The Notebooks of Leonardo Da Vinci (47 page)

If you want it to throw a ball of stone, make the length of the gun
to be 6, or as much as 7 diameters of the ball; and if the ball is
to be of iron make it as much as 12 balls, and if the ball is to be
of lead, make it as much as 18 balls. I mean when the gun is to have
the mouth fitted to receive 600 lbs. of stone ball, and more.

The thickness at the muzzle of small guns should be from a half to
one third of the diameter of the ball, and the length from 30 to 36
balls.

740.

The furnace must be luted before you put the metal in it, with earth
from Valenza, and over that with ashes.

[Footnote 1. 2.:
Terra di Valenza
.—Valenza is north of
Alessandria on the Po.]

When you see that the bronze is congealing take some willow-wood cut
in small chips and make up the fire with it.

I say that the cause of this congealing often proceeds from too much
fire, or from ill-dried wood.

You may know when the fire is good and fit for your purpose by a
clear flame, and if you see the tips of the flames dull and ending
in much smoke do not trust it, and particularly when the flux metal
is almost fluid.

Metal for guns must invariably be made with 6 or even 8 per cent,
that is 6 of tin to one hundred of copper, for the less you put in,
the stronger will the gun be.

The tin should be put in with the copper when the copper is reduced
to a fluid.

You can hasten the melting when 2/3ds of the copper is fluid; you
can then, with a stick of chestnut-wood, repeatedly stir what of
copper remains entire amidst what is melted.

Introductory Observations on the Architectural Designs (XII), and
Writings on Architecture (XIII).

Until now very little has been known regarding Leonardo's labours
in the domain of Architecture. No building is known to have been
planned and executed by him, though by some contemporary writers
incidental allusion is made to his occupying himself with
architecture, and his famous letter to Lodovico il Moro,—which has
long been a well-known document,—in which he offers his service as
an architect to that prince, tends to confirm the belief that he was
something more than an amateur of the art. This hypothesis has
lately been confirmed by the publication of certain documents,
preserved at Milan, showing that Leonardo was not only employed in
preparing plans but that he took an active part, with much credit,
as member of a commission on public buildings; his name remains
linked with the history of the building of the Cathedral at Pavia
and that of the Cathedral at Milan.

Leonardo's writings on Architecture are dispersed among a large
number of MSS., and it would be scarcely possible to master their
contents without the opportunity of arranging, sorting and comparing
the whole mass of materials, so as to have some comprehensive idea
of the whole. The sketches, when isolated and considered by
themselves, might appear to be of but little value; it is not till
we understand their general purport, from comparing them with each
other, that we can form any just estimate of their true worth.

Leonardo seems to have had a project for writing a complete and
separate treatise on Architecture, such as his predecessors and
contemporaries had composed—Leon Battista Alberti, Filarete,
Francesco di Giorgio and perhaps also Bramante. But, on the other
hand, it cannot be denied that possibly no such scheme was connected
with the isolated notes and researches, treating on special
questions, which are given in this work; that he was merely working
at problems in which, for some reason or other he took a special
interest.

A great number of important buildings were constructed in Lombardy
during the period between 1472 and 1499, and among them there are
several by unknown architects, of so high an artistic merit, that it
is certainly not improbable that either Bramante or Leonardo da
Vinci may have been, directly or indirectly, concerned in their
erection.

Having been engaged, for now nearly twenty years, in a thorough
study of Bramante's life and labours, I have taken a particular
interest in detecting the distinguishing marks of his style as
compared with Leonardo's. In 1869 I made researches about the
architectural drawings of the latter in the Codex Atlanticus at
Milan, for the purpose of finding out, if possible the original
plans and sketches of the churches of Santa Maria delle Grazie at
Milan, and of the Cathedral at Pavia, which buildings have been
supposed to be the work both of Bramante and of Leonardo. Since 1876
I have repeatedly examined Leonardo's architectural studies in the
collection of his manuscripts in the Institut de France, and some of
these I have already given to the public in my work on
"Les Projets
Primitifs pour la Basilique de St. Pierre de Rome",
P1. 43. In 1879
I had the opportunity of examining the manuscript in the Palazzo
Trivulzio at Milan, and in 1880 Dr Richter showed me in London the
manuscripts in the possession of Lord Ashburnham, and those in the
British Museum. I have thus had opportunities of seeing most of
Leonardo's architectural drawings in the original, but of the
manuscripts tliemselves I have deciphered only the notes which
accompany the sketches. It is to Dr Richter's exertions that we owe
the collected texts on Architecture which are now published, and
while he has undertaken to be responsible for the correct reading of
the original texts, he has also made it his task to extract the
whole of the materials from the various MSS. It has been my task to
arrange and elucidate the texts under the heads which have been
adopted in this work. MS. B. at Paris and the Codex Atlanticus at
Milan are the chief sources of our knowledge of Leonardo as an
architect, and I have recently subjected these to a thorough
re-investigation expressly with a view to this work.

A complete reproduction of all Leonardo's architectural sketches
has not, indeed, been possible, but as far as the necessarily
restricted limits of the work have allowed, the utmost completeness
has been aimed at, and no efforts have been spared to include every
thing that can contribute to a knowledge of Leonardo's style. It
would have been very interesting, if it had been possible, to give
some general account at least of Leonardo's work and studies in
engineering, fortification, canal-making and the like, and it is
only on mature reflection that we have reluctantly abandoned this
idea. Leonardo's occupations in these departments have by no means
so close a relation to literary work, in the strict sense of the
word as we are fairly justified in attributing to his numerous notes
on Architecture.

Leonardo's architectural studies fall naturally under two heads:

I. Those drawings and sketches, often accompanied by short remarks
and explanations, which may be regarded as designs for buildings or
monuments intended to be built. With these there are occasionally
explanatory texts.

II. Theoretical investigations and treatises. A special interest
attaches to these because they discuss a variety of questions which
are of practical importance to this day. Leonardo's theory as to the
origin and progress of cracks in buildings is perhaps to be
considered as unique in its way in the literature of Architecture.

Architectural Designs.

I. Plans for towns.

A. Sketches for laying out a new town with a double system of high-
level and low-level road-ways.

Pl. LXXVII, No. 1 (MS. B, 15b). A general view of a town, with the
roads outside it sloping up to the high-level ways within.

Pl. LXXVII, No. 3 (MS. B, 16b. see No. 741; and MS. B. 15b, see No.
742) gives a partial view of the town, with its streets and houses,
with explanatory references.

Pl. LXXVII, No. 2 (MS. B, 15b; see No. 743). View of a double
staircaise with two opposite flights of steps.

Pl. LXXVIII, Nos. 2 and 3 (MS. B, 37a). Sketches illustrating the
connection of the two levels of roads by means of steps. The lower
galleries are lighted by openings in the upper roadway.

B. Notes on removing houses (MS. Br. M., 270b, see No. 744).

741.

The roads
m
are 6 braccia higher than the roads
p s
, and each
road must be 20 braccia wide and have 1/2 braccio slope from the
sides towards the middle; and in the middle let there be at every
braccio an opening, one braccio long and one finger wide, where the
rain water may run off into hollows made on the same level as
p s
.
And on each side at the extremity of the width of the said road let
there be an arcade, 6 braccia broad, on columns; and understand that
he who would go through the whole place by the high level streets
can use them for this purpose, and he who would go by the low level
can do the same. By the high streets no vehicles and similar objects
should circulate, but they are exclusively for the use of gentlemen.
The carts and burdens for the use and convenience of the inhabitants
have to go by the low ones. One house must turn its back to the
other, leaving the lower streets between them. Provisions, such as
wood, wine and such things are carried in by the doors
n
, and
privies, stables and other fetid matter must be emptied away
underground. From one arch to the next

742.

must be 300 braccia, each street receiving its light through the
openings of the upper streets, and at each arch must be a winding
stair on a circular plan because the corners of square ones are
always fouled; they must be wide, and at the first vault there must
be a door entering into public privies and the said stairs lead from
the upper to the lower streets and the high level streets begin
outside the city gates and slope up till at these gates they have
attained the height of 6 braccia. Let such a city be built near the
sea or a large river in order that the dirt of the city may be
carried off by the water.

743.

The construction of the stairs: The stairs
c d
go down to
f g
,
and in the same way
f g
goes down to
h k
.

744.

Let the houses be moved and arranged in order; and this will be done
with facility because such houses are at first made in pieces on the
open places, and can then be fitted together with their timbers in
the site where they are to be permanent.

[9] Let the men of the country [or the village] partly inhabit the
new houses when the court is absent [12].

[Footnote: On the same page we find notes referring to Romolontino
and Villafranca with a sketch-map of the course of the "Sodro" and
the "(Lo)cra" (both are given in the text farther on). There can
hardly be a doubt that the last sentence of the passage given above,
refers to the court of Francis I. King of France.—L.9-13 are
written inside the larger sketch, which, in the original, is on the
right hand side of the page by the side of lines 1-8. The three
smaller sketches are below. J. P. R.]

_II. Plans for canals and streets in a town.

Pl. LXXIX, 1. and 2, (MS. B, 37b, see No. 745, and MS. B. 36a, see
No. 746). A Plan for streets and canals inside a town, by which the
cellars of the houses are made accessible in boats.

The third text given under No. 747 refers to works executed by
Leonardo in France._

745.

The front
a m
will give light to the rooms;
a e
will be 6
braccia—
a b
8 braccia —
b e
30 braccia, in order that the rooms
under the porticoes may be lighted;
c d f
is the place where the
boats come to the houses to be unloaded. In order to render this
arrangement practicable, and in order that the inundation of the
rivers may not penetrate into the cellars, it is necessary to chose
an appropriate situation, such as a spot near a river which can be
diverted into canals in which the level of the water will not vary
either by inundations or drought. The construction is shown below;
and make choice of a fine river, which the rains do not render
muddy, such as the Ticino, the Adda and many others. [Footnote 12:
Tesino, Adda e molti altri, i.e.
rivers coming from the mountains
and flowing through lakes.] The construction to oblige the waters to
keep constantly at the same level will be a sort of dock, as shown
below, situated at the entrance of the town; or better still, some
way within, in order that the enemy may not destroy it [14].

[Footnote: L. 1-4 are on the left hand side and within the sketch
given on Pl. LXXIX, No. I. Then follows after line 14, the drawing
of a sluicegate—
conca
—of which the use is explained in the text
below it. On the page 38a, which comes next in the original MS. is
the sketch of an oval plan of a town over which is written "
modo di
canali per la citta
" and through the longer axis of it "
canale
magior
" is written with "
Tesino
" on the prolongation of the
canal. J. P. R.]

746.

Let the width of the streets be equal to the average height of the
houses.

747.

The main underground channel does not receive turbid water, but that
water runs in the ditches outside the town with four mills at the
entrance and four at the outlet; and this may be done by damming the
water above Romorantin.