Page:Encyclopædia Britannica, Ninth Edition, v. 13.djvu/549

I V O I V R 525 considerable quantities, frequently under the name of "Corozo " nuts, a name by which the fruits of some species of Attalea are known in Central America, their uses being chiefly for small articles of turnery. The question of the position of this plant in the vegetable kingdom is one upon which botanists have been much divided. The plant has at different times occupied the attention of such well-known botanical authorities as Ruiz and Pavon, who gave to it its scientific name of Pliytdeplias macrocarpa, and of Martins, Morren, Humboldt, Bonpland, Spruce, and others, by whom it has been considered respectively to be neir to the Palmeas or the Pandanese, or to belong to a separate and distinct order, the Phytelephasiese of Brong- niart. This order is now placed by Le Maout and Decaisne between Palmes, and Paiidanex, and Phytelephas is of course retained in it as the type, one other genus only, that of Wettinia, being included. IVORY, JAMES (1765-1842), a Scottish mathematician, was born in Dundee in 1765. In 1779 he entered the university of St Andrews, where after four years study he graduated M.A., distinguishing himself especially as an ardent and successful student of mathematics. He then entered on a regular course of theological training ; but, after two sessions at St Andrews and one at Edinburgh, he abandoned all idea of the church, and in 1786 settled in his native town as assistant-teacher of mathematics and natural philosophy in a newly established academy. Three years later he became partner in and manager of a flax- spinning company at Douglastown in Forfarshire, still, however, prosecuting in moments of leisure his favourite studies. He was essentially a self-trained mathematician, and was not only deeply versed in the ancient and modern geometry, but had also, what was extremely rare in his country in those days, a full knowledge of the analytical methods and discoveries of the Continental mathematicians. His earliest memoir, dealing with an analytical expression for the rectification of the ellipse, is published in the Transactions of the Royal Society of Edinburgh for the year 1796; and this and his later papers on "Cubic Equations" (1799) and " Kepler s Problem " (1802) evince great facility in the handling of algebraic formulae. In 1804 after the dissolution of the flax-spinning company of which he was manager, he obtained one of the mathema tical chairs in the Royal Military College at Marlow (after wards removed to Sandhurst); and till the year 1816, when failing health obliged him to resign, he discharged his professional duties with remarkable success. During this period he published in the Philosophical Transactions several important memoirs, which earned for him the Copley medal in 1814, and ensured his election as a Fellow of the Royal Society in 1815. Of special importance in the history of attractions is the first of these earlier memoirs (Phil. Trans., 1809), in which the problem of the attraction of a homogeneous ellipsoid upon an external point is reduced to the simpler case of the attraction of another but related ellipsoid upon a corresponding point interior to it. This beautiful theorem is known as Ivory s theorem. His later papers in the Philosophical Transac tions treat of astronomical refractions, of planetary pertur bations, of equilibrium of fluid masses, &c. For his investigations in the first named of these he received a royal medal in 1826 and a,gain in 1839. In 1831, on the recommendation of Lord Brougham, King William IV. granted him a pension of 300 per annum, and conferred on him the Hanoverian Guelphic order of knighthood, His more purely scientific honours sufficiently prove the high position he held among his contemporaries. Thus, besides being directly connected with the chief scientific societies of his own country, the Royal Society of Edin burgh, the Royal Irish Academy, &c., he was corresponding member of the Royal Academy of Sciences both of Paris and Berlin, and of the Royal Society of Gottingen. He died September 21, 1842. IVORY COAST, that part of the West African seaboard which lies between the Grain Coast (now almost all belong ing to Liberia) and the Gold Coast, or between Cape Palnias on the west and the Assini river on the east. Slightly different limits are assigned by different writers, and part of the territory which belongs to the traditional Ivory Coast is now officially incorporated in the Gold Coast region, the western limit of which is placed at 5 W. long., a good way to the west of the Assini river. In the older books of travel (both English and foreign) we often find the alternative names Tooth Coast (Zahn-Kiiste) or Quaqua Coast, and less frequently the coast of the five and six stripes (alluding to a kind of cotton fabric in favour with the natives). The trade in ivory has long lost its importance, and at the present day there are very few European trading stations in this part of Guinea. Fort Nemour, Grand Bassam, Piccaninny Bassam, Drewin, and Walloo are the chief points of interest. IVREA, the ancient Eporedia, a town of northern Italy, capital of a district of the same name, is -situated at the foot of the Alps on an eminence at the southern extremity of the beautiful and luxurious Val d Aosta, near the river Dora Baltea, and at the termination of a branch railway line from Chivasso, 29 miles north-north-east of Turin. It is irregularly built, and has an antique and picturesque appearance. The -site of the old fortifications is now occupied by promenades. The town possesses an old citadel with three lofty brick towers ; a cathedral, sup posed to occupy the site of a temple of Apollo ; an ecclesi astical seminary, a gymnasium, and several convents and benevolent institutions. The river is crossed by a Roman bridge of one arch. There are important silk manufac tures, and a considerable trade in cheese, cattle, and other produce of the Alps. The population of the town in 1871 was 5093. Ivrea occupied the site of the old Eoman Eporedia, which origin ally belonged to the Salassi, and received a Roman colony about 100 B.C., founded in accordance with the directions of the Sibylline books. It afterwards became the seat of the Longobardian dukes, and on the conquest of the Longobards by Charlemagne it was made the capital of a marquisate. In 950 Berenger II. of Ivrea suc ceeded in mounting the Italian throne, but he held this position for only a short time. His grandson Otho became the founder of the line of the dukes of Burgundy. Arduin, marquis of Ivrea, again aspired to the throne of Italy after the death of Otho III. in 1002, and also disputed the possession of the imperial dignity with Henry II. , but was defeated by Henry in 1003, after which Ivrea was incorpo rated with the empire. In 1248 the town and marquisate were given to the counts of Savoy. The town was occupied by the French in 1554, 1641, and 1704. In. 1796 they again made themselves masters of it ; and, after losing it for some time, they reacquired it in 1800, and held it till 1814, making it the capital of the department of Doire. IVRY-SUR-SEINE, a town and commune of France, in the arrondissement of Sceaux and the department of Seine, is situated near the left bank of the river Seine, 4 miles south-east of Paris. It has an interesting old church, but of the castle of the 17th century the fine gar dens are the chief memorial. In the Petit Chateau died the duchess of Orleans, mother of Louis-Philippe. Ivry manufactures cordage, organs, glass, matches, manure, and chemicals. There are numerous handsome villas and fine gardens in the neighbourhood. The population in 1876 was 15,247. Ivry-sur-Scine is of ancient foundation. In a charter of Louis IV. (D Outremer), its name appears as Ivriacum, and in contem porary documents as Yvriacum. The fort of Ivry played an import ant part in the defence of Paris against the Germans in 1870-71, and in the Communist struggle of the latter year. Ivry-la-Bataille, in the department of Eure, where Henry IV. won his victory over the Leaguers in 1590, is not to be confounded with Ivry-sur-Seine,