The Notebooks of Leonardo Da Vinci (74 page)

[Footnote: Lines 6-18 are partly reproduced in the facsimile on p.
254, and the whole of lines 19-25.

The following names are written along the rivers on the larger
sketch,
era f
(the Loire)
scier f
(the Cher) three times.
Pote
Sodro
(bridge of the Soudre).
Villa francha
(Villefranche)
banco
(sandbank)
Sodro
(Soudre). The circle below shows the
position of Romorantin. The words '
orologio del sole
' written
below do not belong to the map of the rivers. The following names
are written by the side of the smaller sketch-map:—
tors
(Tours),
Abosa
(Amboise)
bres
—for Bles (Blois)
mo rica
(Montrichard).
Lione
(Lyons). This map was also published in the 'Saggio'
(Milano, 1872) Pl. XXII, and the editors remark:
Forse la linia
retta che va da Amboise a Romorantin segna l'andamento proposto d'un
Canale, che poi rembra prolungarsi in giu fin dove sta scritto
Lione.

M. Ravaisson has enlarged on this idea in the Gazette des Beaux Arts
(1881 p. 530):
Les traces de Leonard permettent d'entrevoir que le
canal commencant soit aupres de Tours, soit aupres de Blois et
passant par Romorantin, avec port d'embarquement a Villefranche,
devait, au dela de Bourges, traverser l'Allier au-dessous des
affluents de la Dore et de la Sioule, aller par Moulins jusqu' a
Digoin; enfin, sur l'autre rive de la Loire, depasser les monts du
Charolais et rejoindre la Saone aupres de Macon.
It seems to me
rash, however, to found so elaborate an hypothesis on these sketches
of rivers. The slight stroke going to
Lione
is perhaps only an
indication of the direction.—With regard to the Loire compare also
No. 988. l. 38.]

1079.

At 1/4 from the South to the South East. At 1/3 from the South to
the South East. At 1/4 from the South to the South East. At 1/5 from
the South to the South East. Between the South West and South, to
the East bearing to the South; from the South towards the East 1/8;
thence to the West, between the South and South West; at the South.

[Footnote: The meaning is obscure; a more important passage
referring to France is to be found under No. 744]

On the Germans (1080. 1081).

1080.

The way in which the Germans closing up together cross and
interweave their broad leather shields against the enemy, stooping
down and putting one of the ends on the ground while they hold the
rest in their hand. [Footnote: Above the text is a sketch of a few
lines crossing each other and the words
de ponderibus
. The meaning
of the passage is obscure.]

1081.

The Germans are wont to annoy a garrison with the smoke of feathers,
sulphur and realgar, and they make this smoke last 7 or 8 hours.
Likewise the husks of wheat make a great and lasting smoke; and also
dry dung; but this must be mixed with olive husks, that is olives
pressed for oil and from which the oil has been extracted.
[Footnote: There is with this passage a sketch of a round tower
shrouded in smoke.]

The Danube.

1082.

That the valleys were formerly in great part covered by lakes the
soil of which always forms the banks of rivers,—and by seas, which
afterwards, by the persistent wearing of the rivers, cut through the
mountains and the wandering courses of the rivers carried away the
other plains enclosed by the mountains; and the cutting away of the
mountains is evident from the strata in the rocks, which correspond
in their sections as made by the courses of the rivers [Footnote 4:
Emus
, the Balkan;
Dardania
, now Servia.], The Haemus mountains
which go along Thrace and Dardania and join the Sardonius mountains
which, going on to the westward change their name from Sardus to
Rebi, as they come near Dalmatia; then turning to the West cross
Illyria, now called Sclavonia, changing the name of Rebi to Albanus,
and going on still to the West, they change to Mount Ocra in the
North; and to the South above Istria they are named Caruancas; and
to the West above Italy they join the Adula, where the Danube rises
[8], which stretches to the East and has a course of 1500 miles; its
shortest line is about l000 miles, and the same or about the same is
that branch of the Adula mountains changed as to their name, as
before mentioned. To the North are the Carpathians, closing in the
breadth of the valley of the Danube, which, as I have said extends
eastward, a length of about 1000 miles, and is sometimes 200 and in
some places 300 miles wide; and in the midst flows the Danube, the
principal river of Europe as to size. The said Danube runs through
the middle of Austria and Albania and northwards through Bavaria,
Poland, Hungary, Wallachia and Bosnia and then the Danube or Donau
flows into the Black Sea, which formerly extended almost to Austria
and occupied the plains through which the Danube now courses; and
the evidence of this is in the oysters and cockle shells and
scollops and bones of great fishes which are still to be found in
many places on the sides of those mountains; and this sea was formed
by the filling up of the spurs of the Adula mountains which then
extended to the East joining the spurs of the Taurus which extend to
the West. And near Bithynia the waters of this Black Sea poured into
the Propontis [Marmora] falling into the Aegean Sea, that is the
Mediterranean, where, after a long course, the spurs of the Adula
mountains became separated from those of the Taurus. The Black Sea
sank lower and laid bare the valley of the Danube with the above
named countries, and the whole of Asia Minor beyond the Taurus range
to the North, and the plains from mount Caucasus to the Black Sea to
the West, and the plains of the Don this side—that is to say, at
the foot of the Ural mountains. And thus the Black Sea must have
sunk about 1000 braccia to uncover such vast plains.

[Footnote 8:
Danubio
, in the original
Reno
; evidently a mistake
as we may infer from
come dissi
l. 10 &c.]

The straits of Gibraltar (1083-1085).

1083.

A river of equal depth runs with greater speed in a narrow space
than in a wide one, in proportion to the difference between the
wider and the narrower one.

This proposition is clearly proved by reason confirmed by
experiment. Supposing that through a channel one mile wide there
flows one mile in length of water; where the river is five miles
wide each of the 5 square miles will require 1/5 of itself to be
equal to the square mile of water required in the sea, and where the
river is 3 miles wide each of these square miles will require the
third of its volume to make up the amount of the square mile of the
narrow part; as is demonstrated in
f g h
at the mile marked
n
.

[Footnote: In the place marked A in the diagram
Mare Mediterano
(Mediterranean Sea) is written in the original. And at B,
stretto
di Spugna
(straits of Spain,
i.e.
Gibraltar). Compare No. 960.]

1084.

The reason is that if you put together the mouths of the rivers
which discharge into the Mediterranean sea, you would find the sum
of water to be larger than that which this sea pours through the
straits into the ocean. You see Africa discharging its rivers that
run northwards into this sea, and among them the Nile which runs
through 3000 miles of Africa; there is also the Bagrada river and
the Schelif and others. [Footnote 5:
Bagrada
(Leonardo writes
Bragada) in Tunis, now Medscherda;
Mavretano
, now Schelif.]
Likewise Europe pours into it the Don and the Danube, the Po, the
Rhone, the Arno, and the Tiber, so that evidently these rivers, with
an infinite number of others of less fame, make its great breadth
and depth and current; and the sea is not wider than 18 miles at the
most westerly point of land where it divides Europe from Africa.

1085.

The gulf of the Mediterranean, as an inland sea, received the
principal waters of Africa, Asia and Europe that flowed towards it;
and its waters came up to the foot of the mountains that surrounded
it and made its shores. And the summits of the Apennines stood up
out of this sea like islands, surrounded by salt water. Africa
again, behind its Atlas mountains did not expose uncovered to the
sky the surface of its vast plains about 3000 miles in length, and
Memphis [Footnote 6:
Mefi.
Leonardo can only mean here the citadel
of Cairo on the Mokattam hills.] was on the shores of this sea, and
above the plains of Italy, where now birds fly in flocks, fish were
wont to wander in large shoals.

1086.

Tunis.

The greatest ebb made anywhere by the Mediterranean is above Tunis,
being about two and a half braccia and at Venice it falls two
braccia. In all the rest of the Mediterranean sea the fall is little
or none.

1087.

Libya.

Describe the mountains of shifting deserts; that is to say the
formation of waves of sand borne by the wind, and of its mountains
and hills, such as occur in Libya. Examples may be seen on the wide
sands of the Po and the Ticino, and other large rivers.

1088.

Majorca.

Circumfulgore is a naval machine. It was an invention of the men of
Majorca. [Footnote: The machine is fully described in the MS. and
shown in a sketch.]

1089.

The Tyrrhene Sea.

Some at the Tyrrhene sea employ this method; that is to say they
fastened an anchor to one end of the yard, and to the other a cord,
of which the lower end was fastened to an anchor; and in battle they
flung this anchor on to the oars of the opponent's boat and by the
use of a capstan drew it to the side; and threw soft soap and tow,
daubed with pitch and set ablaze, on to that side where the anchor
hung; so that in order to escape that fire, the defenders of that
ship had to fly to the opposite side; and in doing this they aided
to the attack, because the galley was more easily drawn to the side
by reason of the counterpoise. [Footnote: This text is illustrated
in the original by a pen and ink sketch.]

The Levantine Sea.

1090.

On the shores of the Mediterranean 300 rivers flow, and 40, 200
ports. And this sea is 3000 miles long. Many times has the increase
of its waters, heaped up by their backward flow and the blowing of
the West winds, caused the overflow of the Nile and of the rivers
which flow out through the Black Sea, and have so much raised the
seas that they have spread with vast floods over many countries. And
these floods take place at the time when the sun melts the snows on
the high mountains of Ethiopia that rise up into the cold regions of
the air; and in the same way the approach of the sun acts on the
mountains of Sarmatia in Asia and on those in Europe; so that the
gathering together of these three things are, and always have been,
the cause of tremendous floods: that is, the return flow of the sea
with the West wind and the melting of the snows. So every river will
overflow in Syria, in Samaria, in Judea between Sinai and the
Lebanon, and in the rest of Syria between the Lebanon and the Taurus
mountains, and in Cilicia, in the Armenian mountains, and in
Pamphilia and in Lycia within the hills, and in Egypt as far as the
Atlas mountains. The gulf of Persia which was formerly a vast lake
of the Tigris and discharged into the Indian Sea, has now worn away
the mountains which formed its banks and laid them even with the
level of the Indian ocean. And if the Mediterranean had continued
its flow through the gulf of Arabia, it would have done the same,
that is to say, would have reduced the level of the Mediterranean to
that of the Indian Sea.

The Red Sea. (1091. 1092).

1091.

For a long time the water of the Mediterranean flowed out through
the Red Sea, which is 100 miles wide and 1500 long, and full of
reefs; and it has worn away the sides of Mount Sinai, a fact which
testifies, not to an inundation from the Indian sea beating on these
coasts, but to a deluge of water which carried with it all the
rivers which abound round the Mediterranean, and besides this there
is the reflux of the sea; and then, a cutting being made to the West
3000 miles away from this place, Gibraltar was separated from Ceuta,
which had been joined to it. And this passage was cut very low down,
in the plains between Gibraltar and the ocean at the foot of the
mountain, in the low part, aided by the hollowing out of some
valleys made by certain rivers, which might have flowed here.
Hercules [Footnote 9: Leonardo seems here to mention Hercules half
jestingly and only in order to suggest to the reader an allusion to
the legend of the pillars of Hercules.] came to open the sea to the
westward and then the sea waters began to pour into the Western
Ocean; and in consequence of this great fall, the Red Sea remained
the higher; whence the water, abandoning its course here, ever after
poured away through the Straits of Spain.

1092.

The surface of the Red Sea is on a level with the ocean.

A mountain may have fallen and closed the mouth of the Red Sea and
prevented the outlet of the Mediterranean, and the Mediterranean Sea
thus overfilled had for outlet the passage below the mountains of
Gades; for, in our own times a similar thing has been seen [Footnote
6: Compare also No. 1336, ll. 30, 35 and 36.— Paolo Giovio, the
celebrated historian (born at Como in 1483) reports that in 1513 at
the foot of the Alps, above Bellinzona, on the road to Switzerland,
a mountain fell with a very great noise, in consequence of an
earthquake, and that the mass of rocks, which fell on the left
(Western) side blocked the river Breno (T. I p. 218 and 345 of D.
Sauvage's French edition, quoted in ALEXIS PERCY,
Memoire des
tremblements de terre de la peninsule italique; Academie Royale de
Belgique.
T. XXII).—]; a mountain fell seven miles across a valley
and closed it up and made a lake. And thus most lakes have been made
by mountains, as the lake of Garda, the lakes of Como and Lugano,
and the Lago Maggiore. The Mediterranean fell but little on the
confines of Syria, in consequence of the Gaditanean passage, but a
great deal in this passage, because before this cutting was made the
Mediterranean sea flowed to the South East, and then the fall had to
be made by its run through the Straits of Gades.