The "balance of power" among European nations has hitherto been maintained because the formation of a single nation out of the Balkan States has not been possible. Although the people of these states have similar pursuits, and live much alike in all regions, they have preserved their original racial differences. A village of Albanians may be within a few miles of a village of Greeks. Yet through centuries both have remained racially distinct. Here and there the barriers have given way somewhat, but in general the races persist side by side, sometimes peaceably, more often in mutual distrust or open feud. Such division has been fostered by the great nations, and new states have been created, as recently Albania, since the formation of a great state in the Balkans by the union of all or the absorbing greatness of one, would overthrow the balance of power, and besides interpose an insurmountable obstacle between Austria and Russia, and the sea. Thus the states have been played against each other. Sometimes the game has been one of diplomacy, or one of force, hurling the states at each other's throats. HOW WAR WAS DECLARED _Ultimatum, by Austria to Servia--War Declared by Austria-- Russia Mobilizes--Germany Declares War on Russia August 1--France and England Involved--Germans Enter Belgium--Scenes in European Capitals_. On Sunday, June 28, 1914, a Servian student named Prinzep shot and killed the Archduke Francis Ferdinand, heir to the thrones of Austria-Hungary, and his morganatic wife, the Duchess of Hohenberg, in the streets of Serajevo, a town in Bosnia which the royal couple were visiting. Nearly four weeks later, on July 23, the Austro-Hungarian government, fixing responsibility for the assassination upon Servian intrigues, presented to Servia a number of demands which formed a very drastic ultimatum, requiring compliance within forty-eight hours, with the alternative of war. Servia was required to condemn "the propaganda directed against Austria" and to take proceedings against all accessories to the plot against the Archduke Francis Ferdinand who were in Servia. Austrian delegates were to supervise the proceedings, and Servia was also to arrest certain Servian officials whose guilt was alleged. These exorbitant conditions made it quite obvious that no concessions on Servians part would be accepted. It was a plain prelude to war. Nevertheless, a virtual acceptance by Servia followed. Acting on the advice of Russia, Servia acceded to all that was required of her, making only two reservations of the most reasonable character. These reservations were found enough to serve as an excuse for war. Austria at once declared herself dissatisfied and though the actual declaration of war was delayed for a brief period, a state of war practically existed between the two countries from Saturday evening, July 25. EFFORTS TO LOCALIZE THE WAR