a river of England, rising in Bala lake, Merionethshire. In the first part of its course, which lies through the beautiful valley of Llangollen, its current is exceedingly rapid. After passing Wynnstay it turns northwards, and forms the boundary line which separates Denbighshire from Flintshire and Cheshire. In its after course it runs wholly within Cheshire. After nearly encircling the city of Chester, it is continued by an artificial channel for about nine miles until it falls into a spacious tidal estuary, which at its communication with the sea is nearly six miles wide. Its principal tributary is the Alwyn, which joins it at Holt. Its whole course is upwards of 70 miles in length.

a river of Scotland, rising in the Cairngorm hills, about 25 miles above Braemar. After an easterly course of 95 miles, chiefly through the beautiful valley of Deeside, it falls into the German Ocean at Aberdeen. Its salmon fishery is one of the most valuable in Scotland.

John, a mathematician and astrologer, was born in July 1527, at London, where his father was a wealthy vintner. In 1542 he was sent to St John's College, Cambridge. After five years' close application to mathematical studies, particularly astronomy, he went to Holland, in order to visit several eminent mathematicians on the Continent. Having remained abroad nearly a year, he returned to Cambridge, and was elected a fellow of Trinity College, then first erected by King Henry VIII. In 1548 he took the degree of master of arts; but in the same year he found it necessary to leave England on account of the suspicions then entertained of his being a conjuror. A piece of machinery in the Irene of Aristophanes, which he exhibited to the University, and in which he represented the scarabaeus flying up to Jupiter, with a man and a basket of victuals on its back, had helped to give currency to these surmises, and his subsequent conduct was little fitted to allay the popular prejudice.

On leaving England he repaired to the University of Louvain, where he resided about two years. He then set out for France, where, in the college of Rheims, he read lectures on Euclid's Elements with great applause. In 1551 he returned to England, and was introduced by the Secretary Cecil to King Edward, who assigned him a pension of a hundred crowns, which he afterwards exchanged for the rectory of Upton-upon-Severn. Soon after the accession of Mary, he was accused of using enchantments against the queen's life; but after a tedious confinement, he obtained his liberty in 1555, by an order of council.

When Elizabeth ascended the throne, Dee was asked by Lord Dudley to name a propitious day for her majesty's coronation. On this occasion he was introduced to the queen, who took lessons in the mystical interpretation of his writings, and made him great promises, which, however, were never fulfilled. In 1564 he again visited the Continent, in order to present a book which he had dedicated to the Emperor Maximilian. He returned to England in the same year; but in 1571 we find him in Lorraine, where, being dangerously ill, two physicians were sent to his relief by the queen. Having once more returned to his native country, he settled at Mortlake, in Surrey, where he continued his studies with unremitting ardour, and made a collection of curious books and manuscripts, and a variety of instruments, most of which were destroyed by the mob during his absence, on account of Dee's supposed familiarity with the devil. In 1578 Dee was sent abroad to consult with German physicians and astrologers, in regard to the illness of the queen. But having returned to England, we find him employed in investigating the title of the crown to the countries recently discovered by British subjects, and in furnishing geographical descriptions. Two large rolls containing the desired information, which he presented to the queen, are still preserved in the Cottonian Library. A learned treatise on the reformation of the calendar, written by him about the same time, is still preserved in the Ashmolean Library at Oxford.

From this period the philosophical researches of Dee degenerated into mere necromantic vagaries. In 1581 he became acquainted with one Edward Kelly, by whose assistance he performed various incantations, and maintained a frequent imaginary intercourse with spirits. Shortly after, Kelly and Dee were both introduced to a Polish nobleman, Albert Laski, palatine of Siradia, who was addicted to the same ridiculous pursuits, and persuaded the two friends to accompany him to his native country. They embarked for Holland in September 1583, and travelling overland, arrived at the town of Laski in February following. Their patron, however, finding himself deceived by their idle pretensions, persuaded them to pay a visit to Rudolph, king of Bohemia, who, though a credulous man, soon became disgusted with their practices. They were afterwards introduced to the king of Poland, but with no better success. They were, however, invited by a rich Bohemian nobleman to his castle of Trebona, where they continued for some time in great affluence, owing, as they asserted, to their power of transmutation exerted by means of a powder in the possession of Kelly.

Dee, having at length quarrelled with his companion, quitted Bohemia and returned to England, where he was made warden of Manchester College in 1595. He afterwards returned to his house at Mortlake, where he died in 1608, aged eighty-one.

His principal works are Propæudemata Aphoristica, Lond. 1558, 12mo; Monas Hieroglyphica, Antwerp, 1564; Epistolæ ad Fredericum Commandinum, Pisauri, 1570; Preface to the English Euclid, 1570; Divers Annotations and Inventions added to the tenth book of the English Euclid, 1570; Epistolæ praefixa Ephemeridibus Joannis Feldii, a 1557; Parallactice Commentationis Praeexquis nucleus quadam, London, 1573. The catalogue of his printed and published works is to be found in his Compendious Rehearsal, as well as in his letter to Archbishop Whitgift, to which the reader is referred.