PRISCILLIAN, a Spaniard of noble birth, who introduced a Gnostic and Manichaean heresy into Spain, and founded a sect called after him, and was put to death by the Emperor Maximius in 385; his followers were an idly speculative sect, who practised a rigidly ascetic style of life, and after being much calumniated did not survive him over 60 years.

PRISMATIC COLOURS, the seven colours a ray of pure white light is resolved into when refracted through a prism, applied figuratively by Carlyle to the pure light refracted through the soul of a man of genius.

PRISONER OF CHILLON, the name given to FRANCOIS DE BONIVARD (q. v.), who was for six years kept prisoner in the castle of Chillon, on the Lake of Geneva, and is the subject of a well-known poem by Byron.

PRIVATEER, a private vessel licensed by Government under a letter of marque to seize and plunder the ships of an enemy, otherwise an act of the kind is treated as piracy.

PRIVY COUNCIL, is theoretically a council associated with the sovereign to advise him in matters of government.  As at present constituted it includes the members of the royal family, the Cabinet, the two archbishops and the bishop of London, the principal English and Scotch judges, some of the chief ambassadors and governors of colonies, the Commander-in-Chief, the First Lord of the Admiralty, &c.  No members attend except those summoned, usually the Cabinet, the officers of the Household, and the Primate.  The functions of the Privy Council may be grouped as:  (1) executive, in which its duties are discharged by the Cabinet, which is technically a committee of the Privy Council; (2) administrative—­the Board of Trade, the Local Government Board, and the Board of Agriculture originated in committees; the Education Department is still a committee, and the Council retains such branches as the supervision of medical, pharmaceutical, and veterinary practice, the granting of municipal charters, &c.; (3) judicial—­the Judicial Committee is a court of law, whose principal function is the hearing of appeals from ecclesiastical courts and from Indian and colonial courts.

PRIVY SEAL, the seal of the sovereign appended to grants that do not require to pass the great seal.

PROBUS, MARCUS AURELIUS, Roman emperor from 276 to 282, born in Pannonia; having distinguished himself in the field as a soldier, was elected by the army and the citizens to succeed Tacitus; defended the empire successfully against all encroachments, and afterwards devoted himself to home administration, but requiring the service of the soldiers in public works, which they considered degrading, was seized by a body of them compelled so to drudge, and put to death.

PROCLUS, a Neo-Platonic philosopher, born in Constantinople; appears to have held a Trinitarian view of the universe, and to have regarded the All abstractly viewed as contained in the Divine ever emerging from it and returning into it, a doctrine Implied in John i. 1, but far short of the corresponding trinity in the ripe philosophy of Hegel (412-485).