a decime is the tenth part of a franc, and a centime the hundredth ))art. The monetary system of the United States of .meriea, like that of nearly every civilized country except England, is decimal. Indeed, the numerical system in general use the world over is the most notable example. See Metric Svsteii ; Nitmebals ; Notation ; and Fraction. DEC'IMA'TION (Fr. dc^cimation, Lat. decima- tio, from diciniitrc, to decimate, from dcccm, ten). A punishment sometimes inllicted in the armies of ancient lone. In instances wlieie a crime had been committed by soldiers en masse, which would merit desith in the individual, one-tenth of the wliole number would be put to death. The individuals were selected by lot. DECIUS, de'shl-us, Gaus JIessii s Qiintvs Traiaxus. a Itonian KmiM>ror (a.d. 241'-251). He was a native of Pannonia, and of lUyrian stock. He commanded the troops of the Em- peror Philippus on tlie Danube, and in a.d. 248, at the end of the year, his soldiers in iloesia revolted, and forced him, against his will, to proclaim himself emperor, and lead them into Italy. Philippus marched against him, but was .slain iu battle near Verona. In 250 Decius or- dered all Christians to renounce their faith, and a cruel persecution ensued, notably at liome, Carthage, Alexandria, Jerusalem, and Antioch, Fabianus, Bishop of Kome, was martyred on Januarv 20, Cyprian, Bishop of Carthage, was forced to leave his see, and the bishops of Alex- andria and Antioch perished in prison, Tlie great Origen also was cast into prison and tor- tured iu Ctesarea, In the following year (251) Decius was called to Thrace to check a great invasion of the Goths, but was abandoned by his general, Treboniauus Gallus, who sought the throne for himself, and Decius, together with his son, perished in battle. DECIUS MUS, PuBurs. Father, son, and grandson, consuls and generals of the Roman Republic, around whose memory grew traditions of noble heroism. The first commanded the Roman army in the Latin War (B.C. 337), and just before a battle was fought near Vesuvius, he had a vision and was told that the army of one side and the general of the otlier were de- voted to the gods of the dead. Accordingly, De- cius Mus exposed liimself to the attack of the enemy and lost his own life that the hostile army might be destroyed. The son found himself in a similar position against the Gauls at the battle of Sentinum (n.c. 295), when his heroic death gave the victory to the Romans; and again the grandson was said to have lost his life voluntarily for the same cause at the battle of Aseulum (B.C. 279), in the war with Pyrrhus. DE CIVITATE DEI, de slv'i-t:-i'te dC-'i. See AVGl'STIXE, SaIXT. DECK. The flooring or platform formed by covering the deck beams with steel or planking. The term is sometimes used to express the space above a deck to the under side of the next higher deck. In old type rigged men-of-war the upper deck was called the spar deck: the next deck, the gun deck — if guns were carried on it — if not, it was called the bcrlh deck: the next deck below the berth deck was the orlop deck. In old tliree- deckers (i.e. wooden lineof-battle .ships carrying guns on three covered decks) these were called the main, middle, and loiccr decks. The half- deck, in vessels having one or more covered gun decks, was that portion of the next deck below the spar deck extending from the mainmast to the cabin bulkheads. The quarter-deck was the part of the upper deck which was abaft the mainmast. These terms, quarter and half, were derived from the character of the decks in the days of high castle-like poops and forecastles.
