the skins of the desert animals for spears, knives, and tobacco.[246] Fertile agricultural lands adjoining pastoral regions of deserts and steppes have in all times drawn to their border markets the mounted plainsmen, bringing the products of their herds to exchange for grain; and in all times the abundance of their green fields has tempted their ill-fed neighbors to conquest, so that the economic bond becomes a preliminary to a political bond and an ethnic amalgamation growing out of this strong vicinal location.  The forest lands of Great Russia supplement the grain-bearing Black Lands of Little Russia; the two are united through geographico-economic conditions, which would not permit an independent existence to the smaller, weaker section of the south, ever open to hostile invasion from Asia.[247]

[Sidenote:  Types of location.]

Leaving now the ethnic and economic ties which may strengthen the cohesive power of such vicinal grouping, and considering only its purely geographic aspects, we distinguish the following types: 

I. Central location.  Examples:  The Magyars in the Danube Valley; the Iroquois Indians on the Mohawk River and the Finger Lakes; Russia from the 10th to the 18th century; Poland from 1000 to its final partition in 1795; Bolivia, Switzerland, and Afghanistan.

II.  Peripheral location:  Ancient Phoenicia; Greek colonies in Asia Minor and southern Italy; the Roman Empire at the accession of Augustus; the Thirteen Colonies in 1750; island and peninsula lands.

III.  Scattered location:  English and French settlements in America prior to 1700; Indians in the United States and the Kaffirs in South Africa; Portuguese holdings in the Orient, and French in India.

     IV.  Location in a related series:  Oasis states grouped along desert
     routes; islands along great marine routes.

[Sidenote:  Continuous and scattered location.]

All peoples in their geographical distribution tend to follow a social and political law of gravitation, in accordance with which members of the same tribe or race gather around a common center or occupy a continuous stretch of territory, as compactly as their own economic status, and the physical conditions of climate and soil will permit.  This is characteristic of all mature and historically significant peoples who have risen to sedentary life, maintained their hold on a given territory, and, with increase of population, have widened their boundaries.  The nucleus of such a people may be situated somewhere in the interior of a continent, and with growing strength it may expand in every direction; or it may originate on some advantageous inlet of the sea and spread thence up and down the coast, till the people have possessed themselves of a long-drawn hem of land and used this peripheral location to intercept the trade between their back country and the sea.