



DK MORGAN, AUGUSTUa 



DBMOSTHBlfBa, 



his election into the Royal Society, as well ns, ultimately, the corre- 

 sponding societies of Paris and Berlin. The c-titnate formed of hU 

 abilities, acquirements, and impartiality, is prored by his being nomi- 

 nated as a fit person to decide on the rival claims of Leibnitz ami 

 Newton to the invention of the method of fluxion*. 



Demoirra lived to the advanced age of more than eighty seven ; but 

 u he outlived most of bis early associates and friends, his circum- 

 stance! became greatly reduced. He is said to have sunk into a state 

 of almost total lethargy, the attacks of which often lasted for several 

 days ; and his subsistence was latterly dependent on the solution of 

 questions relative to games of chance and other matters connected 

 with the value of probabilities, which he was in the habit of giving at 

 a tavern or coffee- house in St. Martin's Lane. He died on the 27th 

 of November 1754. 



Demoivre's writings, we have already remarked, are distinguished 

 by considerable originality of character. His separate publications 

 are as follows : 



1. 'Miscellanea Analytica, de Sericbus et Quadratures,' 1730, 4to. 

 This work contains several very elegant improvements in the then 

 known methods of termination of series, as well as gome new methods. 



2. 'The Doctrine of Chances, or the Method of Calculating the 

 Probabilities of Events at Play,' 1718, 4to. This work was dedicated 

 to Sir Isaac Newton: it was reprinted in 1738, with considerable 

 alterations and additions. A third edition was afterwards published, 

 differing little in anything of consequence from the second. 



3. 'Annuities on Lives,' 1724, 8vo. A work on the same subject, 

 published by the distinguished Thomas Simpson, in 1742, iu which 

 some well-deserved compliments to Demoivre were introduced, led 

 our author to publish a second edition of his work ; and it is to be 

 regretted that he was induced to insert some harsh reflections on 

 Simpson's work, which were as unfounded as they were uncalled for 

 by the manner in which Simpson had treated his predecessor's first 

 edition. Simpson however replied to it in an appendix to his work in 

 the following year, " containing some remarks ou a late book on the 

 subject, with answers to some personal and malignant representations 

 in the preface thereof." The only excuse that cau be urged for 

 Demoivre in this matter is, that he was an old man, that he considered 

 the domain his own, and Simpson as a mere poacher on it, and that 

 he was under the influence of men who wished to crush the rising 

 genius and talents of a roan like Simpson, who had not been born to 

 the advantages which enabled him to obtain a regular academical 

 education. Demoivre, notwithstanding his age, had the good sense to 

 see that he had attacked a man with whom he could not cope ; but 

 Mill i ridi: prevented his making any apology to his youcger compe- 

 titor. In 1750 he published a third edition of his work, in which he 

 m. r,-ly omitted the offensive reflections of his former preface ; and 

 here the dispute seems to have terminated. Demoivre also pub- 

 lished a considerable number of papers in the ' Philosophical Tran- 

 saction*.' There is not one of these which is not of sterling value on 

 the subjects of which they treat. 



DE MOUQAN, AUGUSTUS, was born in 1806 in the small East 

 Indian island of Madura, situated on the north-east coast of Java. 

 His father was an officer iu the British army. He can trace his 

 descent also from the mathematician James Dodsou, author of the 

 ' Anti-Logarithmic Canon.' Educated at Trinity College, Cambridge, 

 Mr. De Morgan was Fourth Wrangler iu 1827, when he took th<- degree 

 of B.A. Owing to an objection to the subscription test he did not 

 proceed to the M.A. degree. He had entered at Lincoln's Inn and begun 

 bis studies with a view to the English bar, when the foundation of 

 the University of London (1823) opened up to him a more congenial 

 career. [What is now known u " University College, London," bore 

 at the time of its foundation the name of " The Uuiventity of London," 

 and retained this name till 11137. Then, on the proposal of the 

 government to constitute a distinct degree-granting body under the 

 dfignatiou of the " University of London," to which a number of 

 colleges might be affiliated on the principle of the non subscription of 

 teats, the original institution agreed to give up the more general 

 name and, u one of the affiliated colleges, to assume the name of 

 " University College/] Appointed to the Professorship of Mathe- 

 matics in the new institution, Mr. De Morgan retained it till 1 S31, 

 when be resigned. On the death of his successor in 1886 however he 

 returned to the post, which ever since that time be has continued to 

 fill to the great distinction of the college, besides his professorship, 

 Mr. De Morgan has bad ample occupation as a consulting actuary, 

 advising insurance office*, and as one of the secretaries and a member 

 of the council of the Royal Astronomical Society. He is also a 

 member of the Cambridge Philosophical Society. But to the world 

 at Urge he is best known as the author of many mathematical and 

 miscellaneous works. Of the chief of these, published in his own 

 name, the following is a list :' Elements of Arithmetic,' 1830; 

 Elements of Algebra, preliminary to the Differential Calculus,' 1835 ; 

 'The Connexion of Number and Magnitude: an Attempt to Explain 

 the Fifth Hook of Euclid,' 1S3C; 'Element* of Trigonometry and 

 Mometrical Analysin, preliminary to the Differential Calculus,' 

 ; ' Essay on Probabilities, and on thtir Application to Life 

 Contingencies and Insurance Offices,' 1838; 'First Notions of Logic, 

 preparatory to the study of Geometry,' 1839; 'The Globes, Celestial 

 and Terrestrial/ 1845 ; ' Formal Logic ; or the Calculus of Inference 



necessary and probable,' 1847; 'Arithmetical Books, from the Inven- 

 tion of Printing to the Present Time ; being brief notices of n largo 

 number of woiks drawn up from actual inspection," 1847 ; ' Trigono- 

 metry and IXmble Algebra,' 1849; "The Book of Almanacs, with an 

 Index of Reference by which the Almanac may be found for every 

 year up to A.D. 2000 ; with Means of finding the Day of any New or 

 Full Moon from ii.c. 2000 to A.D. 2000,' 1851. Besides these works 

 Professor De Morgan is the author of the treatises on ' The I Hfferential 

 and Integral Calculus,' and 'Spherical Trigonometry,' published by 

 the Society for the Diffusion of Useful Knowledge. He contributed 

 largely to other publications of this Society, of the managing com- 

 mittee of which he was for some time a member. He was one of the 

 most extensive contributors to the original edition of the ' 1'cnny 

 Cyclopaedia ; ' most of the mathematical and astronomical articles, as 

 well as many of the articles of scientific biography were written by 

 him. Among other periodicals to which he has contributed are, ' The 

 Companion to the Almanac,' 'The Transactions of the Cambridge 

 Philosophical Society,' ' The Philosophical Magazine,' the ' North 

 British Review/ the ' Athenaeum,' Ac., 4c. Besides being a profound 

 mathematician and astronomer, he has a great affection for and an 

 extensive and minute erudition in all kinds of literary hi-tory. 

 biography, and antiquities. He is also versed in metaphysical and 

 logical studies ; and his ' Formal Logic ' mentioned in the above list is 

 one of the most remarkable of recent works in logical science. In 

 connection with this work is still remembered, as one of the most 

 interesting of the learned controversies of the day, a controversy 

 which took place in the year 1847 between Mr. De Morgan and Sir 

 William Hamilton of Edinburgh, relative to Mr. De Morgan's title to 

 an independent discovery of a new principle iu the theory of syllogism 

 expounded by Sir William Hamilton. A pamphlet on "the subject 

 was published by Sir William ; to which Professor De Morgan replied. 

 In the recent agitation for a decimal coinage Professor De Morgan has 

 taken an active port, throwing much light ou the subject by numerous 

 letters and articles. 



DEMO'STHENES was born probably in B.C. 384 or 385. He was 

 the son of Demosthenes, an Athenian citi/.cn of the demus Ptoania, 

 who carried on the trades of cutler tnd cabinet-maker, and of Cleobulc, 

 the daughter of Qylon. This Gylon, who had been governor of Ny ui- 

 phtcum, an Athenian settlement in the Tauric Chersontsus, bet 

 it to the Scythians, and afterwards taking refuge with their chief, 

 married a Scythian woman, who was the maternal grandmother of 

 Demosthenes. This impurity of blood, and the misconduct of Gylon, 

 his maternal grandfather, formed a theme for the taunts of }'.- 

 ('Oration against Ctesiphon.') There is a well-known allusion iu 

 Juvenal to tho trade of Demosthenes the older (x. 130). The point 

 of tho satirist is however somewhat lost, when we remember that 

 Plutarch applies to the father a term which expresses all that can be 

 said to the advantage of a man, and that ho had two manufactories 

 containing on the whole more than fifty slaves. (Creuzer, ' View of 

 Slavery in Rome/ note 40, and the ' Orations of Demosthenes against 

 Aphobus.') 



Demosthenes tho older died when his son was seven years old, 

 leaving him and a sister, younger than himself, to the care of three 

 guardians Aphobus and Demophon, his fin-t cousins, and Therippides, 

 a friend. The property left by him amounted to fifteen talents (above 

 30001. in specie, taking silver as the standard). The guardians how- 

 ever, as we learn from Demosthenes himself, disregarded all his fatlu r' 

 injunctions, and, while they neglected to improve the property of 

 which they were trustees, embezzled nearly the whole of it (' Orations 

 against Aphobus.') Plutarch states that they also deprived Demos 

 them s of proper masters. He himself however, in a passage where it 

 is his object to magnify all that concerns his own history, boosts of 

 tho fitting education which he had received. ('Orations on tl,. 

 Crown,' p. 31Z) He is said to have studied philosophy under Plato, 

 and to have been a pupil of Eubulides of Miletus. 



Having heard Callintratua plead ou one occasion, he was fired by 

 that orator's success with ambition to become an orator himself, ami 

 he accordingly received instructions in the rhetorical art from IMUUH. 

 Cicero (' De Oratore,' ii. 94) mentions Demosthenes as one of thoso 

 who came forth from the school of Isocrates : Plutarch, on the other 

 hand, expressly states that he was not a pupil of Isocrates, and goes 

 out of his way to invent reasons why Demosthenes should have pre- 

 ferred the instructions of Issms. We assume however that Istcug was 

 his principal instructor, in accordance with the testimony of the 

 various biographers. (Libaniux, Zosimus.) We are told that many 

 suspected the speeches against his guardians to have been written, 

 while others said that they were corrected, by Issous, partly because 

 Demosthenes was so young when they wero delivered, and partly 

 became they bora marks of the style of INCUS. He is said to hare 

 taken lessons in action from Aristonicus, a player. 



The physical disadvantages under which Demosthenes laboured aro 

 well known, and the manner in which ho surmounted them is often 

 quoted OH an example to encourage other* to persevere. It should bo 

 observed however that the authority for some of these stories is but 

 small, and that they rest on the assertions of writers of late date. He 

 was naturally of a weak constitution ; he bod a feeble voice, an indis- 

 tinct articulation, and a shortness of breath. Finding that th- sfl 

 defects impaired tho effect of his speeches, ho set resolutely to work 



