time. Such a movement was often introduced into a sonata, and formed the
conventional finale to an opera or ballet until the time of Gluck.

CHAD [CEADDA], SAINT (d. 672), brother of Cedd, whom he succeeded as
abbot at Lastingham, was consecrated bishop of the Northumbrians by
Wine, the West Saxon bishop, at the request of Oswio in 664. On the
return of Wilfrid from France, where he had been sent to be consecrated
to the same see, a dispute of course arose, which was settled by
Theodore in favour of Wilfrid after three years had passed. Chad
thereupon retired to Lastingham, whence with the permission of Oswio he
was summoned by Wulfhere of Mercia to succeed his bishop Jaruman, who
died 667. Chad built a monastery at Barrow in Lincolnshire and fixed his
see at Lichfield. He died after he had held his bishopric in Mercia two
and a half years, and was succeeded by Wynfrith. Bede gives a beautiful
character of Chad.

See Bede's _Hist. Eccl._ edited by C. Plummer, iii. 23, 24, 28; iv. 2,
3 (Oxford, 1896); Eddius, _Vita Wilfridi_, xiv., xv. edited by J.
Raine, Rolls Series (London, 1879).

CHAD, a lake of northern Central Africa lying between 12 deg. 50' and 14
deg. 10' N. and 13 deg. and 15 deg. E. The lake is situated about 850
ft. above the sea in the borderland between the fertile and wooded
regions of the Sudan on the south and the arid steppes which merge into
the Sahara on the north. The area of the lake is shrinking owing to the
progressive desiccation of the country, Saharan climate and conditions
replacing those of the Sudan. The drying-up process has been
comparatively rapid since the middle of the 19th century, a town which
in 1850 was on the southern margin of the lake being in 1905 over 20 m.
from it. On the west the shore is perfectly flat, so that a slight rise
in the water causes the inundation of a considerable area--a fact not
without its influence on the estimates made at varying periods as to the
size of the lake. Around the north-west and north shores is a continuous
chain of gently sloping sand-hills covered with bush. This region
abounds in big game and birds are plentiful. In the east, the country
of Kanem, the desiccation has been most marked. Along this coast is a
continuous chain of islands running from north-west to south-east. But
what were islands when viewed by Overweg in 1851, formed in 1903 part of
the mainland and new islands had arisen in the lake. They are generally
low