"I'm going to give 'em a shot," called out the Major, casting a glance at Jim over his shoulder. "You see, I don't know the ins and outs of this lagoon, and those fellows might yet escape us if they happen to have had time to do a little exploration. See here, Tomkins, send a ball a foot or two ahead of them; and if that does not bring them to a stop, put one right through her funnel. You can do it without fear of hitting one of the men."

"Sure! I'd back myself nine times out of ten to bring off a shot like that. I'll just wait till we're out of the shadow."

Anxious eyes flitted from the dark shape fleeting through the waters of the lagoon to the long, bony fingers of the policeman. He stepped to the front of the cab, leaned forward with his elbows on the deck, and clicked the bolt of his rifle open. Then he dropped the weapon into position, and there was a tense silence aboard as Tomkins squinted along his sights. A second later the report came, for the policeman was too old a hand with his weapon to hesitate. While he shot the empty cartridge out and slipped in a fresh one all eyes went to the boat ahead, and no doubt the bullet which Tomkins had dispatched had passed but a few feet in front of her, conveying a message and a warning; but the effect it had was entirely nil. The launch held on her course as though there was no such thing as a pursuing vessel with arms aboard able to reach the miscreants who were escaping.

"Guess they've got to have it then," growled Tomkins. "This time I'll put one through the funnel, and there ain't a doubt that it'll send them bobbing."

As cool as an icicle, the man stretched himself out again, half on the deck and half in the cab of the launch. Once more his eyes went down to the sights, and on this occasion the pause he made was long, so long, in fact, that when the rifle belched forth a stream of fire the suddenness of the report startled his comrades. Then they fixed their eyes upon the launch steaming ahead of them.

"Didn't I tell you! Got it sure, plump through the centre, and a bare foot above their heads," cried Tomkins, dropping his rifle. "See there, the flames tell you what happened."

His finger shot out instantly, and drew the attention of all to the funnel. Flames and sparks were still belching from the opening above, but that was not all, for low down now, but a bare foot above the heads of the two men crouching beside the engine, the sheet-iron tube was punctured, and a thin stream of fire was issuing from the hole. Clank! The sound of the furnace door being dragged violently open came clearly to the ears of the pursuers, in spite of the hum of their own motor, while that same red glow which had once before enveloped the launch again surrounded her. It was the only answer the rascals aboard made to Tomkins's shot, that and a dense column of smoke which now shot up, mingling with the flames and smoke from the funnel.

"Their last kick," cried the Major. "That shot tells them that we mean business. Tomkins, my lad, just give 'em another. Say, Jim, how's the motor running?"

"Fine! fine! Couldn't be doing better. Sing out when you want me to cut her down a little."

To all appearances the end of an exciting chase was already in sight, for there was no doubt that now Jim and his party were running two feet for the one covered by the escaping launch. But they had wily men to deal with, and that fact was impressed upon them within the space of a few seconds, for hardly had the third shot rung out when the launch in front ran into another long shadow by one of the islands, her form being instantly blotted out by the blackness.