Book 15 of matters worn away by water._The Notebooks of Leonardo Da Vinci

921.

First you shall make a book treating of places occupied by fresh

waters, and the second by salt waters, and the third, how by the

disappearance of these, our parts of the world were made lighter and

in consequence more remote from the centre of the world.

922.

First write of all water, in each of its motions; then describe all

its bottoms and their various materials, always referring to the

propositions concerning the said waters; and let the order be good,

for otherwise the work will be confused.

Describe all the forms taken by water from its greatest to its

smallest wave, and their causes.

923.

Book 9, of accidental risings of water.

924.

THE ORDER OF THE BOOK.

Place at the beginning what a river can effect.

925.

A book of driving back armies by the force of a flood made by

releasing waters.

A book showing how the waters safely bring down timber cut in the

mountains.

A book of boats driven against the impetus of rivers.

A book of raising large bridges higher. Simply by the swelling of

the waters.

A book of guarding against the impetus of rivers so that towns may

not be damaged by them.

926.

A book of the ordering of rivers so as to preserve their banks.

A book of the mountains, which would stand forth and become land, if

our hemisphere were to be uncovered by the water.

A book of the earth carried down by the waters to fill up the great

abyss of the seas.

A book of the ways in which a tempest may of itself clear out filled

up sea-ports.

A book of the shores of rivers and of their permanency.

A book of how to deal with rivers, so that they may keep their

bottom scoured by their own flow near the cities they pass.

A book of how to make or to repair the foundations for bridges over

the rivers.

A book of the repairs which ought to be made in walls and banks of

rivers where the water strikes them.

A book of the formation of hills of sand or gravel at great depths

in water.

927.

Water gives the first impetus to its motion.

A book of the levelling of waters by various means,

A book of diverting rivers from places where they do mischief.

A book of guiding rivers which occupy too much ground.

A book of parting rivers into several branches and making them

fordable.

A book of the waters which with various currents pass through seas.

A book of deepening the beds of rivers by means of currents of

water.

A book of controlling rivers so that the little beginnings of

mischief, caused by them, may not increase.

A book of the various movements of waters passing through channels

of different forms.

A book of preventing small rivers from diverting the larger one into

which their waters run.

A book of the lowest level which can be found in the current of the

surface of rivers.

A book of the origin of rivers which flow from the high tops of

mountains.

A book of the various motions of waters in their rivers.

928.

[1] Of inequality in the concavity of a ship. [Footnote 1: The first

line of this passage was added subsequently, evidently as a

correction of the following line.]

[1] A book of the inequality in the curve of the sides of ships.

[1] A book of the inequality in the position of the tiller.

[1] A book of the inequality in the keel of ships.

[2] A book of various forms of apertures by which water flows out.

[3] A book of water contained in vessels with air, and of its

movements.

[4] A book of the motion of water through a syphon. [Footnote 7:

_cicognole_, see No. 966, 11, 17.]

[5] A book of the meetings and union of waters coming from different

directions.

[6] A book of the various forms of the banks through which rivers

pass.

[7] A book of the various forms of shoals formed under the sluices

of rivers.

[8] A book of the windings and meanderings of the currents of

rivers.

[9] A book of the various places whence the waters of rivers are

derived.

[10] A book of the configuration of the shores of rivers and of

their permanency.

[11] A book of the perpendicular fall of water on various objects.

[12] Abook of the course of water when it is impeded in various

places.

[12] A book of the various forms of the obstacles which impede the

course of waters.

[13] A book of the concavity and globosity formed round various

objects at the bottom.

[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.

THE BEGINNING OF THE TREATISE ON WATER.

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.

OF THE NATURE OF WATER.

The arrangement of Book I.

930.

THE ORDER OF THE FIRST BOOK ON WATER.

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.

OF WHAT IS WATER.

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

instability.

932.

THE BEGINNING OF THE BOOK ON WATER.

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.

OF THE CENTRE OF THE OCEAN.

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.

OF THE SEA WHICH CHANGES THE WEIGHT OF THE EARTH.

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.

WHETHER THE EARTH IS LESS THAN THE WATER.

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.

OF THE EARTH.

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.

THE FIGURES OF THE ELEMENTS.

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.

PROVES HOW THE EARTH IS NOT GLOBULAR AND NOT BEING GLOBULAR CANNOT

HAVE A COMMON CENTRE.

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.

OF THE HEAT THAT IS IN THE WORLD.

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.

OF THE SEA, WHICH TO MANY FOOLS APPEARS TO BE HIGHER THAN THE EARTH

WHICH FORMS ITS SHORE.

_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.

OF CERTAIN PERSONS WHO SAY THE WATERS WERE HIGHER THAN THE DRY LAND.

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.

THE OPINION OF SOME PERSONS WHO SAY THAT THE WATER OF SOME SEAS IS

HIGHER THAN THE HIGHEST SUMMITS OF MOUNTAINS; AND NEVERTHELESS THE

WATER WAS FORCED UP TO THESE SUMMITS.

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

945.

have flowed from the summits of the mountains of Armenia, it must be

believed that all the water of the ocean has passed very many times

through these mouths. And do you not believe that the Nile must have

sent more water into the sea than at present exists of all the

element of water? Undoubtedly, yes. And if all this water had fallen

away from this body of the earth, this terrestrial machine would

long since have been without water. Whence we may conclude that the

water goes from the rivers to the sea, and from the sea to the

rivers, thus constantly circulating and returning, and that all the

sea and the rivers have passed through the mouth of the Nile an

infinite number of times [Footnote: _Moti Armeni, Ermini_ in the

original, in M. RAVAISSON'S transcript _"monti ernini [le loro

ruine?]"_. He renders this _"Le Tigre et l'Euphrate se sont deverses

par les sommets des montagnes [avec leurs eaux destructives?] on

pent cro're" &c. Leonardo always writes _Ermini, Erminia_, for

_Armeni, Armenia_ (Arabic: _Irminiah_). M. RAVAISSON also deviates

from the original in his translation of the following passage: "_Or

tu ne crois pas que le Nil ait mis plus d'eau dans la mer qu'il n'y

en a a present dans tout l'element de l'eau. Il est certain que si

cette eau etait tombee_" &c.]

II.

ON THE OCEAN.

Refutation of Pliny's theory as to the saltness of the sea (946.

947).

946.

WHY WATER IS SALT.

Pliny says in his second book, chapter 103, that the water of the

sea is salt because the heat of the sun dries up the moisture and

drinks it up; and this gives to the wide stretching sea the savour

of salt. But this cannot be admitted, because if the saltness of the

sea were caused by the heat of the sun, there can be no doubt that

lakes, pools and marshes would be so much the more salt, as their

waters have less motion and are of less depth; but experience shows

us, on the contrary, that these lakes have their waters quite free

from salt. Again it is stated by Pliny in the same chapter that this

saltness might originate, because all the sweet and subtle portions

which the heat attracts easily being taken away, the more bitter and

coarser part will remain, and thus the water on the surface is

fresher than at the bottom [Footnote 22: Compare No. 948.]; but this

is contradicted by the same reason given above, which is, that the

same thing would happen in marshes and other waters, which are dried

up by the heat. Again, it has been said that the saltness of the sea

is the sweat of the earth; to this it may be answered that all the

springs of water which penetrate through the earth, would then be

salt. But the conclusion is, that the saltness of the sea must

proceed from the many springs of water which, as they penetrate into

the earth, find mines of salt and these they dissolve in part, and

carry with them to the ocean and the other seas, whence the clouds,

the begetters of rivers, never carry it up. And the sea would be

salter in our times than ever it was at any time; and if the

adversary were to say that in infinite time the sea would dry up or

congeal into salt, to this I answer that this salt is restored to

the earth by the setting free of that part of the earth which rises

out of the sea with the salt it has acquired, and the rivers return

it to the earth under the sea.

[Footnote: See PLINY, Hist. Nat. II, CIII [C]. _Itaque Solis ardore

siccatur liquor: et hoc esse masculum sidus accepimus, torrens

cuncta sorbensque._ (cp. CIV.) _Sic mari late patenti saporem

incoqui salis, aut quia exhausto inde dulci tenuique, quod facillime

trahat vis ignea, omne asperius crassiusque linquatur: ideo summa

aequorum aqua dulciorem profundam; hanc esse veriorem causam, quam

quod mare terrae sudor sit aeternus: aut quia plurimum ex arido

misceatur illi vapore: aut quia terrae natura sicut medicatas aquas

inficiat_ ... (cp. CV): _altissimum mare XV. stadiorum Fabianus

tradit. Alii n Ponto coadverso Coraxorum gentis (vocant B Ponti)

trecentis fere a continenti stadiis immensam altitudinem maris

tradunt, vadis nunquam repertis._ (cp. CVI [CIII]) _Mirabilius id

faciunt aquae dulces, juxta mare, ut fistulis emicantes. Nam nec

aquarum natura a miraculis cessat. Dulces mari invehuntur, leviores

haud dubie. Ideo et marinae, quarum natura gravior, magis invecta

sustinent. Quaedam vero et dulces inter se supermeant alias._]

947.

For the third and last reason we will say that salt is in all

created things; and this we learn from water passed over the ashes

and cinders of burnt things; and the urine of every animal, and the

superfluities issuing from their bodies, and the earth into which

all things are converted by corruption.

But,--to put it better,--given that the world is everlasting, it

must be admitted that its population will also be eternal; hence the

human species has eternally been and would be consumers of salt; and

if all the mass of the earth were to be turned into salt, it would

not suffice for all human food [Footnote 27: That is, on the

supposition that salt, once consumed, disappears for ever.]; whence

we are forced to admit, either that the species of salt must be

everlasting like the world, or that it dies and is born again like

the men who devour it. But as experience teaches us that it does not

die, as is evident by fire, which does not consume it, and by water

which becomes salt in proportion to the quantity dissolved in

it,--and when it is evaporated the salt always remains in the

original quantity--it must pass through the bodies of men either in

the urine or the sweat or other excretions where it is found again;

and as much salt is thus got rid of as is carried every year into

towns; therefore salt is dug in places where there is urine.-- Sea

hogs and sea winds are salt.

We will say that the rains which penetrate the earth are what is

under the foundations of cities with their inhabitants, and are what

restore through the internal passages of the earth the saltness

taken from the sea; and that the change in the place of the sea,

which has been over all the mountains, caused it to be left there in

the mines found in those mountains, &c.

The characteristics of sea water (948. 949).

948.

The waters of the salt sea are fresh at the greatest depths.

949.

THAT THE OCEAN DOES NOT PENETRATE UNDER THE EARTH.

The ocean does not penetrate under the earth, and this we learn from

the many and various springs of fresh water which, in many parts of

the ocean make their way up from the bottom to the surface. The same

thing is farther proved by wells dug beyond the distance of a mile

from the said ocean, which fill with fresh water; and this happens

because the fresh water is lighter than salt water and consequently

more penetrating.

Which weighs most, water when frozen or when not frozen?

FRESH WATER PENETRATES MORE AGAINST SALT WATER THAN SALT WATER

AGAINST FRESH WATER.

That fresh water penetrates more against salt water, than salt water

against fresh is proved by a thin cloth dry and old, hanging with

the two opposite ends equally low in the two different waters, the

surfaces of which are at an equal level; and it will then be seen

how much higher the fresh water will rise in this piece of linen

than the salt; by so much is the fresh lighter than the salt.

On the formation of Gulfs (950. 951).

950.

All inland seas and the gulfs of those seas, are made by rivers

which flow into the sea.

951.

HERE THE REASON IS GIVEN OF THE EFFECTS PRODUCED BY THE WATERS IN

THE ABOVE MENTIONED PLACE.

All the lakes and all the gulfs of the sea and all inland seas are

due to rivers which distribute their waters into them, and from

impediments in their downfall into the Mediterranean --which divides

Africa from Europe and Europe from Asia by means of the Nile and the

Don which pour their waters into it. It is asked what impediment is

great enough to stop the course of the waters which do not reach the

ocean.

On the encroachments of the sea on the land and vice versa

(952-954).

952.

OF WAVES.

A wave of the sea always breaks in front of its base, and that

portion of the crest will then be lowest which before was highest.

[Footnote: The page of FRANCESCO DI GIORGIO'S _Trattato_, on which

Leonardo has written this remark, contains some notes on the

construction of dams, harbours &c.]

953.

That the shores of the sea constantly acquire more soil towards the

middle of the sea; that the rocks and promontories of the sea are

constantly being ruined and worn away; that the Mediterranean seas

will in time discover their bottom to the air, and all that will be

left will be the channel of the greatest river that enters it; and

this will run to the ocean and pour its waters into that with those

of all the rivers that are its tributaries.

954.

How the river Po, in a short time might dry up the Adriatic sea in

the same way as it has dried up a large part of Lombardy.

The ebb and flow of the tide (955-960).

955.

Where there is a larger quantity of water, there is a greater flow

and ebb, but the contrary in narrow waters.

Look whether the sea is at its greatest flow when the moon is half

way over our hemisphere [on the meridian].

956.

Whether the flow and ebb are caused by the moon or the sun, or are

the breathing of this terrestrial machine. That the flow and ebb are

different in different countries and seas.

[Footnote: 1. Allusion may here be made to the mythological

explanation of the ebb and flow given in the Edda. Utgardloki says

to Thor (Gylfaginning 48): "When thou wert drinking out of the horn,

and it seemed to thee that it was slow in emptying a wonder befell,

which I should not have believed possible: the other end of the horn

lay in the sea, which thou sawest not; but when thou shalt go to the

sea, thou shalt see how much thou hast drunk out of it. And that men

now call the ebb tide."

Several passages in various manuscripts treat of the ebb and flow.

In collecting them I have been guided by the rule only to transcribe

those which named some particular spot.]

957.

Book 9 of the meeting of rivers and their flow and ebb. The cause is

the same in the sea, where it is caused by the straits of Gibraltar.

And again it is caused by whirlpools.

958.

OF THE FLOW AND EBB.

All seas have their flow and ebb in the same period, but they seem

to vary because the days do not begin at the same time throughout

the universe; in such wise as that when it is midday in our

hemisphere, it is midnight in the opposite hemisphere; and at the

Eastern boundary of the two hemispheres the night begins which

follows on the day, and at the Western boundary of these hemispheres

begins the day, which follows the night from the opposite side.

Hence it is to be inferred that the above mentioned swelling and

diminution in the height of the seas, although they take place in

one and the same space of time, are seen to vary from the above

mentioned causes. The waters are then withdrawn into the fissures

which start from the depths of the sea and which ramify inside the

body of the earth, corresponding to the sources of rivers, which are

constantly taking from the bottom of the sea the water which has

flowed into it. A sea of water is incessantly being drawn off from

the surface of the sea. And if you should think that the moon,

rising at the Eastern end of the Mediterranean sea must there begin

to attract to herself the waters of the sea, it would follow that we

must at once see the effect of it at the Eastern end of that sea.

Again, as the Mediterranean sea is about the eighth part of the

circumference of the aqueous sphere, being 3000 miles long, while

the flow and ebb only occur 4 times in 24 hours, these results would

not agree with the time of 24 hours, unless this Mediterranean sea

were six thousand miles in length; because if such a superabundance

of water had to pass through the straits of Gibraltar in running

behind the moon, the rush of the water through that strait would be

so great, and would rise to such a height, that beyond the straits

it would for many miles rush so violently into the ocean as to cause

floods and tremendous seething, so that it would be impossible to

pass through. This agitated ocean would afterwards return the waters

it had received with equal fury to the place they had come from, so

that no one ever could pass through those straits. Now experience

shows that at every hour they are passed in safety, but when the

wind sets in the same direction as the current, the strong ebb

increases [Footnote 23: In attempting to get out of the

Mediterranean, vessels are sometimes detained for a considerable

time; not merely by the causes mentioned by Leonardo but by the

constant current flowing eastwards through the middle of the straits

of Gibraltar.]. The sea does not raise the water that has issued

from the straits, but it checks them and this retards the tide; then

it makes up with furious haste for the time it has lost until the

end of the ebb movement.

959.

That the flow and ebb are not general; for on the shore at Genoa

there is none, at Venice two braccia, between England and Flanders

18 braccia. That in the straits of Sicily the current is very strong

because all the waters from the rivers that flow into the Adriatic

pass there.

[Footnote: A few more recent data may be given here to facilitate

comparison. In the Adriatic the tide rises 2 and 1/2 feet, at

Terracina 1 1/4. In the English channel between Calais and Kent it

rises from 18 to 20 feet. In the straits of Messina it rises no more

than 2 1/2 feet, and that only in stormy weather, but the current is

all the stronger. When Leonardo accounts for this by the southward

flow of all the Italian rivers along the coasts, the explanation is

at least based on a correct observation; namely that a steady

current flows southwards along the coast of Calabria and another

northwards, along the shores of Sicily; he seems to infer, from the

direction of the fust, that the tide in the Adriatic is caused by

it.]

960.

In the West, near to Flanders, the sea rises and decreases every 6

hours about 20 braccia, and 22 when the moon is in its favour; but

20 braccia is the general rule, and this rule, as it is evident,

cannot have the moon for its cause. This variation in the increase

and decrease of the sea every 6 hours may arise from the damming up

of the waters, which are poured into the Mediterranean by the

quantity of rivers from Africa, Asia and Europe, which flow into

that sea, and the waters which are given to it by those rivers; it

pours them to the ocean through the straits of Gibraltar, between

Abila and Calpe [Footnote 5: _Abila_, Lat. _Abyla_, Gr. , now

Sierra _Ximiera_ near Ceuta; _Calpe_, Lat. _Calpe_. Gr., now

Gibraltar. Leonardo here uses the ancient names of the rocks, which

were known as the Pillars of Hercules.]. That ocean extends to the

island of England and others farther North, and it becomes dammed up

and kept high in various gulfs. These, being seas of which the

surface is remote from the centre of the earth, have acquired a

weight, which as it is greater than the force of the incoming waters

which cause it, gives this water an impetus in the contrary

direction to that in which it came and it is borne back to meet the

waters coming out of the straits; and this it does most against the

straits of Gibraltar; these, so long as this goes on, remain dammed

up and all the water which is poured out meanwhile by the

aforementioned rivers, is pent up [in the Mediterranean]; and this

might be assigned as the cause of its flow and ebb, as is shown in

the 21st of the 4th of my theory.

III.

SUBTERRANEAN WATER COURSES.

Theory of the circulation of the waters (961. 962).

961.

Very large rivers flow under ground.

962.

This is meant to represent the earth cut through in the middle,

showing the depths of the sea and of the earth; the waters start

from the bottom of the seas, and ramifying through the earth they

rise to the summits of the mountains, flowing back by the rivers and

returning to the sea.

Observations in support of the hypothesis (963-969).

963.

The waters circulate with constant motion from the utmost depths of

the sea to the highest summits of the mountains, not obeying the

nature of heavy matter; and in this case it acts as does the blood

of animals which is always moving from the sea of the heart and

flows to the top of their heads; and here it is that veins burst--as

one may see when a vein bursts in the nose, that all the blood from

below rises to the level of the burst vein. When the water rushes

out of a burst vein in the earth it obeys the nature of other things

heavier than the air, whence it always seeks the lowest places. [7]

These waters traverse the body of the earth with infinite

ramifications.

[Footnote: The greater part of this passage has been given as No.

849 in the section on Anatomy.]

964.

The same cause which stirs the humours in every species of animal

body and by which every injury is repaired, also moves the waters

from the utmost depth of the sea to the greatest heights.

965.

It is the property of water that it constitutes the vital human of

this arid earth; and the cause which moves it through its ramified

veins, against the natural course of heavy matters, is the same

property which moves the humours in every species of animal body.

But that which crowns our wonder in contemplating it is, that it

rises from the utmost depths of the sea to the highest tops of the

mountains, and flowing from the opened veins returns to the low

seas; then once more, and with extreme swiftness, it mounts again

and returns by the same descent, thus rising from the inside to the

outside, and going round from the lowest to the highest, from whence

it rushes down in a natural course. Thus by these two movements

combined in a constant circulation, it travels through the veins of

the earth.

966.

WHETHER WATER RISES FROM THE SEA TO THE TOPS OF MOUNTAINS.

The water of the ocean cannot make its way from the bases to the

tops of the mountains which bound it, but only so much rises as the

dryness of the mountain attracts. And if, on the contrary, the rain,

which penetrates from the summit of the mountain to the base, which

is the boundary of the sea, descends and softens the slope opposite

to the said mountain and constantly draws the water, like a syphon

[Footnote 11: Cicognola, Syphon. See Vol. I, Pl. XXIV, No. 1.] which

pours through its longest side, it must be this which draws up the

water of the sea; thus if _s n_ were the surface of the sea, and the

rain descends from the top of the mountain _a_ to _n_ on one side,

and on the other sides it descends from _a_ to _m_, without a doubt

this would occur after the manner of distilling through felt, or as

happens through the tubes called syphons [Footnote 17: Cicognola,

Syphon. See Vol. I, Pl. XXIV, No. 1.]. And at all times the water

which has softened the mountain, by the great rain which runs down

the two opposite sides, would constantly attract the rain _a n_, on

its longest side together with the water from the sea, if that side

of the mountain _a m_ were longer than the other _a n_; but this

cannot be, because no part of the earth which is not submerged by

the ocean can be lower than that ocean.

967.

OF SPRINGS OF WATER ON THE TOPS OF MOUNTAINS.

It is quite evident that the whole surface of the ocean--when there

is no storm--is at an equal distance from the centre of the earth,

and that the tops of the mountains are farther from this centre in

proportion as they rise above the surface of that sea; therefore if

the body of the earth were not like that of man, it would be

impossible that the waters of the sea--being so much lower than the

mountains--could by their nature rise up to the summits of these

mountains. Hence it is to be believed that the same cause which

keeps the blood at the top of the head in man keeps the water at the

summits of the mountains.

[Footnote: This conception of the rising of the blood, which has

given rise to the comparison, was recognised as erroneous by

Leonardo himself at a later period. It must be remembered that the

MS. A, from which these passages are taken, was written about twenty

years earlier than the MS. Leic. (Nos. 963 and 849) and twenty-five

years before the MS. W. An. IV.

There is, in the original a sketch with No. 968 which is not

reproduced. It represents a hill of the same shape as that shown at

No. 982. There are veins, or branched streams, on the side of the

hill, like those on the skull Pl. CVIII, No. 4]

968.

IN CONFIRMATION OF WHY THE WATER GOES TO THE TOPS OF MOUNTAINS.

I say that just as the natural heat of the blood in the veins keeps

it in the head of man,--for when the man is dead the cold blood

sinks to the lower parts--and when the sun is hot on the head of a

man the blood increases and rises so much, with other humours, that

by pressure in the veins pains in the head are often caused; in the

same way veins ramify through the body of the earth, and by the

natural heat which is distributed throughout the containing body,

the water is raised through the veins to the tops of mountains. And

this water, which passes through a closed conduit inside the body of

the mountain like a dead thing, cannot come forth from its low place

unless it is warmed by the vital heat of the spring time. Again, the

heat of the element of fire and, by day, the heat of the sun, have

power to draw forth the moisture of the low parts of the mountains

and to draw them up, in the same way as it draws the clouds and

collects their moisture from the bed of the sea.

969.

That many springs of salt water are found at great distances from

the sea; this might happen because such springs pass through some

mine of salt, like that in Hungary where salt is hewn out of vast

caverns, just as stone is hewn.

[Footnote: The great mine of Wieliczka in Galicia, out of which a

million cwt. of rock-salt are annually dug out, extends for 3000

metres from West to East, and 1150 metres from North to South.]

IV.

OF RIVERS.

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

970.

OF THE ORIGIN OF RIVERS.

The body of the earth, like the bodies of animals, is intersected

with ramifications of waters which are all in connection and are

constituted to give nutriment and life to the earth and to its

creatures. These come from the depth of the sea and, after many

revolutions, have to return to it by the rivers created by the

bursting of these springs; and if you chose to say that the rains of

the winter or the melting of the snows in summer were the cause of

the birth of rivers, I could mention the rivers which originate in

the torrid countries of Africa, where it never rains--and still less

snows--because the intense heat always melts into air all the clouds

which are borne thither by the winds. And if you chose to say that

such rivers, as increase in July and August, come from the snows

which melt in May and June from the sun's approach to the snows on

the mountains of Scythia [Footnote 9: Scythia means here, as in

Ancient Geography, the whole of the Northern part of Asia as far as

India.], and that such meltings come down into certain valleys and

form lakes, into which they enter by springs and subterranean caves

to issue forth again at the sources of the Nile, this is false;

because Scythia is lower than the sources of the Nile, and, besides,

Scythia is only 400 miles from the Black sea and the sources of the

Nile are 3000 miles distant from the sea of Egypt into which its

waters flow.

The tide in estuaries.

971.

Book 9, of the meeting of rivers and of their ebb and flow. The

cause is the same in the sea, where it is caused by the straits of

Gibraltar; and again it is caused by whirlpools.

[3] If two rivers meet together to form a straight line, and then

below two right angles take their course together, the flow and ebb

will happen now in one river and now in the other above their

confluence, and principally if the outlet for their united volume is

no swifter than when they were separate. Here occur 4 instances.

[Footnote: The first two lines of this passage have already been

given as No. 957. In the margin, near line 3 of this passage, the

text given as No. 919 is written.]

On the alterations, caused in the courses of rivers by their

confluence (972-974).

972.

When a smaller river pours its waters into a larger one, and that

larger one flows from the opposite direction, the course of the

smaller river will bend up against the approach of the larger river;

and this happens because, when the larger river fills up all its bed

with water, it makes an eddy in front of the mouth of the other

river, and so carries the water poured in by the smaller river with

its own. When the smaller river pours its waters into the larger

one, which runs across the current at the mouth of the smaller

river, its waters will bend with the downward movement of the larger

river. [Footnote: In the original sketches the word _Arno_ is

written at the spot here marked _A_, at _R. Rifredi_, and at _M.

Mugnone_.]

973.

When the fulness of rivers is diminished, then the acute angles

formed at the junction of their branches become shorter at the sides

and wider at the point; like the current _a n_ and the current _d

n_, which unite in _n_ when the river is at its greatest fulness. I

say, that when it is in this condition if, before the fullest time,

_d n_ was lower than _a n_, at the time of fulness _d n_ will be

full of sand and mud. When the water _d n_ falls, it will carry away

the mud and remain with a lower bottom, and the channel _a n_

finding itself the higher, will fling its waters into the lower, _d

n_, and will wash away all the point of the sand-spit _b n c_, and

thus the angle _a c d_ will remain larger than the angle _a n d_ and

the sides shorter, as I said before.

[Footnote: Above the first sketch we find, in the original, this

note: "_Sopra il pote rubaconte alla torricella_"; and by the

second, which represents a pier of a bridge, "_Sotto l'ospedal del

ceppo._"]

974.

WATER.

OF THE MOVEMENT OF A SUDDEN RUSH MADE BY A RIVER IN ITS BED

PREVIOUSLY DRY.

In proportion as the current of the water given forth by the

draining of the lake is slow or rapid in the dry river bed, so will

this river be wider or narrower, or shallower or deeper in one place

than another, according to this proposition: the flow and ebb of the

sea which enters the Mediterranean from the ocean, and of the rivers

which meet and struggle with it, will raise their waters more or

less in proportion as the sea is wider or narrower.

[Footnote: In the margin is a sketch of a river which winds so as to

form islands.]

Whirlpools.

975.

Whirlpools, that is to say caverns; that is to say places left by

precipitated waters.

On the alterations in the channels of rivers.

976.

OF THE VIBRATION OF THE EARTH.

The subterranean channels of waters, like those which exist between

the air and the earth, are those which unceasingly wear away and

deepen the beds of their currents.

The origin of the sand in rivers (977. 978).

977.

A river that flows from mountains deposits a great quantity of large

stones in its bed, which still have some of their angles and sides,

and in the course of its flow it carries down smaller stones with

the angles more worn; that is to say the large stones become

smaller. And farther on it deposits coarse gravel and then smaller,

and as it proceeds this becomes coarse sand and then finer, and

going on thus the water, turbid with sand and gravel, joins the sea;

and the sand settles on the sea-shores, being cast up by the salt

waves; and there results the sand of so fine a nature as to seem

almost like water, and it will not stop on the shores of the sea but

returns by reason of its lightness, because it was originally formed

of rotten leaves and other very light things. Still, being

almost--as was said--of the nature of water itself, it afterwards,

when the weather is calm, settles and becomes solid at the bottom of

the sea, where by its fineness it becomes compact and by its

smoothness resists the waves which glide over it; and in this shells

are found; and this is white earth, fit for pottery.

978.

All the torrents of water flowing from the mountains to the sea

carry with them the stones from the hills to the sea, and by the

influx of the sea-water towards the mountains; these stones were

thrown back towards the mountains, and as the waters rose and

retired, the stones were tossed about by it and in rolling, their

angles hit together; then as the parts, which least resisted the

blows, were worn off, the stones ceased to be angular and became

round in form, as may be seen on the banks of the Elsa. And those

remained larger which were less removed from their native spot; and

they became smaller, the farther they were carried from that place,

so that in the process they were converted into small pebbles and

then into sand and at last into mud. After the sea had receded from

the mountains the brine left by the sea with other humours of the

earth made a concretion of these pebbles and this sand, so that the

pebbles were converted into rock and the sand into tufa. And of this

we see an example in the Adda where it issues from the mountains of

Como and in the Ticino, the Adige and the Oglio coming from the

German Alps, and in the Arno at Monte Albano [Footnote 13: At the

foot of _Monte Albano_ lies Vinci, the birth place of Leonardo.

Opposite, on the other bank of the Arno, is _Monte Lupo_.], near

Monte Lupo and Capraia where the rocks, which are very large, are

all of conglomerated pebbles of various kinds and colours.

ON MOUNTAINS.

The formation of mountains (979-983).

979.

Mountains are made by the currents of rivers.

Mountains are destroyed by the currents of rivers.

[Footnote: Compare 789.]

980.

That the Northern bases of some Alps are not yet petrified. And this

is plainly to be seen where the rivers, which cut through them, flow

towards the North; where they cut through the strata in the living

stone in the higher parts of the mountains; and, where they join the

plains, these strata are all of potter's clay; as is to be seen in

the valley of Lamona where the river Lamona, as it issues from the

Appenines, does these things on its banks.

That the rivers have all cut and divided the mountains of the great

Alps one from the other. This is visible in the order of the

stratified rocks, because from the summits of the banks, down to the

river the correspondence of the strata in the rocks is visible on

either side of the river. That the stratified stones of the

mountains are all layers of clay, deposited one above the other by

the various floods of the rivers. That the different size of the

strata is caused by the difference in the floods--that is to say

greater or lesser floods.

981.

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.

982.

In every concavity at the summit of the mountains we shall always

find the divisions of the strata in the rocks.

983.

OF THE SEA WHICH ENCIRCLES THE EARTH.

I find that of old, the state of the earth was that its plains were

all covered up and hidden by salt water. [Footnote: This passage has

already been published by Dr. M. JORDAN: _Das Malerbuch des L. da

Vinci, Leipzig_ 1873, p. 86. However, his reading of the text

differs from mine.]

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

984.

Since things are much more ancient than letters, it is no marvel if,

in our day, no records exist of these seas having covered so many

countries; and if, moreover, some records had existed, war and

conflagrations, the deluge of waters, the changes of languages and

of laws have consumed every thing ancient. But sufficient for us is

the testimony of things created in the salt waters, and found again

in high mountains far from the seas.

VI.

GEOLOGICAL PROBLEMS.

985.

In this work you have first to prove that the shells at a thousand

braccia of elevation were not carried there by the deluge, because

they are seen to be all at one level, and many mountains are seen to

be above that level; and to inquire whether the deluge was caused by

rain or by the swelling of the sea; and then you must show how,

neither by rain nor by swelling of the rivers, nor by the overflow

of this sea, could the shells--being heavy objects--be floated up

the mountains by the sea, nor have carried there by the rivers

against the course of their waters.

Doubts about the deluge.

986.

A DOUBTFUL POINT.

Here a doubt arises, and that is: whether the deluge, which happened

at the time of Noah, was universal or not. And it would seem not,

for the reasons now to be given: We have it in the Bible that this

deluge lasted 40 days and 40 nights of incessant and universal rain,

and that this rain rose to ten cubits above the highest mountains in

the world. And if it had been that the rain was universal, it would

have covered our globe which is spherical in form. And this

spherical surface is equally distant in every part, from the centre

of its sphere; hence the sphere of the waters being under the same

conditions, it is impossible that the water upon it should move,

because water, in itself, does not move unless it falls; therefore

how could the waters of such a deluge depart, if it is proved that

it has no motion? and if it departed how could it move unless it

went upwards? Here, then, natural reasons are wanting; hence to

remove this doubt it is necessary to call in a miracle to aid us, or

else to say that all this water was evaporated by the heat of the

sun.

[Footnote: The passages, here given from the MS. Leic., have

hitherto remained unknown. Some preliminary notes on the subject are

to be found in MS. F 8oa and 8ob; but as compared with the fuller

treatment here given, they are, it seems to me, of secondary

interest. They contain nothing that is not repeated here more

clearly and fully. LIBRI, _Histoire des Sciences mathematiques III_,

pages 218--221, has printed the text of F 80a and 80b, therefore it

seemed desirable to give my reasons for not inserting it in this

work.]

That marine shells could not go up the mountains.

987.

OF THE DELUGE AND OF MARINE SHELLS.

If you were to say that the shells which are to be seen within the

confines of Italy now, in our days, far from the sea and at such

heights, had been brought there by the deluge which left them there,

I should answer that if you believe that this deluge rose 7 cubits

above the highest mountains-- as he who measured it has

written--these shells, which always live near the sea-shore, should

have been left on the mountains; and not such a little way from the

foot of the mountains; nor all at one level, nor in layers upon

layers. And if you were to say that these shells are desirous of

remaining near to the margin of the sea, and that, as it rose in

height, the shells quitted their first home, and followed the

increase of the waters up to their highest level; to this I answer,

that the cockle is an animal of not more rapid movement than the

snail is out of water, or even somewhat slower; because it does not

swim, on the contrary it makes a furrow in the sand by means of its

sides, and in this furrow it will travel each day from 3 to 4

braccia; therefore this creature, with so slow a motion, could not

have travelled from the Adriatic sea as far as Monferrato in

Lombardy [Footnote: _Monferrato di Lombardia_. The range of hills of

Monferrato is in Piedmont, and Casale di Monferrato belonged, in

Leonardo's time, to the Marchese di Mantova.], which is 250 miles

distance, in 40 days; which he has said who took account of the

time. And if you say that the waves carried them there, by their

gravity they could not move, excepting at the bottom. And if you

will not grant me this, confess at least that they would have to

stay at the summits of the highest mountains, in the lakes which are

enclosed among the mountains, like the lakes of Lario, or of Como

and il Maggiore [Footnote: _Lago di Lario._ Lacus Larius was the

name given by the Romans to the lake of Como. It is evident that it

is here a slip of the pen since the the words in the MS. are: _"Come

Lago di Lario o'l Magare e di Como,"_ In the MS. after line 16 we

come upon a digression treating of the weight of water; this has

here been omitted. It is 11 lines long.] and of Fiesole, and of

Perugia, and others.

And if you should say that the shells were carried by the waves,

being empty and dead, I say that where the dead went they were not

far removed from the living; for in these mountains living ones are

found, which are recognisable by the shells being in pairs; and they

are in a layer where there are no dead ones; and a little higher up

they are found, where they were thrown by the waves, all the dead

ones with their shells separated, near to where the rivers fell into

the sea, to a great depth; like the Arno which fell from the

Gonfolina near to Monte Lupo [Footnote: _Monte Lupo_, compare 970,

13; it is between Empoli and Florence.], where it left a deposit of

gravel which may still be seen, and which has agglomerated; and of

stones of various districts, natures, and colours and hardness,

making one single conglomerate. And a little beyond the sandstone

conglomerate a tufa has been formed, where it turned towards Castel

Florentino; farther on, the mud was deposited in which the shells

lived, and which rose in layers according to the levels at which the

turbid Arno flowed into that sea. And from time to time the bottom

of the sea was raised, depositing these shells in layers, as may be

seen in the cutting at Colle Gonzoli, laid open by the Arno which is

wearing away the base of it; in which cutting the said layers of

shells are very plainly to be seen in clay of a bluish colour, and

various marine objects are found there. And if the earth of our

hemisphere is indeed raised by so much higher than it used to be, it

must have become by so much lighter by the waters which it lost

through the rift between Gibraltar and Ceuta; and all the more the

higher it rose, because the weight of the waters which were thus

lost would be added to the earth in the other hemisphere. And if the

shells had been carried by the muddy deluge they would have been

mixed up, and separated from each other amidst the mud, and not in

regular steps and layers-- as we see them now in our time.

The marine shells were not produced away from the sea.

988.

As to those who say that shells existed for a long time and were

born at a distance from the sea, from the nature of the place and of

the cycles, which can influence a place to produce such

creatures--to them it may be answered: such an influence could not

place the animals all on one line, except those of the same sort and

age; and not the old with the young, nor some with an operculum and

others without their operculum, nor some broken and others whole,

nor some filled with sea-sand and large and small fragments of other

shells inside the whole shells which remained open; nor the claws of

crabs without the rest of their bodies; nor the shells of other

species stuck on to them like animals which have moved about on

them; since the traces of their track still remain, on the outside,

after the manner of worms in the wood which they ate into. Nor would

there be found among them the bones and teeth of fish which some

call arrows and others serpents' tongues, nor would so many

[Footnote: I. Scilla argued against this hypothesis, which was still

accepted in his days; see: _La vana Speculazione, Napoli_ 1670.]

portions of various animals be found all together if they had not

been thrown on the sea shore. And the deluge cannot have carried

them there, because things that are heavier than water do not float

on the water. But these things could not be at so great a height if

they had not been carried there by the water, such a thing being

impossible from their weight. In places where the valleys have not

been filled with salt sea water shells are never to be seen; as is

plainly visible in the great valley of the Arno above Gonfolina; a

rock formerly united to Monte Albano, in the form of a very high

bank which kept the river pent up, in such a way that before it

could flow into the sea, which was afterwards at its foot, it formed

two great lakes; of which the first was where we now see the city of

Florence together with Prato and Pistoia, and Monte Albano. It

followed the rest of its bank as far as where Serravalle now stands.

>From the Val d'Arno upwards, as far as Arezzo, another lake was

formed, which discharged its waters into the former lake. It was

closed at about the spot where now we see Girone, and occupied the

whole of that valley above for a distance of 40 miles in length.

This valley received on its bottom all the soil brought down by the

turbid waters. And this is still to be seen at the foot of Prato

Magno; it there lies very high where the rivers have not worn it

away. Across this land are to be seen the deep cuts of the rivers

that have passed there, falling from the great mountain of Prato

Magno; in these cuts there are no vestiges of any shells or of

marine soil. This lake was joined with that of Perugia [Footnote:

See PI. CXIII.]

A great quantity of shells are to be seen where the rivers flow into

the sea, because on such shores the waters are not so salt owing to

the admixture of the fresh water, which is poured into it. Evidence

of this is to be seen where, of old, the Appenines poured their

rivers into the Adriatic sea; for there in most places great

quantities of shells are to be found, among the mountains, together

with bluish marine clay; and all the rocks which are torn off in

such places are full of shells. The same may be observed to have

been done by the Arno when it fell from the rock of Gonfolina into

the sea, which was not so very far below; for at that time it was

higher than the top of San Miniato al Tedesco, since at the highest

summit of this the shores may be seen full of shells and oysters

within its flanks. The shells did not extend towards Val di Nievole,

because the fresh waters of the Arno did not extend so far.

That the shells were not carried away from the sea by the deluge,

because the waters which came from the earth although they drew the

sea towards the earth, were those which struck its depths; because

the water which goes down from the earth, has a stronger current

than that of the sea, and in consequence is more powerful, and it

enters beneath the sea water and stirs the depths and carries with

it all sorts of movable objects which are to be found in the earth,

such as the above-mentioned shells and other similar things. And in

proportion as the water which comes from the land is muddier than

sea water it is stronger and heavier than this; therefore I see no

way of getting the said shells so far in land, unless they had been

born there. If you were to tell me that the river Loire [Footnote:

Leonardo has written Era instead of Loera or Loira--perhaps under

the mistaken idea that _Lo_ was an article.],which traverses France

covers when the sea rises more than eighty miles of country, because

it is a district of vast plains, and the sea rises about 20 braccia,

and shells are found in this plain at the distance of 80 miles from

the sea; here I answer that the flow and ebb in our Mediterranean

Sea does not vary so much; for at Genoa it does not rise at all, and

at Venice but little, and very little in Africa; and where it varies

little it covers but little of the country.

The course of the water of a river always rises higher in a place

where the current is impeded; it behaves as it does where it is

reduced in width to pass under the arches of a bridge.

Further researches (989-991).

989.

A CONFUTATION OF THOSE WHO SAY THAT SHELLS MAY HAVE BEEN CARRIED TO

A DISTANCE OF MANY DAYS' JOURNEY FROM THE SEA BY THE DELUGE, WHICH

WAS SO HIGH AS TO BE ABOVE THOSE HEIGHTS.

I say that the deluge could not carry objects, native to the sea, up

to the mountains, unless the sea had already increased so as to

create inundations as high up as those places; and this increase

could not have occurred because it would cause a vacuum; and if you

were to say that the air would rush in there, we have already

concluded that what is heavy cannot remain above what is light,

whence of necessity we must conclude that this deluge was caused by

rain water, so that all these waters ran to the sea, and the sea did

not run up the mountains; and as they ran to the sea, they thrust

the shells from the shore of the sea and did not draw them to wards

themselves. And if you were then to say that the sea, raised by the

rain water, had carried these shells to such a height, we have

already said that things heavier than water cannot rise upon it, but

remain at the bottom of it, and do not move unless by the impact of

the waves. And if you were to say that the waves had carried them to

such high spots, we have proved that the waves in a great depth move

in a contrary direction at the bottom to the motion at the top, and

this is shown by the turbidity of the sea from the earth washed down

near its shores. Anything which is lighter than the water moves with

the waves, and is left on the highest level of the highest margin of

the waves. Anything which is heavier than the water moves, suspended

in it, between the surface and the bottom; and from these two

conclusions, which will be amply proved in their place, we infer

that the waves of the surface cannot convey shells, since they are

heavier than water.

If the deluge had to carry shells three hundred and four hundred

miles from the sea, it would have carried them mixed with various

other natural objects heaped together; and we see at such distances

oysters all together, and sea-snails, and cuttlefish, and all the

other shells which congregate together, all to be found together and

dead; and the solitary shells are found wide apart from each other,

as we may see them on sea-shores every day. And if we find oysters

of very large shells joined together and among them very many which

still have the covering attached, indicating that they were left

here by the sea, and still living when the strait of Gibraltar was

cut through; there are to be seen, in the mountains of Parma and

Piacenza, a multitude of shells and corals, full of holes, and still

sticking to the rocks there. When I was making the great horse for

Milan, a large sack full was brought to me in my workshop by certain

peasants; these were found in that place and among them were many

preserved in their first freshness.

Under ground, and under the foundations of buildings, timbers are

found of wrought beams and already black. Such were found in my time

in those diggings at Castel Fiorentino. And these had been in that

deep place before the sand carried by the Arno into the sea, then

covering the plain, had heen raised to such a height; and before the

plains of Casentino had been so much lowered, by the earth being

constantly carried down from them.

[Footnote: These lines are written in the margin.]

And if you were to say that these shells were created, and were

continually being created in such places by the nature of the spot,

and of the heavens which might have some influence there, such an

opinion cannot exist in a brain of much reason; because here are the

years of their growth, numbered on their shells, and there are large

and small ones to be seen which could not have grown without food,

and could not have fed without motion--and here they could not move

[Footnote: These lines are written in the margin.]

990.

That in the drifts, among one and another, there are still to be

found the traces of the worms which crawled upon them when they were

not yet dry. And all marine clays still contain shells, and the

shells are petrified together with the clay. From their firmness and

unity some persons will have it that these animals were carried up

to places remote from the sea by the deluge. Another sect of

ignorant persons declare that Nature or Heaven created them in these

places by celestial influences, as if in these places we did not

also find the bones of fishes which have taken a long time to grow;

and as if, we could not count, in the shells of cockles and snails,

the years and months of their life, as we do in the horns of bulls

and oxen, and in the branches of plants that have never been cut in

any part. Besides, having proved by these signs the length of their

lives, it is evident, and it must be admitted, that these animals

could not live without moving to fetch their food; and we find in

them no instrument for penetrating the earth or the rock where we

find them enclosed. But how could we find in a large snail shell the

fragments and portions of many other sorts of shells, of various

sorts, if they had not been thrown there, when dead, by the waves of

the sea like the other light objects which it throws on the earth?

Why do we find so many fragments and whole shells between layer and

layer of stone, if this had not formerly been covered on the shore

by a layer of earth thrown up by the sea, and which was afterwards

petrified? And if the deluge before mentioned had carried them to

these parts of the sea, you might find these shells at the boundary

of one drift but not at the boundary between many drifts. We must

also account for the winters of the years during which the sea

multiplied the drifts of sand and mud brought down by the

neighbouring rivers, by washing down the shores; and if you chose to

say that there were several deluges to produce these rifts and the

shells among them, you would also have to affirm that such a deluge

took place every year. Again, among the fragments of these shells,

it must be presumed that in those places there were sea coasts,

where all the shells were thrown up, broken, and divided, and never

in pairs, since they are found alive in the sea, with two valves,

each serving as a lid to the other; and in the drifts of rivers and

on the shores of the sea they are found in fragments. And within the

limits of the separate strata of rocks they are found, few in number

and in pairs like those which were left by the sea, buried alive in

the mud, which subsequently dried up and, in time, was petrified.

991.

And if you choose to say that it was the deluge which carried these

shells away from the sea for hundreds of miles, this cannot have

happened, since that deluge was caused by rain; because rain

naturally forces the rivers to rush towards the sea with all the

things they carry with them, and not to bear the dead things of the

sea shores to the mountains. And if you choose to say that the

deluge afterwards rose with its waters above the mountains, the

movement of the sea must have been so sluggish in its rise against

the currents of the rivers, that it could not have carried, floating

upon it, things heavier than itself; and even if it had supported

them, in its receding it would have left them strewn about, in

various spots. But how are we to account for the corals which are

found every day towards Monte Ferrato in Lombardy, with the holes of

the worms in them, sticking to rocks left uncovered by the currents

of rivers? These rocks are all covered with stocks and families of

oysters, which as we know, never move, but always remain with one of

their halves stuck to a rock, and the other they open to feed

themselves on the animalcules that swim in the water, which, hoping

to find good feeding ground, become the food of these shells. We do

not find that the sand mixed with seaweed has been petrified,

because the weed which was mingled with it has shrunk away, and this

the Po shows us every day in the debris of its banks.