Suddenly a low, deep rumble of a reverberation echoed and reechoed from the hills over the water. The field-gun had bellowed defiance.

A solid shot crashed through the cabin, smashing the door. Astounded, the men jumped back. As they did so, in their fear, the cable, released, slipped back over the rail in a great splash of safety into the water and sank.

"The deuce take you--you fools," swore Del Mar, springing forward in rage, and looking furiously toward the sh.o.r.e.

Two of the men had been hit by splinters. It was impossible to drag again. Besides, again the gun crew loaded and fired.

The first shot had dismantled the doorway of the cabin. Elaine crouched fearfully in the furthest corner, not knowing what to expect next.

Suddenly another shot tore through just beside the door, smashing the woodwork terrifically. She shrank back further, in fright.

Anything was better than this hidden terror. Nerved up, she ran through the broken door.

Arnold was gazing through his gla.s.s at the effect of the shots. He could now see Del Mar and the others leaping into a swift little motor-boat alongside the steamer which they had been using to help them in dragging for the cable.

Just then he saw Elaine run, screaming, out from the cabin and leap overboard.

"Stop!" shouted Arnold in a fever of excitement, lowering his gla.s.s.

"There's a girl--by Jove--it's Miss Dodge!"

"Impossible!" exclaimed Woodward.

"I tell you, it is," reiterated Arnold, thrusting the gla.s.s into the Lieutenant's hand.

The motor-boat had started when Del Mar saw Elaine in the water.

"Look," he growled, pointing, "There's the Dodge girl."

Elaine was swimming frantically away from the boat. "Get her," he ordered, shielding his face so that she could not see it.

They turned the boat and headed toward her. She struck out harder than ever for the sh.o.r.e. On came the motor-boat.

Arnold and Woodward looked at each other in despair. What could they do?

Somehow, by a sort of instinct, I suppose, I made my way as quickly as I could along the sh.o.r.e toward Fort Dale, thinking perhaps of Lieutenant Woodward.

As I came upon the part of the grounds of the Fort that sloped down to the beach, I saw a group of young officers standing about a peculiar affair on the sh.o.r.e in the shallow water--half bird, half boat.

As I came closer, I recognized it as a Thomas hydroaeroplane.

It suggested an idea and I hurried, shouting.

One of the men, seated in it, was evidently explaining its working to the others.

"Wait," he said, as he saw me running down the sh.o.r.e, waving and shouting at them. "Let's see what this fellow wants."

It was, as I soon learned, the famous Captain Burnside, of the United States Aerial Corps. Breathless, I told him what I had seen and that we were all friends of Woodward's.

Burnside thought a moment, and quickly made up his mind.

"Come--quick--jump up here with me," he called. Then to the other men, "I'll be back soon. Wait here. Let her go!"

I had jumped up and they spun the propeller. The hydroaeroplane feathered along the water, throwing a cloud of white spray, then slowly rose in the air.

The sensation of flying was delightful, as the fresh morning wind cut our faces. We seemed to be hardly moving. It was the earth or rather the water that rushed past under us. But I forgot all about my sensations in my anxiety for Elaine.

As we rose we could see over the curve in the sh.o.r.e.

"Look!" I exclaimed, straining my eyes. "She's overboard. There's a motor-boat after her. Faster--over that way!"

"Yes, yes," shouted Burnside above the roar of the engine which almost made conversation impossible.

He shifted the planes a bit and crowded on more speed.

The men in the boat saw us. One figure, tall, m.u.f.fled, had a familiar look, but I could not place it and in the excitement of the chase had no chance to try. But I could see that he saw us and was angry.

Apparently the man gave orders to turn, for the boat swung around just as we swooped down and ran along the water.

Elaine was exhausted. Would we be in time?

We planed along the water, while the motor-boat sped off with its baffled pa.s.sengers. Finally we stopped, in a cloud of spray.

Together, Burnside and I reached down and caught Elaine, not a moment too soon, dragging her into the boat of the hydroaeroplane.

If we had not had all we could do, we might have heard a shout of encouragement and relief from the hill where Woodward and Arnold and the rest were watching anxiously.

I threw my coat about her, as the brave girl heroically clung to us, half conscious.

"Oh--Walter," she murmured, "you were just in time."

"I wish I could have been sooner," I apologized.

"They--they didn't cut the cable--did they?" she asked, as we rose from the water again, bearing her now to safety. "I did my best."

CHAPTER XI

THE WIRELESS DETECTIVE

Del Mar made his way cautiously along the bank of a little river at the mouth of which he left the boat after escaping from the little steamer.

Quite evidently he was worried by the failure to cut the great Atlantic cable and he was eager to see whether any leak had occurred in the organization which, as secret foreign agent, he had so carefully built up in America.

As he skirted the sh.o.r.e of the river, he came to a falls. Here he moved even more cautiously than before, looking about to make certain that no one had followed him.

It was a beautiful sheet of water that tumbled with a roar over the ledge of rock, then raced away swiftly to the sea in a cloud of spray.