The young motorist paused.

"Captain," said he, "wouldn't Cassidy be the right man for carrying out the work that brought us into these waters? He is the mate, you know, and I think he expects——"

"Cassidy is here to obey orders," interrupted the captain. "Cassidy has a failing, and that failing is drink. No man that takes his liquor is ever to be depended on. As long as I'm around, and can watch him, Cassidy keeps pretty straight, but if I'm laid up at Belize, as I expect to be, I prefer to have some one in command of the Grampus whom I can trust implicitly. Read the orders."

Matt tore open the envelope and removed the inclosed sheet.

"On Board U. S. Cruiser Seminole, at Sea.
"Captain Nemo, Jr.,
"Submarine Grampus.

"Sir: Acting under orders from the Secretary of the Navy, I have the honor to request that the Grampus lend her aid to the rescue of United States Consul Jeremiah Coleman, who has been sequestered by Central American revolutionists, presumably under orders from Captain James Sixty, of the brig Dolphin, who is now a prisoner in our hands. Mr. Hays Jordan, the United States consul at Belize, will inform you as to the place where Mr. Coleman is being held. This is somewhere up the Rio Dolce, in a place inaccessible to even gunboats of the lightest draught, and it is hoped the Grampus may be able to accomplish something. Present this letter to Mr. Jordan immediately upon reaching Belize, and be guided in whatever you do by his knowledge and judgment. I have the honor to remain, sir,

"Your most obedient,
"Arthur Wynekoop, Captain Cruiser Seminole."

A movement behind Matt caused him to look around. Cassidy had descended quietly from the conning tower and was steering the ship entirely by the periscope.

"We are off Belize, sir," announced Cassidy, "and two small sailboats are coming this way. We are to anchor at the surface, I suppose?"

Matt did not know how long the mate had been in the periscope room, but supposed he had been there long enough to overhear the instructions.

"Certainly," said the captain.

Cassidy touched a jingler connected with the engine room. The hum of the motor slowly ceased.

"Get out an anchor fore-and-aft, Speake," the mate called through one of the speaking tubes.

"Aye, aye, sir," came the response through the tube.

A little later a muffled rattling could be heard as a chain was paid out through the patent water-tight hawse hole. Presently the rattling stopped, and the Grampus shivered and swung to her scope of cable. More rattling came from the stern, and soon two anchors were holding the submarine steady in her berth.

"I want you to go ashore, Matt," said Captain Nemo, Jr., "and see the American consul. Find a place where I can be taken care of; also, show that letter to the consul and tell him you are my representative. Better take Dick with you."

"Very good, sir," replied Matt.

A bluish tinge had crept into the pallor of the captain's face. Matt had been covertly watching, and his anxiety on the captain's account had increased. The captain must be taken ashore as quickly as possible and placed in a doctor's hands.

"Come on, Dick," called Matt, starting up the conning tower ladder.

With his chum at his heels, Matt crawled over the rim of the conning tower hatch and lowered himself to the rounded steel deck.

The port of Belize, nestling in a tropical bower of cocoanut trees, was about a mile distant. Owing to her light draught, the Grampus had been able to come closer to the town than other ships in the harbor. The submarine lay between a number of sailing vessels and steamboats and the line of white buildings peeping out of the greenery beyond the beach.

Two small sailboats, manned by negroes, were approaching the Grampus. Matt motioned to one of them, and her skipper hove-to alongside, caught a rope thrown by Dick, and pulled his craft as near the deck of the submarine as the rounded bulwarks would permit. A plank was pushed over the side of the sailboat, and Matt and Dick climbed over the lifting and shaking board.

"Golly, boss," grinned the negro, "dat's de funniest boat dat I ever seen in dis port. Looks like er bar'l on er raft."

"Never mind that," said Matt, "but lay us alongside the wharf as soon as you can."

The two negroes comprising the sailboat's crew were Caribs. They talked together in their native tongue, every word seeming to end in "boo" or "boo-hoo."

"A whoop, two grunts and a little blubbering," said Dick, "will give a fellow a pretty fair Carib vocabulary. What ails Cassidy?"

"I think he sampled the flask of brandy when he brought it to the captain," replied Matt.

"That was plain enough, for he had a breath like a rum cask. But it wasn't that alone that made him so grouchy. There's something else at the bottom of his locker."

"Well, he's the mate," went on Matt, dropping his voice and turning a cautious look on the two negroes, "and I suppose he thinks Captain Nemo, Jr., ought to have put him in command. To have a fellow like me jumped over his head may have touched him a little."

"Mayhap," murmured Dick, "but it's a brand-new side of his character Cassidy's showing. I never suspected it of him. Do you think the captain's trouble is anything serious?"

"I hope not, Dick, but I'm worried. The sickness came on so suddenly I hardly know what to think."

"Probably he has some of the poison from that idol's head still under his hatches. Main queer, though, that he should be so long getting over it, when Carl cut himself adrift from the same thing so handsomely."

"Things of that kind never affect two people in exactly the same way."

The negroes brought their boat alongside the wharf. As Matt paid for their services, and climbed ashore, Dick called his attention to the Grampus. Cassidy could be seen on the speck of deck running the Stars and Stripes to the top of the short flagstaff. The other sailboat, to the boy's surprise, was standing in close to the submarine.

Having finished with the flag, Cassidy could be seen to throw a rope to the skipper of the sailboat, and then, a moment later, to spring aboard.

"What does that move mean?" queried Dick.

"Give it up," answered Matt, with a mystified frown. "Probably we shall know, before long. Just now, though, we've got to think of the captain and send off a doctor to the Grampus."

Turning away, he and Dick walked rapidly to the shore and on into the town.

CHAPTER IV.

THE AMERICAN CONSUL.

"There's a bobby," cried Dick, catching sight of a policeman, "a real London bobby, blue-and-white striped cuffs and all. We'll bear down on him, Matt, and ask the way to the American consul's."

The policeman was dark-skinned, but kind and obliging for all that. Drawing the boys out into the street, he pointed to a low, white building with the American flag flying over the door. There were palms and trees around the building, and a middle-aged man in white ducks was sitting in a canvas chair on the veranda. He was Mr. Hays Jordan, and when the boys told him they were from the submarine Grampus, the consul got up and took them by the hand.

Matt lost not a moment in telling of the captain's illness, and of his desire for a doctor and of comfortable lodging ashore. The consul seemed disappointed by the news.

"I reckon that puts a stop to the work that brought the Grampus here," said the consul.

"Not at all," replied Matt. "The Grampus is at the service of the government within an