Part 2

But Leonardo was not yet worrying about how to make himself a success. A young man of seventeen and still an apprentice of Verrochio, Leonardo continued to meet new friends with new ideas. It was at about this time that he met Benedetto Aritmetico, a prominent scholar and mathematician. It is probable that this man drew Leonardo’s attention to the practical needs of industry and commerce so that some of Leonardo’s energy was directed toward the study and improvement of existing machinery and the invention of labor-saving devices. At any rate, during these months Leonardo was walking the streets of Florence, wandering into shops and mills, making careful observations of all the various methods of manufacturing. The more he saw, the more he thought to himself that one man could do the work of many—if only he had the proper machine. He even made drawings of laborers with picks and shovels to see if he could determine by mathematics better ways to swing and hold the tools.

In addition, the particular problems in the engagement of joints fascinated Leonardo, leading him on to the study of more general problems such as the transmission of power by gears and the strength of materials. He also spent long hours studying geometrical theories and reading Greek and Latin classical works. Laboriously, he translated these into his own formulas and made comments about them in his notebooks. He attended the lectures of John Argyropoulos, a Greek, who talked of the Aristotelian theories of natural history, and who had translated Aristotle’s _Physics_.

The study of physics opened to Leonardo a whole new world of ideas. He experimented with cogwheels, and with the improvement of ways to lift weights. He became fascinated with the then-known laws of friction and built a bench upon which he tested various devices for the overcoming of frictional drag; he also tested the natural power of one body to set another in motion. This bench with its rollers and weights was similar in principle to the one used by the French physicist A. C. Coulomb almost three centuries later. Leonardo was indeed growing into a man of genius. Now everything from the stars to the flight of an insect occupied his thoughts.

At the same time, he continued his studies of drawing and painting. Frequently he was seen in Florence following someone whose face had interested him—sometimes for the better part of the day—and then at night he would fill a page with sketches of this same person from memory.

By developing his powers of observation in this way Leonardo came to rely more upon his own experiences and less upon what he was told or what he read. This brought him into frequent conflict with the astrologers, the alchemists and even the Church. The astrologers were men who told fortunes by the movements of the stars. The alchemists, with their knowledge of chemistry, pretended to be able to talk with ghosts and to tell the future. These men Leonardo held in contempt. Although he was a devoutly religious man, Leonardo objected to many attitudes of the Church which he considered outmoded and which stood in the way of scientific progress; because of these objections, he was frequently called a pagan.

In this same year of 1469, Leonardo met the aging Paolo del Pozzo Toscanelli. Toscanelli was a famous physician, philosopher and mathematician who, just the previous year, had marked off on the cathedral floor the famous meridian line for determining the dates of the various Church holidays. The old man and the boy became not only the famous teacher and ardent pupil, but close friends.

One evening at Toscanelli’s house, the old man showed young Leonardo a globe of the world. Much of it was marked “unknown,” but Toscanelli had filled in some areas from his own careful calculations and from the stories told him by sailors and travelers. Visions of distant lands, remote mountain ranges and vast oceans filled Leonardo’s imagination as Toscanelli spoke. Then Toscanelli tapped the globe to the westward of Spain, saying:

“Here will be found a quicker route to India than the world has ever known before.” Then, turning to Leonardo he murmured, “You will see it happen, my boy, in your lifetime.”

One by one, Leonardo’s childhood questions were being answered. Toscanelli told him much about the stars, the fossils of creatures long disappeared from the world, and how he believed the earth’s early formation took place. He also taught the boy the art of drawing a map. Not only did Toscanelli greatly influence Leonardo, but the course of history as well. Ten years after Toscanelli had died, Christopher Columbus, struggling westward over the Atlantic Ocean, was using a map that old Toscanelli had sent him, carefully notated with all his accumulated wisdom.

Leonardo, in keeping with his own philosophy, tested all this knowledge with experiments of his own. Because astronomical instruments were rare, crude, and costly, Leonardo borrowed them where he could and later set about making his own. He went on to experiment with time measurements, devising the first example of the application of a pendulum to regulate a clock; by means of two springs, it measured the minutes as well as the hours. So for the next three years Leonardo worked in Verrochio’s studio and continued his studies and experiments.

In 1472 Leonardo’s name was inscribed in the Red Book of the Painters of Florence, which was the official _guild_, or artists’ union of that time. But he was so poor that he couldn’t afford the dues and hardly had the money for the necessary candles to be burnt before St. Luke, the patron saint of all painters. Although his father now had a spacious apartment in a house on one of the main squares of Florence, Leonardo continued to live with Verrochio. In fact, he stayed on past his formal training period for about four more years, grateful to the kindly man for the food and bed he offered.

3 _A Studio of His Own_

On Sunday, April 26, 1478, the bells of the cathedral were ringing loudly over Florence, almost drowning out the noise of the crowds in the street. Shutters were being thrown open and people were shouting excited questions at each other. Distantly at first, but growing in volume, was another sound—an ugly one—the sound of an approaching, angry mob. Leonardo, holding a roll of drawings closer under his arm, stopped and listened.

Suddenly the questioning voices stopped. The bells continued ringing and now the angry shouts of the mob could be heard.

“Lorenzo is dead! Giuliano is dead! Death to traitors! Pazzi! Pazzi!”

“On to the Palace of the Signoria! They’ve captured the Archbishop! He’s a prisoner there!”

“Get a ram and we’ll break the door down!”

The people in the street were caught up in the surging mass. Already soldiers of the Medici were spreading out through the city. Cobblestones were ripped from the street, and swords, knives, and clubs were being brandished in the air.

Leonardo, backed against a wall of a house, was soon left in an almost deserted street. Still holding the drawings, he made his way carefully back to his studio.

As it turned out, Lorenzo was not dead at all.

It was on this Sunday that the Pazzi conspiracy had broken out in Florence. In the cathedral, the ailing Giuliano de’ Medici, brother of Lorenzo, was killed by assassins. Lorenzo himself escaped with only a scratched arm. The Pazzi family were rival bankers of the Medicis and had joined in this plot with Girolamo Riario, a relative of Pope Sixtus IV, and Francesco Salviati, a long-time enemy of Lorenzo. A hired professional thug completed the members of the conspiracy.

Girolamo Riario hated the Medicis because they refused him money for his own ambitions, and the Pope opposed Lorenzo because Lorenzo was supporting raids against papal territory. As for Archbishop Salviati, he had for years nursed a personal hatred for Lorenzo.

When the assassination attempt failed, the Archbishop and Francesco de’ Pazzi fled to the Palace of the Signoria for protection. However, the members of the Council of Florence, who were meeting, then became suspicious and bolted the doors after them. Both men were later killed by the Medici followers and their bodies were hung from the barred windows of the Palace. In the terror of the days afterward, eighty victims lost their lives. The Pazzi conspiracy also had an effect on Leonardo’s future, as we shall see later on.

Leonardo had been on his way to the Palace that morning. He had been given his first painting assignment, or commission, the previous January. This was to paint an altarpiece for the chapel of San Bernardo in the Palace, and just the month before he had received the sum of twenty-five florins as a partial payment.

Some time before January of 1478, Leonardo had left Verrochio and had found a place of his own. The commission had come to Leonardo through the influence of his father, who was now one of the leading notaries, or lawyers, of the city. Though still poor, Leonardo could now devote this new independence to his widening fields of study.

Leonardo’s studio was like his childhood room in one respect—it was still filled with all the different things that had aroused his curiosity. Books were everywhere—on his tables and shelves and piled on the floor—books by Ptolemy, Pliny, and Strabo on geography and natural history, by Aristotle on physics, even one by Guido, a tenth-century monk, who has been called the father of modern music. In addition, there were books on arithmetic, agriculture, geometry, grammar, philosophy, fables, poetry and even one containing jokes. A map of the world hung on the wall, together with his drawings; and, scattered throughout the whole studio were the plants, fossils, rocks and animal skeletons he was still collecting from his trips into the country.

There was also a huge table extending down the middle of Leonardo’s studio upon which were many drawings and instruments for working geometrical problems. His easel near the window supported a painting—a study for his commission in the Palazzo. And on his desk was a confusion of papers containing notes all written in his “secret” writing.

At twenty-six Leonardo was deep in the study of mechanical law, geometry, and botany. For example, he had observed the rings in trees and their relationship to the age of the trees. In mechanics, he was absorbed in drawing models of a “variable speed drive.” By meshing three cogged wheels of different diameters to a common lantern wheel, Leonardo saw that different speeds of rotation could be obtained at the same time. This same principle is used in the gear shift of modern automobiles. About mechanics Leonardo wrote that it was “the paradise of the mathematical sciences because by means of it one comes to the fruit of mathematics.”

Now, too, he was starting to write about his observations on the flight of birds, the formations of clouds and the behavior of smoke in the air. He compared the flying of birds to the swimming of fish in the sea, and the flow of air to the flow of water. Two hundred years before Newton, Leonardo would define the principles of aerodynamic reciprocity, as contained in Newton’s Third Law of Motion.

At this time, Leonardo had an idea for making the Arno river navigable all the way from Florence to Pisa by the addition of canals, thus giving Florence an outlet to the sea. He also had thoughts for the improvement of irrigation in order to make use of land that did not have enough water. Nothing that Leonardo saw in his day’s activities was too small to pass unnoticed and unquestioned. The flight of a butterfly, the stratification of rock in a cliffside, the shape of a mighty cumulus cloud, the turning of a carriage wheel on a bumpy road, the play of muscles in a farmer’s back, the curling of water around a rock in a stream—all of these aroused Leonardo’s curiosity. Continually, he studied these things and painstakingly drew them and wrote about them in his notebooks.

Unfortunately, Leonardo’s painting commission for the Palace of the Signoria was never completed. By the end of the year 1478, the Pope, angered by the killing of the Archbishop during the Pazzi conspiracy, had declared war on the Republic of Florence. Ferdinand, the King of Naples, was persuaded to help in this war against Florence and the Medicis. As the papal forces were approaching the fortresses on the Florentine hills, the Council of Florence discontinued Leonardo’s commission in order to conserve money for the defense of the city.

Disappointed though he was, Leonardo did not allow this setback to discourage him. From a page of drawings in the Uffizi Gallery of Florence on which are sketched various arms and war materials, we learn that he turned from his artistic to his mechanical skills and began designing engines of war. Besides being a Florentine concerned with the defense of his city, Leonardo was eager to gain an appointment with Lorenzo as military engineer to make up for the painting commission he had just lost. Also, as the fifteenth century was a turning point in the methods of waging war, Leonardo was attracted to all the mechanical possibilities of the new artillery. Before then soldiers had used spears, bows and arrows, and stone-throwing catapults, among other primitive methods. One of Leonardo’s designs included a light cannon whose barrel could be raised or lowered to proper elevation by means of a hand-cranked screw and whose horizontal direction could be determined by a maneuverable cradle.

The military appointment that Leonardo hoped for didn’t come. Unfortunately for the Medicis, the war with the papal forces was being lost. One by one, the fortresses under siege surrendered; more and more of the Florentine troops were fleeing.

Leonardo continued the work on his military machines for, although he was having some success painting Madonnas for private homes and had even received a commission from the King of Portugal for a tapestry design, he still wanted official recognition for his inventions from Lorenzo de’ Medici.

During these weeks late in the year of 1479, Leonardo conceived many ingenious devices to wage war. Besides the small artillery piece, he designed a _bombard_, or rock-throwing cannon, which did not recoil when it was fired. This was followed by a light gun arranged in three tiers of barrels, mounted so that while one tier was fired, the second was being loaded and the third was cooling (a forerunner of the modern machine gun). Another was a device to repel enemy ladders. It consisted of a horizontal beam laid parallel to the top of a fortress wall; the beam could be pushed outward by one man or several men using a system of pulleys.

Unfortunately for Leonardo, just as he was ready to show these inventions to Lorenzo de’ Medici, the last fortress outside Florence surrendered and a three-month truce followed. Lorenzo himself went to Naples and persuaded King Ferdinand to withdraw from the war. By 1480, peace returned once again to Florence.

As for the Medicis, military machines no longer interested them. Greatly disappointed at not having his inventions used—or even looked at—Leonardo began to search about for new fields of creative activity.

4 _Years Of Frustration_

The old monk spread the papers out before him on the table.

“Master Leonardo,” he said, “these are the terms of the commission. We at the monastery wish to have an altarpiece painted for our chapel. Your father has recommended you, and, as you know, he is our lawyer. Of course your reputation has already reached our ears, and we are satisfied in our choice.”

The year was 1480. The monk represented the monastery of San Donato a Scopeto near the Porta Romana, just outside Florence. Leonardo shook his head slowly at the terms of the commission. The painting had to be completed in thirty months at the most. Moreover, he must pay for his own colors and even—Leonardo looked up as if to protest but resumed reading—even pay for any gold or gold leaf he might use. Nevertheless, it was an opportunity, and Leonardo needed work. Since the papal war had ended, he had not received any commissions—and his skill at military engineering was still too unknown to have won him recognition.

Although Lorenzo de’ Medici was a great supporter of the arts and sciences, he had not granted Leonardo any of his patronage. In Lorenzo’s court were many men with much book-learning but little talent. They guarded their positions jealously and kept the way to Lorenzo barred to any applicant whom they did not like. Of them, Leonardo wrote in his notes: “They strut about puffed up and pompous, decked out and adorned, not with their own labors, but by those of others, and they will not even allow me my own. And if they despise me who am an inventor, how much more blame be given to themselves, who are not inventors but trumpeters and reciters of the work of others?”

In accepting the commission to paint the altarpiece, Leonardo hoped to attract attention to himself. Perhaps then Lorenzo might welcome him to his court and grant him patronage. So, with his usual thoroughness, Leonardo set about the task of preparing an Adoration of the Magi—a favorite subject of that time. This was to be a picture of the Holy Family surrounded by the three wise men from the East, shepherds and animals, old and young, rich and poor, paying their adoration to the Christ child.

Since he wanted his subjects perfect in every detail, Leonardo set about drawing countless youths, old men, sheep, oxen, horses, and donkeys. In a separate drawing for the background, he worked out with mathematical mastery the problems of perspective, that is, drawing objects to make them appear three-dimensional and either close or far away in space. In addition, he made studies for the composition of the whole picture—studies in which his knowledge of geometry was used to heighten the excitement of this great religious subject.

Among these sketches that Leonardo made for his “Adoration of the Magi” is a page on which appears an inspiration for one of his greatest masterpieces—a drawing of the “Last Supper.” And on this same page is another drawing—one of a hygrometer. A hygrometer is an instrument for measuring the amount of moisture in the air. Leonardo’s design consists of a simple, graded disk with a balanced pointer, weighted at one end with sand and at the other with a sponge or some salt. As the sponge or salt absorbed the moisture in the air, the added weight was indicated on the graded disk, thus measuring the amount of humidity.

Leonardo’s researches for the altar painting took him almost a year. Although the monks began to grumble at his slowness, Leonardo would not be hurried. He was determined to produce a painting that was perfect in all respects. To quiet their impatience Leonardo did odd jobs for them in the cloister. He repainted their old clock and for this extra work they advanced him some much-needed money. In March of 1481 Leonardo was ready to begin the actual drawing for the altarpiece. As he progressed with the composition, the monks crowded around with exclamations of delight. So different was it from all the other Adoration pictures they had ever seen, that the monks sent Leonardo some sacks of corn as a token of their appreciation.

One day, Leonardo was walking slowly toward the monastery over the Ponte Vecchio—the Old Bridge—across the Arno River. He made his way slowly up the hill past the construction for the new Pitti Palace. The morning was hot and the farmers moving into the city with their heavily laden carts were short-tempered. Leonardo stood to one side as he watched a pair of oxen straining to haul a wagon up a rise in the road. Their owner, his shirt unbuttoned to the waist, was shouting angrily, lashing the animals with his leather-thonged whip. It was a cruel sight and Leonardo turned away. From some experiments he had been making, Leonardo realized that the poor animals were struggling not only with the hill, but the drag of friction on the creaking axle. This drag could be eased, he thought to himself, by simply resting the axle in two sets of roller-bearings attached to the bottom of the cart near each wheel. In his mind he formed the plan for such a model as he made his way to the monastery.

The drawing of the altarpiece was nearing completion. The monks were fascinated by the spectacle of the Adoration appearing before their eyes. The soft, umber outlines deepened with gray, the ochre highlighting the central figures charmed them and they sent another gift to Leonardo’s house—a cask of Tuscan red wine.

As it turned out, Leonardo never finished this altarpiece. It is not known why. But the drawing for it can be seen today in the Uffizi Gallery in Florence just as Leonardo left it.

It is certain, however, that Leonardo was far from idle during this time. He drew the design for eliminating the friction of a turning axle by mounting the axle in roller-bearings. He experimented with, and solved the problem of, transmitting motion to revolving machine parts by friction—the possible forerunner of our modern friction clutch. Another device, found in modern automobiles—the differential—was also drawn by Leonardo. This idea provided for the difference in speed between the two drive wheels when rounding a curve.

Leonardo also drew the first known plans for a self-propelled vehicle—an “automobile.” It was designed to operate by a system of elastic springs wound by hand by the person on the vehicle; the “car” was then supposed to run the short distance allowed it by the unwinding of the springs.

In addition, Leonardo continued designing machines for both offensive and defensive military action. One of these was a breech-loading cannon, together with the first known projectiles that took into consideration better penetration through the air and greater stability in their trajectory. Indeed, these very much resembled present-day aerial bombs, with pointed noses and stabilizing fins.

As the months passed, however, Leonardo began to feel that his time and talents were being wasted in Florence. Although the monks and friends of the monastery were pleased with the work he was doing, other artists were being called to greater tasks in Rome. For example, Domenico di Tommaso del Ghirlandaio, Sandro Botticelli, and even Leonardo’s fellow student, Pietro Perugino, had left Florence to work in the chapel of Pope Sixtus IV in Rome—known to us as the Sistine Chapel. Now, too, it was becoming clear that Lorenzo and his court had no time for this solitary genius whose ideas stretched beyond his age.

So Leonardo looked about him. He was thirty years old and the walls of Florence seemed to bind his spirit. To what city could he go where his talents would be put to fruitful use? Rome seemed to hold out no hope, for no one had offered him a position there.

But Leonardo remembered that there had been a visitor to the Medicis from another city in recent months. This man was Ludovico Sforza, the ruling prince of Milan, the great city-state of the north. Ludovico, who was also called “Il Moro” (the Moor) because of his dark complexion, was seeking the friendship and alliance of the Medicis. He was fascinated with the art and culture of Florence and sought to gather to his own court of Milan as many artists, scientists, philosophers, and musicians as he could.