"Where is the firing?"
"It must be from one of the Austrian batteries near Semlin. They are bombarding the city of Belgrade, I suppose."
And then there was a deafening roar, a sound far greater than the firing of even the heaviest guns of modern warfare would make, and to the east, toward the Danube, there was a great flash of fire. Instantly the searchlight swung away from them and pointed in the opposite direction, and as the beams of light were concentrated on the spot where the flash had been, the three observers in the boat saw a strange and wonderful sight. The lights played full on the great steel railway bridge across the Save, and in their white glare they could see the beams collapsing, the piers melting away, while the whole central span of the bridge collapsed in utter ruin, leaving a gap where the river now flowed unbridged.
"Yes, the war has come!" said Steve impressively. "That was to be our first act—the destruction of the bridge. They will not send their troops into Servia so easily as that!"
"P—ss—t!"
A sharp hiss came to their ears, seemingly from the water. And not only seemingly. Looking down, they saw the upturned face of a swimmer. Mischa hailed him joyfully.
"Peter!" he said.
"Take this rope. We saw what had happened," said the swimmer, "and so I swam out, and waited until their accursed searchlight was not playing on you. We will draw you ashore. If they fire, lie low in the boat, and they will never hit you. But you are safe now unless the searchlight comes back again. They can never see you in this darkness."
"Good man, Peter!" said Steve, his voice hushed. "Swim back, now. We have the rope. It is better for you not to come into the boat now."
Peter did not answer, but turned at once and began cutting the water with long, powerful strokes. Nevertheless, though he made good progress, he disturbed the water very little, and he had not gone more than a few yards before it was almost impossible for even those in the boat to see him. Only a faint rippling of the water behind him marked his trail.