PERLITE 



includes the island of Langkawi. 

 Rice, rubber, and coconut are 

 cultivated, and tin is mined. The 

 state is traversed by the N. section 

 of the main W. rly. from Singapore 

 to Siam. Kangar, on the river 

 Perlis, is the chief town. The 

 area is 316 sq. m. Pop. 33,000. 



Perlite. In geology, name given 

 to an igneous rock of perlitic 

 structure. Glassy of texture, the 

 rock easily breaks up into small 

 rounded masses that have a pearly 

 lustre and give it its alternative 

 name of pearlstone. See Hyalite. 



Perlitic Structure. In geology, 

 name given to the presence in vol- 

 canic rocks of small concentric fis- 

 sures or cracks. These cracks form 

 planes of decomposition, breaking 

 the rocks up into round fragments 

 like pearls giving the structure its 

 name. 



Perm. Government of Russia, 

 partly in Europe and partly in 

 Asia. Its area is about 127,500 sq. 

 m., and it is divided into two parts 

 by the Ural Mountains. It is a 

 great mining area, gold, silver, 

 copper, lead, iron, platinum, and 

 coal being found here. Most of the 

 area is heavily forested. Pop. 

 4,000,000. 



Perm. Town of Russia, capital 

 of the govt. of the same name. It 

 stands on the Kama and the Perm- 

 Tyumen Rly. The chief industries 

 are tanning, distilling, and the 

 making of bricks, candles, matches, 

 and machinery. There is a busy 

 trade in silk and cotton stuffs, 

 tea, leather, sugar, and furs. Perm 

 owes its prosperity to the copper 

 mines discovered in the 17th cen- 

 tury. In Dec., 1918, Koltchak (q.v. ) 

 captured it from the Bolshevists. 

 Pop. 105,000. 



Permanganates. Calts of per- 

 manganic acid. The best known is 

 potassium permanganate, a purple- 

 coloured substance used in solution 

 as a disinfecting agent, and also as 

 an oxidising agent in analytical 

 chemistry. Tkt> acid is unknown 

 in the pure state, but exists as a 

 crimson, strongly acid solution. Its 

 chemical formula is HMnCv 



Permian. In geology, name 

 given by Sir R. Murchison to the 

 rocks overlying the coal measures. 

 So called from their occurrence in 

 Perm, Russia, in which country 

 they cover a very large area, they 

 consist largely of sandstones and 

 shales, and reach a thickness of 

 over 4,000 ft. in some strata. The 

 Permian rocks were at one time 

 reckoned as a division of the 

 Triassic, and they are found over 

 large areas of Europe, N. America, 

 in Africa, Australia, and Asia. 



In Germany the Permian rocks 

 are known as the Dyas from their 

 two natural subdivisions, the red 



sandstones, breccias, marls, and 

 volcanic rocks, and the fossil if erous 

 limestones, dolomites, and marls. 

 In Scotland, Permian rocks are 

 found in Ayrshire, Dumfriesshire, 

 Nithsdale, etc., as red sandstones ; 

 similar red sandstones occur in the 

 English Permian from Newcastle 

 to Birmingham ; in N. America, in 

 the Appalachian area, in Missouri, 

 Kansas, Nebraska, etc. Permian 

 sandstones and shales are 1,000 

 to 5,000 ft. thick. They are sources 

 of immense deposits of rock salt 

 in Kansas in America, and Speren- 

 * berg in Germany. 



The Permian rocks supply a fine 

 quality of building stone, the mag- 

 nesian limestone of the N.E. of 

 England being particularly not- 

 able. In Kansas there are im- 

 portant deposits of gypsum, as 

 well as in England and Germany. 

 The rock salt and gypsum deposits 

 indicate immense salt-water lakes 

 existing in Permian times, paral- 

 leled by the Great Salt Lake of N. 

 America of the present age. 



Permian rocks are rich in fossils, 

 including the proterosaurus, platy- 

 somus, palaeoniscus, the shells of 

 many mollusca, corals, etc., tree 

 ferns, and many other varieties of 

 plants. See Carboniferous System. 



Permo- Carboniferous. In 

 geology, term used for the border 

 line rocks of the Permian and Car- 

 boniferous series. The term post- 

 carbon has been used for such 

 strata. See Carboniferous; Permian. 



Permutation. Interchange or 

 transmutation. In mathematics, 

 the different orders in which things 

 can be arranged are called their 

 permutations. Thus the permuta 

 tions of the let- 

 ters a, b, c, iaken F 

 two together, are ' 

 ab, ba, ac, ca, be, 

 cb. It will be 

 noticed that the 

 order in fhich the 

 things are placed 

 is Lnportant, i.e. 

 tb is different 

 from ba. 



The combina- 

 tions of things are 

 the different col- 

 lections that can 

 be formed out of 

 them, neglecting 

 the order in 



PERNAMBUCO 



Pernambuco. Maritime state 

 of N.E. Brazil. Situated S. of 

 Parahyba and N. of Alagoas, it is 

 well forested, fertile, and thickly 

 peopled. There are plantations of 

 cotton, sugar, coffee, cocoa, and 

 rice ; tobacco, cereals, and fruits are 

 also cultivated. The chief exports 

 include timber, dye-woods, drugs, 

 rubber, and gold. The E. part of 

 the state is served by rlys. The 

 river Sao Francisco flows along 

 part of the S. boundary, and 

 many small rivers water the state. 

 Its area is 49,573 sq. m. Pop. 

 2,000,000. Pron. Pairnumbooko. 



Pernambuco OR RECIFE. Sea- 

 port and town of Brazil, capital of 

 the state of Pernambuco. It stands 

 on the Atlantic coast, 380 m. N.E. 

 of Bahia, and is a terminus of rly. 

 lines running to the N., S., and 

 interior, besides being tb* nearest 



Pernambuco, Brazil. The old town of Recife, with 



the anchorage, from Sao Antonio ; top, the cathedral, 



situated in Boa Vista 



which the things are placed. Thus 

 the combinations of a, b, c, taken 

 two together, are ab, ac, be ; 

 for ab and ba, though different 

 permutations, form the same com- 

 bination. The theories of per- 

 mutations and combinations are 

 important in the calculations of 

 algebraic and other series, in the 

 theory of probability, and in 

 statistical work. 



S. American port to Europe. The 

 third city of importance in Brazil, 

 it comprises three quarters: (1) 

 the old settlement of Recife, 

 still the chief commercial centre, 

 founded in 1504 and occupied by 

 the Dutch from 1630-54; it is 

 situated on a sandy peninsula, 

 and connected with the mainland 

 by bridges ; (2) Sao Antonio, on the 

 island of Sao Antonio, formed by 



