ipitate
exactly a known weight of the chloride; the mean value obtained being
136.84; T. W. Richards (_Zeit. anorg. Chem._, 1893, 6, p. 89), by
determining the equivalent of barium chloride and bromide to silver,
obtained the value 137.44. For the relation of barium to radium, see
RADIOACTIVITY.

BARKER, EDMUND HENRY (1788-1839), English classical scholar, was born at
Hollym in Yorkshire. He entered Trinity College, Cambridge, as a scholar in
1807, but left the university without a degree, being prevented by
religious scruples from taking the oath then required. He had previously
obtained (in 1809) the Browne medal for Greek and Latin epigrams. After
acting as amanuensis to the famous Samuel Parr, the vicar of Hatton in
Warwickshire, he married and settled down at Thetford in Norfolk, where he
lived for about twenty-five years. He was in the habit of adding the
initials O. T. N. (of Thetford, Norfolk) to the title-page of his published
works. In later life he became involved in a law-suit in connexion with a
will, and thus exhausted his means. In 1837-1838 he was a prisoner for debt
in the king's bench and in the Fleet. He died in London on the 21st of
March 1839. Barker was a prolific writer on classical and other subjects.
In addition to contributing to the Classical Journal, he edited portions of
several classical authors for the use of schools. He was one of the first
commentators to write notes in English instead of Latin. In a volume of
letters he disputed the claims of Sir Philip Francis to the authorship of
the Letters of Junius; his _Parriana_ (1828) is a vast and ill-digested
compilation of literary anecdotes and criticisms. He also saw through the
press the English edition of Lempriere's _Classical Dictionary_ (revised by
Anthon) and of Webster's _English Dictionary_. It is as a lexicographer,
however, that Barker is chiefly known. While at Hatton, he conceived the
design of a new edition of Stephanus's _Thesaurus Graecae Linguae_. The
work was undertaken by A. J. Valpy, and, although not expressly stated, it
was understood that Barker was the responsible editor. When a few parts had
appeared, it was severely criticized in the _Quarterly Review_ (xxii.,
1820) by Blomfield; the result was the curtailment of the original plan of
the work and the omission of Barker's name in connexion with it. It was
completed in twelve volumes (1816-1828). The strictures of the _Quarterly_
were answered by Barker in his _Aristar