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The Notebooks of Leonardo Da Vinci, Volume 2

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1076.

As to whether it is better that the water should all be raised in a
single turn or in two?

The answer is that in one single turn the wheel could not support
all the water that it can raise in two turns, because at the half
turn of the wheel it would be raising 100 pounds and no more; and if
it had to raise the whole, 200 pounds in one turn, it could not
raise them unless the wheel were of double the diameter and if the
diameter were doubled, the time of its revolution would be doubled;
therefore it is better and a greater advantage in expense to make
such a wheel of half the size (?) the land which it would water and
would render the country fertile to supply food to the inhabitants,
and would make navigable canals for mercantile purposes.

The way in which the river in its flow should scour its own channel.

By the ninth of the third; the more rapid it is, the more it wears
away its channel; and, by the converse proposition, the slower the
water the more it deposits that which renders it turbid.

And let the sluice be movable like the one I arranged in Friuli
[Footnote 19: This passage reveals to us the fact that Leonardo had
visited the country of Friuli and that he had stayed there for some
time. Nothing whatever was known of this previously.], where when
one sluice was opened the water which passed through it dug out the
bottom. Therefore when the rivers are flooded, the sluices of the
mills ought to be opened in order that the whole course of the river
may pass through falls to each mill; there should be many in order
to give a greater impetus, and so all the river will be scoured. And
below the site of each of the two mills there may be one of the said
sluice falls; one of them may be placed below each mill.

1078.

A trabocco is four braccia, and one mile is three thousand of the
said braccia. Each braccio is divided into 12 inches; and the water
in the canals has a fall in every hundred trabocchi of two of these
inches; therefore 14 inches of fall are necessary in two thousand
eight hundred braccia of flow in these canals; it follows that 15
inches of fall give the required momentum to the currents of the
waters in the said canals, that is one braccio and a half in the
mile. And from this it may be concluded that the water taken from
the river of Ville-franche and lent to the river of Romorantin
will..... Where one river by reason of its low level cannot flow
into the other, it will be necessary to dam it up, so that it may
acquire a fall into the other, which was previously the higher.

The eve of Saint Antony I returned from Romorantin to Amboise, and
the King went away two days before from Romorantin.

>From Romorantin as far as the bridge at Saudre it is called the
Saudre, and from that bridge as far as Tours it is called the Cher.

I would test the level of that channel which is to lead from the
Loire to Romorantin, with a channel one braccio wide and one braccio
deep.

[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.

THE ROAD TO ORLEANS

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.]

III.

THE COUNTRIES OF THE WESTERN END OF THE MEDITERRANEAN.

The straits of Gibraltar (1083-1085).

1083.

WHY THE SEA MAKES A STRONGER CURRENT IN THE STRAITS OF SPAIN THAN
ELSEWHERE.

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.

WHY THE CURRENT OF GIBRALTAR IS ALWAYS GREATER TO THE WEST THAN TO
THE EAST.

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.]

IV.

THE LEVANT.

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.

At _a_ the water of the Mediterranean fell into the ocean.

All the plains which lie between the sea and mountains were formerly
covered with salt water.

Every valley has been made by its own river; and the proportion
between valleys is the same as that between river and river.

The greatest river in our world is the Mediterranean river, which
moves from the sources of the Nile to the Western ocean.

And its greatest height is in Outer Mauritania and it has a course
of ten thousand miles before it reunites with its ocean, the father
of the waters.

That is 3000 miles for the Mediterranean, 3000 for the Nile, as far
as discovered and 3000 for the Nile which flows to the East, &c.

[Footnote: See Pl. CXI 2, a sketch of the shores of the
Mediterranean Sea, where lines 11 to 16 may be seen. The large
figures 158 are not in Leonardo's writing. The character of the
writing leads us to conclude that this text was written later than
the foregoing. A slight sketch of the Mediterranean is also to be
found in MS. I', 47a.]

The Nile (1093-1098).

1093.

Therefore we must conclude those mountains to be of the greatest
height, above which the clouds falling in snow give rise to the
Nile.

1094.

The Egyptians, the Ethiopians, and the Arabs, in crossing the Nile
with camels, are accustomed to attach two bags on the sides of the
camel's bodies that is skins in the form shown underneath.

In these four meshes of the net the camels for baggage place their
feet.

[Footnote: Unfortunately both the sketches which accompany this
passage are too much effaced to be reproduced. The upper represents
the two sacks joined by ropes, as here described, the other shows
four camels with riders swimming through a river.]

1095.

The Tigris passes through Asia Minor and brings with it the water of
three lakes, one after the other of various elevations; the first
being Munace and the middle Pallas and the lowest Triton. And the
Nile again springs from three very high lakes in Ethiopia, and runs
northwards towards the sea of Egypt with a course of 4000 miles, and
by the shortest and straightest line it is 3000 miles. It is said
that it issues from the Mountains of the Moon, and has various
unknown sources. The said lakes are about 4000 braccia above the
surface of the sphere of water, that is 1 mile and 1/3, giving to
the Nile a fall of 1 braccia in every mile.

[Footnote 5: _Incogniti principio._ The affluents of the lakes are
probably here intended. Compare, as to the Nile, Nos. 970, 1063 and
1084.]

1096.

Very many times the Nile and other very large rivers have poured out
their whole element of water and restored it to the sea.

1097.

Why does the inundation of the Nile occur in the summer, coming from
torrid countries?

1098.

It is not denied that the Nile is constantly muddy in entering the
Egyptian sea and that its turbidity is caused by soil that this
river is continually bringing from the places it passes; which soil
never returns in the sea which receives it, unless it throws it on
its shores. You see the sandy desert beyond Mount Atlas where
formerly it was covered with salt water.

Customs of Asiatic Nations (1099. 1100).

1099.

The Assyrians and the people of Euboea accustom their horses to
carry sacks which they can at pleasure fill with air, and which in
case of need they carry instead of the girth of the saddle above and
at the side, and they are well covered with plates of cuir bouilli,
in order that they may not be perforated by flights of arrows. Thus
they have not on their minds their security in flight, when the
victory is uncertain; a horse thus equipped enables four or five men
to cross over at need.

1100.

SMALL BOATS.

The small boats used by the Assyrians were made of thin laths of
willow plaited over rods also of willow, and bent into the form of a
boat. They were daubed with fine mud soaked with oil or with
turpentine, and reduced to a kind of mud which resisted the water
and because pine would split; and always remained fresh; and they
covered this sort of boats with the skins of oxen in safely crossing
the river Sicuris of Spain, as is reported by Lucant; [Footnote 7:
See Lucan's Pharsalia IV, 130: _Utque habuit ripas Sicoris camposque
reliquit, Primum cana salix madefacto vimine parvam Texitur in
puppim, calsoque inducto juvenco Vectoris patiens tumidum supernatat
amnem. Sic Venetus stagnante Pado, fusoque Britannus Navigat oceano,
sic cum tenet omnia Nilus, Conseritur bibula Memphitis cymbo papyro.
His ratibus transjecta manus festinat utrimque Succisam cavare nemus
]

The Spaniards, the Scythians and the Arabs, when they want to make a
bridge in haste, fix hurdlework made of willows on bags of ox-hide,
and so cross in safety.

Rhodes (1101. 1102).

1101.

In [fourteen hundred and] eighty nine there was an earthquake in the
sea of Atalia near Rhodes, which opened the sea--that is its
bottom--and into this opening such a torrent of water poured that
for more than three hours the bottom of the sea was uncovered by
reason of the water which was lost in it, and then it closed to the
former level.

[Footnote: _Nello ottanto_ 9. It is scarcely likely that Leonardo
should here mean 89 AD. Dr. H. MULLER- STRUBING writes to me as
follows on this subject: "With reference to Rhodes Ross says (_Reise
auf den Griechischen Inseln, III_ 70 _ff_. 1840), that ancient
history affords instances of severe earthquakes at Rhodes, among
others one in the second year of the 138th Olympiad=270 B. C.; a
remarkably violent one under Antoninus Pius (A. D. 138-161) and
again under Constantine and later. But Leonardo expressly speaks of
an earthquake "_nel mar di Atalia presso a Rodi_", which is
singular. The town of Attalia, founded by Attalus, which is what he
no doubt means, was in Pamphylia and more than 150 English miles
East of Rhodes in a straight line. Leake and most other geographers
identify it with the present town of Adalia. Attalia is rarely
mentioned by the ancients, indeed only by Strabo and Pliny and no
earthquake is spoken of. I think therefore you are justified in
assuming that Leonardo means 1489". In the elaborate catalogue of
earthquakes in the East by Sciale Dshelal eddin Sayouthy (an
unpublished Arabic MS. in the possession of Prof. SCHEFER, (Membre
de l'Institut, Paris) mention is made of a terrible earthquake in
the year 867 of the Mohamedan Era corresponding to the year 1489,
and it is there stated that a hundred persons were killed by it in
the fortress of Kerak. There are three places of this name. Kerak on
the sea of Tiberias, Kerak near Tahle on the Libanon, which I
visited in the summer of l876--but neither of these is the place
alluded to. Possibly it may be the strongly fortified town of
Kerak=Kir Moab, to the West of the Dead Sea. There is no notice
about this in ALEXIS PERCY, _Memoire sur les tremblements de terres
ressentis dans la peninsule turco- hellenique et en Syrie (Memoires
couronnes et memoires des savants etrangers, Academie Royale de
Belgique, Tome XXIII)._]

1102.

Rhodes has in it 5000 houses.

Cyprus (1103. 1104).

1103.

SITE FOR [A TEMPLE OF] VENUS.

You must make steps on four sides, by which to mount to a meadow
formed by nature at the top of a rock which may be hollowed out and
supported in front by pilasters and open underneath in a large
portico,

[Footnote: See Pl. LXXXIII. Compare also p. 33 of this Vol. The
standing male figure at the side is evidently suggested by Michael
Angelo's David. On the same place a slight sketch of horses seems to
have been drawn first; there is no reason for assuming that the text
and this sketch, which have no connection with each other, are of
the same date.

_Sito di Venere._ By this heading Leonardo appears to mean Cyprus,
which was always considered by the ancients to be the home and birth
place of Aphrodite (Kirpic in Homer).]

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