upon them the distasteful necessity of union within to withstand
aggressions crowding upon them from without. Hence the growth of the
Swiss constitution since 1798 has meant a fight of the Confederation
against the canton in behalf of general rights, expanding the functions
of the central government, contracting those of canton and commune.[16]

[Sidenote: Local and remote geographic factors.]

Every country forms an independent whole, and as such finds its national
history influenced by its local climate, soil, relief, its location
whether inland or maritime, its river highways, and its boundaries of
mountain, sea, or desert. But it is also a link in a great chain of
lands, and therefore may feel a shock or vibration imparted at the
remotest end. The gradual desiccation of western Asia which took a fresh
start about 2,000 years ago caused that great exodus and displacement of
peoples known as the _Völkerwanderung_, and thus contributed to the
downfall of Rome; it was one factor in the Saxon conquest of Britain and
the final peopling of central Europe. The impact of the Turkish hordes
hurling themselves against the defenses of Constantinople in 1453 was
felt only forty years afterward by the far-off shores of savage America.
Earlier still it reached England as the revival of learning, and it gave
Portugal a shock which started its navigators towards the Cape of Good
Hope in their search for a sea route to India. The history of South
Africa is intimately connected with the Isthmus of Suez. It owes its
Portuguese, Dutch, and English populations to that barrier on the
Mediterranean pathway to the Orient; its importance as a way station on
the outside route to India fluctuates with every crisis in the history
of Suez.

[Sidenote: Direct and indirect effects of environment.]