PLAYFAIR                                                 1504                                                  PLEROME

which proved so successful that from that time he was the favorite dramatist of his day. His plays were very popular, not only with the common people, but with the educated classes, and were acted in the time of Emperor Diocletian, five centuries later. The scenes of his comedies are always laid in Athens or in some other Greek town; but his Greek characters speak and act like Romans. Shakspere himself is not more careless about inconsistencies of this kind. The charm of Plautus lies in his genuine humor and grasp of character. He goes to the depths of human nature, and delights his readers to-day as truly as when he made the Roman theaters ring with applause or as when Jerome solaced himself in his cell by reading the well-loved comedies. Shakspere has imitated the plot of the Mencechmi, entirely recasting it in his Comedy of Errors. He died in 184 B. C. See Roman Poets of the Republic by Sellar.

Play'fair, Lyon, formerly known as Sir Lyon Playfair, an English chemist and statesman, was born in India, May 21, 1818, but educated at St. Andrews University, Scotland. He early became interested in chemistry, to which he devoted himself assiduously, going to Germany in 1838 to study under Baron Liebig. He served ten years as professor of chemistry in the University of Edinburgh, and in 1868 he was elected to Parliament to serve for the Universities of St. Andrews and Edinburgh, holding a seat for 17 years. He was postmaster-general, deputy speaker of the house and vice-president of the council at various periods. He was lord-in-waiting to the queen and counsel to the Prince of Wales. In 1883 he was made a K.C.B. In 1885 he was president of the Association for the Advancement of Science. He was raised to the peerage as Baron Playfair of St. Andrews in 1892. He was the author of works upon his chosen profession and edited an edition of Liebig's Chemistry in Its Application to Agriculture and Physiology. He died at London, May 29, 1898.

Play'grounds have originated in large cities, as London and New York, through the need of providing open spaces where the young may exercise freely yet under the necessary supervision. In London they developed from the movement in favor of parks for the people. London has 17,876 acres of parks; and, in addition, every public school has a playground attached. The movement in favor of open-air playgrounds for both men and boys was taken up in London by the Metropolitan Public Gardens Association; and afterwards by the London County Council. There are public gymnasia in all the parks, except the royal ones. In each p1ayground there is a caretaker in uniform.

In New York playgrounds are established

for systematic sports during two months of the school vacation. In 1902 no playgrounds were thus organized, some in schoolgrounds, others on schoolhouse roofs, others again on piers or in parks. The afternoon sports in a summer playground are inaugurated perhaps by a grand march and one or two patriotic songs. Then the time is spent either in gymnastic drill or in free play. The little children play their kindergarten games. There are intervals for rest, during which music is played, a song sung or a story told. There are those who prefer to continue the manual occupations of the morning vacation school; and these give their attention to painting, weaving, modelling and the like. Some of the boys have little plots in which to raise vegetables. The swimming-pool is a valuable adjunct to the school's playground. The evening roof-gardens, with their fresh air and brass bands or, at least, pianos, supplement the function of the afternoon playgrounds. Small parks and playgrounds are provided also in Chicago and other large cities. See, also, Vacation Schools.

Plays. See Drama.

Pleiades {plē'ya-dēz), The, in Greek mythology, were, according to the most general account, the seven daughters of Atlas and Pleione. According to some accounts they committed suicide from grief, either at the death of their sisters, the Hyades, or at the fate of Atlas, their father; according to others they were companions of Diana, and, when pursued by Orion, were rescued from him by the gods translating them to the sky; all authorities, however, agree that after their death or translation they were transformed into stars. Their names are Electra, Maia, Taygeta, Alcyone, Calaeno, Sterope and Merope. The group of the Pleiades, called the Seven Stars, is placed on the shoulders of Taurus, the second sign of the zodiac, and with the pole-star and the twins, Castor and Pollux, forms the three angular points of a triangle.

Ple'rome (in plants). At the growing tip of a stem or a root the great regions are organized in embryonic form. Both in stems and roots there are three such regions. On the outside is dermatogen (which see), which gives rise to the epidermis; within the dermatogen is the periblem (which see), which gives rise to the cortex; within the periblem and forming the central axis of the stem or root is the plerome, which gives rise in the mature stem or root to what is known as the stele, in which the woody bundles arise. A longitudinal section of an ordinary root or dicotyledonous stem will reveal these three great regions. Of course the pith which exists within the woody cylinder of the stem is a part of the stele.