The Notebooks of Leonardo Da Vinci — Complete
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.
MINT AT ROME.
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.
POWDER FOR MEDALS.
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.
OF TAKING CASTS OF MEDALS.
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.
STUCCO.
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.
STUCCO.
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.
STUCCO FOR MOULDING.
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.
GLUE.
Take mastic, distilled turpentine and white lead.
On bronze casting generally (731-740).
731.
TO CAST.
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.
TO CAST BRONZE IN PLASTER.
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.
HOW CASTS OUGHT TO BE POLISHED.
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.
HOW TO REMOVE THE ROUGH EDGES FROM BRONZE.
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.
TO FACILITATE MELTING.
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.
TO PREVENT THE COPPER COOLING IN THE FURNACE.
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 LARGE CAST.
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.
HOW TO PROCEED TO BREAK A LARGE MASS OF BRONZE.
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.
TO COMBINE LEAD WITH OTHER METAL.
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.
OF THE THICKNESS OF THE COATING.
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.
OF THE THICKNESS OF THE GUN.
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.
OF THE LENGTH OF THE BODY OF THE GUN.
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.
OF THE THICKNESS OF SMALL GUNS.
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.
OF LUTING THE FURNACE WITHIN.
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.]
OF RESTORING THE METAL WHEN IT IS BECOMING COOL.
When you see that the bronze is congealing take some willow-wood cut
in small chips and make up the fire with it.
THE CAUSE OF ITS CURDLING.
I say that the cause of this congealing often proceeds from too much
fire, or from ill-dried wood.
TO KNOW THE CONDITION OF THE FIRE.
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.
OF ALLOYING THE METAL.
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.
WHEN THE TIN SHOULD BE ADDED TO THE COPPER.
The tin should be put in with the copper when the copper is reduced
to a fluid.
HOW TO HASTEN THE MELTING.
You can hasten the melting when 2/3ds of the copper is fluid; you