OLDENBURG, a sovereign duchy in the north-east of Germany, but consisting also of two other portions separated from it, though both of them are of small extent. One of these smaller divisions in the north is called the principality of Lubeck, consisting of a small territory surrounded by the Danish territory of Holstein, and some small spots on the banks of the 1rave, and near Schwartau, adjoining to the territory of the republic of Lubeck. The other of these small divisions is on the western side of the Rhine; it is called the principality of Birkenfeld, and is whol!y surrounded by the Prussian province of the Lower Fhme. The whole of these three divisions extend over 2 21 square miles, and comprehend nine cities, ten mar ket-towns, and 776 villages and hamlets, with 233,400 inhabitants, of whom 161,420 adhere to the Lutheran church, 68,000 are Catholics, and the remainder, excepting 900 Jews, are Calvinists. The population of the principality of Lubeck is 19,070, that of Birkenfeld is 21,180, and the remainder is found in Oldenburg proper. The revenues of the state amount to about L. 130,000 annually, arising partly from tolls on the Weser, and partly from taxes on foreign goods, but chiefly from domains. The state has no debt. The army consists of 1650 men; but the state is bound to contribute to the force of the German confederacy a contingent of 2177 men. The principal river is the Weser, into which the smaller streams flow, and it is the ordinary channel of marine commerce. The soil is in general poor and sandy, but near to the rivers there are some rich marshes, obtained by draining and embankments, which fatten cattle, and afford the productions of the dairy. The cultivation is badly conducted in the large division. There are a great number of small proprietors, who cultivate their own fields, and thereby procure a bare subsistence. The climate is raw, cold, and exceedingly variable.

Oldenburg, a city, the capital of the duchy of the same name in the north-east of Germany. It is situated on the river Hunte, which is navigable to the Weser, and is surrounded with walls planted with lime trees, being well built and clean, but in an antique style. The duke has a large and old, but not an elegant palace, on the grand parade, adjoining to the city. The city contains two churches, two hospitals, and 660 houses, with 5420 inhabitants, who subsist chiefly from the expenditure of the court, of the tribunals, and of the civil officers of the government. It has little trade excepting at its two great fairs. Long. 8. 6.1. E. Lat. 53. 8. 33. N.

Oldenburg, Henry, was born in the duehy of Bremen, in Lower Saxony. During the long parliament, he was appointed consul for his countrymen, at London, after the usurpation of Cromwell; but being discharged of that employment, he was appointed tutor to the Lord Henry O’Bryan, an Irish nobleman, whom he attended to the university of Oxford, where lie was admitted to study in the Bodleian Library in the beginning of the year 1656. He was afterwards tutor to William Lord Cavendish, and was acquainted with Milton the poet. During his residence at Oxford he became acquainted with the members of that body, which there gave birth to the Royal Society, upon the foundation of which he was elected a fellow; and when the society had found it necessary to have two secretaries, he was chosen as assistant secretary to Dr Wilkins. He applied himself with extraordinary diligence to the business of his office, and in the year 1664 began the publication of the Philosophical Transactions, which he continued to publish to No. xxxvi. 25th June 1677. After this the publication was discontinued till the January following, when it was again resumed by his successor in the office of secretary, Mr Nehemiah Grew, who carried it on till the end of February 1678. Mr Oldenburg died at his house at Charlcton, near Greenwich, in Kent, in August 1678.