PROF. G.F. SWAIN'S LECTURE

Professor G.F. Swain, of the civil engineering department, delivered a lecture on "The Relation of Forests to the Flow of Streams" before the Engineering Society and Forestry Club in Pierce 110 yesterday afternoon.

The relation between forests and streams is of two kinds; first, the relation between forests and the regularity of flow of the streams, and second, the relation between forests and the erosion of the soil and consequent silting up of streams.

It is claimed by many that forests act as equalizers of the flow of streams, by diminishing, in general, the frequency and violence of the freshets and increasing the low water flow.

It is evident that these two phenomena, the presence of forests and the flow of the streams, are only two of a large number of mutually interdependent phenomena, so inductive methods, used disastrously by other scientists, are not to be relied upon.

First the effect of forests upon rainfall is to be considered. They cause the presence of a greater total amount of moisture in the air and they cool the air, thereby facilitating its precipitation, while its bed of humus will act like a sponge and absorb the percolation.