The Sources of Rivers

Most of the remaining rivers flow northwards from the Hercenian Mountains, which are the greatest in height and extent about that region. Even where rivers flow from marshes, the marshes in almost every case are found to lie below mountains or gradually rising ground. The fact that rivers rise at the foot of mountains proves that a place transmits the water it contains by gradual percolation of many drops, little by little. This is how the sources of rivers originate.