Realizing this, it was decided to place fairly strong advance guards at all probable points of invasion with orders to resist as long as possible; until, in fact, defensive tactics could be adapted to the situation and the main Serbian army could be brought up to offer battle.

However, two points stood out as the most probable.  These were the two already mentioned; the north, along the line from Obrenovatz to Belgrade and to Semendria; or, the front Obrenovatz-Ratza-Losnitza-Liubovia.  The first possibility had the advantage to the Austrians of offering the shortest route to the center of the country—­the Morava Valley, their natural objective.  But it also necessitated a difficult crossing of the Danube, which would have had to be preceded by the building of pontoon bridges.  This would have given the Serbians time to move up their main forces.  The second alternative, an invasion from the east, would have entailed a longer journey, but the advantage of natural covering and easy crossing made it a sounder plan.

On July 28, 1914, the Serbians concentrated their forces in anticipation of either event.  The outpost forces were stationed at or near Losnitza, Shabatz, Obrenovatz, Belgrade, Semendria, Pozarevatz and Gradishte.  But their principal armies were centrally grouped along the line Palanka-Arangelovatz-Lazarevatz, while weaker, though important, detachments were stationed in the vicinity of Valievo, a branch railroad terminus, and Uzitze.  This narrowed the field down to such limits that it was possible to march the troops from point to point, while the few railway facilities available were utilized for food and ammunition supplies.

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CHAPTER XLVIII

AUSTRIAN SUCCESSES

On the morning of July 29, 1914, the day after war had been declared, the residents of Belgrade were startled by a deep roar, followed by the whistling shriek of a huge body hurtling through the air, and a shell burst over the battlements of the old Turkish citadel, doing no damage.  Immediately there came another deep shock; the Serbian guns were responding.  Thence on the cannonading along the Danube front continued for week after week, with only now and then a lull.

The Austrian batteries bombarded not only Belgrade, but Semendria, Gradishte and a number of other points along the river bank.  Next they were seen building a pontoon bridge out to one of the little islands in the river, opposite the city and barges were towed alongside the landings on the opposite shore, presently to be crowded with black masses of Austrian troops.  Naturally, the Serbian gunners made these objects the targets of their fire.  But these were mere bluffs, such feints as the skilled boxer makes when he wants to get behind the guard of his opponent.  If anything, these demonstrations only served to deepen the conviction of General Putnik that the real danger was not from this quarter.