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Vasari on Technique
By Giorgio Vasari
Dover Publications, Inc.Copyright © 1960 Dover Publications, Inc.
All rights reserved.
Of the different kinds of Stone which are used by Architects for ornamental details, and in Sculpture for Statues; that is, Of Porphyry, Serpentine, Cipollaccio, Breccia, Granites, Paragon or Test-stone, Transparent Marbles, White Marbles and Veined Marbles, Cipollini, Saligni, Campanini, Travertine, Slate, Peperigno, Ischia Stone, Pietra Serena and Pietra Forte.
§ 1. The author's object in the Discussion of Architecture.
How great is the utility of Architecture it does not fall to me to tell, since the subject has been treated at length and most carefully by many writers. For this reason, leaving on one side the limes, sands, wood, iron armatures, mode of preparing the foundations, as well as everything else that is used in a building; disregarding also the questions of water and localities and sites, already enlarged on by Vitruvius and by our own Leon Battista Alberti, I shall only discuss, for the use of our artificers and for whoever likes to know, the essential qualities of buildings, and in what proportions they should be put together and of what parts composed in order to obtain that graceful beauty that is desired. In short, I shall collect all that seems to me necessary for the purpose in view.
§ 2. Of the working of hard stones, and first of Porphyry.
In order that the great difficulty of working very hard and compact stones may be clearly understood, we shall treat distinctly but briefly of every variety which our workmen handle, and first of porphyry. This is a red stone, with minute white specks, brought into Italy from Egypt, where it is generally believed that the stone when quarried is softer than it is after it has been exposed to rain, frost and sunshine; because all these influences make it harder and more difficult to work. Of this stone numberless works are to be seen, some of them shaped with the chisel, some sawn into shape, and some again gradually worked up by means of wheels and emery. There are many different examples in divers places; for instance, square, round, and other pieces smoothed for pavements, statues for edifices, a great number of columns large and small, and fountains with various masks, all carved with the greatest care. There are also sarcophagi still extant, with figures in low and half relief, laboriously wrought, as at the temple of Bacchus, outside Rome, by Sant' Agnese, where is said to be the sarcophagus of Santa Costanza, daughter of the Emperor Constantine, on which are carved many figures of children with grapes and vine-leaves, that testify how great was his labour who worked them in a stone so hard. There is another example in an urn, near to the door known as the Porta Santa in San Giovanni in Laterano, which is decorated with scenes containing a great number of figures. There is also in the piazza della Ritonda a very beautiful urn made for sepulchral purposes that is worked with great care and diligence. It is of extremely graceful and beautiful form, and is very different from the others. In the house of Egizio and of Fabio Sasso there used to be a seated figure, measuring three and a half braccia, preserved to our days with the remains of the other statues in the Casa Farnese. In the courtyard also of the Casa la Valle, over a window, is a she-wolf most excellently sculptured, and, in the garden of the same house, the two prisoners bound, each four braccia in height, executed in this same porphyry by the ancients with extraordinary skill. These works are lavishly praised to-day by all skilled persons, knowing, as they do, the difficulty the workers had in executing them owing to the hardness of the stone.
In our day stone of this sort is never wrought to perfection, because our artificers have lost the art of tempering the chisels and other instruments for working them. It is true that they can still, with the help of emery, saw drums of columns into slices, and cut other pieces to be arranged in patterns for floors, and make various other ornaments for buildings. The porphyry is reduced little by little by means of a copper saw, without teeth, drawn backwards and forwards between two men, which, with the aid of emery reduced to powder, and kept constantly wet with water, finally cuts its way through the stone. Although at different times many ingenious attempts have been made to find out the method of working porphyry used by the ancients, all have been in vain, and Leon Battista Alberti, the first to make experiments therein not however in things of great moment, did not find, among the many tempering-baths that he put to the test, any that answered better than goats' blood; because, though in the working it removed but little of that hardest of stones and was always striking sparks of fire, it served him nevertheless so far as to enable him to have carved, in the threshold of the principal door of Santa Maria Novella in Florence, the eighteen antique letters, very large and well proportioned, which are seen on the front of the step, in a piece of porphyry. These letters form the words BERNARDO ORICELLARIO. And because the edge of the chisel did not suit for squaring the corners, or giving the necessary polish and finish, he had a little revolving drill made, with a handle like a spit, which was easily worked by placing the said handle against the chest, and putting the hands into the crank in order to turn it. At the working end, instead of a chisel or bit, he fixed copper discs, larger or smaller according to need, and these, well sprinkled with emery, gradually reduced and smoothed the stone, producing a fine surface and finishing the corners, the drill all the while being dexterously twirled by the hand. But all this effort cost so much time, that Leon Battista lost heart, and did not put his hand to anything else, either in the way of statues, or vases, or other delicate work. Others, afterwards, who set themselves to smoothing stones and restoring columns by the same special process, have done it in this way. They make for the purpose large and heavy hammers, with the points of steel, keenly tempered with goats' blood, and worked in the manner of diamond points; with these they carefully tap on the porphyry, and ' scabbling ' it, or working it down, little by little the best way they can, finally reduce it, with much time and trouble, to the round or the flat, as the workman chooses,—not however to the form of statues, because of this we have lost the art—and they polish it with emery and leather, scouring it till there comes a lustre very clear and well finished.
Now although every day refinements are being made on human inventions, and new things enquired into, yet even the moderns, who from time to time have tried fresh methods of carving porphyry, various tempering-baths, and very carefully refined steels, have, as was said above, up till recent years laboured in vain. Thus in the year 1553 Pope Julius III, having been presented by Signor Ascanio Colonna with a very handsome antique porphyry basin, measuring seven braccia across, ordered it to be restored, for some pieces were missing, that it might adorn his vineyard: the work was undertaken, and many things tried by the advice of Michelagnolo Buonarroti and of other excellent masters, but after a great length of time the enterprise was despaired of, chiefly because it was found impossible to preserve some of the arrises, a matter essential to the undertaking: Michelagnolo, moreover, even though accustomed to the hardness of stones, gave up the attempt, as did all the others, and nothing more was done.
At last, since no other thing in our days was lacking to the perfection of our arts, except the method of satisfactorily working porphyry, that not even this should still be to seek, it was rediscovered in the following manner. In the year 1555, Duke Cosimo, wishing to erect a fountain of remarkable beauty in the court of his principal palace in Florence, had excellent water led there from the Pitti Palace and Garden, and ordered a basin with its pedestal to be made for the said fountain from some large pieces of porphyry found among broken fragments. To make the working of it more easy to the master, he caused an extract to be distilled from an herb, the name of which is unknown to me, and this extract had such virtue, that red-hot tools when plunged into it acquired the hardest possible temper. With the aid of this process then, Francesco del Tadda, the carver of Fiesole, executed after my design the basin of the said fountain, which is two and a half braccia in diameter, together with its pedestal, just as it may be seen to-day in the above-named palace. Tadda, judging that the secret imparted to him by the duke was very precious, set himself to put it to the test by carving something, and he has succeeded so well that in a short time he has made, in three ovals, life-size portraits in half-relief of Duke Cosimo and of the duchess Leonora, and a head of Christ, executed so perfectly that the hair and beard, most difficult to reproduce in carving, are finished in a manner equal to that of the ancients. The Duke was talking one day of these works with Michelagnolo when his Excellency was in Rome, and Buonarroti would not believe in them; therefore, by the Duke's order, I sent the head of Christ to Rome where it was seen by Michelagnolo with great wonder, who praised it highly and rejoiced greatly to see the sculpture of our time enriched by this rare gift, which until our day had been searched for in vain. Tadda has recently finished the head of the elder Cosimo de' Medici in an oval, like those mentioned above, and he has executed and continues to execute many other similar works.
All that remains to be said of porphyry is that, because the quarries are now lost to knowledge, it is necessary to make use of what is left of it in the form of ancient fragments, drums of columns and other pieces; and that in consequence he who works in porphyry must ascertain whether or not it has been subjected to the action of fire, because if it have, although it does not completely lose its colour, nor crumble away, it lacks much of its natural vividness and never takes so good a polish as when it has not been so subjected; and, what is worse, it easily fractures in the working. It is also worth knowing, as regards the nature of porphyry, that, if put into the furnace, it does not burn away (non si cuoce), nor allow other stones round it to be thoroughly burnt; indeed, as to itself, it grows raw (incrudelisce) as is shown in the two columns the men of Pisa gave to the Florentines in the year 1117 after the acquisition of Majorca. These columns now stand at the principal door of the church of San Giovanni; they are colourless and not very well polished in consequence of having passed through fire, as Giovanni Villani relates in his history.
§ 3. Of Serpentine.
After porphyry we come to serpentine, which is a green stone, rather dark, with little crosses long and yellowish all through its texture. The artificers busy themselves with making columns and slabs for pavements in edifices from it, in the same way as from porphyry. It is never seen carved into figures, although it is very often used for the bases of columns, the pedestals ot tables, and other works of a ruder kind. Though this sort of stone is liable to fracture, and is harder than porphyry, it is sweeter to work and involves less labour. Serpentine is quarried in Egypt and Greece and the sound pieces are not very large; consequently no work of greater dimensions than three braccia in any direction is ever seen of serpentine, and such works as exist are slabs and pieces of pavement. A few columns are found also but not very massive nor thick, as well as some masks and sculptured brackets, but figures never. This stone is worked in the same manner as porphyry.
§ 4. Of Cipollaccio.
Softer than serpentine is cipollaccio, a stone quarried in various places; it is of a crude yellowish green colour and has within it some square black marks, large and small, and also biggish white marks. Of this material one may see in various places columns both massive and slender, as well as doors and other ornaments, but not figures. There is a fountain of this stone in Rome in the Belvedere, that is to say a niche in a corner of the garden where are the statues of the Nile and of the Tiber; Pope Clement VII had this niche made, after a design by Michelagnolo, to adorn the statue of a river god that it might look very beautiful in this setting made in imitation of natural rocks, as indeed it actually does. Cipollaccio is also sawn into panels, round and oval, and into similar pieces which, when arranged with other stones in pavements and other flat surfaces, make lovely compositions. It takes a polish like porphyry and serpentine and is sawn in the same manner. Numberless pieces of it are found in Rome, buried under the ruins; these come to light daily and thus of ancient things modern works are made, such as doors and other ornamental details, which, wherever placed, are decorative and very beautiful.
§ 5. Of Breccia ('Mischio,' Conglomerate).
Here is now another stone, called 'mischio ' (breccia), from the mixture of various stones coagulated together and made one by time and by the mordant action of water. It is found in abundance in several places, as in the mountains of Verona, in those of Carrara, and of Prato in Tuscany, and in the hills of the Impruneta in the neighbourhood of Florence. But the best and choicest breccias have been found, not long ago, at San Giusto at Monte Rantoli, five miles distant from Florence. In this material Duke Cosimo has commissioned me to decorate all the new rooms of the palace with doors and chimney pieces, and the effect is most beautiful. Also for the garden of the Pitti, very fine columns seven braccia high have been quarried from the same place, and I am astonished that in this stone such large pieces should be found free from flaws. Being of the nature of limestone, it takes a beautiful polish and in colour inclines to a reddish purple streaked with white and yellowish veins. But the finest examples of all are in Greece and Egypt, where the stone is much harder than ours in Italy, and it is found in as many different colours as mother nature has delighted and still delights to produce in all perfection. In the breccias formed in this way one sees at Rome at the present day both ancient and modern works, such as columns, vases, fountains, door ornaments, and various inlays on buildings, as well as many pieces in the pavements. There are various sorts, of many colours; some draw to yellow and red, others to white and black, others again to grey and white speckled with red and veined with numerous colours; then there are certain reds, greens, blacks and whites which are oriental: and of this sort of stone the Duke has an antique urn, four and a half braccia across, in his garden at the Pitti, a thing most precious, being as I said of oriental breccia very beautiful and extremely hard to work. Such stones are all very hard, and exquisite in colour and quality, as is shown by the two columns, twelve braccia high at the entrance of St. Peter's in Rome, which support the first arcades of the aisles, one on each side. Of this stone, the kind which is found in the hills of Verona, is very much softer than the oriental; and in that place is quarried a sort which is reddish, and inclines towards a vetch colour. All these kinds are worked easily in our days with the tempering-baths and the tools used for our own local stones. Windows, columns, fountains, pavements, door posts and mouldings are made of them, as is seen in Lombardy and indeed throughout Italy.
§ 6. Of Granite.
There is another sort of extremely hard stone, much coarser and speckled with black and white and sometimes with red, which, on account of its grain and consistency, is commonly called granite. In Egypt it exists in solid masses of immense size that can be quarried in pieces incredibly long, such as are seen nowadays in Rome in obelisks, needles, pyramids, columns, and in those enormous vessels for baths which we have at San Pietro in Vincola, at San Salvadore del Lauro and at San Marco. It is also seen in columns without number, which for hardness and compactness have had nothing to fear from fire or sword, so that time itself, that drives everything to ruin, not only has not destroyed them but has not even altered their colour. It was for this reason that the Egyptians made use of granite in the service of their dead, writing on these obelisks in their strange characters the lives of the great, to preserve the memory of their prowess and nobility.
From Egypt there used also to come another variety of grey granite, where the black and white specks draw rather towards green. It is certainly very hard, not so hard however, but that our stonecutters, in the building of St. Peter's, have made use of the fragments they have found, in such a manner that by means of the temper of the tools at present adopted, they have reduced the columns and other pieces to the desired slenderness and have given them a polish equal to that of porphyry.
Excerpted from Vasari on Technique by Giorgio Vasari. Copyright © 1960 Dover Publications, Inc.. Excerpted by permission of Dover Publications, Inc..
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