PLAIN 



4694 



PLANE 



best disinfectant. Patients should be isolated a 

 month after apparent recovery. 



The first visitation of the plague to Europe 

 occurred at Athens in 430 B. c. One of the mo.-t 

 disastrous epidemics of ancient times was that 

 of Rome, in 262, when 5,000 persons succumbed 

 daily. The disease was taken to Europe by the 

 Crusaders in the thirteenth century. From 1334 

 to 1351. China, India, Persia, Russia, Germany. 

 Italy. France, England and Norway were devas- 

 tated by the plague, then known as the black 

 death. In succeeding centuries the scourge con- 

 tinued to claim its victims, and between 1603 

 and 1665 London lost 153,849 souls. In Mar- 

 seilles, in 1720, 60,000 succumbed in seven 

 months, and Moscow was almost depopulated 

 in 1771. Africa and Asia suffered no less than 

 twenty-three epidemics between 1783 and 1844. 

 Constantinople lost 260,000 of its inhabitants 

 in two epidemics (1803 and 1813). New York 

 City was, visited in 1899 and San Francisco 

 in 1900, but the disease did not spread. 



Consult Blue's The Post-Mortem Diagnosis of 

 Plague. 



PLAIN, playn, a broad, level expanse of 

 land generally rising not more than 1,000 feet 

 above the sea. There is often no line of sepa- 

 ration between a plain and a plateau; this is 

 illustrated by the great central plain of North 

 America, where the ground gradually slopes 

 up from the Mississippi River to an altitude 

 of 2,000 feet before it joins the plateau upon 

 which the Rocky Mountains rise (see PLATEAU). 

 Within the United States the great plain is 

 treeless for 500 miles east of the mountains, 

 on account of the dry climate, but in Canada, 

 where there is more rainfall, large forests cover 

 parts of the land. Much of the surface of the 

 plains is covered with a more or less abundant 

 growth of herbage. On this herds of count- 

 less buffaloes once fed, but domestic cattle 

 have now taken their place. 



Plains are often formed along the seashore, 

 where the waves wash up a great deal of sedi- 

 ment brought down by the rivers, until in 

 the course of centuries a broad expanse of 

 low land is constructed. Such land, called a 

 coastal plain, is found along the borders of 

 various continents and often furnishes splendid 

 .-oil for raising crops, like that which extends 

 along the Southern Atlantic coast of the 

 United States (see COASTAL PLAIN). Other 

 plains were originally at the bottom of the 

 sea, but as the water receded, the level land 

 was left uncovered, forming large tracts in 

 Northern Africa, Central North America and 



Siberia. The basins of dried-up lakes often 

 form plains, such as that in the valley of tin- 

 Red River of the North, where a large lake 

 disappeared after the Glacial period. 



Most inland plains have a rich soil upon 

 which abundant crops will grow in favorable 

 weather, and transportation is also a simple 

 problem on the level country; such regions are 

 therefore generally well populated. 



Subject*. The reader is referred to 

 the following articles in these volumes : 

 Llanos Prairie 



Pampas Selvas 



Plateau Steppes 



PLAIN 'FIELD, N. J., one of the most at- 

 tractive residential suburbs of New York City 

 and Newark. It is in Union County, in the 

 northeastern part of the state, and is pictur- 

 esquely located at the foot of a densely-wooded, 

 steep ridge known as First Mountain. New- 

 ark and New York are respectively sixteen 

 and twenty-four miles northeast. Transporta- 

 tion is provided by the Central Railroad of 

 New Jersey and by electric lines which operate 

 northeast and southwest from the city. Plain- 

 field has a number of beautiful parks, hand- 

 some homes, country clubs and a public library. 

 The Y. M. C. A. building and Muhlenberg 

 Hospital are worthy of note. Although it is 

 chiefly a residential city, the town has a con- 

 siderable output of manufactured products, 

 which include silk and cotton goods, silver- 

 plated ware, gloves, lumber and foundry and 

 machine-shop products. The first settlement 

 was made in 1684, but the first frame house 

 was not built here until 1735. In 1847 the 

 town was incorporated and in 1867 the city 

 was chartered. The population increased from 

 20,550 in 1910 to 24,516 (state census) in 1915. 

 The area is about six square miles. 



PLANE, playn, a term used to define the 

 simplest of geometrical surfaces a surface 

 such that the straight line joining any two 

 of its points lies wholly within the surface. 

 It is also defined as a surface which is deter- 

 mined by any three of its points not in a 

 straight line, by a straight line and a point 

 not in the line, or by two intersecting lines 

 or by two parallels. When two planes in- 

 tersect, their intersection is a straight line. A 

 plane has no curvature. A plane figure is a 

 portion of a plane bounded by lines either 

 straight or curved. If the' lines are straight, 

 it is said to be rectilinear; if they are curved, 

 it is curvilinear. Thus a square is a rectilinear 

 and a circle a curvilinear plane figure. 



