Page:Popular Science Monthly Volume 33.djvu/393

Rh noticed. A great many were also seen swimming sluggishly upon the surface of the water, with their dorsal fins well out, and apparently little life left. Their fins and tails all presented a stringy appearance, and were sloughing off. The natives say that these fish ascend the river but never go down; they go to the headwaters, spawn, and swim ashore to die. In our own experience, the salmon were constantly ascending the river; the later the season, the higher up they were found, and none were known to pass down. In the spring the young salmon go down and out to sea.

The valley of the Coobuck or Putnam River is about thirty miles in width. For half a mile on either bank is a heavy growth of spruce, cottonwood, and birch trees. Between this and the mountains is rolling tundra-land. The first forty-five miles of the river from the coast is the delta, with numerous lakes and marshes of various sizes, all connected by small streams, running in every direction, and communicating with numerous arms leading to the main stream. Most of the channels are too intricate to be followed. There are thirteen mouths to the river; the smallest and shoalest empties into Selewik Lake; all the others empty into Hotham Inlet. The main and most easily navigated entrance lies about one mile west of Selewik Lake. It is about fifty yards wide with twelve feet of water on the bar. Seven miles from this entrance it is eleven hundred yards wide and thirty feet deep; forty miles beyond it leads into the river proper.

The general direction of the river is westward. Its width varies from fifty to twelve hundred yards, according to the nature of the country. It is extremely tortuous, and at no place can be seen a straight course of two miles. Traces in the valley show that it has often changed its course. The current varies from three to five miles, according to the width and height of the river. Near the head-waters are rapids. The banks in places rise so gradually as to be barely noticeable, while in other places are foot-hills one hundred and fifty feet high. The river is filled with islands and has numerous tributaries.

The river freezes in October and opens in June. During the month of February the maximum thickness of ice made in twenty-four hours was four inches; the minimum, one half inch; and for the month, six feet. There is a hot spring near the river's bank about four hundred miles from its mouth. This was visited in midwinter, and its temperature found to be 100° above zero, the temperature of the surrounding atmosphere being 50° below zero. The natives state that it is so hot at times that meat can be cooked in it.

Winter is the only season in which one can travel in the interior of northern Alaska. The marshy tundra is then frozen and covered with snow, making it possible to cross. The natives kill