Page:The New International Encyclopædia 1st ed. v. 14.djvu/897

OHIO UNIVERSITY. $70,000 by direct tax. The income for 1902 was $85,000, and the value of the college property was estimated at $400,000.  OHIO WESLEYAN UNIVERSITY. A coeducational institution of higher learning under the control of the Methodist Episcopal Church at Delaware, Ohio, opened in 1844. The Ohio Wesleyan Female College, founded in 1853, was united with the university, and in 1896 an existing medical school at Cleveland was annexed under the name of the Cleveland College of Physicians and Surgeons. The university embraces a college of liberal arts, an academic department, and schools of music, oratory, business, fine arts, and medicine. In 1849 the trustees authorized the sale of scholarships to secure an endowment, and during the next five years 3740 scholarships were sold, calling for more than 25,000 years of tuition. In 1902 the faculty numbered 111 and the student body 1385. The endowment was $954,121, and the value of the grounds, fifteen buildings, and equipment, $742,503. The library contained 42,000 volumes.  OHLAU,. A town of Silesia, Prussia, 10 miles southeast of Breslau, on the Ohlau, a tributary of the Oder (Map:, G 3). The town has a gymnasium. The surrounding country is a tobacco district, so the town has large tobacco and cigar factories, and in addition manufactures of white lead, machinery, lime, wagons, bone-dust, and slices. There are also saw-mills and brick-kilns, and the town has steamboat communication with Breslau. Ohlau was formerly a residence of the dukes of Brieg and of the Sobieskis, and in 1742 became part of Prussia. Population, in 1900, 9235.  OHLIGS, (formerly ). A town in the Rhine Province, Prussia, near the Rhine, 10 miles southeast of Düsseldorf (Map:, B 3). There are manufactures of steel goods, umbrella frames, cloth, silk, and bricks. Population, in 1900, 20,682.  OHM (named after Georg S. Ohm). The practical unit of electrical resistance. It is defined as being the electrical resistance offered to the passage of an unvarying electric current by a column of mercury, 106.3 cm. long, of uniform cross-section, having a mass of 14.4521 grams, the mercury being at the temperature of 0° C. (This would require a cross-section of 1.00003 square millimeters.) The ohm is substantially equal to 109 C.G.S. electro-magnetic units of resistance. See ;.  OHM,, (1787-1854). A German physicist and discoverer of the famous law in electricity bearing his name. He was born and educated at Erlangen, and, after giving instruction in mathematics and physics in a number of schools, he was called in 1817 to a chair in the gymnasium at Cologne. He made a study of the laws of galvanic currents, and while investigating the relative conductivity of metals finally discovered the relation known as ‘Ohm's law,’ which underlies all electrical theory and measurement. The experimental proof of this law was first published in a paper in Schweiggers Journal für Chemie und Physik, vol. xlvi. (1820), under the title of “Bestimmung des Gesetzes nach welchem Metalle die Contaktelectricität leiten,” etc. An exposition of the theory is contained in The Galvanic Chain, Mathematically Worked Out (1854). He resigned his professorship at Cologne in 1826, was director of the Nuremberg Polytechnic School 1833-49, and was then called to the chair of physics at Munich. The name ohm was given to the unit of electrical resistance by the Paris Congress of Physicists (1881). Previously (1846) the British Association had called the unit of resistance the ohmad. See Scientific Works of Georg Simon Ohm, by Eugene Lommel, a biographical sketch in Smithsonian Report, 1891, Washington; also, Mann, Georg Simon Ohm (Leipzig, 1892).  OHM'S LAW. See, section on Laws of Steady Electric Currents.  OHNET,, (1848—). A popular French novelist and dramatist. Ohnet left law for journalism, attempted the stage with Regina Sarpi (1875), and began his novelistic series, “Les batailles de la vie,” in 1881. Of these the most successful were: Le maître de forges (1882); La comtesse Sarah (1883); Lise Fleuron (1884); Le docteur Rameau (1888). Most of Ohnet's novels have been translated and several of them dramatized. Story and character are conventional; the tone is monotonously optimistic. But Ohnet manages commonplace material with a melodramatic skill that has won a remarkable commercial success. <section end="Ohnet, Georges" /><section begin="Oidium" /> OIDIUM, (Neo-Lat., from Gk., ōon, egg). The conidial form of certain Erysipheæ, an important family of minute fungi growing on animal and vegetable substances. The species of Oidium consist of tiny tubular white or bright colored threads, forming flocks, simple or irregularly branched, assuming in their upper part the form of strings of beads, which finally break up into elliptic spores. Oidium albicans is found on the epithelium in the mouth and throat in the disease called aphthæ, or thrush. It is more common in children and aged persons than in those who are in the prime of life. Another species, Oidium Tuckeri, which has attracted great attention in Europe, is regarded by many as producing a destructive grape disease. It is the conidial form of Uncinula necator, or Uncinula spiralis. It makes its appearance at first in the form of a mycelium of creeping, branching filaments, which send out upright or decumbent jointed stems. Each bead-like joint of the stems develops into a sort of spore, numbers of which are finally discharged in little clouds. The grape disease was first observed in Kent, England, in the spring of 1845. The disease rapidly spread over other English vineries; was observed about the same time in the vineries of Paris, and soon in the vineyards of almost all parts of France, Italy, Greece, Tyrol, and Hungary, finally, and in a slighter degree, affecting the vineyards of the Rhine. Its ravages extended to Algeria, Syria, Asia Minor, and many other countries, among which is particularly to be noted the island of Madeira, where it proved almost completely destructive to the grapes and nearly put an end to the production of the celebrated Madeira wine. It is probable that the complete isolation of the Madeira vineyards made the progress of the disease more rapid, and its result more complete than elsewhere, by reason of the prevalence of the conditions favorable for it. This disease is more fully described under as powdery mildew, for which remedies are there suggested. <section end="Oidium" />