DEMOGORGON. lU DEMOLITION. (or Lutntius) Placiilus to the Thebnla of Statins (iv. 51ti) as till- name of llie iiiighly l>ciiig wlmiii all the powi'is of the lower world obey. Other iiianuseripts show varviiij; forms, and it is very probable that we have to do with a eopyist's corruption of the (.ireek iriiMovpyis, dOniioiirgos. Mythologieal writers of the Kenaissanee.especially Boeeaceio, took up the word as the name of a su- preme power, and thente it passed, into Arioslo and other poets. Amonj; Kn;;lish writers lie- niogorgon is mentioned l)y Spenser and Milton, and in Shelley's I'roiiullnus inbound is intro- dueed as the mighty ]iowcr which overthrows Jove. Even if the form of the name is correct, there is no reason to su)(pose that name or being was known to any classical writer. DEMOGRAPHY ( Fr. di'moi/raphic, from Gk. irj/MSyt (li'iiiuis, country, people + ypd<petv, gra- pluin, to write, describe). A branch of the science of statistics. In its narrower sense it deals ex- chisively with vital statistics, the statistics of population. In its broader sense it has been ■ letined as "the science of statistics applied to questions concerning the .social well-being of the people," and it has been considered as synonymous with statistics. The term was first used by Achille Guillard in his h'lenicnts de slalistiqite hnmaine oil demographic com /larve (Paris, 1855), and since then it lias been adopted in all coun- tries, although it has not been accepted by all statisticians. Demographic statistics are so closely associated with anthropology that demog- raphy has been called a branch of anthropologj'. They are also of special iiiiportance for sociology. Statistics of population are fundamental. In general they measure the growth and decay of population, the normal and abnormal conditions, the working of great social inlluences, and the pressure of anti-social forces in the community. In a more detailed form demographic data may include the following: (I) The composition of the population; the numbers, density, sex, age, jiarcntage, defective classes, physical condition in relaticm to disease and epidemics, and manner of grouping from point of view of race, occuj)a- tion, or civil position. (2) Changes in |>oi)ula- tion, as expressed in births, marriages, and deaths. (.3) Migrations and their elVeets, both individual and local, and their relation to eco- nomic conditions. (4) Morality, with statistics of crime, illegitimacy, and suicide. (5) Degrees of education. (0) Kconomic and social statistics, especially relating to insurance. In drawing con- clusions from these statistics an important theo- retical topic is their application to the doctrines of Malthas. Demography is recognized as a cognate subject to hygiene, and since 1HS7 the International Congress of Hygiene and Demograplij' has held annual meetings in the dill'erent European cities. Demographic material is found in all national bureau reports on population. In the I'nited States the word is less widely used, and in its narrow sense. For instance, Prof. Mayo Smith divides population for the study of social lugaiii- zation into demographic. so<ial, and ethnograph- ic classes, and only includes in the lirst the individuals who are distinguished by dilTerences in sex. age, conjugal condition, and physical health. The American Statistical Association also publjclies niiirh demographic material wllli- oiit so rlistingiiishing it. f'onsult: MayoSmitli, gta/i/..v „,../ s,„i„logy (New York, IH!)')) ; Lc- vasseur, "History of Demography," in Report of lull riiiilioniil i'ongrms of Hygiene and Uemug- laphtj, vnl. i. (Butlapcst, 18!)4). See Statistics. DEMOISELLE, dt ■mwii'zel'. A fish of the family Pomacentridir. These fishes are remarkable for their graceful form and brilliant colors, and abound in tropical seas, haunting the coral reef~ and feeding upon corals and other small crea tures, niucli after the manner of coral-lishes. A cliaraclcristically brilliant species is pictured on the Colored Plate of Piiii.ippiNK Kismcs. DE MOIVRE, .1. mwii'vr', Ahhaium (lOOV- I7.J4). A distinguished Krciiih mathematician. Tie was born at itry, Chanipagnc. but spent the greater jiart of his life in England, whither he lied in lti88, with many others, after the revoca- tion of the Edict of Nantes (KiSS). He su|i- porled himself by private tutoring and public lecturing, and, toward the end of his life, by solving problems in chance, play, and annuities. lie was a fellow of the lioyal SiK'iety of London and member of the Rerlin and Paris academies, file I'liih'xopliical Truti>iarlions of Loiiilon con- tain many of his contributions. He was so esteemed by the Itoyal Society that he was elioseu to decide the famous contest between Xewtiai and Leibnitz concerning the invention of the calculus. De Moivre's researches, with those of Lambert, created the jiart of trigonometry (q.v. ) , which deals with the imaginary quantities, and he contributed much to the advancement of the theory of numbcis and of probability. AmoiiL' his published works are: Miseellaiiea Aiiah/lifi de Seriebiis el Quadrat iiris (1730) : Doelrine of Chances (1st ed. 1718: 2d ed. 1738): Annm ties upon Lives (1725, and several subsequent editions). The well-known theorem which bears liis name is connected with complex numbers (q.v.). It may be stated thus: (cos^J + isiii 9)n = COSH (J + isinn^. DEMOLITION ( Fr. di'molition, Lat. dcmo- lilin, from deinoliri, to pull down, from de, down + moliri, to build). The scieutilic de- struction of an enemy's works or property. In modern warfare the destruction of material is often deemed by military commanders to be essential to the success of their operations, 'fhe material which has been destroyed on various occasions has included every kind which may be of use to an army acting either on the olTensive or defensive. In some cases, as in the famous raid through the Shenandoah Valley. 'a., piac tically everything which it was thought might contribute to the success, <lirectly or indirectly, of the Confederate Army was destroyed by tleii cral Sheridan with a view of rendering it im- practicable for the Confederate Armj' to operate in the valley as it had been doing. At the other extreme lies the destruction of .some single piece of material which acts as a barrier to the prog less of an army. . typical instance of this kind was the destruction of a door during the recent hostilities in China, 'fhe progress of the ,Iapa nese troojis was delayed at one of the gates, or doors, the a|iproaclies to which were well covereil by the (Ire of tlic Chinese. . .Japanese corporal iindi'rtook to eirect the demolition of the gate by an explosion. After he had |)laced the charge, ignited a fuse, and withdrawn from its imme- diate vicinity, the llame was extinguished by the Chinese. This operation havinu' been rcpcjilcd several times, he finally drew his sword after lighting the fuse and stood over the explosive,
