PLENIST, name given to one who holds the doctrine that all space is filled with matter.

PLESIOSAURUS, an extinct marine animal with a small head and a long neck.

PLEURA, the serous membrane that lines the interior of the thorax and invests the lungs.

PLEURA-PNEUMONIA, an inflammation of the lungs and pleura, Pleurisy being the inflammation of the pleura alone.

PLEVNA (14), a fortified town in Bulgaria, in which Osman Pasha entrenched himself in 1877, and where he was compelled to capitulate and surrender to the Russians with his force of 42,000 men.

PLEYDELL, MR. PAULUS, a shrewd lawyer in Scott’s “Guy Mannering.”

PLIMSOLL, SAMUEL, “the sailor’s friend,” born at Bristol; after experience in a Sheffield brewery entered business in London as a coal-dealer; interesting himself in the condition of the sailor’s life in the mercantile marine, he directed public attention to many scandalous abuses practised by unscrupulous owners, the overloading, under-manning, and insufficient equipment of ships and sending unseaworthy vessels out to founder for the sake of insurance money; entering Parliament for Derby in 1868, he secured the passing of the Merchant Shipping Act in 1876 levelled against these abuses; his name has been given to the circle with horizontal line through the centre, now placed by the Board of Trade on the side of every vessel to indicate to what depth she may be loaded in salt water (1824-1898).

PLINLIMMON (i. e. five rivers), a mountain 2469 ft. high, with three summits, on the confines of Montgomery and Cardigan, so called as source of five different streams.

PLINY, THE ELDER, naturalist, born at Como, educated at Rome, and served in the army; was for a space procurator in Spain, spent much of his time afterwards studying at Borne; being near the Bay of Naples during an eruption of Vesuvius, he landed to witness the phenomenon, but was suffocated by the fumes; his “Natural History” is a repertory of the studies of the ancients in that department, being a record, more or less faithful, from extensive reading, of the observation of others rather than his own; d.  A.D. 79.

PLINY, THE YOUNGER, nephew of the preceding, the friend of Trajan; filled various offices in the State; his fame rests on his “Letters,” of special interest to us for the account they give of the treatment of the early Christians and their manner of worship, as also of the misjudgment on the part of the Roman world at the time of their religion, as in their eyes, according to him, “a perverse and extravagant superstition” (62-115).

PLOTINUS, an Alexandrian philosopher of the Neo-Platonic school, born at Lycopolis, in Egypt; he taught philosophy at Rome, a system in opposition to the reigning scepticism of the time, and which based itself on the intuitions of the soul elevated into a state of mystical union with God, who in His single unity sums up all and whence all emanates, all being regarded as an emanation from Him (207-270).