"That's all right," his friend said heartily, "I've enjoyed having you, and so has Paul, I know. I shall hear from you occasionally, I hope, and maybe the _Golden Falcon_ will have you on board for some other trip."

"Thank you ever so much, sir," Colin answered; "but I guess I'm booked for college steadily until next summer, and the Bureau of Fisheries during vacation."

But Colin was mistaken in his idea that almost a year would elapse before he was busy again with Fisheries work, for shortly before the end of his first term, he received a letter from his father in which the suggestion was made that the boy should spend a week on the Great Lakes during the Christmas vacation, to get an idea of what winter work was like. Colin smiled as he read the letter, for he knew well that he was 'in for it,' since his father would make him go through every step of the training.

Accordingly, one cold day, he found himself aboard the steamer _Mary N.

Lewis_, which had been chartered by the Bureau for a couple of weeks'

trawling in Lake Michigan. A bitter wind was blowing and lumps of ice floated near the sh.o.r.es. The whitefish were not plentiful that winter, and when the nets came up and Colin had to pick fish out, b-r-r-r, but it was cold! A great many of the fish were not ripe for sp.a.w.ning and had to be thrown back again, which delayed matters greatly and kept the party on the water for several days.

Frequently Colin's lips were blue and his fingers numb, while his ears and cheekbones and chin felt as though they were being sliced off gradually by the blasts blowing down from icy Canada, but he knew that, to a certain extent, he was on trial, and he laughed and joked and managed to keep his spirits up, though his teeth chattered. There was no great amount of excitement in catching the whitefish and securing the sp.a.w.n for development in the hatchery, but it was a test of endurance, and incidentally the boy learned much about the fishes of the Great Lakes.

"There's one thing I don't quite see, though," he said one day to the government fish culturist, with whom he was working; "and that is, why we need to do this."

"How do you mean, Dare?"

"Well, in the West, they hatch young salmon because the old salmon are caught going up the river before they sp.a.w.n, and they die, anyway; but here they have all the room they want for sp.a.w.ning, and I should think Nature would look after it."

"You don't want to forget," the fish culturist replied, "that Nature is very exact. Everything has to balance. The whitefish born are ten times as many as those that mature, but the number that matures is just precisely enough to keep the supply going."

"I see that, all right," the boy answered.

"Well, then, if you disturb this balance by extensive fishing, isn't it easy to see that you've got to make up for it somewhere? We don't have to worry over keeping up the supply of catfish, for example, because Nature is being left alone, and she has worked the problem out. But if suddenly a big catfish market developed--as it easily might, because, in spite of popular opinion, catfish is good eating--and if thousands of them were caught, it would be necessary to find some way to help Nature in keeping up the supply.

"Now, the whitefish," he continued, "isn't like the salmon, which sp.a.w.ns carefully. The lake fish does that in a sort of hit-or-miss manner, with the result that only a small percentage of the eggs get a fair start. It is not difficult for us to put hundreds of millions of young fish into the lakes every year, and the proportion of these that survive will not merely keep the supply constant, but will even increase it."

"Then that will disturb the balance in another way?"

"Yes," was the reply, "but it will be at the expense of other species which are of no use to man. Nature is like the proverbial Irishman, she can't be drove, but she's mighty easy to lead. When you return to the university, get hold of some books on the means by which all the various kinds of living creatures in the world are kept on an even balance, how they all get their food, and how every tiny speck fits into the whole world scheme. You'll find that sort of reading has more grip to it than any novel--except, perhaps, those of a few of the really great writers, of whom there are some in every age."

[Ill.u.s.tration: WINTER ON THE GREAT LAKES, STRIPPING LAKE-TROUT.

_Courtesy of the U. S. Bureau of Fisheries._]

[Ill.u.s.tration: WINTER WORK ON INLAND STREAMS, PLANTING TROUT FRY IN ICE-COVERED RIVERS.

_Courtesy of the U. S. Bureau of Fisheries._]

"I found that out," answered Colin, "when I was working with Mr.

Collier. He was always saying that things were 'so much worth while,'

and when he started to explain them, they certainly were! It's just like this, I've only seen a little bit of this inland water work, but you handle other species beside whitefish in this work on the Great Lakes, don't you?"

"Yes," was the culturist's reply; "lake trout and pike perch among others. One station alone has handled seventy-one million trout eggs in a season. But the pike perch is a more difficult fish to propagate artificially, though nearly half a million eggs were distributed last year. We gave Canada six million pike perch fry. There's no wasted energy in the Bureau of Fisheries, it's practical all the way through, and you're learning to see it from the right angle--doing the work and seeing the results."

It was this personal contact with the fish-culture work, this direct demonstration of the money value to the country of scientific knowledge, which became Colin's stimulus. His college-mates outdistanced him in many studies, for the boy was not at heart of a scholarly type, but in his scientific work he was far in advance of them all. Seeing his interest and his perseverance, several of the professors and instructors in the scientific department took a liking to Colin, and the lad was sure to be found on every kind of field expedition for which he was eligible. He was quite an athlete, too, but he settled down to swimming as his share in the athletic work of the university. Already quite at home in the water, he worked at improving his stroke with such energy, and was in the tank so much, that before the end of his freshman year, he was by long odds the best swimmer in the college. With his devotion to fish and his prowess in the water, it was a common saying that "Dare's growing fins!" and the college paper took to calling him "Fins,"

a nickname which stuck to him ever after.

As he had intimated to his father long before, Colin was especially anxious to go to Woods Hole, the great marine station of the Bureau of Fisheries, situated on the southwestern corner of Cape Cod, and the most famous marine biological laboratory in the New World. The work of the Fisheries appealed to him a great deal more when it bore a relation to the sea, rather than to rivers and inland waters, and his application for a position on the summer force at Woods Hole had been sent to headquarters shortly after the New Year. Accordingly, just as soon as the term was over, he hurried to Washington.

Disappointment awaited him. His heart had been set on that especial feature of the work, but when he asked Dr. Crafts about it, the Deputy Commissioner shook his head.

"I have thought the matter over," he said, "and if you are equally anxious next year to go to Woods Hole you shall go. But this season I'm going to send you to the Mississippi to do some work on mussels."

"Very well, sir," Colin answered, his expression betraying his regrets, but his will determining that he would make no seeming complaint. "I wish I'd known this winter, and I would have given more attention to the mollusks."

The Deputy Commissioner, who had friends in Brown University, had heard indirectly once or twice about Colin, and smiled to himself. He was pleased by the lad's self-control, and continued:

"The mussel question is of a great deal more interest than you think.

I'm not sure, of course, but there are signs of a pearl-fever, and if there is one, you'll certainly see something doing. The Mississippi and Ohio were like a Klondike in 1903!"

"What is a 'pearl-fever,' Dr. Crafts?" asked the boy.

"A silly infatuation that seems to strike the farmers of the river valleys every few years on hearing that a valuable pearl has been found in a mussel. The get-rich-quick hope is very general, and it seems so much easier to dredge mussels and open them until a fortune is found in one than it does to farm for a living. In 1903, thousands upon thousands of farms were deserted or sold for next to nothing by people who believed that within a week they could be made millionaires by the pearls they would find in Mississippi River mussels."

"But I thought pearls came from oysters!" exclaimed Colin in surprise.

"So they do, but they come from mussels, as well, and clams occasionally. But you ought to remember," the Deputy Commissioner continued, "that the finding of an occasional pearl in an oyster or a mussel is of comparatively little importance, because it's an irregular sort of thing. The mother-of-pearl industry, however, is of big importance, it has an economic value to the country, and consequently it's our business to see that the natural resources are as wisely used as possible. We'll start a party out there on June fifteenth, so you can report here by that time."

"But, sir----"

"Well?"

"That's three weeks away!"

"Is that too long to wait? I'm afraid you'll have to learn patience, Colin; that's as important as any knowledge of fish culture."

"But I was wondering, Dr. Crafts," the boy urged, "if I had three weeks to spend, why I couldn't go down to Beaufort?"

"What for?"

"One of my instructors in biology is there," Colin said. "I believe the Bureau gave him table-room in the laboratory there for some work on turtles, and he said I could help him if you were willing to have me go. I didn't say anything about it, because I wanted to go to Woods Hole right away, but if I have this time to spare, don't you think I ought to use it?"

"I think you ought to use it for a holiday," the Deputy Commissioner answered.

"But I'd rather be doing something!" protested Colin.

"Perhaps," was the firm reply; "but not necessarily at Beaufort. Aside from the hatching of diamond-back terrapin, there's nothing going on there in which you could be of any service. Besides, you'll get 'stale'

unless you have a vacation. 'All work and no play,' you know."

Colin was eager to urge the Deputy Commissioner, but he could see it would be useless.

"I'd read up on turtles, too!" he returned in a disappointed tone.

"H'm--by your instructor you mean Mr. Lark, do you not?"

"Yes, sir."

"Look here, Colin," said the Deputy Commissioner, "since you have practically joined the Bureau by our promise to accept you if you make good, don't forget that we are after results first. I've been a boy myself, and I think I can see what you're driving at. I suppose Lark has been telling you some of his stories about riding diving turtles."