The Notebooks of Leonardo Da Vinci — Complete
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.
V.
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