ted by the undulating movement of the
waves. A hollow cylinder extends from the lower part of the buoy to still
water below the movement of the waves, ensuring that the water inside keeps
at mean level, whilst the buoy follows the movements of the waves. By a
special apparatus the compressed air is forced through the whistle at the
top of the buoy, and the air is replenished by two tubes at the upper part
of the buoy. It is fitted with a rudder and secured in the usual manner.
Automatic buoys cannot be relied on in calm days with a smooth sea. The nun
buoy (fig. 14) for indicating the position of an anchor after letting go,
is secured to the crown of the anchor by a buoy rope. It is usually made of
galvanized iron, and consists of two cones joined together at the base. It
is painted red for the port anchor and green for the starboard.

Mooring buoys (fig. 6) for battleships are built of steel in four
watertight compartments, and have sufficient buoyancy to keep afloat should
a compartment be pierced; they are 13 ft. long with a diameter of 61/2 ft.
The mooring cable (bridle) passes through a watertight 16-in. trunk pipe,
built vertically in the centre of the buoy, and is secured to a "rocking
shackle" on the upper surface of the buoy. Large mooring buoys are usually
protected by horizontal wooden battens and are fitted with life chains.

(J. W. D.)

[1] In carrying out the above system the Northern Lights Commissioners have
adopted a red colour for conical or starboard-hand buoys, and black colour
for can or port-hand buoys, and this system is applicable to the whole of
Scotland.

[2] Useful where floating ice is encountered.

[3] St George and St Andrew crosses are principally employed to surmount
shore beacons.

BUPALUS AND ATHENIS, sons of Archermus, and members of the celebrated
school of sculpture in marble which flourished in Chios in the 6th century
B.C. They were contemporaries of the poet Hipponax (about 540 B.C.), whom
they were said to have caricatured. Their works consisted almost entirely
of draped female figures, Artemis, Fortune, the Graces, whence the Chian
school has been well called a school of Madonnas. Augustus brought many of
the works of Bupalus and Athenis to Rome, and placed them on the gable of
the temple of Apollo Palatinus.

BUPHONIA, in Greek antiquities, a sacrificial ceremony, forming part of the
Diipolia, a religious festival held on the 14th of the month Skirophorion
(June-July) at