Page:Popular Science Monthly Volume 73.djvu/95

Rh as may have the greatest value in the particular localities. By these methods we should avoid the loss incident upon constant drainage of water, secure an unfailing irrigation for crops cultivated in the land portion, secure a valuable source of fertility, and at the same time a valuable aquatic crop. Systems of this character, however, would be gradually developed and modified to suit conditions of particular localities.

A recent number of the National Geographic Magazine gives the areas of swamp lands in the United States (not including Alaska) at sixty millions of acres, almost entirely in the humid regions of the Atlantic slope and the Mississippi Valley.

A bulletin issued later by the U. S. Department of Agriculture gives an estimate of 77,000,000 of acres for swamp and overflowed lands and claims a possible reclamation of practically this entire area.

Both of these authors put great stress upon the wealth to be gained by the drainage of this area, and discuss some of the great national and state projects already in view, but no hint is given by either that any part of this vast area could be put to useful service except by disposing of the water.