The boy leaned over Nelson’s shoulder and looked for a long while without saying anything. Then, with a sigh——

“Yes, that’s it,” he said. “That’s where I live—right there.” He placed a blackened finger on the chart. “It—it’s almost like seeing home, ain’t it?” he asked shyly. Nelson didn’t answer, but he folded the chart up in a determined manner and tossed it to Dan.

“You stay right here with us, Spencer,” he said, “and we’ll put you ashore at Mullen’s Cove, if it takes a week to do it. Now I’m going to look at the engine.”

A moment later he was up again and looking anxiously back across the water. The sun was sinking, and the long, level rays were tipping the little waves with gold. In the hollows purple shadows were floating. Back of them, perhaps a little more than a half mile, the tugboat was following doggedly in their wake. Nelson glanced at Bob and their eyes met.

“She’s missing like anything,” muttered Nelson ruefully. “It’s that blamed gasoline we bought this afternoon; seems like it was half water. I’ve done everything I know how, but it doesn’t make any difference. She’s missing about a third of her explosions. I wish to goodness it would get dark!”

“It will be in about half an hour,” answered Bob hopefully.

“I know, but—” He stopped, staring at Bob. The engine had ceased working! But in another instant it had started again. With a frown, Nelson went below. Bob glanced back at the tug. Already it seemed to have gained on them. Dan and Tom were talking to Spencer, and had not noticed anything. The Vagabond had covered some fourteen miles of the twenty that lay between Sanstable and Provincetown, and now the “toe of the boot,” as the tip end of Cape Cod has been fancifully called, lay before them well defined in the last flare of sunlight. Directly to the east the curving coast was perhaps a mile nearer to them than was the harbor of Provincetown, but to alter their course would be giving an advantage to the pursuers, since it would enable them to cut across, and perhaps head off, the Vagabond before port was reached. Bob studied the chart before him and saw that, even if they turned eastward, they would have difficulty in finding a harbor. If the engine would hold out, their best plan was undoubtedly to keep on around the Cape. It was doubtful if those on the tug would care to keep up the chase when they saw that the Vagabond was not putting in at Provincetown; or, if darkness came before they reached the end of the Cape, they could head northwest and perhaps throw the tugboat off the track. But it all depended on the engine. Bob leaned down so that his head was inside the hatchway and listened. The sound that reached him was not reassuring. The engine was missing spark after spark, sometimes stopping for seconds at a time. He raised his head and again looked back over the darkening water. There was no longer a half mile between the launch and the tug, nor anything like it. Unless something happened, very soon the chase was as good as over!

And something did happen, and almost instantly, but not what Bob would have chosen. The engine stopped altogether! Nor, although Bob listened and waited with anxious ears, did it start up again. Dan and Tom and Spencer looked at Bob and one another with inquiring eyes. The moments passed. The Vagabond slowly lost headway. Then Nelson’s face appeared at the engine-room door.

“It’s all up, I guess,” he said quietly. “I’ll have to take the vaporizer apart, and that will take some time. And even then I’m not sure that she’ll work. Where’s the tug?”

“About a quarter of a mile away, and coming like thunder!” answered Dan.