The Notebooks of Leonardo Da Vinci (65 page)

[14] Abook of conducting navigable canals above or beneath the
rivers which intersect them.

[15] A book of the soils which absorb water in canals and of
repairing them.

[16] Abook of creating currents for rivers, which quit their beds,
[and] for rivers choked with soil.

General introduction.

929.

By the ancients man has been called the world in miniature; and
certainly this name is well bestowed, because, inasmuch as man is
composed of earth, water, air and fire, his body resembles that of
the earth; and as man has in him bones the supports and framework of
his flesh, the world has its rocks the supports of the earth; as man
has in him a pool of blood in which the lungs rise and fall in
breathing, so the body of the earth has its ocean tide which
likewise rises and falls every six hours, as if the world breathed;
as in that pool of blood veins have their origin, which ramify all
over the human body, so likewise the ocean sea fills the body of the
earth with infinite springs of water. The body of the earth lacks
sinews and this is, because the sinews are made expressely for
movements and, the world being perpetually stable, no movement takes
place, and no movement taking place, muscles are not necessary.
—But in all other points they are much alike.

The arrangement of Book I.

930.

Define first what is meant by height and depth; also how the
elements are situated one inside another. Then, what is meant by
solid weight and by liquid weight; but first what weight and
lightness are in themselves. Then describe why water moves, and why
its motion ceases; then why it becomes slower or more rapid; besides
this, how it always falls, being in contact with the air but lower
than the air. And how water rises in the air by means of the heat of
the sun, and then falls again in rain; again, why water springs
forth from the tops of mountains; and if the water of any spring
higher than the ocean can pour forth water higher than the surface
of that ocean. And how all the water that returns to the ocean is
higher than the sphere of waters. And how the waters of the
equatorial seas are higher than the waters of the North, and higher
beneath the body of the sun than in any part of the equatorial
circle; for experiment shows that under the heat of a burning brand
the water near the brand boils, and the water surrounding this
ebullition always sinks with a circular eddy. And how the waters of
the North are lower than the other seas, and more so as they become
colder, until they are converted into ice.

Definitions (931. 932).

931.

Among the four elements water is the second both in weight and in
instability.

932.

Sea is the name given to that water which is wide and deep, in which
the waters have not much motion.

[Footnote: Only the beginning of this passage is here given, the
remainder consists of definitions which have no direct bearing on
the subject.]

Of the surface of the water in relation to the globe (933-936).

933.

The centres of the sphere of water are two, one universal and common
to all water, the other particular. The universal one is that which
is common to all waters not in motion, which exist in great
quantities. As canals, ditches, ponds, fountains, wells, dead
rivers, lakes, stagnant pools and seas, which, although they are at
various levels, have each in itself the limits of their superficies
equally distant from the centre of the earth, such as lakes placed
at the tops of high mountains; as the lake near Pietra Pana and the
lake of the Sybil near Norcia; and all the lakes that give rise to
great rivers, as the Ticino from Lago Maggiore, the Adda from the
lake of Como, the Mincio from the lake of Garda, the Rhine from the
lakes of Constance and of Chur, and from the lake of Lucerne, like
the Tigris which passes through Asia Minor carrying with it the
waters of three lakes, one above the other at different heights of
which the highest is Munace, the middle one Pallas, and the lowest
Triton; the Nile again flows from three very high lakes in Ethiopia.

[Footnote 5:
Pietra Pana
, a mountain near Florence. If for Norcia,
we may read Norchia, the remains of the Etruscan city near Viterbo,
there can be no doubt that by '
Lago della Sibilla
'—a name not
known elsewhere, so far as I can learn—Leonardo meant
Lago di
Vico
(Lacus Ciminus, Aen. 7).]

934.

The centre of the sphere of waters is the true centre of the globe
of our world, which is composed of water and earth, having the shape
of a sphere. But, if you want to find the centre of the element of
the earth, this is placed at a point equidistant from the surface of
the ocean, and not equidistant from the surface of the earth; for it
is evident that this globe of earth has nowhere any perfect
rotundity, excepting in places where the sea is, or marshes or other
still waters. And every part of the earth that rises above the water
is farther from the centre.

935.

The shells, oysters, and other similar animals, which originate in
sea-mud, bear witness to the changes of the earth round the centre
of our elements. This is proved thus: Great rivers always run
turbid, being coloured by the earth, which is stirred by the
friction of their waters at the bottom and on their shores; and this
wearing disturbs the face of the strata made by the layers of
shells, which lie on the surface of the marine mud, and which were
produced there when the salt waters covered them; and these strata
were covered over again from time to time, with mud of various
thickness, or carried down to the sea by the rivers and floods of
more or less extent; and thus these layers of mud became raised to
such a height, that they came up from the bottom to the air. At the
present time these bottoms are so high that they form hills or high
mountains, and the rivers, which wear away the sides of these
mountains, uncover the strata of these shells, and thus the softened
side of the earth continually rises and the antipodes sink closer to
the centre of the earth, and the ancient bottoms of the seas have
become mountain ridges.

936.

Let the earth make whatever changes it may in its weight, the
surface of the sphere of waters can never vary in its equal distance
from the centre of the world.

Of the proportion of the mass of water to that of the earth (937.
938).

937.

Some assert that it is true that the earth, which is not covered by
water is much less than that covered by water. But considering the
size of 7000 miles in diameter which is that of this earth, we may
conclude the water to be of small depth.

938.

The great elevations of the peaks of the mountains above the sphere
of the water may have resulted from this that: a very large portion
of the earth which was filled with water that is to say the vast
cavern inside the earth may have fallen in a vast part of its vault
towards the centre of the earth, being pierced by means of the
course of the springs which continually wear away the place where
they pass.

Sinking in of countries like the Dead Sea in Syria, that is Sodom
and Gomorrah.

It is of necessity that there should be more water than land, and
the visible portion of the sea does not show this; so that there
must be a great deal of water inside the earth, besides that which
rises into the lower air and which flows through rivers and springs.

[Footnote: The small sketch below on the left, is placed in the
original close to the text referring to the Dead Sea.]

The theory of Plato.

939.

Of the figures of the elements; and first as against those who deny
the opinions of Plato, and who say that if the elements include one
another in the forms attributed to them by Plato they would cause a
vacuum one within the other. I say it is not true, and I here prove
it, but first I desire to propound some conclusions. It is not
necessary that the elements which include each other should be of
corresponding magnitude in all the parts, of that which includes and
of that which is included. We see that the sphere of the waters
varies conspicuously in mass from the surface to the bottom, and
that, far from investing the earth when that was in the form of a
cube that is of 8 angles as Plato will have it, that it invests the
earth which has innumerable angles of rock covered by the water and
various prominences and concavities, and yet no vacuum is generated
between the earth and water; again, the air invests the sphere of
waters together with the mountains and valleys, which rise above
that sphere, and no vacuum remains between the earth and the air, so
that any one who says a vacuum is generated, speaks foolishly.

But to Plato I would reply that the surface of the figures which
according to him the elements would have, could not exist.

That the flow of rivers proves the slope of the land.

940.

We see the Nile come from Southern regions and traverse various
provinces, running towards the North for a distance of 3000 miles
and flow into the Mediterranean by the shores of Egypt; and if we
will give to this a fall of ten braccia a mile, as is usually
allowed to the course of rivers in general, we shall find that the
Nile must have its mouth ten miles lower than its source. Again, we
see the Rhine, the Rhone and the Danube starting from the German
parts, almost the centre of Europe, and having a course one to the
East, the other to the North, and the last to Southern seas. And if
you consider all this you will see that the plains of Europe in
their aggregate are much higher than the high peaks of the maritime
mountains; think then how much their tops must be above the sea
shores.

Theory of the elevation of water within the mountains.

941.

Where there is life there is heat, and where vital heat is, there is
movement of vapour. This is proved, inasmuch as we see that the
element of fire by its heat always draws to itself damp vapours and
thick mists as opaque clouds, which it raises from seas as well as
lakes and rivers and damp valleys; and these being drawn by degrees
as far as the cold region, the first portion stops, because heat and
moisture cannot exist with cold and dryness; and where the first
portion stops the rest settle, and thus one portion after another
being added, thick and dark clouds are formed. They are often wafted
about and borne by the winds from one region to another, where by
their density they become so heavy that they fall in thick rain; and
if the heat of the sun is added to the power of the element of fire,
the clouds are drawn up higher still and find a greater degree of
cold, in which they form ice and fall in storms of hail. Now the
same heat which holds up so great a weight of water as is seen to
rain from the clouds, draws them from below upwards, from the foot
of the mountains, and leads and holds them within the summits of the
mountains, and these, finding some fissure, issue continuously and
cause rivers.

The relative height of the surface of the sea to that of the land
(942-945).

942.

b d
is a plain through which a river flows to the sea; this plain
ends at the sea, and since in fact the dry land that is uncovered is
not perfectly level—for, if it were, the river would have no
motion—as the river does move, this place is a slope rather than a
plain; hence this plain
d b
so ends where the sphere of water
begins that if it were extended in a continuous line to
b a
it
would go down beneath the sea, whence it follows that the sea
a c
b
looks higher than the dry land.

Obviously no portions of dry land left uncovered by water can ever
be lower than the surface of the watery sphere.

943.

Certainly I wonder not a little at the common opinion which is
contrary to truth, but held by the universal consent of the judgment
of men. And this is that all are agreed that the surface of the sea
is higher than the highest peaks of the mountains; and they allege
many vain and childish reasons, against which I will allege only one
simple and short reason; We see plainly that if we could remove the
shores of the sea, it would invest the whole earth and make it a
perfect sphere. Now, consider how much earth would be carried away
to enable the waves of the sea to cover the world; therefore that
which would be carried away must be higher than the sea-shore.

944.

Water would not move from place to place if it were not that it
seeks the lowest level and by a natural consequence it never can
return to a height like that of the place where it first on issuing
from the mountain came to light. And that portion of the sea which,
in your vain imagining, you say was so high that it flowed over the
summits of the high mountains, for so many centuries would be
swallowed up and poured out again through the issue from these
mountains. You can well imagine that all the time that Tigris and
Euphrates