DEMONOLOGY. 119 DEMOSTHENES. demons iu the old Brahmanic gods, and the jiuHs ol" Mohanitm-danism are the heathen Arabic deities in disguise. The worship of demons has ied to the cult termed diabolism or satanism (ii.v.). The earliest mention of such a belief is in the Avesta (q.v. ), where adherents of uon-Zoroastriau faiths are called daevavasnians or demon worshipers. Persia still has a numerous sect of devil- worship- ers, called Vezidis (q.v.), who endeavor to keep on jiood terms with the devil that he may not injure them in the future world. A similar tendency existed to a marked degree in early Christian (Inosticism (q.v.). The .sect of the Ophites, for instance, regarded Yahweh as an evil divinity, but the serjient, because of his promise of knowledge (Gen. iii. 5), as the highest god and a benefactor of mankind. The modem cult of satanism seems to be a survival of early Gnosticism. This worship, which is, for obvious reasons, of an occult nature, seems to unite to diabolism the widespread notions of phallicism, or worship of the reproductive powers of nature. Satanism, which is now mainly a travesty of Christianity, finds its culmination in the "so-called black mass, where the Christian ritual is parodied in most revolting ways. Consult: Collin de Planey, Diclionnaire in- fernal (Paris, 1844) ; Lecanu, Bistoire de Satan, sa chute, son citlte, scs manifestations, ses oeuvres (Paris, ISlil ) : P>oskofi", Ocschichte des Teufels (2 vols., Leipzig, 1869) : Hild, Etude sur les demons (Paris, 1881); Laengin, Wunder und Diimviicnulanhe dcr Gegenuart (Leipzig, 1S87); Conway, Demonologt/ ami Dctil-Lure (2 vols., Xew York. 1880) : i?ois, Satanisme el la mac/ie (Paris, 1805) : Cams, History of the Deril and the Idea of Evil from the Earliest Times to the Present Dai/ (Chicago, 1000) ; Jaulmes, Essai sur le satanisme et la superstition an nioyen age (Montauban, 1000) : Alexander. Demonaic Pos- session in the Old Testament (Edinburgh, 1902) ; and see Axgel: Devil; Sopiiiologt: Slpersti- TIO.V. DEMONSTRATION, iliLiTARY. An opera- tion designed to deceive an enemy, persuading him that danger is threatening from another quarter, and inducing him to divide his force so as to meet the apparent as well as real danger. A denmnstration jnade during the attack, in order to cover the development of the real point of attack, or to <liscover a vulnerable point in the defense. i< called a feint. DEMONSTRATIVE LEGACY. See Legacy. DE MOR'GAN. Augustus (180fi-71). An Kngli-h niatlii'iriatician. born at Madura. Madras. He was (Mlucated at Trinity College. Caniliridge; was graduated as fourth wrangler (1827), and was professor of mathematics in the University of London (afterwards I'niversitv College) from 1828 to IS.'?] and from lS.-?0 In' 1800. Besides being a mathematician of high rank, he was ex- tensively versed in the history of mathematical and physical science. He gave much time in atteni])ting to formulate .ristotelian logic into a symbidic system: contributed to the nietbods of calculating insurances and to the encouragement of a decimal coinage. De Morgan was the first presidcntof the Loiiilon Mathematical Society, and was a member of the Itoyal Astronomical Society. He was a remarkable teacher and suggestive writer, and his Essay on ProbaliUties (1838) is st ill one of the best in English. He died in London. The following are among his chief works: Ele- ments of Arithmetic (1831) ; Elements of Alge- bra, Preliminary to the Differential Calculus (1835); Essay on Probabilities, and on Their Application to Life Contingencies and Insurance Offices (1838): THgonometry and Double Alge- bra. (1849); Formal Logic, or the Calculus of Inference Xeeessary and Probable (1847); Ar- ithmetical Books (1847): Treatises on the Dif- ferential and Integral Calculus (1842), pub- lished by the Society for the Ditlusion of Useful Knowledge; contributions to the Penny Cyelo- pwdia and to the Encyclopwdia Metropolitana. A memoir of De Morgan by his widow was pub- lished in London in 1SS2. DE'MOS (C4k. S^/wc, demos, people). A wonl used in Cireek to denote the whole body of -Vthenian citizens — that is, the State. It also has a narrower meaning, usually expressed in English by the word deme. See Deme. DEMOS'THENES (Gk. ATj^offOMf) (c.383- 322 ii.c). The greatest orator of the ancient world. He was bom in the deme Pii>ania, in Attica. His father, a wealthy manufacturer, died early, leaving his fortune and children to the care of three guardians, wlio abused their trust. As soon as Demosthenes came of age he prosecuted at law these trustees and gained his case; but much of the property had already been squandered, and he recovered only enough to save him from poverty. His success in this and some other civil causes fixed his resolution to devote himself to public life, and he set him- self to master the law and politics of his country with a labor and perseverance almost without parallel. His first appearance before the people was a failure, but this spurred him to overcome his defects. His first care was to conquer the physical disadvantages under %hich he labored. His health was naturally feeble, his voice harsh and tunelesSj and his action ungraceful. We are told that, to strengthen his lungs, he used to climb steep hills, reciting as he went, or declaim on the shores of the sea in stormy weather. To improve his delivery, he took instructions from Satyrus, the actor, and did not disdain to study ell'ects before a mirror. His feebleness of health he never fairly overcame; but he obviated the defects of his early training by the severest study pursued for months at a time without an inter- ruption. Demosthenes first began to take part in public atTairs when he was about twenty-five years of age, and from that time till his death his his- tory is the history of Athens. The States of Greece were at this time miserably weak and divided, and had recklessly shut tbeir eyes to the dangerous eneroachment-s which Philip of Maccdon was already making on their common liberties. The first period of Dcmosthenes's pub- lic life was spent in warning his countrymen to abate their mutual jealousies, and unite their forces against the common enemy, whose crafty and grasping policy he exposed, about n.c. 351, in the oration known as the I'irst I'hilippic. In i:.f. 347 Philip became master of Olynthus. the hist outpost of Athenian power in the north, which, in a series of splendid harangues — the three Olynthiacs — Demosthenes had implored his countr>'men to defend. Peace was now necessary for Athens, and Demosthenes was among the ambassadors sent to negotiate with the con-
