SERBIAN RESISTANCE TO AUSTRIA.--An Austrian attempt to overwhelm Serbia in the first weeks of the war met with disastrous failure. This was due to two causes: (1) the brave resistance of the Serbian troops; (2) the fact that the greater part of the Austrian forces had to be used for defense against the Russian invaders of Galicia. Serbia after severe fighting compelled the Austrians to retreat beyond their own boundaries. Early in September the Serbians took the offensive and began an invasion of Austria-Hungary. This venture failed, and before long Serbia was once more resisting the enemy on her own soil. Belgrade fell into Austrian hands on December 2. It did not long remain in the possession of the conquerors. On the 14th, it was regained by the Serbians, and the Austrian armies once more expelled. The little Balkan kingdom seemed to be holding her own. TURKEY ENTERS THE WAR.--In the years before the war, Germany had carefully cultivated the friendship of the Turkish government. By means of intrigue, she had practically made herself master of that country, particularly in military matters. The Turkish army had been trained by Germans, and many of its officers were Germans. Although at the opening of the war Turkey declared herself neutral, she soon showed herself an ally of the Central Powers. There is evidence to show that as early as August 4 she had entered into a secret treaty with Germany. In October Turkey startled the world by bombarding a Russian port on the Black Sea and destroying French and Russian vessels at Odessa. These acts were regarded by Russia as acts of war. A few days later France and Great Britain declared war on Turkey. [Illustration: GERMAN COLONIES and locations of early naval engagements.] Germany welcomed the entrance of Turkey into the war for two reasons. In the first place she expected that the Mohammedans under English and French rule, that is, those living in Morocco, Algeria, Egypt, and India, would join the Turkish Sultan, the religious head of the Mohammedan world, and engage in a "Holy War" against Great Britain and France. In this hope she was doomed to disappointment. In the second place Germany rejoiced at the arrival of a new enemy for Russia who might keep the Russians occupied along their southern borders and so weaken their efforts on other fronts. GERMAN COLONIES IN THE PACIFIC.--During the first four months of the war all of Germany's possessions in the Pacific were lost to her. On the outbreak of the war, Australia and New Zealand promptly organized expeditionary forces which attacked and captured the German colonies and coaling stations situated south of the Equator. German Samoa, the first to be taken, surrendered to the New Zealand expeditionary force August 29. The other German possessions in the South Pacific surrendered to the Australians.