GEOGRAPHICAL DEFINITIONS. 



15 



part of a circle, it is necessarily greatest at the 

 equator, and thence decreases to the poles, 

 where it is nothing. 



Map is a plane figure, representing either the 

 whole or a part of the earth's surface; being a 

 projection ol'the different countries, seas, moun- 

 tains, coast, rivers, and other features of the 

 globe, in their relative situations and proportions, 

 as nearly as the nature of the problem will ad- 

 mit; for a globular surface cannot be correctly 

 represented on a plane. Maps are therefore 

 either general or particular, as they represent 

 the whole or part of the earth. 



The object to be obtained by the construction 

 of a map must determine both its kind and size. 

 If it is to be a general map, embracing a large 

 portion of the earth's surface, the size must be 

 large, and the projection employed such as will 

 introduce but little alteration into the configura- 

 tions of the countries it contains. Otherwise, 

 the multiplicity of objects it must comprehend, 

 and the alteration they would undergo, would 

 render the representation altogether inadequate 

 to the purpose. If, for instance, it is intended 

 to construct a planisphere to be used in the study 

 of astronomical geography, the stercographic 

 projection on the plane of the horizon is best 

 adapted If a map of the world, for the pur- 

 poses of physical geography be the object, the 

 plane of the meridian is to be preferred, as this 

 enables the geographer to present the old and 

 new continents unbroken ; the one being exhib- 

 ited in the eastern, and the other in the western. 

 The principal aim in this choice should be to 

 exhibit the most faithful picture of the regions 

 to be represented, upon the largest scale which 

 the size of the map will admit, and consequent- 

 ly to exclude every thing foreign to the object in 

 view. The top of a map is considered as north, 

 the bottom south, the right hand east, and the 

 left hand west. 



Measure. The English statute mile consists of 

 5,280 feet, 1,760 yards, or 8 furlongs. The Rus- 

 sian werst is little more than f of a mile English. 

 The Scotch and Irish mile is about \\ English. 

 The Dutch, Spanish, and Polish, is about 3,^ 

 English. The German is more than 4 English. 

 The Swedish, Danish, and Hungarian, is from 5 

 to 6 English. The French common league is 

 near .3 English. The English marine league is 

 3 English miles. 



Meridicni ls a great circle, passing through the 

 poles of the earth, and any given place on its 

 surface. It therefore divides this surface into 

 two hemispheres, the one being the eastern, and 

 the other the western. The first meridian of 

 any country is that from which its geographers, 

 navigators, and astronomers commence their 

 reckoning of longitude. 



Minule of a degree, is the 60th part of a de- 

 gree ; this is subdivided into 60 seconds, and 

 each of these again into thirds, when necessary. 



Mountain is any considerable elevation on the 



earth's surface. This name is applied both to 

 detached heights, and connected groups or 

 chains of these eminences. 



JVorlh is that point of the horizon which ig 

 equally distant from the east and west points, 

 and is diametrically opposed to the south. 



Oasis is a term frequently applied to a fertile 

 district amidst vast deserts of sand. Several of 

 these occur in the sandy oceans of the African 

 deserts; where the contrast was so great, as to 

 induce the ancients to regard them as the Hcs- 

 perides, or isles of the blessed. 



Ocean is the term by which the vast mass of 

 waters covering about two thirds of the earth's 

 surface is designated. For the sake of perspi- 

 cuity, geographers have supposed it to be divid- 

 ed into various parts, to which they have given 

 particular names. 



Pampas is a name given by the South Ameri 

 cans to the vast plains, which characterize theii 

 country. 



Parallels nf lalihide are small circles of the 

 sphere parallel to the equator. 



Peninsula is any portion of land nearly sur- 

 rounded by water. The term is generally ap- 

 plied to those parts which project into the 

 ocean, and are joined to the main land by an 

 isthmus. 



Plateau is an elevated plain, or any high table- 

 land terminated on all sides by declivities. The 

 central jiarts of Asia, the middle regions of 

 Spain, and the vast elevated lands on which 

 Mexico is situated are all of this kind. 



Polar circles are two small circles of the 

 sphere which encompass the frigid zones, and 

 are 23° 28' distant from the poles. 



Pole is the point on the earth's surface where 

 it is penetrated by the axis. As this axis termi- 

 nates in two opposite points, the one is the north 

 and the other the south pole, and each is 90** 

 from the equator. 



Prairie is a term applied to the unwooded 

 tracts in the great valley of the Mississippi. 



Promontory is a portion of land projecting into 

 the sea, the end of which is generally called a 

 cape. 



River is a considerable body of water collect- 

 ed in the more elevated parts of the land, and 

 descending into the lower, either discharging it- 

 self into another river or flowing into the sea. 

 The courses of rivers ahvays mark the greatest 

 declivities of land over which they flow, and 

 their magnitude is generally proportional to the 

 height and distance of their sources. 



Savanna is a term by which the vast extend- 

 ed plains in America are frequently denoted. 



Sea, in its general extent, implies the whole 

 of that vast body of water which covers a great 

 part of the globe. It is, however, used to de- 

 note a particular part of this fluid, as the Baltic 

 Sea, White Sea, &.c. 



Solar Sifslem is that assemblage of planets 

 and satellites which have tlie sun for their com- 



