disease, of the physical, intellectual, physiological and economical aspects of births, marriages and mortality. The first to employ the word was Achille Guillard in his Éléments de statistique humaine ou démographie comparée (1855), but the meaning which he attached to it was merely that of the science which treats of the condition, general movement and progress of population in civilized countries, i.e. little more than what is comprised in the ordinary vital statistics, gleaned from census and registration reports. The word has come to have a much wider meaning and may now be defined as that branch of statistics which deals with the life-conditions of peoples.
DEMOIVRE, ABRAHAM (1667–1754), English mathematician of French extraction, was born at Vitry, in Champagne, on the 26th of May 1667. He belonged to a French Protestant family, and was compelled to take refuge in England at the revocation of the edict of Nantes, in 1685. Having laid the foundation of his mathematical studies in France, he prosecuted them further in London, where he read public lectures on natural philosophy for his support. The Principia mathematica of Sir Isaac Newton, which chance threw in his way, caused him to prosecute his studies with vigour, and he soon became distinguished among first-rate mathematicians. He was among the intimate personal friends of Newton, and his eminence and abilities secured his admission into the Royal Society of London in 1697, and afterwards into the Academies of Berlin and Paris. His merit was so well known and acknowledged by the Royal Society that they judged him a fit person to decide the famous contest between Newton and G. W. Leibnitz (see Infinitesimal Calculus). The life of Demoivre was quiet and uneventful. His old age was spent in obscure poverty, his friends and associates having nearly all passed away before him. He died at London, on the 27th of November 1754.
The Philosophical Transactions contain several of his papers. He also published some excellent works, such as Miscellanea analytica de seriebus et quadraturis (1730), in 4to. This contained some elegant and valuable improvements on then existing methods, which have themselves, however, long been superseded. But he has been more generally known by his Doctrine of Chances, or Method of Calculating the Probabilities of Events at Play. This work was first printed in 1618, in 4to, and dedicated to Sir Isaac Newton. It was reprinted in 1738, with great alterations and improvements; and a third edition was afterwards published with additions in 1756. He also published a Treatise on Annuities (1725), which has passed through several revised and corrected editions.
See C. Hutton, Mathematical and Philosophical Dictionary (1815). For Demoivre’s Theorem see Trigonometry: Analytical.
DEMONETIZATION, a term employed in monetary science in two different senses. (a) The depriving or divesting of a metal of its standard monetary value. From 1663 to 1717 silver was the standard of value in England and gold coins passed at their market value. The debasement and underrating of the silver coinage insensibly brought about the demonetization of silver in England as a standard of value and the substitution of gold. During the latter half of the 19th century, the tremendous depreciation of silver, owing to its continually increasing production, and consequently the impossibility of preserving any ratio of stability between it and gold, led to the abandonment or demonetization of the metal as a standard and to its use merely as token money. (b) The withdrawal of coin from circulation, as, for example, in England that of all pre-Victorian gold coins under the provisions of the Coinage Act 1889, and the royal proclamation of the 22nd of November 1890.
DEMONOLOGY (Δαίμων, demon, genius, spirit), the branch of the science of religions which relates to superhuman beings which are not gods. It deals both with benevolent beings which have no circle of worshippers or so limited a circle as to be below the rank of gods, and with malevolent beings of all kinds. It may be noted that the original sense of “demon” was a benevolent being; but in English the name now connotes malevolence; in German it has a neutral sense, e.g. Korndämonen. Demons, when they are regarded as spirits, may belong to either of the classes of spirits recognized by primitive animism (q.v.); that is to say, they may be human, or non-human, separable souls, or discarnate spirits which have never inhabited a body; a sharp distinction is often drawn between these two classes, notably by the Melanesians, the West Africans and others; the Arab jinn, for example, are not reducible to modified human souls; at the same time these classes are frequently conceived as producing identical results, e.g. diseases.
Under the head of demons are classified only such spirits as are believed to enter into relations with the human race; the term therefore includes (1) human souls regarded as genii or familiars, (2) such as receive a cult (for which see Ancestor Worship), and (3) ghosts or other malevolent revenants; excluded are souls conceived as inhabiting another world. But just as gods are not necessarily spiritual, demons may also be regarded as corporeal; vampires for example are sometimes described as human heads with appended entrails, which issue from the tomb to attack the living during the night watches. The so-called Spectre Huntsman of the Malay Peninsula is said to be a man who scours the firmament with his dogs, vainly seeking for what he could not find on earth—a buck mouse-deer pregnant with male offspring; but he seems to be a living man; there is no statement that he ever died, nor yet that he is a spirit. The incubus and succubus of the middle ages are sometimes regarded as spiritual beings; but they were held to give very real proof of their bodily existence. It should, however, be remembered that primitive peoples do not distinguish clearly between material and immaterial beings.
Prevalence of Demons.—According to a conception of the world frequently found among peoples of the lower cultures, all the affairs of life are supposed to be under the control of spirits, each ruling a certain element or even object, and themselves in subjection to a greater spirit. Thus, the Eskimo are said to believe in spirits of the sea, earth and sky, the winds, the clouds and everything in nature. Every cove of the seashore, every point, every island and prominent rock has its guardian spirit. All are of the malignant type, to be propitiated only by acceptable offerings from persons who desire to visit the locality where it is supposed to reside. A rise in culture often results in an increase in the number of spiritual beings with whom man surrounds himself. Thus, the Koreans go far beyond the Eskimo and number their demons by thousands of billions; they fill the chimney, the shed, the living-room, the kitchen, they are on every shelf and jar; in thousands they waylay the traveller as he leaves his home, beside him, behind him, dancing in front of him, whirring over his head, crying out upon him from air, earth and water.
Especially complicated was the ancient Babylonian demonology; all the petty annoyances of life—a sudden fall, a headache, a quarrel—were set down to the agency of fiends; all the stronger emotions—love, hate, jealousy and so on—were regarded as the work of demons; in fact so numerous were they, that there were special fiends for various parts of the human body—one for the head, another for the neck, and so on. Similarly in Egypt at the present day the jinn are believed to swarm so thickly that it is necessary to ask their permission before pouring water on the ground, lest one should accidentally be soused and vent his anger on the offending human being. But these beliefs are far from being confined to the uncivilized; Greek philosophers like Porphyry, no less than the fathers of the Church, held that the world was pervaded with spirits; side by side with the belief in witchcraft, we can trace through the middle ages the survival of primitive animistic views; and in our own day even these beliefs subsist in unsuspected vigour among the peasantry of the more uneducated European countries. In fact the ready acceptance of spiritualism testifies to the force with which the primitive animistic way of looking at things appealed to the white races in the middle of the last century.
Character of Spiritual World.—The ascription of malevolence to the world of spirits is by no means universal. In West Africa the Mpongwe believe in local spirits, just as do the Eskimo; but they are regarded as inoffensive in the main; true, the passer-by must make some trifling offering as he nears their place of abode; but it is only occasionally that mischievous acts, such as the throwing down of a tree on a passer-by, are, in the view of the
