"Yes, a great deal. Besides, it is navigable for nearly two thousand miles, clear from St. Paul, Minnesota, to the Gulf. It drains two-fifths of the area of the United States. To put it another way, all the rain and snow that falls between New York State and Montana sooner or later makes its way into the Mississippi River, except for the rain that is used up by plants and animals or that is evaporated before it reaches the river or that drains by underground seepage to the ocean. So you see what a vast amount of water it must carry. Now, boys," he continued, "what kind of banks has the river around here, rock or earth?"
"Mud!" answered Ross, tersely.
"Right," the Forecaster agreed, "and it is mud nearly all the way along. But do you know what mud is?"
FACING A CLIMB ON SHOW-SHOES. | TWENTY-FIVE FOOT DRIFT A MILE LONG. |
FOREST RANGER IN IDAHO. | OBSERVER AMONG THE QUAKING ASPENS. |
Snow Survey work. Courtesy of U. S. Weather Bureau and of J. Cecil Alter. | |
This was rather a poser, but finally Anton said slowly,
"It's a mixture of earth and water, isn't it?"
The Forecaster looked shrewdly at the boy.
"You've hit it just right," he said, "mud is earth or soil that has been washed down by the river. That's what makes the bottom of the river so irregular and why it's always shifting. You can see for yourselves, boys, that if the bottom of the Mississippi is just made of light mud, light enough to be carried down as muddy water for hundreds of miles, any little change in the current of the river will stir up that mud again and scoop out a hole. If it happens to be near a bank, the bank will be eaten away and, naturally, will cave right in."
"About how much mud does the Mississippi carry down, Mr. Levin?" Anton asked.
"In flood time, as much as a thousand tons a minute will be carried past here."