Just then Lieutenant Woodward dashed up with the officer and company and the field-gun.  They wheeled it about and began pointing it and finding the range.

Would they never get it?  Arnold was almost beside himself.  One of Del Mar’s men seized an axe and was about to deliver the fatal blow.  He swung it and for a moment held it poised over his head.

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 shore.

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 glass 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 glass.  “There’s a girl—­by Jove—­it’s Miss Dodge!”

“Impossible!” exclaimed Woodward.

“I tell you, it is,” reiterated Arnold, thrusting the glass 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 shore.  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 shore 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 shore in the shallow water—­half bird, half boat.

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