PLIOCENE 



6196 



PLOUGH 



Pliny, 

 Roman writer 



From a itatut 



he received an excellent education. 

 Beginning as a pleader in the law 

 courts, he had a successful public 

 career, his 

 correspon- 

 dence with the 

 emperor Tra- 

 jan when he 

 was governor 

 of B i t h y n i a 

 (c. A.D. 111) 

 showing him to 

 be possessed of 

 high ideals of 

 duty, though 

 narrow in out- 

 look and lacking in initiative. 



This correspondence is of pecu- 

 I iar interest, inasmuch as it contains 

 Trajan's rescript on the treatment 

 of Christians. Another letter is that 

 to Tacitus describing the eruption of 

 Vesuvius in 79 in which the elder 

 Pliny lost his life. Pliny's Letters, 

 which were published in nine books, 

 suffer from the fact that they were 

 obviously written for publication ; 

 to a certain extent they lack fresh- 

 ness and spontaneity. Yet they are 

 of great value for the light they 

 throw upon the life of the time. 

 See Letters, with Eng. trans, by W. 

 Melmoth, revised by W. M. L. 

 Hutchinson, 1915. 



Pliocene (Gr. pleion, more ; 

 kainos, new). In geology, name 

 given to the uppermost division of 

 the Tertiary system. Pliocene de- 

 posits are chiefly found in Europe, 

 especially in France, Spain, Italy, 

 Greece, and on a smaller scale in 

 England, Belgium, etc. Norfolk 

 and Suffolk crag, the Coralline crag, 

 etc., consisting of shelly sand and 

 clays, represent the pliocene de- 

 posits in England. The pliocene is 

 comparatively poorly represented 

 in N. America, though the Merced 

 series of San Francisco run to a 

 thickness of 6,000 ft. 



The pliocene deposits, the accu- 

 mulations of shallow seas, and the 

 estuaries of large rivers, are rich in 

 fossils, particularly of mollusca, 

 extinct fishes, reptiles, amphibians, 

 and birds. The remarkable fossil 

 of Pithecanthropus erectus probably 

 belongs to this geological epoch 

 (q.v.). See Tertiary. 



Plock. Dist. of Poland. It is 

 bounded by E. and W. Prussia and 

 the dists. of Lomza and Warsaw, 

 and is watered by the Vistula and 

 the Nareff . Agriculture is the chief 

 occupation of the people, rye, pota- 

 toes, and sugar-beets being the 

 chief crops. Its area is 3,641 sq. m. 

 Pop. 790,000. Pron. Plotsk. 



Plock. Town of Poland, capital 

 of the dist. of the same name. It 

 stands on the right bank of the 

 Vistula, 60 m. N.W. of Warsaw. 

 There are manufactures of agricul- 

 tural implements, matches, sugar, 



and soap ; grain, timber, and sugar- 

 beet are exported. The 12th cen- 

 tury Romanesque cathedral con- 

 tains tombs of Polish dukes and 

 kings. Plock was formerly the cap- 

 ital of the principality of Masovia. 

 There is steamer traffic by river 

 to Warsaw. Plock was captured 

 by the Germans in their invasion of 

 Poland, Nov., 1914, and was the 

 scene of a fight between Bolshevist 

 and Polish troops, Aug., 1920. 

 Pop. 31,000, mostly Jews. 



Ploegsteert. Village and wood 

 of Belgium, in the prov. of W. 

 Flanders. The former is 8 m. S. of 

 Ypres, and 3 m. N. of Armentieres, 

 and before the Great War con- 

 tained about 5,000 inhabitants. 

 Both village and its adjacent wood, 

 2 m. in length, figured prominently 

 in the operations conducted by the 

 British in the Ypres salient. After 

 changing hands several times in 

 1914 they were for the next three 

 years in the British front line, and 

 the scene of bitter fighting with the 

 Germans. Captured by the latter 

 in 1918, they were finally retaken 

 by the Allies in Sept. of that year. 

 It was known to the British troops 

 as Plug Street. See Ypres, Battles of. 



Ploeshti, PLOESTI, OR PLOESCI. 

 Town of Rumania, capital of the 

 dept. of Prahova, 35 m. almost 

 due N. of Bukarest. It was, until 

 1916, one of the centres of the great 

 Rumanian oil industry, and as a 

 junction of railways and roads 

 was strategically important. Dur- 

 ing the Great War it was captured 

 by the Austro-Germans, Dec. 6, 

 1916. Pop. 57,000. 



Plombieres. Town and water- 

 ing-place of France. In the dept. of 

 Vosges, it stands on the valley of 

 the Augronne, 7 m. from Remire- 

 mont, and is famous for its mineral 

 springs. Good for gout, rheumat- 

 ism, and nervous complaints, these 

 were known to the Romans, and 

 there are remains of their exten- 

 sive baths. Napoleon III, by fre- 

 quent visits to Plombieres, made it 

 fashionable, and it was here, in 

 1858, that he arranged with Cavour 

 to assist Sardinia against Austria. 

 The springs, 27 in 

 number, are the 

 property of the 

 state. The chief 

 buildings are the 

 bathing e s t a b- 

 lishments, casino, 

 and others for 

 the comfort and 

 pleasure of visi- 

 tors. The chief 

 street is the Rue 

 Stanislas, which 

 took its name 

 from Stanislas, 

 duke of Lorraine. 

 Pop. 2,000. 



Ploner See. Lake of Schleswig- 

 Holstein, Germany. Midway be- 

 tween Kiel and Lubeck Bay is a 

 group of lakes of glacial origin set 

 amidst beech woods. The largest 

 are Eutin and the Great Lake of 

 Plon ; others are Lanker.Keller, and 

 Diek. The great lake is 6 m. long, 

 5 m. wide ; on its shores is Plon, a 

 steamer station, which reaches W. 

 to the small Plon lake. 



Plotinus (A.D. 204-269). Chief 

 representative of neo-Platonism. 

 Born at Lycopolis, of a Roman 

 family settled in Egypt, in 244 he 

 accompanied the emperor Gordian 

 on his expedition against the Per- 

 sian king Shapur. He afterwards 

 settled in Rome, where he taught 

 and lectured with success, and died 

 in Campania. His philosophy, 

 described in his Enneades, is 

 a development of the Platonic 

 theory of ideas, combined with 

 Aristotelianism, Stoicism, Oriental 

 mysticism, and the theory of 

 emanation, or efflux from the god- 

 head. See Ethical Treatises, with 

 Porphyry's Life of P., Eng. trans. 

 S. Mackenna, 1917 ; The Religious 

 Philosophy of P., 1914 ; The Phil- 

 osophy of P., W. R. Inge, 1918. 



Plough. Tillage implement. It 

 works by cutting and turning over 

 " furrow slices " for exposure to the 

 action of the weather. The back- 

 bone of the plough is a slightly bent 

 bar, the beam, to which the follow- 

 ing parts are attached : (1) Hake 

 and chain, to which the horses are 

 coupled. (2) Wheels a furrow 

 wheel to run in the furrow, and a 

 smaller land wheel to move along 

 the unploughed side. The relative 

 height and horizontal distance be- 

 tween these can be adjusted, so as 

 to regulate the depth and breadth of 

 the furrow. (3) Skim coulter, a sort 

 of little ploughshare, is used when 

 it is desired to pare off surface vege- 

 tation or turn in a top dressing of 

 manure. (4) Coulter, a knife for 

 making the vertical cut in the fur- 

 row slice ; its length and angle can 

 be adjusted, and it is sometimes in 

 the form of a revolving cutting 

 disk. (5) Strong iron body, the 



Plombieres, France. One of the principal Roman baths, 

 in Rue Stanislas, the chief thoroughfare 



