The Austrian capital has seen the warring Turks beneath its walls, and shapes its foreign policy with a view to the relative strength of the Sultan and the Czar.
[Sidenote: Unity of the earth.] The earth is an inseparable whole.

Each country or sea is physically and historically intelligible only as a portion of that whole.

Currents and wind-systems of the oceans modify the climate of the nearby continents, and direct the first daring navigations of their peoples.

The alternating monsoons of the Indian Ocean guided Arab merchantmen from ancient times back and forth between the Red Sea and the Malabar coast of India.[33] The Equatorial Current and the northeast trade-wind carried the timid ships of Columbus across the Atlantic to America.

The Gulf Stream and the prevailing westerlies later gave English vessels the advantage on the return voyage.