The Notebooks of Leonardo Da Vinci (70 page)

As for instance in the discussion as to the equilibrium of the mass
of water in the Mediterranean Sea—a subject which, it may be
observed, had at that time attracted the interest and study of
hardly any other observer. The acute remarks, in Nos. 985—993, on
the presence of shells at the tops of mountains, suffice to
prove—as it seems to me—that it was not in his nature to allow
himself to be betrayed into wide generalisations, extending beyond
the limits of his own investigations, even by such brilliant results
of personal study.

Most of these Topographical Notes, though suggesting very careful
and thorough research, do not however, as has been said, afford
necessarily indisputable evidence that that research was Leonardo's
own. But it must be granted that in more than one instance
probability is in favour of this idea.

Among the passages which treat somewhat fully of the topography of
Eastern places by far the most interesting is a description of the
Taurus Mountains; but as this text is written in the style of a
formal report and, in the original, is associated with certain
letters which give us the history of its origin, I have thought it
best not to sever it from that connection. It will be found under
No. XXI (Letters).

That Florence, and its neighbourhood, where Leonardo spent his
early years, should be nowhere mentioned except in connection with
the projects for canals, which occupied his attention for some short
time during the first ten years of the XVIth century, need not
surprise us. The various passages relating to the construction of
canals in Tuscany, which are put together at the beginning, are
immediately followed by those which deal with schemes for canals in
Lombardy; and after these come notes on the city and vicinity of
Milan as well as on the lakes of North Italy.

The notes on some towns of Central Italy which Leonardo visited in
1502, when in the service of Cesare Borgia, are reproduced here in
the same order as in the note book used during these travels (MS.
L., Institut de France). These notes have but little interest in
themselves excepting as suggesting his itinerary. The maps of the
districts drawn by Leonardo at the time are more valuable (see No.
1054 note). The names on these maps are not written from right to
left, but in the usual manner, and we are permitted to infer that
they were made in obedience to some command, possibly for the use of
Cesare Borgia himself; the fact that they remained nevertheless in
Leonardo's hands is not surprising when we remember the sudden
political changes and warlike events of the period. There can be no
doubt that these maps, which are here published for the first time,
are original in the strictest sense of the word, that is to say
drawn from observations of the places themselves; this is proved by
the fact—among others—that we find among his manuscripts not only
the finished maps themselves but the rough sketches and studies for
them. And it would perhaps be difficult to point out among the
abundant contributions to geographical knowledge published during
the XVIth century, any maps at all approaching these in accuracy and
finish.

The interesting map of the world, so far as it was then known,
which is among the Leonardo MSS. at Windsor (published in the
'Archaeologia'
Vol. XI) cannot be attributed to the Master, as the
Marchese Girolamo d'Adda has sufficiently proved; it has not
therefore been reproduced here.

Such of Leonardo's observations on places in Italy as were made
before or after his official travels as military engineer to Cesare
Borgia, have been arranged in alphabetical order, under Nos.
1034-1054. The most interesting are those which relate to the Alps
and the Appenines, Nos. 1057-1068.

Most of the passages in which France is mentioned have hitherto
remained unknown, as well as those which treat of the countries
bordering on the Mediterranean, which come at the end of this
section. Though these may be regarded as of a more questionable
importance in their bearing on the biography of the Master than
those which mention places in France, it must be allowed that they
are interesting as showing the prominent place which the countries
of the East held in his geographical studies. He never once alludes
to the discovery of America.

Canals in connection with the Arno (1001-1008).

1001.

Sluices should be made in the valley of la Chiana at Arezzo, so that
when, in the summer, the Arno lacks water, the canal may not remain
dry: and let this canal be 20 braccia wide at the bottom, and at the
top 30, and 2 braccia deep, or 4, so that two of these braccia may
flow to the mills and the meadows, which will benefit the country;
and Prato, Pistoia and Pisa, as well as Florence, will gain two
hundred thousand ducats a year, and will lend a hand and money to
this useful work; and the Lucchese the same, for the lake of Sesto
will be navigable; I shall direct it to Prato and Pistoia, and cut
through Serravalle and make an issue into the lake; for there will
be no need of locks or supports, which are not lasting and so will
always be giving trouble in working at them and keeping them up.

And know that in digging this canal where it is 4 braccia deep, it
will cost 4 dinari the square braccio; for twice the depth 6 dinari,
if you are making 4 braccia [Footnote: This passage is illustrated
by a slightly sketched map, on which these places are indicated from
West to East: Pisa, Luccha, Lago, Seravalle, Pistoja, Prato,
Firenze.] and there are but 2 banks; that is to say one from the
bottom of the trench to the surface of the edges of it, and the
other from these edges to the top of the ridge of earth which will
be raised on the margin of the bank. And if this bank were of double
the depth only the first bank will be increased, that is 4 braccia
increased by half the first cost; that is to say that if at first 4
dinari were paid for 2 banks, for 3 it would come to 6, at 2 dinari
the bank, if the trench measured 16 braccia at the bottom; again, if
the trench were 16 braccia wide and 4 deep, coming to 4 lire for the
work, 4 Milan dinari the square braccio; a trench which was 32
braccia at the bottom would come to 8 dinari the square braccio.

1002.

>From the wall of the Arno at [the gate of] la Giustizia to the bank
of the Arno at Sardigna where the walls are, to the mills, is 7400
braccia, that is 2 miles and 1400 braccia and beyond the Arno is
5500 braccia.

[Footnote: 2.
Giustizia
. By this the Porta della Giustizia seems
to be meant; from the XVth to the XVIth centuries it was also
commonly known as Porta Guelfa, Porta San Francesco del Renaio,
Porta Nuova, and Porta Reale. It was close to the Arno opposite to
the Porta San Niccolo, which still exists.]

1003.

By guiding the Arno above and below a treasure will be found in each
acre of ground by whomsoever will.

1004.

The wall of the old houses runs towards the gate of San Nicolo.

[Footnote: By the side of this text there is an indistinct sketch,
resembling that given under No.973. On the bank is written the word
Casace
. There then follows in the original a passage of 12 lines
in which the consequences of the windings of the river are
discussed. A larger but equally hasty diagram on the same page
represents the shores of the Arno inside Florence as in two parallel
lines. Four horizontal lines indicate the bridges. By the side these
measures are stated in figures: I. (at the Ponte alla Carraja):
230—largho br. 12 e 2 di spoda e 14 di pile e a 4 pilastri;
2.
(at the Ponte S. Trinita);
l88—largho br. 15 e 2 di spode he 28
di pilastri for delle spode e pilastri so 2;
3. (at the Ponte
vecchio);
pote lung br. 152 e largo;
4. (at the Ponte alle
Grazie):
290 ellargo 12 e 2 di spode e 6 di pili.

There is, in MS. W. L. 2l2b, a sketched plan of Florence, with the
following names of gates:
Nicholo—Saminiato—Giorgo—Ghanolini—Porta San Fredian
—Prato—Faenza—Ghallo—Pinti—Giustitia
.]

1005.

The ruined wall is 640 braccia; 130 is the wall remaining with the
mill; 300 braccia were broken in 4 years by Bisarno.

1006.

They do not know why the Arno will never remain in a channel. It is
because the rivers which flow into it deposit earth where they
enter, and wear it away on the opposite side, bending the river in
that direction. The Arno flows for 6 miles between la Caprona and
Leghorn; and for 12 through the marshes, which extend 32 miles, and
16 from La Caprona up the river, which makes 48; by the Arno from
Florence beyond 16 miles; to Vico 16 miles, and the canal is 5; from
Florence to Fucechio it is 40 miles by the river Arno.

56 miles by the Arno from Florence to Vico; by the Pistoia canal it
is 44 miles. Thus it is 12 miles shorter by the canal than by the
Arno.

[Footnote: This passage is written by the side of a map washed in
Indian ink, of the course of the Arno; it is evidently a sketch for
a completer map.

These investigations may possibly be connected with the following
documents.
Francesco Guiducci alla Balia di Firenze. Dal Campo
contro Pisa
24
Luglio
1503 (
Archivio di Stato, Firenze, Lettere
alla Balia
; published by J. GAYE,
Carteggio inedito d'Artisti,
Firenze
1840,
Tom. II
, p. 62):
Ex Castris, Franciscus
Ghuiduccius,
24.
Jul.
1503.
Appresso fu qui hieri con una di V.
Signoria Alexandro degli Albizi insieme con Leonardo da Vinci et
certi altri, et veduto el disegno insieme con el ghovernatore, doppo
molte discussioni et dubii conclusesi che l'opera fussi molto al
proposito, o si veramente Arno volgersi qui, o restarvi con un
canale, che almeno vieterebbe che le colline da nemici non
potrebbono essere offese; come tucto referiranno loro a bocha V. S.

And,
Archivio di Stato, Firenze, Libro d'Entrata e Uscita di cassa
de' Magnifici Signori di luglio e agosto

1503
a
51
T.: Andata di Leonardo al Campo sotto Pisa. Spese
extraordinarie dieno dare a di XXVI di luglio L. LVI sol. XII per
loro a Giovanni Piffero; e sono per tanti, asegnia avere spexi in
vetture di sei chavalli a spese di vitto per andare chon Lionardo da
Vinci a livellare Arno in quello di Pisa per levallo del lilo suo.
(Published by MILANESI,
Archivio Storico Italiano, Serie III, Tom.
XVI.
} VASARI asserts:
(Leonardo) fu il primo ancora, che
giovanetto discorresse sopra il fiume d'Arno per metterlo in canale
da Pisa a Fiorenza
(ed. SANSONI, IV, 20).

The passage above is in some degree illustrated by the map on Pl.
CXII, where the course of the Arno westward from Empoli is shown.]

1007.

The eddy made by the Mensola, when the Arno is low and the Mensola
full.

[Footnote:
Mensola
is a mountain stream which falls into the Arno
about a mile and a half above Florence.

A=Arno, I=Isola, M=Mvgone, P=Pesa, N=Mesola.]

1008.

That the river which is to be turned from one place to another must
be coaxed and not treated roughly or with violence; and to do this a
sort of floodgate should be made in the river, and then lower down
one in front of it and in like manner a third, fourth and fifth, so
that the river may discharge itself into the channel given to it, or
that by this means it may be diverted from the place it has damaged,
as was done in Flanders—as I was told by Niccolo di Forsore.

How to protect and repair the banks washed by the water, as below
the island of Cocomeri.

Ponte Rubaconte (Fig. 1); below [the palaces] Bisticci and Canigiani
(Fig. 2). Above the flood gate of la Giustizia (Fig. 3);
a b
is a
sand bank opposite the end of the island of the Cocomeri in the
middle of the Arno (Fig. 4). [Footnote: The course of the river Arno
is also discussed in Nos. 987 and 988.]

Canals in the Milanese (1009-1013).

1009.

The canal of San Cristofano at Milan made May 3rd 1509. [Footnote:
This observation is written above a washed pen and ink drawing which
has been published as Tav. VI in the
,,Saggio."
The editors of
that work explain the drawing as
"uno Studio di bocche per
estrazione d'acqua."
]

1010.

By making the canal of Martesana the water of the Adda is greatly
diminished by its distribution over many districts for the
irrigation of the fields. A remedy for this would be to make several
little channels, since the water drunk up by the earth is of no more
use to any one, nor mischief neither, because it is taken from no
one; and by making these channels the water which before was lost
returns again and is once more serviceable and useful to men.

[Footnote:
"el navilio di Martagano"
is also mentioned in a note
written in red chalk, MS. H2 17a Leonardo has, as it seems, little
to do with Lodovico il Moro's scheme to render this canal navigable.
The canal had been made in 1460 by Bertonino da Novara. Il Moro
issued his degree in 1493, but Leonardo's notes about this canal
were, with the exception of one (No. 1343), written about sixteen
years later.]

1011.

No canal which is fed by a river can be permanent if the river
whence it originates is not wholly closed up, like the canal of
Martesana which is fed by the Ticino.

1012.

>From the beginning of the canal to the mill.

>From the beginning of the canal of Brivio to the mill of Travaglia
is 2794 trabochi, that is 11176 braccia, which is more than 3 miles
and two thirds; and here the canal is 57 braccia higher than the
surface of the water of the Adda, giving a fall of two inches in
every hundred trabochi; and at that spot we propose to take the
opening of our canal.