The last days of October were cold and windy and it seemed as if the north wind drove all wild birds before it. Thousands of robins and little yellow-patched birds, the hardy myrtle-warblers, filled the timber on the river islands. Long dark clouds of different kinds of blackbirds passed southward, great whitish gulls came drifting along from somewhere, and the black terns, dull colored in summer, had donned their white autumn plumage.

“I believe I saw 500,000 ducks to-day,” said the trapper as he returned to camp one evening with all the mallards he could carry.

“The birds are going fast, and it will soon be winter. We must cut a lot of wood and pull our boats up to a high place, so they will not freeze in. These woods may be under water next spring and we may need our boats in a hurry.”

Early in November came one of those cold rain-storms that mark sharply the end of Indian summer which often prolongs the warm season far into autumn.

It was the first day that all four campers stayed in the shack, which the trapper and the Indian had during the preceding week transformed into a real cozy cabin. Chunks of ash, elm, maple, and cottonwood slowly burning in the old sheet-iron stove which Barker had set up in the middle of the room kept the cabin dry and warm, while the large spattering drops of rain beat a tattoo on the roof.

The few stray leaves that had until now adhered to their branches were swept away. The river-bottom trees assumed their sharp, undraped silhouettes of winter, and from the bluffs all the bright autumn colors had vanished.

The summer birds had gone. Only a few hardy chickadees, woodpeckers, and nuthatches that defy even the coldest northern winter had remained behind the migrating hosts.

By the middle of November the lake was frozen over.

With the beginning of cold weather little Tim’s health rapidly improved. Soon he was strong enough to go sliding on the ice; and when Barker had a blacksmith at the landing make a pair of skates for each of the boys the joy of the lads was unbounded.

They skimmed lightly over the frozen sloughs, where the trees and banks sheltered them from the wind. From these trips they returned with flushed cheeks and ravenous appetites and many stories of what they had seen.

They had chased pickerel and other fish under the clear ice, they had seen a muskrat swim along with an air bubble attached to his nose, and they had watched clams slowly plowing their furrow in the sand as they withdrew from the shallower banks into deep water.

The Mississippi and its tributaries harbor a large variety of clams whose shells are now used for pearl buttons. The boys were curious about the habits and life of these quiet creatures that were always nearly buried in mud and sand and moved about by queer little jerks. When Tim was still too weak to move about much, he had amused himself for hours dropping clams, which Bill had caught, back into the water, and watching how each shell, slowly opening, put out a sort of white, fleshy foot; slowly righted itself, and crawled away into deep water.

“What do clams eat and how do they spawn?” the boys wanted to know, but on these questions neither trapper nor Indian had any information.

Clams do indeed lead a strange life. They cannot run after their food, so they just open their shells a bit to allow the water to run through, in order to catch any small particles of food the water may contain.

The young clams just hatched are so small that the naked eye can scarcely see them. They have no shell at all and swim about very actively. As soon as possible they attach themselves to the gills of several kinds of fish. The fish do not like it, but they have no way of escaping from the very minute creatures. Embedded in the gills of fish the young clams live for some weeks looking like small pimples. When they have grown a tiny shell they drop to the bottom of the river or lake and begin to live in the usual way of clams. That is the curious life-history of the river clam.

While the skating lasted the boys were well occupied. The camp was run on the plan of two meals a day. Barker and the Indian set a few traps for muskrats and minks, tidied up the cabin, cooked the meals, washed dishes, and cut wood. In all these occupations the lads gladly took a hand. At times they went the round of the traps with the men. When the weather was fine they went on skating trips up and down the glassy ice of the sloughs, which reflected like a mirror the boys at play and the trees on shore.

One who has skated only on artificial rinks and ponds does not know the thrill of traveling on a smooth winding river or on the transparent expanse of a frozen lake.

Tim tired very easily, but he grew visibly stronger every day. His fever had entirely disappeared.

Their Cousin Hicks, the boys seemed to have forgotten, at least they never spoke of him. They were happy and content in the care of their two friends.

The trapper, on the other hand, had become so attached to the lads that he once remarked to Tatanka: “I don’t see how I can ever tear myself away from these lads. It would be hard for me to give them up to their parents, but if that man Hicks ever shows up to claim them, I tell you I’ll fight him to a finish.”

“Where do you think, my friend, that bad white man has gone?” Tatanka asked.

The old trapper thought a moment. He had often asked himself the same question. “Down-river,” he replied then. “He will inquire about us of steamboat men and hotel men. And he is likely to go clear down to Vicksburg. He has some evil design on the lads, but I’ll be hanged if I can figure out what it is. I can only think that for some reason he wants to keep them away from Vicksburg.

“He lost our trail at St. Paul or he would have been upon us long ago. I was on the lookout for him every day until we saw him go down-river lately. For the present we are rid of him, but he has some very strong reason for wanting possession of those boys, and I think we’ll fall in with him somewhere after we start south.”

About the Indian war in Minnesota, the boys and their friends were well informed. Barker and the Indian had in no way exaggerated the danger. The enraged Sioux had killed about eight hundred white people, and if the trapper and Tatanka had not taken the boys away, the lads would surely have lost their lives. At the beginning of winter, the Indian war was over. The whole Sioux tribe had been driven from the State of Minnesota. A good many Indians had been captured by General Sibley and all white captives had been released.

It was much more difficult for Barker and the boys to get a clear idea about the war on the Mississippi River near Vicksburg. They had received no letters from Vicksburg since they had camped at the foot of Lake Pepin, and all they really knew was that Grant was trying to take Vicksburg.

The city of Vicksburg lies under a high bluff on the east bank of the Mississippi. By December, 1862, the Confederates had lost control of the Mississippi River, except for a stretch of two hundred miles between Vicksburg and Port Hudson, both of which points they had strongly fortified. By holding this stretch of the great river, they controlled the mouth of the Red River and could secure large supplies and thousands of men from Louisiana, Arkansas, and Texas.

The lowlands of the Mississippi at Vicksburg are about forty miles wide, and many streams and bayous wind this way and that way through vast marshes and forests.

In December, 1862, Grant tried to attack Vicksburg from the north by way of the Mississippi Central Railway, but the bold Confederate cavalry commander, Van Dorn, destroyed all his supplies at Holly Springs, and Grant was compelled to give up this plan.

After this plan had failed, Grant tried several others, his object being to secure possession of the wooded hills directly east of Vicksburg. For the present he was baffled by the geographical character of the country, which was excellently suited for defense by resolute men who knew every channel, but which presented almost insuperable obstacles to an invading army.