it was on the evening of the fourth day later that captain weston, who was steering the craft, suddenly called out:

"land ho!"

"where away?" inquired tom quickly, for he had read that this was the proper response to make.

"dead ahead," answered the sailor with a smile. "shall we make for it, if i may be allowed the question?"

"what land is it likely to be?" mr. swift wanted to know.

"oh, some small tropical island," replied the seafaring man. "it isn't down on the charts. probably it's too small to note. i should say it was a coral island, but we may be able to find a spring of fresh water there, and some fruit."

"then we'll land there," decided the inventor. "we can use some fresh water, though our distilling and ice apparatus does very well."

they made the island just at dusk, and anchored in a little lagoon, where there was a good depth of water.

"now for shore!" cried tom, as the submarine swung around on the chain. "it looks like a fine place. i hope there are cocoanuts and oranges here. shall i get out the electric launch, dad?"

"yes, you may, and we'll all go ashore. it will do us good to stretch our legs a bit."

carried in a sort of pocket on the deck of the submarine was a small electric boat, capable of holding six. it could be slid from the pocket, or depression, into the water without the use of davits, and, with mr. sharp to aid him, tom soon had the little craft afloat. the batteries were already charged, and just as the sun was going down the gold-seekers entered the launch and were soon on shore.

they found a good spring of water close at hand, and tom's wish regarding the cocoanuts was realized, though there were no oranges. the lad took several of the delicious nuts, and breaking them open poured the milk into a collapsible cup he carried, drinking it eagerly. the others followed his example, and pronounced it the best beverage they had tasted in a long time.

the island was a typical tropical one, not very large, and it did not appear to have been often visited by man. there were no animals to be seen, but myriads of birds flew here and there amid the trees, the trailing vines and streamers of moss.

"let's spend a day here to-morrow and explore it," proposed tom, and his father nodded an assent. they went back to the submarine as night was beginning to gather, and in the cabin, after supper, talked over the happenings of their trip so far.

"do you think we'll have any trouble getting the gold out of the wrecked vessel?" asked tom of captain weston, after a pause.

"well, it's hard to say. i couldn't learn just how the wreck lays, whether it's on a sandy or a rocky bottom. if the latter, it won't be so hard, but if the sand has worked in and partly covered it, we'll have some difficulties, if i may be permitted to say so. however, don't borrow trouble. we're not there yet, though at the rate we're traveling it won't be long before we arrive."

no watch was set that night, as it was not considered necessary. tom was the first to arise in the morning, and he went out on the deck for a breath of fresh air before breakfast.

he looked off at the beautiful little island, and as his eye took in all of the little lagoon where the submarine was anchored he uttered a startled cry.

and well he might, for, not a hundred yards away, and nearer to the island than was the advance, floated another craft—another craft, almost similar in shape and size to the one built by the swifts. tom rubbed his eyes to make sure he was not seeing double. no, there could be no mistake about it. there was another submarine at the tropical island.

as he looked, some one emerged from the conning tower of the second craft. the figure seemed strangely familiar. tom knew in a moment who it was—addison berg. the agent saw the lad, too, and taking off his cap and making a mocking bow, he called out:

"good morning! have you got the gold yet?"

tom did not know what to answer. seeing the other submarine, at an island where he had supposed they would not be disturbed, was disconcerting enough, but to be greeted by berg was altogether too much, tom thought. his fears that the rival boat builders would follow had not been without foundation.

"rather surprised to see us, aren't you?" went on mr. berg, smiling.

"rather," admitted tom, choking over the word.

"thought you'd be," continued berg. "we didn't expect to meet you so soon, but we're glad we did. i don't altogether like hunting for sunken treasure, with such indefinite directions as i have."

"you—are going to—" stammered tom, and then he concluded it would be best not to say anything. but his talk had been heard inside the submarine. his father came to the foot of the conning tower stairway.

"to whom are you speaking, tom?" he asked.

"they're here, dad," was the youth's answer.

"here? who are here?"

"berg and his employers. they've followed us, dad."