Leonardo and the Last Supper (27 page)

The propulsion systems for these birdmen were simply the desperately flapping arms of the pilots. However, by the thirteenth century, mechanical wings were under investigation. The Franciscan friar Roger Bacon, a polymath known as Doctor Mirabilis, made notes on the mechanics of flight, speculating confidently on the possibilities of crank-operated flying machines. In about 1260 he maintained that “flying machines can be constructed so that a man sits in the midst of the machine revolving some engine by which artificial wings are made to beat the air like a flying bird.” He claimed that such devices “have long since been made, as well as in our own day,” including one by a “wise man” of his acquaintance, though any records of these machines have been lost.
⁴¹

One of Leonardo’s notes records his hunt for a printed edition of “Rugieri Bacho.”
⁴²
Perhaps inspired by Bacon’s description, he appears to have constructed his own mechanical flying machine in great secrecy on the roof of the Corte dell’Arengo: “Barricade the top room,” reads one of his notes, “and make a large and tall model.”
⁴³
He evidently planned to launch his prototype from the top of the castle, a place “more suitable in all respects than any other place in Italy.” The site was presumably advantageous because of its height and perhaps the air currents. But there was one disadvantage: he was concerned about workmen on the nearby cathedral (whose domed tower was being constructed) watching his machine take shape. He therefore found a sheltered spot on the roof where he believed he could work unobserved by prying eyes: “And if you stand upon the roof at the side of the tower the men at work upon the
tiburio
will not see you.”
⁴⁴

Leonardo may have been worried about prying eyes because he planned a death-defying flight as a surprise during one of Lodovico’s numerous festivals. A few years later, in 1498, as entertainment for a marriage feast, a mathematician from Perugia, Giovanni Battista Danti, would, according to legend, fashion a pair of wings and launch himself from the city’s tallest tower. To the amazement of the spectators, he sailed across the piazza before his steering mechanism malfunctioned and he crashed onto the roof of a church, breaking a leg but escaping with his life.
⁴⁵

No contemporary documents record that Leonardo’s
uccello
ever took flight. A half century later Gerolamo Cardano, whose father knew Leonardo in Milan, claimed the painter “tried to fly but in vain.”
⁴⁶
Cardano failed to tell where and when the test flight occurred, or why the test was unsuccessful, but a launch from the top of the Corte dell’Arengo seems unlikely. Leonardo’s researches into human aviation were far more sophisticated and advanced than any of the previous ones. He was also more mindful of safety, projecting the use of not only the wineskin lifejacket but also the equivalent of airbags: he hoped to lessen the impact of a crash by means of a series of bags “strung together like a rosary” and fixed to the pilot’s back.
⁴⁷
Even so, it is difficult to imagine his test flight having a happier outcome than those of earlier bird-men, especially if the launch pad was the parapet of a castle in the middle of a crowded city.

Leonardo at this point, in the mid-1490s, was full of optimism about the possibilities of flight. The reverse of the page detailing his plans for a flight from the Corte dell’Arengo shows a sketch of Europe (copied from Ptolemy’s
Cosmographia
) to which he added the words: “In the dream of the conquest of air the immense field open to the miraculous pilot.” All of Europe, in other words, lay at the feet of the miraculous pilot. But the year 1496 marks a temporary end to Leonardo’s studies of flight. After devoting himself to the subject for more than a dozen years, he abruptly ceased his investigations, possibly because of some catastrophic design failure, or else simply due to an awareness that his prototypes were simply not airworthy.

Leonardo would resume his studies some eight years later, back in Florence, when he began his
Codex on the Flight of Birds
. A note on the inside cover testifies to his continued hopes for human aviation: “The great bird will take its first flight on the back of his great swan, filling the universe with wonders; filling all writings with his fame and bringing eternal glory to his birthplace.”
⁴⁸
The “great swan” refers to Montececeri, a mountain outside Florence named for large birds,
ceceri
, that in turn took their name from a protuberance on their beaks shaped like a chickpea (
cece
). Here, above the rock quarries of Fiesole, Leonardo evidently hoped to launch one of his flying machines. Yet if his flight ever did occur, it failed to fill all the writings with his fame: no documentary evidence exists to support it.

CHAPTER 10
A Sense of Perspective

One of the first things Leonardo did after laying his base coat of lead white on the wall of Santa Maria delle Grazie was to hammer a nail into the plaster. This nail marked the very center of the mural, the point on which all lines and all attention would converge: the face of Christ.

A small hole is still visible in the right temple of Christ, like an eerie prevision of the crown of thorns. For Leonardo the nail marked what he called the “diminishing point”: the location on which all lines of sight “tend and converge.”
¹
Rediscovery of the laws of linear perspective revolutionized art during the fifteenth century. Artists learned to create spatially realistic scenes by making lines perpendicular to the picture plane (known as orthogonals) converge on a vanishing point, and by calculating the graduated scale at which horizontal lines (or transversals) recede into the distance. Leonardo wrote extensively on perspective, which he called “the daughter of painting.” He described it as the phenomenon by which “all objects transmit their image to the eye by a pyramid of lines.”
²
The eye was the vertex of
this visual pyramid, and the artist’s job was to capture in a painting precisely the diminution of scale and spatial relationship between objects seen by the eye in nature.

Leonardo created the most famous perspective drawing in history in the early 1480s when he made a pen-and-ink study for his
Adoration of the Magi
. It shows a geometrically rigorous mesh of lines through which swarm, in chaotic contrast to this rigid net, a host of ghostly human and equine figures. He must have done a similar drawing for
The Last Supper
, establishing how the orthogonals (such as the beams on the ceiling and the edges of the table) converge on the right temple of Christ. This drawing would then have been scaled up to create cartoons. But any perspective drawing of
The Last Supper
, like the cartoons and so many other sketches done for the mural, have long since vanished.

The only trace of Leonardo’s efforts to generate his perspective scheme are the nail hole and, radiating outward from it, the lines in the wall marking the orthogonals. The use of a nail and incised lines reveal how he was using a classic fifteenth-century fresco technique pioneered by the Florentine painter Masaccio in works such as
The Holy Trinity
(in Santa Maria Novella) and
The Tribute Money
(in the Brancacci Chapel). In both frescoes Masaccio fixed a nail into the point in the wall at which the orthogonals were to converge; he then attached a long string to the nail, stretched it tight, and “snapped” it into the wet plaster, leaving behind a radiating pattern of orthogonals that are still visible today.

The architectural space that Leonardo created for Christ and the apostles—a narrow, tapestry-hung room with a coffered ceiling and three windows—reveals something intriguing about his approach to design. He longed for (but was so far denied) architectural commissions. However, he had firm ideas about how to organize architectural space, and in
The Last Supper
he painted architectural features that were arranged according to musical harmonies worked out two thousand years earlier by Pythagoras.

As a musician who played and designed stringed instruments, Leonardo was sensitive to the potency of musical harmonies. Like a number of his contemporaries (Verrocchio among them) he believed these harmonies could be translated into optical space. A correspondence existed, as he saw it, between how we hear sounds and how we see objects: “I give the degrees of the objects seen by the eye,” he wrote, “as the musician does the notes heard by the ear.”
³
He was paraphrasing Leon Battista Alberti, who wrote that the same musical harmonies that please the ears “can also fill the eyes and mind with wondrous delight,” and that artists and architects therefore ought to apply the ratios of musical harmonics to their own creations. Leonardo was familiar with one such application: Verrocchio’s tomb slab for Cosimo de’ Medici, whose symmetrical geometrical forms have been found to express musical proportions.
⁴

Leonardo’s perspective scheme for
The Last Supper

An indication that Leonardo intended to use harmonic ratios to structure pictorial space comes from a sketch for
The Last Supper
—the one showing Christ offering the sop of bread to Judas—on which he jotted a series of numbers in a column. His notation reads 3.4.6. -6.3-6-4 = 32. He would have known from various sources that the musical scales could be expressed numerically, since pitch depended on variables such as length and weight of a musical instrument or its constituent parts. For example, if you cut a string in half, its pitch will be an octave higher than the note produced by
the whole string, with the octave therefore expressed by the ratio 1:2. Meanwhile two thirds of the whole length produces the tonal interval of a fifth (expressed by the ratio 2:3) and three quarters of the string a fourth (3:4).

Leonardo used these ratios in the module by which he designed the room in which Christ and the apostles sit, turning musical notes into a kind of visual music. The architectural features of his painting seem to be organized, at any rate, according to a series of units related to the tonal intervals. As one scholar has pointed out, the sequence of twos, threes, fours, and sixes on Leonardo’s drawing are intended to represent the ratios of, respectively, the fourth and fifth within the octave (3:4:6), the octave (3:6), and the fifth (4:6).
⁵

The Last Supper
does appear to reveal an arithmetical progression. For example, if the total width of the refectory wall is divided into twelve units, that of the coffered ceiling at the front of the picture plane is six units, giving a ratio of 1:2 (an octave). The width of the rear wall in the painting is four units, while that of the windows is three (that is, if the measured width is that between the centers of the two flanking windows rather than from their outside edges). Thus we have (with only a little bit of fudging) the ratios 12:6:4:3. Similar ratios can be found in the relationships between the tapestries on the wall in the painting. They are of unequal breadth, with those toward the rear of the room increasing according to the ratios 1:½:⅓:¼—offering (this time without any fudging) the mathematical intervals 12:6:4:3.
⁶

The influence of Verrocchio and Alberti lay behind this musical calibration of optical space. Leonardo probably did not believe, like some of his contemporaries, that these ratios were inherently divine. But, like Alberti, he no doubt believed that their application could bring “wondrous delight” to the eyes as well as to the ears.

Leonardo’s method of working makes it impossible to determine where exactly on the wall he first began painting. Frescoists normally worked their way systematically across a wall or vault, painting adjacent patches of plaster on consecutive days, working (as Pontormo’s diary revealed) on the right arm on Thursday, the left arm on Friday, and a thigh on Saturday. Leonardo had no desire to work in these discrete units. He approached the wall
in the same way that he tackled his panel paintings, on which his style was to work slowly and deliberately, layer by layer, touching and retouching, carefully contemplating the effects as he progressed.