Migrants only proceed a short distance. Migrants enumerated in a certain center of absorption will grow less as distance from the center increases.
the Gravity Model
Migration stream depends on 3 conditions: population size at origin (Pi), population size at destination (Pj), and the geographic distance between i and j, or Dij
Mij = (PiPj/Dij) * K. (k is a constant.)
Migrants proceeding long distances generally go by preference to
one of the great centers of commerce or industry
An increase in the means of locomotion and a development of manufactures and commerce have led to