The Notebooks of Leonardo Da Vinci (46 page)

723.

Of the horse I will say nothing because I know the times. [Footnote:
This passage occurs in a rough copy of a letter to Ludovico il Moro,
without date (see below among the letters).]

724.

During ten years the works on the marbles have been going on I will
not wait for my payment beyond the time, when my works are finished.
[Footnote: This possibly refers to the works for the pedestal of the
equestrian statue concerning which we have no farther information in
the MSS. See p. 6.]

The project of the Trivulzio monument.

725.

[2] Cost of the making and materials for the horse [5].

[Footnote: In the original, lines 2-5, 12-14, 33-35, are written on
the margin. This passage has been recently published by G. Govi in
Vol. V, Ser. 3a, of
Transunti, Reale Accademia dei Linea, sed. del
5 Giugno, 1881,
with the following introductory note:
"Desidero
intanto che siano stampati questi pochi frammenti perche so che sono
stati trascritti ultimamente, e verranno messi in luce tra poco
fuori d'Italia. Li ripubblichi pure chi vuole, ma si sappia almeno
che anche tra noi si conoscevano, e s'eran raccolti da anni per
comporne, quando che fosse, una edizione ordinata degli scritti di
Leonardo."

The learned editor has left out line 22 and has written 3
pie
for
8
piedi
in line 25. There are other deviations of less importance
from the original.]

A courser, as large as life, with the rider requires for the cost of
the metal, duc. 500.

And for cost of the iron work which is inside the model, and
charcoal, and wood, and the pit to cast it in, and for binding the
mould, and including the furnace where it is to be cast … duc.
200.

To make the model in clay and then in wax……… duc. 432.

To the labourers for polishing it when it is cast. ……. duc. 450.

in all. . duc. 1582.

[12] Cost of the marble of the monument [14].

Cost of the marble according to the drawing. The piece of marble
under the horse which is 4 braccia long, 2 braccia and 2 inches wide
and 9 inches thick 58 hundredweight, at 4 Lire and 10 Soldi per
hundredweight.. duc. 58.

And for 13 braccia and 6 inches of cornice, 7 in. wide and 4 in.
thick, 24 hundredweight……. duc. 24.

And for the frieze and architrave, which is 4 br. and 6 in. long, 2
br. wide and 6 in. thick, 29 hundredweight., duc. 20.

And for the capitals made of metal, which are 8, 5 inches in. square
and 2 in. thick, at the price of 15 ducats each, will come to……
duc. 122.

And for 8 columns of 2 br. 7 in., 4 1/2 in. thick, 20 hundredweight
duc. 20.

And for 8 bases which are 5 1/2 in. square and 2 in. high 5 hund'..
duc. 5.

And for the slab of the tombstone 4 br. io in. long, 2 br. 4 1/2 in.
wide 36 hundredweight……. duc. 36.

And for 8 pedestal feet each 8 br. long and 6 1/2 in. wide and 6 1/2
in. thick, 20 hundredweight come to… duc. 20.

And for the cornice below which is 4 br. and 10 in. long, and 2 br.
and 5 in. wide, and 4 in. thick, 32 hund'.. duc. 32.

And for the stone of which the figure of the deceased is to be made
which is 3 br. and 8 in. long, and 1 br. and 6 in. wide, and 9 in.
thick, 30 hund'.. duc. 30.

And for the stone on which the figure lies which is 3 br. and 4 in.
long and 1 br. and 2 in., wide and 4 1/2 in. thick duc. 16.

And for the squares of marble placed between the pedestals which are
8 and are 9 br. long and 9 in. wide, and 3 in. thick, 8
hundredweight . . . duc. 8. in all. . duc. 389.

[33]Cost of the work in marble[35].

Round the base on which the horse stands there are 8 figures at 25
ducats each ………… duc. 200.

And on the same base there are 8 festoons with some other ornaments,
and of these there are 4 at the price of 15 ducats each, and 4 at
the price of 8 ducats each ……. duc. 92.

And for squaring the stones duc. 6.

Again, for the large cornice which goes below the base on which the
horse stands, which is 13 br. and 6 in., at 2 due. per br. ……
duc. 27.

And for 12 br. of frieze at 5 due. per br. ……….. duc. 60.

And for 12 br. of architrave at 1 1/2 duc. per br. ……. duc. 18.

And for 3 rosettes which will be the soffit of the monument, at 20
ducats each ………. duc. 60.

And for 8 fluted columns at 8 ducats each ……… duc. 64.

And for 8 bases at 1 ducat each, duc. 8.

And for 8 pedestals, of which 4 are at 10 duc. each, which go above
the angles; and 4 at 6 duc. each .. duc. 64.

And for squaring and carving the moulding of the pedestals at 2 duc.
each, and there are 8 …. duc. 16.

And for 6 square blocks with figures and trophies, at 25 duc. each
.. duc. 150.

And for carving the moulding of the stone under the figure of the
deceased ………. duc. 40.

For the statue of the deceased, to do it well ………. duc. 100.

For 6 harpies with candelabra, at 25 ducats each ……… duc. 150.

For squaring the stone on which the statue lies, and carving the
moulding ………… duc. 20.

in all .. duc. 1075.

The sum total of every thing added together amount to …… duc.
3046.

726.

It can also be made without a spring. But the screw above must
always be joined to the part of the movable sheath: [Margin note:
The mint of Rome.] [Footnote: See Pl. LXXVI. This passage is taken
from a note book which can be proved to have been used in Rome.]

All coins which do not have the rim complete, are not to be accepted
as good; and to secure the perfection of their rim it is requisite
that, in the first place, all the coins should be a perfect circle;
and to do this a coin must before all be made perfect in weight, and
size, and thickness. Therefore have several plates of metal made of
the same size and thickness, all drawn through the same gauge so as
to come out in strips. And out of [24] these strips you will stamp
the coins, quite round, as sieves are made for sorting chestnuts
[27]; and these coins can then be stamped in the way indicated
above; &c.

[31] The hollow of the die must be uniformly wider than the lower,
but imperceptibly [35].

This cuts the coins perfectly round and of the exact thickness, and
weight; and saves the man who cuts and weighs, and the man who makes
the coins round. Hence it passes only through the hands of the
gauger and of the stamper, and the coins are very superior.
[Footnote: See Pl. LXXVI No. 2. The text of lines 31-35 stands
parallel 1. 24-27.

Farther evidence of Leonardo's occupations and engagements at Rome
under Pope Leo X. may be gathered from some rough copies of letters
which will be found in this volume. Hitherto nothing has been known
of his work in Rome beyond some doubtful, and perhaps mythical,
statements in Vasari.]

727.

The incombustible growth of soot on wicks reduced to powder, burnt
tin and all the metals, alum, isinglass, smoke from a brass forge,
each ingredient to be moistened, with aqua vitae or malmsey or
strong malt vinegar, white wine or distilled extract of turpentine,
or oil; but there should be little moisture, and cast in moulds.
[Margin note: On the coining of medals (727. 728).] [Footnote: The
meaning of
scagliuolo
in this passage is doubtful.]

728.

A paste of emery mixed with aqua vitae, or iron filings with
vinegar, or ashes of walnut leaves, or ashes of straw very finely
powdered.

[Footnote: The meaning of
scagliuolo
in this passage is doubtful.]

The diameter is given in the lead enclosed; it is beaten with a
hammer and several times extended; the lead is folded and kept
wrapped up in parchment so that the powder may not be spilt; then
melt the lead, and the powder will be on the top of the melted lead,
which must then be rubbed between two plates of steel till it is
thoroughly pulverised; then wash it with aqua fortis, and the
blackness of the iron will be dissolved leaving the powder clean.

Emery in large grains may be broken by putting it on a cloth many
times doubled, and hit it sideways with the hammer, when it will
break up; then mix it little by little and it can be founded with
ease; but if you hold it on the anvil you will never break it, when
it is large.

Any one who grinds smalt should do it on plates of tempered steel
with a cone shaped grinder; then put it in aqua fortis, which melts
away the steel that may have been worked up and mixed with the
smalt, and which makes it black; it then remains purified and clean;
and if you grind it on porphyry the porphyry will work up and mix
with the smalt and spoil it, and aqua fortis will never remove it
because it cannot dissolve the porphyry.

If you want a fine blue colour dissolve the smalt made with tartar,
and then remove the salt.

Vitrified brass makes a fine red.

729.

Place stucco over the prominence of the….. which may be composed
of Venus and Mercury, and lay it well over that prominence of the
thickness of the side of a knife, made with the ruler and cover this
with the bell of a still, and you will have again the moisture with
which you applied the paste. The rest you may dry [Margin note: On
stucco (729. 730).] [Footnote: In this passage a few words have been
written in a sort of cipher—that is to say backwards; as in l. 3
erenev
for
Venere
, l. 4
oirucrem
for Mercurio, l. 12
il
orreve co ecarob
for
il everro (?) co borace
. The meaning of the
word before
"di giesso"
in l. 1 is unknown; and the sense, in
which
sagoma
is used here and in other passages is obscure.—
Venere
and
Mercurio
may mean 'marble' and 'lime', of which
stucco is composed.

12. The meaning of
orreve
is unknown.]

well; afterwards fire it, and beat it or burnish it with a good
burnisher, and make it thick towards the side.

Powder … with borax and water to a paste, and make stucco of it,
and then heat it so that it may dry, and then varnish it, with fire,
so that it shines well.

730.

Take of butter 6 parts, of wax 2 parts, and as much fine flour as
when put with these 2 things melted, will make them as firm as wax
or modelling clay.

Take mastic, distilled turpentine and white lead.

On bronze casting generally (731-740).

731.

Tartar burnt and powdered with plaster and cast cause the plaster to
hold together when it is mixed up again; and then it will dissolve
in water.

732.

Take to every 2 cups of plaster 1 of ox-horns burnt, mix them
together and make your cast with it.

733.

When you want to take a cast in wax, burn the scum with a candle,
and the cast will come out without bubbles.

734.

2 ounces of plaster to a pound of metal;— walnut, which makes it
like the curve.

[Footnote: The second part of this is quite obscure.]

735.

[Dried earth 16 pounds, 100 pounds of metal wet clay 20,—of wet
100,-half,- which increases 4 Ibs. of water,—1 of wax, 1 Ib. of
metal, a little less,-the scrapings of linen with earth, measure for
measure.] [Footnote: The translation is given literally, but the
meaning is quite obscure.]

736.

Such as the mould is, so will the cast be.

737.

Make a bunch of iron wire as thick as thread, and scrub them with
[this and] water; hold a bowl underneath that it may not make a mud
below.

Make an iron rod, after the manner of a large chisel, and with this
rub over those seams on the bronze which remain on the casts of the
guns, and which are caused by the joins in the mould; but make the
tool heavy enough, and let the strokes be long and broad.

First alloy part of the metal in the crucible, then put it in the
furnace, and this being in a molten state will assist in beginning
to melt the copper.

When the copper cools in the furnace, be ready, as soon as you
perceive it, to cut it with a long stick while it is still in a
paste; or if it is quite cold cut it as lead is cut with broad and
large chisels.

If you have to make a cast of a hundred thousand pounds do it with
two furnaces and with 2000 pounds in each, or as much as 3000 pounds
at most.

738.

If you want to break up a large mass of bronze, first suspend it,
and then make round it a wall on the four sides, like a trough of
bricks, and make a great fire therein. When it is quite red hot give
it a blow with a heavy weight raised above it, and with great force.

739.

If you wish for economy in combining lead with the metal in order to
lessen the amount of tin which is necessary in the metal, first
alloy the lead with the tin and then add the molten copper.

How TO MELT [METAL] IN A FURNACE.

The furnace should be between four well founded pillars.

The coating should not be more than two fingers thick, it should be
laid on in four thicknesses over fine clay and then well fixed, and
it should be fired only on the inside and then carefully covered
with ashes and cow's dung.

The gun being made to carry 600 Ibs. of ball and more, by this rule
you will take the measure of the diameter of the ball and divide it
into 6 parts and one of these parts will be its thickness at the
muzzle; but at the breech it must always be half. And if the ball is
to be 700 lbs., 1/7th of the diameter of the ball must be its
thickness in front; and if the ball is to be 800, the eighth of its
diameter in front; and if 900, 1/8th and 1/2 [3/16], and if 1000,
1/9th.