Sculpture 

'As practising myself the art of sculpture no less than that of painting, arid doing both the one and the other in the same degree! 

[Notes made in preparation for a statue] 

Of that at Pavia 1 the movement more than anything else is deserving of praise. 

It is better to copy the antique than modern work. 

You cannot combine utility with beauty as it appears in fortresses and men. 

The trot is almost of the nature of the free horse. 

Where natural vivacity is lacking it is necessary to create it fortuitously, c.a. 147 r. b 

The sculptor cannot represent transparent or luminous things. c.a. 215 v. d 

All the heads of the large iron pins. 2 c.a. 216 v. a 

How the eye cannot discern the shapes of bodies within their 
boundaries except by means of shadows and lights; and there are many 
sciences which would be nothing without the science of these shadows 
and lights: as painting, sculpture, astronomy, a great part of perspec- 
tive and the like. 

As may be shown, the sculptor cannot work without the help of 

1 The reference is to the antique bronze equestrian statue representing Odoacer, King 
of the Goths, according to the Anonimo Morelliano, Gisulf according to Antonio Campo 
the historian of Cremona, which was removed by Charlemagne from Ravenna to Pavia 
and stood in the Piazza del Duomo until the time of its destruction, which occurred in a 
revolutionary outbreak in 1796. It was called Regisole, the name being derived from the 
reflections of the sun's rays on the gilded bronze. Petrarch in a letter to Boccaccio says 
of it that 'it was looked upon as a masterpiece of art by all good judges'. 

2 The words are at the side of a drawing in red chalk representing a horse in an 
attitude of walking seen within a frame. 

shadows and lights, since without these the material carved would 
remain all of one colour; and by the ninth of this [book] it is shown 
that a level surface illumined by uniform light does not vary in any 
part the clearness or obscurity of its natural colour, and this uni- 
formity of colour goes to prove the uniformity of the smoothness of 
its surface. It would follow therefore that if the material carved were 
not clothed by shadows and lights, which are necessitated by the 
prominences of certain muscles and the hollows interposed between 
them, the sculptor would not be able uninterruptedly to see the prog- 
ress of his own work, and this the work that he is carving requires, 
and so what he fashioned during the day would be almost as though 
it had been made in the darkness of the night. 

OF PAINTING 

Painting, however, by means of these shadows and lights comes to 
represent upon level surfaces scenes with hollows and raised portions, 
separated from each other by different degrees of distance and in 
different aspects. c.a. 277 v. a 

Measurement of the Sicilian [horse], the leg behind, in front, raised 
and extended. c.a. 291 v. a 

OF STATUES 

If you wish to make a figure of marble make first one of clay, and 
after you have finished it and let it dry, set it in a case, which should 
be sufficiently large that — after the figure has been taken out — it can 
hold the block of marble wherein you purpose to lay bare a figure re- 
sembling that in clay. Then after you have placed the clay figure inside 
this case make pegs so that they fit exactly into holes in the case, and 
drive them in at each hole until each white peg touches the figure at 
a different spot; stain black such parts of the pegs as project out of the 
case, and make a distinguishing mark for each peg and for its hole, so 
that you may fit them together at your ease. Then take the clay model 
out of the case and place the block of marble in it, and take away 
from the marble sufficient for all the pegs to be hidden in the holes up 
to their marks, and in order to be able to do this better, make the case

so that the whole of it can be lifted up and the bottom may still remain 
under the marble; and by this means you will be able to use the 
cutting tools with great readiness. a 43 r. 

OF THE BLOW OF SCULPTORS 

Because the time of the blow is indivisible, like the contact caused by 
this blow, its operation is of such swiftness that time does not permit 
this blow to transfer itself to the foundations of the things struck with 
sufficient swiftness to prevent the blow being already dead in its upper 
parts, like the mason who breaks a stone in his hand with a hammer 
without violence or damage to the hand. 

And this is why, after the iron a b has been struck by the blow of 
the hammer in its upper part a, this part has obeyed the nature of the 
blow rather than transferred it to its base b, so that the extremity is 
enlarged more than the base. 

And from this it follows that sculptors work to better effect upon 
their marbles when they rough-hew with a pointed hammer than 
with a chisel struck by the hammer. 

A sharp sword will also cut a roll in the air. c 6 v. 

[Sculpture] 

When you have finished building up the figure you will make the 
statue with all its surface measurements. Quaderni in 3 r. 

Some have erred in teaching sculptors to surround the limbs of their 
figures with wires, as though believing that these limbs were of equal 
roundness at each part at which they were surrounded by these wires. 

Quaderni vi 10 r. 

Casting 

'0f the horse I will say nothing because I know* the times! 

. . . the cold will have sufficient thickness to touch the plaster, and 
you pour out the rest and fill with plaster and then break the mould, 
and put the iron pins across, boring through the wax and plaster, and 
then clean the wax at your leisure; afterwards put it in a case, and 
put a mould of plaster over it, leaving the air holes and the mouth for 
the casting. Through this mouth turn the mould upside down, and 
after it has been heated you will be able to draw out the wax contained 
within it; and you will be able to fill up the vacuum which remains 
with your liquefied material, and the thing cast will become hollow. 
But in order to prevent the plaster from becoming broken while being 
rebaked you must place within it what you know of. c.a. 352 r. c 

[With drawing of apparatus] 

This is the way in which the forms rapidly dry and are continually 
turned like roasts. Tr. 29 a 

HOW CASTS OUGHT TO BE POLISHED 

You should make a bunch of iron wire as thick as fine string and 
scrub them with it with water, but keeping a tub beneath so that it 
may not cause mud below. 

HOW TO REMOVE THE ROUGH EDGES OF THE BRONZE 

You should make an iron rod which may be of the shape of a large 
chisel, and rub it along the edges which remain upon the casts of the 
guns and which are caused by the joins in the mould; but see that the 
rod is a good weight and let the strokes be long and sweeping. 

TO FACILITATE THE MELTING 

First alloy part of the metal in the crucible and then put it in the 
furnace: this being in a molten state will make a beginning in the 
melting of the copper. 

TO GUARD AGAINST THE COPPER COOLING IN THE 

FURNACE 

When the copper begins to cool in the furnace proceed instantly as 
soon as you see this to slice it up with a stirring pole while it is in a 
paste, or if it has become entirely cold, cut it as you would lead with 
broad large chisels. 

FOR THE MAKING OF A LARGE CAST 

If you have to make a cast of a hundred thousand pounds, make it 
with five furnaces with two thousand pounds for each, or as much as 
three thousand pounds at most. Tr. 47 a 

HOW THE BOARD SHOULD BE PLACED WHICH SUPPORTS 

THE MORTAR 

The board that serves as a guide to the shape of the mortar ought 
therefore to be reduplicated from the centre backwards by the breadth 
of a great plank, to the end that it should not become twisted, and 
where this board has the impress of the frames and form of the cannon 
is the face not the edge, and when you add the tallow burnish this 
face with a pig's tooth so that it may be solid, and let the tallow be 
finely strained in order that as it turns it may not make marks. 

WHAT TO DO IN ORDER TO BREAK UP A LARGE MASS OF 

BRONZE 

If you wish to break a large mass of bronze suspend it first, then 
make a wall round it on the four sides in the shape of a hod for bricks, 
and make a great fire there; and when it is quite red-hot give it a blow 
with a great weight raised above it and do this with great force. 

1022 CASTING 

| With two sketches] 

OF CASTING MANY SMALL CANNON AT THE SAME TIME 

Make the courses for the bronze as is shown here just now; and keep 
d b c stopped up, but leave the course a entirely open; and when that 
is full unstop b, and when that is full unstop c, and then d\ and the 
door of the courses should be of brick, the thickness of three fingers 
and well covered with ashes and then it is opened with the pincers; and 
branches of the courses when they also are cast ought to be divided 
witn small plates of iron covered with earth before they are fastened. 

Tr. 48 a 

HOW TO MAKE LEAD COMBINE WITH OTHER METAL 

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

OF A NECESSITY FOR MELTING IN A FURNACE 
The furnace should be between four pillars with strong foundations. 

OF THE THICKNESS OF THE COATING 

The coating ought not to exceed the thickness of two fingers, and it 
ought to be laid on in four thicknesses over the fine clay and then well 
prepared, and it should be annealed only on the inside and then given 
a fine dressing of ashes and cattle dung. 

OF THE THICKNESS OF THE MORTAR 

The mortar ought to carry a ball of six hundred pounds and more, 
and by this rule you will take the measure of the diameter of the ball 
and divide it in six parts, and one of these parts will be its thickness 
at the muzzle, and it will always be half at the breech. And if the ball 
is to be of seven hundred pounds one seventh of the diameter of the 
ball will be its thickness at the muzzle, and if the ball is to be eight 

hundred it will be the eighth of its diameter at the muzzle, and if 
nine hundred one eighth and one half of it, and if one thousand one 
ninth. 

OF THE LENGTH OF THE TUBE OF THE MORTAR 

If you wish it to throw a ball of stone, make the length of the tube 
as six or up to seven times the diameter of the ball; and if the ball is 
to be of iron make this tube up to twelve times the ball, and if the ball 
is to be of lead make it up to eighteen times. I mean when the mortar 
is to have its mouth fitted to receive within it six hundred pounds of 
*cone ball and over. 

OF THE THICKNESS OF SMALL CANNON 

The thickness of small cannon at the muzzle ought not to exceed 
from a third to a half of the diameter of the ball, nor the length from 
thirty to thirty six times its diameter. Tr. 49 a 

OF LUTING THE FURNACE ON THE INSIDE 

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

OF RESTORING THE METAL WHEN IT SEEMS ON THE 
POINT OF COOLING 

When you see that the bronze is on the point of becoming congealed 
take wood of the willow cut into small chips and make up the fire 
with it. 

THE CAUSE OF ITS CONGEALING 

I say the cause of this congealing is often derived from there being 
loo much fire and also from the wood being only half-dried. 

TO KNOW THE CONDITION OF THE FIRE 

You will know when the fire is good and suitable by the clear flames, 
and if you see the points of these flames turbid and ending in much

smoke do not trust it, and especially when you have the molten metal 
almost in fluid state. 

WHAT KINDS OF WOOD ARE SUITABLE 

Wood is suitable when it is the young willow, or if willow cannot be 
procured get alder, and let each branch be young and well dried. 

OF ALLOYING THE METAL 

The metal used for bombards must invariably be made with six nr 
even eight parts to a hundred, that is six parts of tin to one hundred 
of copper, but the less you put in the stronger will be the bombard. 

WHEN THE TIN SHOULD BE ADDED TO THE COPPER 

The tin should be put with the copper when you have the coppet 
changed into a fluid state. 

HOW THE PROCESS OF MELTING MAY BE EXPEDITED 

You can expedite the process of melting when the copper is two- 
thirds changed to a fluid state. With a chestnut rod you will then be 
able frequently to manage to stir the remainder of the copper which 
is still in one piece amid the melted part. Tr. 50 a 

THE FINE EARTH OF THE BOMBARDS 

Take the dust of wool clippings and fix it on a wall in thin plaster 
so that it drives well. Then pound it and sift in fine powder, and to 
fifty parts of this powder add ten parts of brick, not over-baked 
and well pounded and sifted, also a small quantity of fine wool clip- 
pings or fustian cloth; and then to this compound add six parts of 
ashes which you will sift when moistened with water well salted; and 
this you will apply liquid and thin two or three times with a plasterer's 
brush, leaving it every time to dry without fire. Also it would be ad- 
visable to add first to this mixture ashes of burnt ox-dung moistened 
with salt water. 

OF THE TALLOW 

The tallow ought to be applied mixed with soot from a blacksmith, 
and as fine as you can, or if you desire ashes of ox-dung. 

OF THE FRAMES 

The frames should be made almost to the limit of the cord as though 
[one were winding] a peg-top, and above this the frames should be 
completed with fine earth and polished with the said tallow and soot, 
and the ornaments should be of wax. 

THE FRAME 

The frame of the tail ought to have as its final covering a square in 
which are brickdust and ashes with salt water. Or it is even better to 
apply ashes of ox-dung with salt water over the said frame. 

OF DIRECTING THE FRAME 

The frame should first be put in the trench with grappling-hooks as 
you saw before, then annealed little by little, emerging in the manner 
somewhat of the colour of brick {di poi lau [?] con uno negnietto) 
striking softly bit by bit, and where you hear it resound bind with 
iron wire, but in order not to go astray place it to turn everywhere. 

EARTH SUITABLE FOR GENERAL USE 

The earth to be generally used ought to be that of which bricks are 
made, mixed with ox-dung or clippings of woollen cloth. Tr. 51 a 

The bottom of the stove, three rows of unbaked bricks of ordinary 
clay and an inch and a half of ashes, the vault one layer of unbaked 
bricks of Valenza clay and another layer of baked bricks. 

Loose earth [?] x should be put with the ashes. 

The wood of the frame of the bombards should be covered an inch 
deep in cinders. 

1 MS. / calossi 

Hoare's Ital. Diet. art. loscio has terra loscia, loose earth. 

The mouth of the stove, that is where the flame enters, ought to be 
of large bricks of Valenza clay. 

Each of two flues ought to be for the half of the window for the en- 
trance of the flame. Tr. 54 a 

NOTES ON USE OF 'SAGOMA' 1 

Let the plumb-line be extended in two directions opposite to the 
centre of the poles a c, and let the plane surface be formed of plaster 
(MS. osseg^= gesso) little by little under the movement of the 
'sagoma'. 

And when the pavement is entirely finished the whole should be 
corrected again minutely with the 'sagoma'; and this 'sagoma' when 
used on the prepared surface (MS. otasseg = gessato) should be used 
with the greatest possible care. g 14 r. 

[Of friction of the sagoma] 

The friction of the polishing instrument against its surface ought 
not to be done with the edge of the instrument, except when first pre- 
paring the said surface. But when it is necessary to refine this surface 
then the instrument ought not to be of less width than half the sur- 
face. This may be proved: suppose / e d c to be the said polishing in- 
strument and f e n m the smoothed surface. I maintain that if this 
polishing instrument were to have only one cutting edge, as in d c 
with a b, it would have far greater weight when the perpendicular line 
was upon the part d c of the smoothed surface than when it was on 
the position / e of the said surface. And for this reason it would wear 
away the rubbed parts much more if it were straight than if it were 
slanting. And the concaveness of this surface would be unequal, such 
inequality as cannot be formed by the great contact of the polishing 
instrument with the surface which it polishes. 

But it would be better that the instrument and the surface should 
be the equal the one of the other, for when one of the sides of the in- 
strument was in the middle of the said surface its extremity would 
receive all the accidental weight of this instrument. 

1 A mould, also 'an instrument for smoothing and polishing a surface' — Ravaisson- 
Mollien. 

But the polishing instrument with one cutting edge is necessary, 
merely in order to give the form to its smoothed surface by means oi 
three or four movements, which should make it entirely perfect. 

c 16 r. 

The cogs that cause the movement of the sagoma set in their 
grooves. c 37 r. 

The sagoma should be as that used on the road of Fiesole — with 
water. 

Because it is necessary that in proportion as the said instrument is 
lowered so it wears itself away, and as after having been lowered it 
becomes very strong it is therefore necessary to make the pulleys with 
nuts so that screws turn within them, and that it shuts and opens be- 
tween a c as b shows between a c, and that these rings which form 
nuts for the screws should be drawn with the cords d e f g. c 43 v. 

VARNISH OF THE FIRED SURFACE 1 

Mercury with Jupiter and Venus : 2 after the paste has been made it 
should be worked upon the sagoma continully until Mercury is entirely 
separated from Jupiter and Venus. g 46 v. 

USE OF THE SAGOMA 

Let the concavity be pressed with the instrument first several times 
backwards and forwards before it is varnished, then the varnish should 
be applied to the moist surface, and go over it with the sieve; use the 
mould two or three times, then expose it to the furnace, and when it 
acquires lustre immediately apply the mould while it is hot. 

The centre of the revolution of the mould upon the structure ought 
to be fixed, and such that it can be raised and lowered, and moved 
forward and backward, so that its . . . falls upon the centre of the 
mould. 

The base of the oven should be of the same shape as that of the 
object placed in the oven; and it is well that it should be of one piece 

1 Vernicie della igna. 

2 i.e., according to Richter, quicksilver with iron and copper. 

of tufa stone, so that it can resist like an anvil the transverse percus- 
sion of the heavy mould which strikes it. c 47 r. 

Let the wood of the sagoma be well covered over with pitch (MS. 
otaicepni = inpeciato) so that it may not bend. c 51 v. 

In the polishing instrument there is a space left in order to be able to 
insert the lead moulding, and so that one may be able to change these 
from time to time as they are consumed. And so with the emery, one 
will guide the 'male' of the fired surface to perfection, and upon this 
one will afterwards print the copper (MS. emar = rame) after it has 
been made absolutely smooth. 

N> surface, is of Saturn 1 and it serves for the process of smoothing 
conjoined with the motive power, m below, in margin. 

The motive power is Neptune. 

This will keep the object to be polished below and the polishing in- 
strument above; and the pole will find itself above, and so this pole not 
being weighed down as is that of the instrument represented above 
will come to maintain itself, and as it is not able to consume itself the 
process will be complete. 

Moreover the thing polished will support above itself the substance 
which polishes it, and the polishing instrument being of lead may be 
recast and adjusted many times. 

The mould may be of Venus, Jupiter or Saturn, and often cast back 
into the lap of its mother, and it may be worked over with fine emery; 
and the mould may be of Venus and Jupiter plastered over Venus. 

But first you will put to the test Venus and Mercury mixed with 
Jupiter, and manage so that Mercury may escape, and then roll them 
up tightly so that Venus and Jupiter become blended in Neptune as 
thinly as possible. 

[Figure] 

This ought to be upside down, in order that the mould may weigh 
upon the surface it treats with a perpendicular weight. Thus the 
centre of the object in circumvolution will not consume itself, in order 
not to have the weight upon itself; and apart from this the polishing 
process will serve to receive and support it, as I have said in the first 
instance. g 53 r. 

1 Lead, Richtef. 

HOW TO MAKE A CURVE WHICH LEAVES THE 
PLATE PARALLEL PRECISELY 

Have a frame of stout walnut wood upon which build a square 
frame with raised centering, and upon this are fixed both ends of the 
drawn plate, which is separated at the end from the sides of the wall, 
carrying and holding with it all the plates that are nailed above. And 
this frame should always be with the above-mentioned dark plates. 

g 74 v. 

STUCCO 

Cover with stucco the boss of the . . . (ingnea?) of plaster, and let 
this be made of Venus and Mercury 1 and smear this boss well over 
with a uniform thickness of the blade of a knife, doing it with a rule 
(sagoma?) and cover this with the body of a bell so that it may drip, 
and you will have again the moisture with which you formed the 
paste: dry the rest well and then fire it, and beat or burnish it with a 
good burnisher, and make it thick towards the side. 

Powder the glass to a paste with borax and water, and make 
stucco; then drain it of? so as to dry it, then varnish it with fire so that 
it shines well. g 75 v. 

If you wish to make a large thin metal plate of lead, make a smooth 
level surface and fill it with glowing coals and melt lead in it, and then 
with a smooth rake take away the coals and allow it to cool and it is 
made. Forster n 46 v. 

When you wish to cast in wax burn off the scum with a candle and 
the cast will come without holes. 

Grind verdigris with rue many times together with juice of lemon 
and keep it from Naples yellow. Forster 11 64 v. 

The steel is first beaten well for the length, then broken in squares, 
and these are placed one above another and well covered with earth 
of Valenza and powdered talc, and it is dried over a slow fire and 
gradually heated; and when it has been thoroughly heated both inside 

1 Ingnea, Venus and Mercury are written backwards in the text, i.e. they appear as 
aengni, erenev and oirucrem. Dr. Richter suggests that Venus and Mercury may mean 
'marble' and 'lime' of which stucco is composed. 

and out then the fire exerts its force and makes it become molten. Bur 
first insert flakes of iron, then have the earth gradually removed and 
beat it lengthwise; and this is good steel. Forster in 33 v. 

Dry earth sixteen pounds; a hundred pounds of metal; moistened 
earth twenty; moisten the hundred of metal which adds four pounds 
of water; one of wax, one pound of metal somewhat less; cloth clip- 
pings with earth measure for measure. Forster in 36 

V. 

Two ounces of plaster to a pound of metal; [oil of] walnut eases it 
at the curve. Forster in 37 r. 

TO MAKE A PLASTER CAST FOR BRONZE 

Take for every two cupfuls of plaster one of burnt ox-horn, and 
mix them together and make the cast. Forster in 39 v. 

FOR CASTING 

Tartar burnt and powdered with plaster and used in casting causes 
such plaster to adhere together when it is annealed; then it is dis- 
solved in water. Forster in 42 v. 

For mirrors, thirty of tin upon a hundred of copper; but first clarify 
the two metals and plunge them in water and granulate them, and 
then fuse the copper and put it upon the tin. Forster in 87 v. 

MOULD OF THE HORSE 

Make the horse upon legs of iron, strong and firm in a good founda- 
tion. Then rub it with tallow and give it a good coating, letting it dry 
thoroughly layer by layer. And by this you will increase its thickness 
by the breadth of three fingers. Then fix and bind it with iron ac- 
cording to need. Besides this hollow out the mould, then get it to the 
required thickness, and then fill up the mould again by degrees and 
continue until it is entirely filled. Then bind it round with its irons 
and strap it up, and anneal it on the inner side where it has to touch 
the bronze. 

OF MAKING THE MOULD IN PIECES 

Mark upon the horse when finished all the pieces of the mould with 
which you wish to cover the horse, and after the clay has been laid on 
cut it to correspond in every piece, so that when the mould is finished 
you can take it off and then replace it in its first position with its 
catches by the countersigns. 

The square block a b will go between the cover and the core, that is 
in the hollow space where the liquefied bronze is to be; and these 
square blocks of bronze will keep the spaces between the mould and 
the cover at an equal distance, and for this reason these blocks are of 
great importance. 

The clay must be mixed with sand. 

Take wax to give back and to pay for what has been used. 

Dry one layer after another. Make the outer mould of plaster in 
order to save time in drying and the cost of wood; and with this 
plaster fasten the iron bands outside and inside for a thickness of two 
fingers; make terra cotta. 

And this mould you will take a day to make; half a boat-load of 
plaster will serve you. 

Good. 

Stop it up again with paste and clay, or white of egg and brick and 
rubble. Windsor: Drawings 12347 r * 

Three irons which bind the mould 1 

If you wish to make casts rapidly and simply, make them with a 
box of river sand moistened with vinegar. 

After having made the mould upon the horse you will make the 
thickness of the metal in clay. 

Note in alloying how may hours are needed for each hundred- 
weight. In casting each keep the furnace with its fire closed up. Let 
all the inside of the mould be saturated with linseed oil or turpentine. 
Then take a handful of powdered borax and hard rosin with aqua 
vitae and put a coat of pitch over the mould so that while under- 
ground the damp may not [injure it?]. 

In order to manage the large mould make a model of the small 
mould; make a small room in proportion. 

I have followed Richter's order of arrangement in this passage. 

Make the vents in the mould while it is upon the horse. 

Hold the hoofs in tongs and cast them with fish-glue. 

Weigh the parts of the mould to find out what amount of metal it 
will take to fill them, and give so much to the furnace that it may 
supply each part with its quantity of metal; and this you will ascer- 
tain by weighing the clay of that part of the mould to which the 
quantity in the furnace has to correspond. And this is done so that the 
furnace that is for the legs fills them and does not have to supply 
metal for the head from the legs which would be impossible. 

Cast at the same casting as the horse the little door (sportello) of 
the .... Windsor: Drawings 12350