From being a place which had little existence besides a name on the map, Grayport had suddenly blossomed out into quite a celebrated spot. Naturally, Hargraves’s story of the attack on the submarine experimenters, and the stories of the other men concerning the interesting tests, excited a great deal of attention. All sorts of people began to flock to Grayport. Among them came several cranks. All day long quite a flotilla of small boats maneuvered about the submarine as she lay at anchor, but nobody was allowed aboard. Even the newspaper correspondents, after they had been given that first story, were barred.

For two days following the adventures of the night of Mr. Lockyer’s abduction, the Lockyer lay idle at her moorings. But within her steel shell, things were anything but idle. Incessant work was going forward on the engines, getting them to the highest possible state of efficiency. The reason for this was, at present, a mystery to the boys, but it lay in the fact that Lieutenant Parry’s report had been so favorable that the Government had decided to send a special board to Grayport to investigate the little diving vessel.

So it came about, that on the morning of the third day, when Mr. Lockyer was completely recovered, and his usual active, nervous self once more, a trim-looking gunboat steamed into Grayport harbor, and cast anchor not far from the little vessel. Lieutenant Parry, calling his crew together, then made an announcement which thrilled them all. That evening, in all probability, they would start on a long trial spin with the members of the board as passengers. He impressed them all that he wished the Lockyer to be put through her best paces. Mr. Lockyer thanked him with a look for his words. So far, the submarine had done all that she should, but the crucial test, under keen, impartial eyes, remained.

Shortly afterward, Lieutenant Parry, in a shore boat, left the Lockyer for the gunboat—the Louisville. He was on his way to pay his respects to Captain McGill, the president of the testing board, and his brother officers. When he returned on board again before noon, it was with the five officers comprising the party of investigation. All wore their uniforms and made an imposing array.

The Lockyer, too, with the naval members of her crew in blue uniform, was decked out like a fighting ship. From her stern fluttered the Stars and Stripes. From her forward mooring-bits, to the last bolt on her keelson plate, she had been scoured and polished.

“A smart-looking little craft,” commented Captain McGill, after he had been introduced to Mr. Lockyer. The inventor colored with pleasure.

“I hope to prove to you, sir, that she is as smart as she looks,” he rejoined.

The officers now took possession of the cabin, and the boys and the remainder of the crew were banished to the engineers’ quarters. They were rather cramped, and Ned was not sorry when it came to the turn of himself and Herc to take watch on deck.

They were kept busy enough up there, answering questions and fending off too-inquisitive boats, whose occupants were eager to come on board. After an inspection of the vessel, the naval party went ashore in the gunboat’s launch to send some despatches to Washington. This done, they embarked once more to take council with Captain McGill on board the Louisville.

This afforded the men left on board more freedom, and they took turns at coming on deck for a bit of fresh air. Toward the middle of the afternoon—to the boys’ consternation—a heavy fog came rolling in. It began to look as if the distance cruise that night might have to be abandoned. Old Tom gazed at the wreaths of vapor as they came drifting in from the Sound, wrapping the waters about the Lockyer in a white obscurity.

“If this don’t lift by sundown it’s good for all night,” he remarked. “Say,” he went on suddenly, “did I ever tell you lads about the time I was in a fog in the English Channel on board the old wind-jammer Wampus?”

The boys shook their heads.

“Well, here goes for the yarn, then,” said old Tom. “The Wampus was one of them bluff-bowed old craft that they used to build by the mile, and sell by the foot. I was on board her on a voyage from Brest to Boston. All went well till we got in the English Channel, when a thick, pea-soup-kind of a fog shut down on us. It was so bad that you couldn’t see the forecastle from the stern.

“It was my trick at the wheel that afternoon, and for company I had the skipper, an old Maine Yankee. He was so plum nervous that all he could do was to pace up and down and cuss the fog. The English Channel is crowded with shipping, and every now and then——

“M-o-o-o-o-o-m! would go some fog horn off in the smother.

“All to once, we both give a jump. Right dead ahead of us we heard a fog horn start up.

“M-o-o-o-o-o-o-o-o-m!

“I tell you, it gave me the shivers to hear it. ‘Hard over!’ bawls the skipper, and I spun that wheel round like a squirrel, I tell you. Well, her head swung off, but it didn’t seem to be no good.

“M-o-o-o-o-o-o-m! come that sound again, and it seemed ter be jest ther same place as it was before.

“‘Confound them, are they tagging us?’ shouts Captain Wellfleet.

“‘Looks like it, sir,’ says I, swinging her over and going off on the other tack. But no sooner was we headed the other way than I’m blessed if that same old horn didn’t start up again.

“M-o-o-o-o-m!

“‘It’s the Flying Dutchman!’ declares the skipper, who was one of the old-school, hard-shell sailormen, and believed in Adamaster and all them things. By that time, although I didn’t take much stock in such yarns as that, I began to think there was something out of the ordinary in the wind. Well, sir, for half an hour or more we swung to and fro, and always we’d have that same old ‘M-o-o-o-o-o-m!’ dead ahead of us.

“And so it kept up till it came time to change watches. The fog was just as thick as ever, and we didn’t see my relief coming from for’ard till he reached the waist. By this time the skipper was jumping about from one foot to the other, pretty nearly daffy. And still, every now and then, we’d hear that ‘M-o-o-o-o-m!’ right off our bow. It was fairly uncanny, I’m telling you, the way it chased us.

“‘Send the cook aft, and tell him to make me a cup of tea,’ roars the skipper, as my relief comes up. ‘My nerves is knocked plum galley-west.’

“‘Sorry, sir,’ says the man; ‘the cook is doctoring the cow.’

“‘Doctoring the cow?’ bellows the skipper.

“‘Aye, aye, sir,’ says my mate; ‘she’s ate suthin’ that disagreed with her an’ she’s got a tummy-ache. Hark!’

“He held up his finger, and we hears that fog horn noise again.

“‘M-o-o-o-o-o-m!’

“‘Is that the horn-swoggled cow?’ roars the skipper, fair beside himself.

“‘Aye, aye, sir!’ says my mate, touching his cap; ‘she’s bin’ bellering that way fer an hour or more.’

“‘Great shades of Neptune!’ yells the skipper, ‘and we’ve bin tagging all over the Channel, trying ter git away from the beller of our own cow.’

“And that,” concluded old Tom solemnly, “was the worst fog I was ever in, boys. They do say, too, that bovine made fine corned beef, and they used the tin cow—condensed milk—for the rest of that ’ere voyage.”

“Say, Tom, do you expect us to believe that?” asked Herc, with a wink at Ned, after their laughter had subsided.

“Of course,” said the old man-o’-warsman indignantly. “If there’s any insulting doubt in your mind I’ll tell you the year and date of the month.”

“Ahoy, Lockyer!” came a hail through the fog at this moment.

“Ahoy!” hailed Ned, “what boat’s that?”

“Lockyer!” came the answer.

Ned knew at once from this, though the fog hid the boat, that it was Lieutenant Parry and his party returning.

As commander pro tem of the submarine, Lieutenant Parry had answered to Ned’s hail by giving the boat’s name. This—under Navy usage—signified that he was the captain. Other commissioned officers would have hailed: “Aye, aye.” Enlisted men would have replied: “Halloo!”

The short flight of steel steps, which did duty as an officer’s gangway, was hastily lowered from the starboard side of the submarine, and the party received on board in Navy style.

“Doesn’t look much like a cruise to-night, Lockyer, I’m afraid.” Ned, standing at attention by the gangway, heard Lieutenant Parry remark this to the inventor as they went below.

But good fortune was to favor the submarine after all. At sundown a brisk breeze sprung up, before which the fog rapidly melted away. By dusk the skies were clear, and outside the harbor a sharp wind was kicking up white-caps in dancing water-rows. It was ideal weather for cruising, and when, after supper, the order came to up anchor, the command was obeyed with alacrity.

But smart as the Lockyer had been in hastening to make ready for her start after the fog had lifted, another boat in the harbor was ahead of her in getting to sea. This was a largish catboat, which had come in that morning. Some time before the order came to “up anchor” on their own craft, the crew of the Lockyer had watched the catboat, on which were two men, slip from her moorings and, heeling gracefully before the breeze, run out of the harbor. Soon she was skipping across the Sound, bobbing about like a dancer in a quadrille. The dying light glowed goldenly on her big, single sail.

“Those fellows are off for a night’s cruise, too,” commented Herc, as he watched the white canvas glimmering more and more dimly in the gathering dusk.

“Guess they’re reaching off for a run to Bridgeport,” rejoined Ned. But in this surmise he came far—very far—from guessing the real object of the catboat’s cruise.