981

The formation of mountains.

The summits of mountains for a long time rise constantly.

The opposite sides of the mountains always approach each other below; the depths of the valleys which are above the sphere of the waters are in the course of time constantly getting nearer to the centre of the world.

In an equal period, the valleys sink much more than the mountains rise.

The bases of the mountains always come closer together.

In proportion as the valleys become deeper, the more quickly are their sides worn away.

Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.

980 * 982

XIV * XVII

Notebooks of Leonoardo da Vinci

XVI: Physical Geography.

. . .

Theory of the circulation of the waters.

961,

962

Observations in support of the hypothesis.

963,

964,

965,

966,

967,

968,

969

On the way in which the sources of rivers are fed.

970

The tide in estuaries.

971

confluence.

972,

973,

974

Whirlpools.

975

On the alterations in the channels of rivers.

976

The origin of the sand in rivers.

977,

978

The formation of mountains.

979,

980,

981,

982,

983

The authorities for the study of the structure of the earth.

984,

985

Doubts about the deluge.

986

That marine shells could not go up the mountains.

987

The marine shells were not produced away from the sea.

988

Further researches.

989,

990,

991