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diff --git a/old/54827-8.txt b/old/54827-8.txt deleted file mode 100644 index a6e337e..0000000 --- a/old/54827-8.txt +++ /dev/null @@ -1,4884 +0,0 @@ -The Project Gutenberg EBook of Leonardo da Vinci, Pathfinder of Science, by -Henry Sampson Gillette - -This eBook is for the use of anyone anywhere in the United States and most -other parts of the world at no cost and with almost no restrictions -whatsoever. You may copy it, give it away or re-use it under the terms of -the Project Gutenberg License included with this eBook or online at -www.gutenberg.org. If you are not located in the United States, you'll have -to check the laws of the country where you are located before using this ebook. - -Title: Leonardo da Vinci, Pathfinder of Science - -Author: Henry Sampson Gillette - -Release Date: June 2, 2017 [EBook #54827] - -Language: English - -Character set encoding: ISO-8859-1 - -*** START OF THIS PROJECT GUTENBERG EBOOK LEONARDO DA VINCI, PATHFINDER OF SCIENCE *** - - - - -Produced by Stephen Hutcheson and the Online Distributed -Proofreading Team at http://www.pgdp.net - - - - - - - [Illustration: _Portrait of Leonardo da Vinci, after a woodcut - published in_ Lives of the Painters, _by Vasari. The Latin - inscription reads_ - LIONARDO DA VINCI PITT. E SCVLTOR FIOR. - _Leonardo da Vinci, Painter & Sculptor of Florence._] - - - - - _Immortals of Science_ - - - - - LEONARDO - DA VINCI - _Pathfinder of Science_ - - - _Henry S. Gillette_ - - PICTURES BY THE AUTHOR - - - _Franklin Watts, Inc., 575 Lexington Avenue - New York 22, New York_ - - - _To my wife Trudy_ - - FIRST PRINTING - - _Library of Congress Catalog Card Number: 62-8426_ - Copyright © 1962 by Franklin Watts, Inc. - _Manufactured in the United States of America_ - - DESIGNED BY BERNARD KLEIN - - -AUTHOR'S NOTE - -It is natural that, within the confines of these few pages, many facets -of Leonardo's extraordinary personality will be missing. That he was an -artist, a man of letters, a poet and a philosopher are well known. That -he was also a man of humor, as well as a prophet whose vision extended -far beyond his times, are facts that I have also tried to include in -this biography. There are many gaps in our knowledge of his life, and -these I have sometimes filled with my own imagination to give some -continuity to his story. Little is known of his early days, his period -of travels after leaving Milan and his years in Rome. There is, too, a -certain mystery in his relations to those around him, since our -descriptions of him derive mostly from his often cryptic, personal notes -and from biographers who wrote of him many years after he had died. - -This book is about Leonardo the scientist, and to fully write of his -many accomplishments would require an encyclopedic mind. My intent has -been to extract the essence of his story in the hopes that it would -arouse the enthusiasm of a reader to further his interest in those -other, more fully documented books--and, above all, in the notebooks -that Leonardo himself wrote. - - --H. S. G. - - _Rome, August 1961_ - - - - - _Contents_ - - - 1 _The Shield_ 1 - 2 _Florence_ 9 - 3 _A Studio of His Own_ 20 - 4 _Years of Frustration_ 28 - 5 _Milan_ 37 - 6 _The Monument_ 49 - 7 _Success_ 60 - 8 _The French_ 73 - 9 _Cesare Borgia_ 86 - 10 _Shattered Hopes_ 98 - 11 _The Return to Milan_ 114 - 12 _Rome_ 129 - 13 _The Last Years_ 147 - 14 _Mankind's Debt to Leonardo_ 159 - _Significant Dates in Leonardo's Life_ 162 - _Index_ 164 - - - - - 1 - _The Shield_ - - -Dusk was beginning to gather in the valley at the foot of Monte Albano -as young Leonardo turned toward home. Stopping by a rushing stream to -wash the dust of the day's explorations from his face, he laid aside his -cap and his leather pouch and plunged his hands into the cold mountain -water. He felt the force of the current and watched the whirl and flow -of bubbles around his bare arms. There was the same feeling, he thought, -to the flow of air he had experienced blowing around the rocky crags of -the mountains. - -This evening, however, there was no time to sit awhile and think. He was -in a hurry to get home. Hastily scooping the water in his cupped palms, -he splashed it over his head and face, then shaking the water from his -hair he rose and picked up his cap. He took a satisfied look in his -pouch, slung it over his shoulder and headed down the stony trail to the -village of Vinci. - -Vinci was a small hill town situated on a spur of Monte Albano. Its -castle and the bell tower above the houses seemed like sentinels -guarding the slopes of vineyards and olive groves spreading down into -the valley. - -Leonardo da Vinci, which means "Leonardo from the town of Vinci," -thought about his home. He knew that he had been born in Anchiano, near -Vinci, on April 15 of the year 1452, to a peasant girl named Caterina. -At the age of five, he had been sent for by his natural father, Piero da -Vinci, to come and live at his family's house in Vinci, a comfortable -and roomy place with a spacious garden. Piero, five years before, had -married Albiera di Giovanni Amadori, a girl of sixteen. They had had no -children of their own, and Leonardo was welcomed into the home with -affection by his young stepmother. - -When Leonardo was about eleven, young Albiera died, leaving a darkened -and saddened house. Two years later his father married another girl by -the name of Francesca Lanfredini. Although laughter and song soon -replaced the grief, Leonardo never forgot the love of his first -stepmother. - -Also in the house lived Antonio, his grandfather, who was eighty-five, -his grandmother, his uncle Allessandro Amadori and family, and, best of -all, his uncle Francesco. The da Vincis, who could trace their -beginnings in the town back to the thirteenth century, had always been -respected lawyers and landowners. Because Uncle Francesco was neither a -lawyer nor a great landowner, the people of the town said he did -nothing; but he tended the family vineyards, and, to the delight of -Leonardo, he raised his own silkworms. - -As Leonardo entered the main gate, he noticed that the oil lamps were -being lit above the stalls of the marketplace, and the lively confusion -of the last hours of business was in full swing. People nodded and -smiled to him, for as a boy of fifteen he was already a striking figure. -He was tall with long, auburn hair falling to his shoulders and his face -was so charming that it was frequently compared to those of the angels -painted in the chapels of the church. The music of his lute, the sound -of his voice, and the gentleness of his person were such that all hearts -and doors were open to him. - -Tonight, however, Leonardo avoided the usual invitations to stop and -chat. His father would be back from Florence; he had been going there -more and more frequently as his fame as a lawyer grew. Now Leonardo was -thinking that he had almost finished the assignment his father, half -jokingly, had given him many weeks ago--so many weeks ago that he was -sure his father had forgotten about it. At that time a peasant, whose -skill in providing fish and game for the table of Piero's big household -was greatly appreciated, had asked a favor of him. This man had a round, -wooden shield cut from a fig tree and he had asked Piero to have a -design painted on it for him in Florence. Piero, who had noticed the -sketches his son was making of plants, rock formations, and scenes in -his wanderings about the countryside, decided to test his son's ability -and gave the shield to the boy. In the secrecy of his room, into which -no one was allowed, Leonardo had smoothed and prepared the wood, and on -it he was painting a monster. - -Scrambling over rocks, through streams, and into caves, Leonardo had -been in the habit of gathering all manner of creeping and crawling life. -Patiently he would bring these home in his leather pouch and carefully -study and draw them. Maggots, bats, butterflies, locusts, and snakes -added to the confusion of the boy's already cluttered room. Everywhere -he went he collected the things that aroused his curiosity; and as a -result, his room was always filled with rocks, dried plants, flowers, -the skeletons of small animals--and his pages of notations and drawings. -Now Leonardo had combined the features of these small forms of life to -make a monster--emerging from a dark grotto and breathing fire and -smoke--a thing more terrifying than if done from imagination, for each -feature was a duplicate of a reality in nature. - -Unobserved, Leonardo reached the privacy of his room and emptied this -day's collection on a table beside the shield. He lit a candle and -examined his catch--a lizard and a large grasshopper. These would -complete his picture; and, the most extraordinary find of the day--a -fossil seashell found high on the slopes of a mountain! How did it get -there? Was it a result of the flood about which his religion had taught -him? Had an immense wave deposited this ancient sea-life high on the -Albano mountains? Looking more closely he saw that it was a type of -sea-snail and in almost perfect preservation. This he would have to -think about and examine later. - -Now, however, the picture must be completed, for he hoped to surprise -his father in the morning. But just then, Leonardo heard the family -stirring below and his father calling him to dinner. Reluctantly he left -his table, made himself presentable and went downstairs. - -"Ah, Leonardo," his father said when he appeared in the family dining -room. "I saw Benedetto dell'Abbaco on the way in town and he tells me -you haven't been to school as often as you should--is that true?" - -"Yes, Papa--but I'm not doing badly." - -"Signor Benedetto might agree, at least in your mathematics. He tells me -you ask him questions that often make him stop and think. But Leonardo, -you have other subjects--Latin, reading, and writing--as well as -arithmetic. You mustn't neglect the others, my boy. But come--let us -eat." - -Together they sat down with the rest of the family--a large, prosperous, -and happy gathering. When dinner was over Leonardo made hurried excuses -to all the family, protesting that he was too tired to sing, and escaped -back into his room. For a long time he worked, unaware that the house -was growing quieter. Finally he laid down his brushes and his maul -stick, pushed his chair back and smiled a triumphant smile. The shield -was finished. Tomorrow he would ask his father in to look at it. - -Conscious now that everybody had gone to bed, Leonardo blew out his -candle and opened the shutters. The night sky was a panoply of stars and -only here and there was the dark loneliness of the valley relieved by -pinpoints of light. Leonardo leaned his head against the window frame -and stared at the blue infinity above him. What exactly were the stars? -Did all of them move around the earth? What was the haze that obscured -the horizon ever so faintly? What was that sea-snail doing in the -mountains? Why? How? - -The next morning Leonardo found his father and Uncle Francesco in the -garden deep in conversation about their vineyards and olive groves. - -"Papa, I have a surprise for you up in my room--can you come now?" - -"Yes, Leonardo. What is it you have found now--not a better way to raise -my grapes, I'll wager!" - -The elder da Vinci put his arm around the boy's shoulder and went with -him up to the door of his room. - -"Wait here, Papa, until I say to come in." - -Leonardo unlocked his door, lifted the cloth from the shield standing on -the easel and opened the shutter just a trifle so that a soft light -filled the room. - -"Papa--you can come in now." - -Piero entered--he had long forgotten the round piece of wood--and -suddenly he froze in the middle of the room. - -"Have mercy on me!" he said when he saw the horrible fire-breathing -creature. In the dimness of the room, the monster and the murky cave -from which it was emerging were terribly real. Piero actually started to -back out of the room in fright, when Leonardo laid a hand on his -shoulder. - -"Papa, this work has served its purpose; take it away, then, for it has -produced the intended effect." - -The shield was the talk of the house; it was set up and marveled at. As -for Piero, he resolved to take it with him to Florence secretly and sell -it, giving his peasant friend some cheap substitute that he would buy in -the marketplace. - -So, a few days later, Leonardo's father saddled his horse and had the -shield wrapped and packed in his saddlebag. Also, unknown to his son, he -took some of the boy's drawings. Piero had now realized that Leonardo -might have a rare talent. Moreover, he was planning to move to Florence -with his family so that he could be nearer to the Badia, or the law -offices of the city, for whom he had been frequently employed. There, -thought Piero, Leonardo's talent could be developed under the best of -teachers. - -It was many days before Leonardo's father returned; when he did, he -gathered his family together and it was obvious to all that he had -exciting news. First, Piero announced that he and Francesca would move -to Florence since he and a law partner were now engaged in securing -office space from the Badia. It was a handsome office centrally located -opposite the palace of the _Podestà_, or chief magistrate. - -Then, turning to Leonardo, he said: "I have shown some of your drawings -to Master Andrea del Verrochio and his enthusiasm for your skill has -decided me to place you in his studio as an apprentice. What do you -think of that?" - -Leonardo was stunned. Verrochio, the great artist and sculptor! -Florence! The city-state whose power and influence had spread far beyond -her own walls. Now he would study in earnest; now he would find the -answers to his never-ending questions. He embraced his father and could -say nothing. - - - - - 2 - _Florence_ - - -The Italy of Medieval and Renaissance days was not a unified country as -it is today. It was, of course, part of the Holy Roman Empire, but the -main governing forces in the land were in the city-states, of which -Florence was one of the most powerful. A city-state was much more than a -city--it was almost a kingdom in itself. Each had its own army, and very -often there were large-scale wars between such city-states as Milan, -Naples, Rome, Venice--and of course Florence. The Italians of those days -considered themselves citizens--not of Italy as a whole--but of their -particular cities; people coming from other cities were looked upon as -"foreigners," even though they looked the same, wore the same style of -clothing, and spoke the same language! - -All the power, influence, and ideas of this period in history were -concentrated within the city-states. A man might be a very fine artist, -engineer, or philosopher, but unless he managed to bring his work to the -attention of the ruler of one of the cities, he was likely to remain in -obscurity. Thus it was that Piero da Vinci, knowing that his son would -have to have a powerful patron if he was to succeed at all, brought -Leonardo to Florence. - -In 1467, when the da Vinci family entered Florence, the city had been -under the rule of the Medici family for some thirty-three years. As it -was in most of these city-states, the head of the ruling family--at this -time Piero de' Medici--was in charge of the government of Florence and -the surrounding countryside. But Piero was fifty-one years old and -ailing, and he had only two years of life left at the time of Leonardo's -arrival. - - -None of this was in Leonardo's mind as he rode with his father through -one of the great, guarded gates of the city. He was thinking, not of -politics, but of the fabulous sights that awaited him in this rich -center of commerce and activity. - -The narrow streets of the city were so crowded that is was necessary for -the da Vinci family, together with their servants and the donkeys laden -with household effects, to go single file. Leonardo rode behind his -father, shouting questions, and, at the same time, turning his head from -side to side so as not to miss a thing. Brought up in the solitude of -mountains and valleys, and accustomed to the quiet life of a village, -the boy of fifteen was overwhelmed with the excitement of the city. - - [Illustration: _Leonardo rode behind his father, turning his head - from side to side so as not to miss a thing._] - -The party was now making its way past the booths of hundreds of shops, -past magnificent palaces built by wealthy merchants, and across squares -filled with the produce from hundreds of farms. Every now and then, -Leonardo caught a glimpse of the cathedral dome, one of the -architectural marvels of its day. He had seen the cathedral with its -bell tower and also the towering spire of the Palazzo della -Signoria--which means the Palace of the Lords--from a hill as they -approached the city. This palace still stands and today it is called the -Palazzo Vecchio or Old Palace. But now these sights were lost to view in -the midst of the narrow streets, other churches, flags, and the lines of -washing that seemed to hang everywhere. Frequently, Piero's party was -pressed against a wall as a procession shoved its way through a street. -Sometimes it was by armed horsemen escorting a rich banker to some -appointment; other times it was a file of cowled monks observing some -saint's day and carrying huge wax candles before them. - -After they had crossed the magnificent square of the Signoria, in front -of the Palace of the same name, Piero leaned down from his horse and -asked a blacksmith where Verrochio's studio might be. The man shouted -above the din of clanging hammers: - -"Everybody knows that shop, Signor--it's down that street and to the -right! You can't miss it--ask anybody!" - -The man was right, for the workshop of Verrochio was not hard to find. -Verrochio was considered one of Florence's finest artists and everybody -knew of him. He was a short, broad-shouldered man of thirty-two with a -round face, shrewd eyes, a thin mouth and dark curly hair that reached -almost to his shoulders. In his workshop were two other -apprentices--young Pietro Perugino, who was six years older than -Leonardo, and Lorenzo di Credi, a boy of eight. They all lived in the -house together and, after Leonardo was shown where he would sleep and -had put away the few things he had brought with him from Vinci, he was -taken to the place where he would work. - -Verrochio, whose real name was Andrea di Michele di Francesco de' Cioni, -had taken the name of his teacher, a renowned goldsmith, as was the -custom in the shops at that time. Verrochio himself was a skilled -goldsmith. But to be an artist and to have your own workshop in the year -1467 meant being a specialist in many things. Into Verrochio's place -came a great variety of artistic work--painting pictures, sculpting and -architecture, goldsmithing, designing and making armor, creating -decorated furniture, designing mechanical toys, and even preparing stage -scenery. - -Verrochio, of course, would attend to the greater creative tasks, while -his apprentices did the chores of grinding colors, preparing panels for -painting, making armatures for his sculpture, hewing to size the marble -for a statue, preparing molds for casting, building models for a new -palace or church--in fact, all the countless number of preparations to -the finished work. Sometimes, if an apprentice showed extraordinary -talent, he would be allowed to work on the finished painting or assist -with the final strokes of the chisel. Verrochio was a busy man and a -successful artisan. To further his own ambitions, he was now absorbed in -the perfecting of mathematical perspective and the study of geometry. - -The curious Leonardo had come to the right man. In Verrochio's workshop, -where so many crafts were learned at the same time, his powers of -observation were able to develop; his hunger to know about mathematics -was fed. In Verrochio, Leonardo found a teacher who would encourage -these investigations and urge him to study a wide variety of subjects. -Leonardo now felt his lack of a fuller education. He started to borrow -mathematics textbooks and to seek out men who could teach him what he -needed to know. After each day's work was over, Leonardo would continue -on into the night, catching up on his neglected studies and discovering -for himself new areas of thought such as anatomy, movement and weight, -botany, and another subject which was to occupy much of his later -years--_hydraulics_, or the useful application of water power. - -In these early years, Leonardo commenced his famous _Notes_. He had -developed his own "secret" writing in his childhood at Vinci. These -notes--consisting of observations, proportions, and reminders to -himself--were inscribed on his drawings. They were, however, unreadable -to the eye--until held up to a mirror. Leonardo was lefthanded and could -write fluently in this strange manner. It could have been for many -reasons that he did so--perhaps from a natural desire for secrecy, -perhaps for reasons of safety from possible enemies. In those days, -plots and counterplots of all sorts were commonplace--a rumor or a -whisper in the right ear could destroy a reputation or financially ruin -a career. - -Leonardo was popular in Florence. He traveled with the young men of the -town, and his handsome appearance and enormous strength (he could bend a -horseshoe in his hands) made him a welcome figure in many houses. He -continued to play the lute and the lyre. He wrote poetry, composed his -own music, and sang with a pleasing voice. His blue eyes were kind and -his manner gentle. He always avoided arguments and competition when he -could. When he walked through the marketplace and came upon the caged -birds, he would buy them--just to set them free. Indeed, his love of -animals had become so great that he no longer ate meat. - -During these years in Verrochio's service, Leonardo grew in stature as -an artist and rapidly developed into a scientist of promise. He amazed -his master when he painted an angel in an altarpiece that had been -assigned to Verrochio. He painted it in the new oil colors recently -acquired from the Flemish painters. So astounded was Verrochio with its -grace that the master vowed he would never lift a brush again if a "mere -child" could so surpass him. In this picture there is a tuft of grass -beside a kneeling figure, also painted by Leonardo, which indicates by -its careful attention to detail the amount of research he did before -committing it to canvas. In other paintings he made beautiful drawings -of a lily and studies of animals and crabs, giving a hint of what was to -come. For, in these preparatory works, Leonardo could not be satisfied -until he had thoroughly studied the characteristics of plants and -animals in general. Later in life, he was to become more and more -absorbed in these researches until they occupied the greater part of his -time. - -In 1469, when Leonardo had been in Florence only two short years, Piero -de' Medici died and was succeeded by his son, the mighty Lorenzo de' -Medici--or Lorenzo the Magnificent, as he was often called. Now the city -of Florence felt itself under the control of a man who really knew how -to use power. Lorenzo was Florence; nothing happened without his making -it happen, and he became one of the most prominent patrons of art and -scholarship in all of Italy. If Leonardo was to make any headway in -Florence, he would have to make himself noticed by this new Medici -ruler. - -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. - - [Illustration: _Leonardo, backed against a wall, was soon left in an - almost deserted street._] - -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. - - [Illustration: _Leonardo's design for a machine gun. It had - thirty-three barrels in three banks of eleven each. While one bank - was fired, one cooled and the other was reloaded._] - -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. - - [Illustration: _Leonardo's hygrometer._] - -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. - -Perhaps, thought Leonardo, his future lay in Milan. So he began -collecting his countless drawings, diagrams of machines and instruments -of war, his notes, his plans for canals and irrigation--even a drawing -for a monument that he knew Ludovico wanted to erect to his father--and -made a package of it to send to Ludovico. Then he sat down to write a -letter to that nobleman. In it he set forth in ten numbered paragraphs -his qualifications as military and naval engineer, architect, and -hydraulics expert. Almost as an afterthought to the tenth item, he -wrote: "I can carry out sculpture in marble, bronze, or clay, and also I -can do in painting whatever may be done, as well as any other, be he who -he may." - -When he had finished the letter, Leonardo took out a strange instrument. -It was a lyre of silver in the shape of a horse's head. He had designed -it himself, and now with an air of peace, he commenced to play. Its rich -tone was sweet to hear and the music was his own composition. - -Leonardo had also designed other instruments--lyres, lutes, viols, and a -kind of zither. He had perfected the single-stringed monochord of -Pythagoras, replacing the tablet of wood with thin strips of drum that -gave the instrument a low or high note according to the tightness of the -string. In addition, he introduced stops or small pistons in the holes -of wooden reed instruments; and, he had even invented a set of -mechanical chords by using a wheel of reeds which plucked a set of -strings as it was turned. His skill as a musician, composer, and singer -was well known among his friends and his bass voice had retained the -pureness of his boyhood. - -As it happened, news of Leonardo's silver lyre had reached Lorenzo de' -Medici. All Leonardo's paintings, all his designs for cannons and -fortifications, all his inventions for commercial machinery had failed -to interest Lorenzo--yet this single musical oddity excited the ruler's -curiosity. Leonardo was summoned to the Medici palace. - -Lorenzo was enchanted both by the instrument and Leonardo's musical -talent. When Leonardo had finished playing, Lorenzo, surrounded by -members of his court, applauded and said, - -"It would please us if Master Leonardo da Vinci would present us with -this beautiful instrument so that we, in turn, could make a gift of it -to His Highness, Ludovico Sforza, of Milan." - -Leonardo bowed and replied, - -"Your Grace's request is my pleasure. Moreover, Sire, it would further -that pleasure to bear the gift myself to His Excellency in Milan." - -The idea delighted Lorenzo. He immediately directed that Leonardo be -given a letter to Ludovico and that every protection be given Leonardo -for his journey. - -Leonardo, with the silver lyre and the letter of recommendation, hurried -home to make his final preparations. He called on a friend and pupil, -young Atalante Migliorotti, to accompany him. - -Toward the end of 1482 or the beginning of 1483, with the letter to -Ludovico folded in a leather pouch, Leonardo and Atalante mounted their -horses and left Florence for the long journey to Milan. - - - - - 5 - _Milan_ - - -Milan at this time was one of the greatest and wealthiest city-states in -all Europe. Its battlements and the spires of its mighty cathedral rose -impressively from the lush plain of Lombardy. Towering over the city in -the distance were the snow-capped peaks of the Alps. Groves of mulberry -trees for the production of its famous silk industry and vast stretches -of rice paddies extended far into the surrounding countryside. - -Leonardo and Atalante rode along the embankment of one of the many -canals. The sight of the city hastened their pace although the journey -had been a long one. Frequently on the trip Leonardo had stopped to make -notes. Riding over the mountains and ravines surrounding Florence he had -drawn some of the rushing streams and the stratifications of exposed -cliffs. And when they had descended to the plains he observed the -irrigation ditches and made notes on ways of improving the crude systems -of dams and waterwheels. - -Leonardo was excited by this new city and by his prospects at the court -of Ludovico. On the way to his lodgings, he also noticed that Milan was -a great center of arms manufacture. Shop after shop displayed its wares -of swords, spears, shields, armor for man and horse, and signs -advertising foundries for the making of cannon. Perhaps here he might -find an outlet for his military inventions. - -In the inn where he and Atalante stayed, Leonardo overheard the current -political rumors. All around him was talk of the war. Girolamo Riario -was again in the field, and Ludovico's ally, Alfonso of Calabria, had -just been defeated by the Venetians in a bloody battle at Campo Morto. - -Leonardo reread the letter he had written setting forth his own -accomplishments and decided that now was the time to present himself as -a military engineer. He would minimize the bronze monument, his music, -and his painting, and instead, he would stress his skills in the -inventions of war. - -When Leonardo appeared before Ludovico, he was a handsome young man of -thirty-one. Tall and strong, he was dressed not according to fashion, -but simply--almost severely. His hair hung in curls on his shoulders and -his auburn mustache and neatly trimmed beard accented his ruddy -complexion and deep-set blue eyes. Indeed, he presented a striking -contrast to the nobleman seated before him. Il Moro, with his dark skin -and straight black hair, his richly embroidered doublet with its broad -sleeves and the heavy gold chains across his thick chest, was the exact -opposite of Leonardo. - -Ludovico set aside Leonardo's letter, rose from his chair, and walked to -the heavy table on which Leonardo had spread out his drawings. - -Plans for all manner of war machines were there--those that Leonardo had -designed for Lorenzo de' Medici without success, together with many new -additions. For example, there were plans for a self-propelled bomb with -flames to be shot out in all directions--a bomb that was later to be -called a "rotatory rocket" when it was actually invented in 1846. -Leonardo also explained to Ludovico his idea for "poison gas" bombs -containing sulfur: the fumes of these bombs would "produce stupor," and -they could be used both on land and sea, together with masks to protect -those who were using them. Shrapnel shells, hand grenades, and javelins -that burst into flame when they struck their objectives--these and many -more were among his ideas. - -But perhaps the most unusual to Ludovico's eyes was the design for an -armored vehicle. It was shaped like a giant turtle, with overlapping -sheets of reinforced wood so that enemy shells would bounce off its -surface. The armor was pierced by loopholes for the breech-loading -cannon and there was an opening at the top for ventilation. Power for -the vehicle was supplied by eight men inside turning cranks which in -turn were cogged to other wheels, setting in motion the four drive -wheels. This of course was the forerunner of the tank and the armored -car used in modern warfare. - - [Illustration: _Forerunner of the tank or armored car, as conceived - by Leonardo. Motion was supposed to be supplied by four cogged - wheels turned by manpower. Sheets of reinforced wood were supposed - to serve as "armor" against enemy projectiles._] - -In addition, Leonardo laid before Ludovico all manner of cannons and -designs for tunneling under the enemy's defenses. Actually, with respect -to warfare itself, Leonardo called it a most brutal "madness"; however, -he recognized the necessity of being prepared. In his notebook, he -wrote, "When besieged by ambitious tyrants I find a means of offense and -defense in order to preserve the chief gift of nature, which is -liberty." - -Ludovico was very much interested in the things Leonardo had showed him. -Although he was a man of limited imagination and was not able to grasp -the scope of Leonardo's proposals, he was nevertheless involved in a -war. Since Ludovico's aging military engineer was to be replaced, -Leonardo left the forbidding castle of the Sforzas with high hopes of -getting the position. - -In the meantime, he was commissioned to paint the portrait of a young -girl from a noble family in Milan. At the same time, he began the bronze -equestrian statue of Ludovico's father, Francesco Sforza. For this work, -he began an intensive study of horses. Since hunting was the popular -sport at the court of the Sforzas, Ludovico owned a stable of the finest -Arabian horses, and here Leonardo commenced his drawings. Again, his -research for a work of art led him beyond just making preparatory -sketches. His studies developed into notes, and his notes into a planned -book on the anatomy of the horse. - -During these months of waiting for the appointment as military engineer, -Leonardo furthered his experiments with cannon. In the course of these -experiments, he came across a power that would later revolutionize all -industry--steam. He devised--although he attributed the original idea to -Archimedes--a water vessel connected to a copper tube which was heated -by a fire. The water when flowing into the red-hot tube changed into -steam and the pressure of the steam blew out a ball at the mouth of the -tube with great force. Leonardo experimented with steam in other ways. -He built an apparatus for measuring the transformation of water into -vapor. It consisted of a metal box in which was a thin animal bladder -partly filled with water. Resting on the top of the bladder was a flat -lid attached by a cord hung from two pulleys to a counterweight on the -outside. As the water was heated, the steam in the bladder pushed up the -lid. As the lid rose both the volume and the pressure could be measured. -There were distillation experiments with various condensers, one in -particular that anticipated the modern condenser of Leibig, introducing -double walls that formed a complete jacket for cooling with water in -continual circulation. - -Not content with having an idle moment, Leonardo again turned to -searching out books that he had not read and trying to fill the gaps in -his education. He became especially interested in the German -philosopher, Cardinal Cusanus. Cusanus, like himself, had been -influenced by Toscanelli and was a man devoted to the natural sciences. -Leonardo also studied the philosophy of Aristotle and the writings of -St. Augustine. Throughout his life Leonardo believed in an active mind -for, as "iron rusts from disuse, stagnant water loses its purity and in -cold weather becomes frozen, even so does inaction sap the vigor of the -mind." - -Unfortunately, the post of military engineer went to a man named -Ambrogio Ferrari. The extent and variety of Leonardo's proposals were -too great for Ludovico to trust. He did not believe that one man could -possibly bring all those ideas into being. Ferrari, on the other hand, -was a military engineer only, and a man who was content with the -customary methods of warfare. Furthermore, Ludovico had at last decided -that peaceful negotiations would gain him more than fighting. Thus -Leonardo's chance of recognition was again postponed. - -Meanwhile, the money that Leonardo had brought with him from Florence -was almost gone. He had been forced to move from his apartment to a -single room and now he was barely able to live from day to day. Although -the court of Ludovico Sforza was one of the richest in the world, -artists were frequently treated as servants; often they were the last to -be paid for their services. Also, Leonardo was a foreigner in the city, -which meant he was regarded with suspicion. - -Because of these reasons, Leonardo finally decided to do what the -Milanese artists did--they banded together in groups sharing work and -costs. Leonardo had met a young artist of twenty-eight, Giovanni -Ambrogio de Predis, at the court of Ludovico. Ambrogio was court painter -to the Sforza family and had achieved some success. Ambrogio recognized -in the handsome stranger from Florence, however, the touch of genius, -and he realized that his own talents would be furthered by learning from -Leonardo. The two young men decided to pool their abilities. Ambrogio -offered both lodging and a studio; and, in association with his two -half-brothers, one a woodcarver, another a miniaturist, and his elder -brother, a minter of coins, they would not lack for commissions. - -Commissions weren't long in coming. On April 25, 1483, a contract was -signed between Bartolommeo degli Scarlione, a prior of the Fraternity of -the Immaculate Conception, and Ambrogio and Leonardo for an altarpiece. -The fee was two hundred ducats, with a promise of more if it were -delivered on time and was satisfactory to the Fraternity. Delivery date -was to be December 8, 1484. Ambrogio was to paint the altar wings and -Leonardo the center piece--a picture of the Blessed Virgin and Child. - -But when the painting was finished, it was not according to the -instructions set forth in the contract. Leonardo had too independent a -mind to be bound by conformity. Nor was it completed on time. Indeed, -for twenty years the quarrel between the Fraternity and the painters -went on. After ten years, Ludovico was asked to intervene for the money -owed; after he failed, another ten years went by and the King of France -himself was finally asked to settle the dispute. Leonardo wanted his one -hundred ducats and the Fraternity offered twenty-five. Eventually, a -secret agreement was arrived at and the painting was restored to -Leonardo and Ambrogio. Leonardo's painting, the masterpiece entitled the -"Virgin of the Rocks," now hangs in the museum of the Louvre in Paris. - -The day this contract was signed, Leonardo walked back through the city -to Ambrogio's studio near the Ticino gate. He was low in spirits from -reading the petty instructions of the contract, and, in this mood, he -became aware of the city streets and crowds about him. The noise, the -confusion, the smells--yes, the smells were the worst. Garbage, filth, -and dust were in heaps where the last rainwater had left them and they -buzzed with flies. - -Moreover the houses were jammed together and shopkeepers crowded their -wares to the edges of the streets, leaving just enough room for the -occasional horseman to get through. Latrines were only for the better -houses; here, the streets, alleys and even open doorways were toilets. -People flung their scraps out of the window and at night in the poorly -lit streets could be heard the scurrying of rats. Leonardo stopped, -thinking half aloud: - -"Two levels. Streets running one above the other--one for pedestrians -and one for carts and horses. Yes, and cutting through the whole city a -system of canals to carry the city's waste to a river or to the sea. Why -not even ten cities of, say, five thousand houses in each--say, no more -than thirty thousand people to a city?" - -Intent now on his thoughts he hurried to his home, his mind busy with -his visions of new cities. - - -During the years 1484 and 1485 the bubonic plague swept Italy--the same -dreaded Black Death so prevalent in medieval times. Milan was one of the -cities most severely stricken. Every courtyard became a hospital and the -streets were deserted except for the rumbling carts picking up the dead. -On the roads from the city were lines of refugees fleeing to the -country. Surrounding cities that had not been infected manned their -fortress walls as in wartime to keep the fleeing populations out. - -Ludovico at first tried to protect Milan from the spread of the disease; -then, frightened, he and his court fled. Even the ruler's official -documents had to be "disinfected" by perfume and then held for a period -of time before he would allow them near him. - -Leonardo, sensing opportunity, drew out his plans for his new cities. -Canals running through them were to be used for barges and the -underground conduits greatly resembled those of modern sewage systems. -Paths were to have gutters for the adequate drainage of the streets. -Public toilets were to be installed. Leonardo even had plans for the -control of smoke collecting over the city--by sending it up tall -chimneys where it was picked up by fans and driven away over the roofs. -The widths of the streets were to be in proportion to the heights of the -houses--light and air would circulate freely. Two levels would be -connected by graceful ramps--the lower level for the commercial traffic -and the upper level for the pedestrians. Where stairs were used they -were designed so one could ascend or descend without one person seeing -the other. Stables were devised so that animals were fed through -openings in their mangers and under these were tunnels of flowing water -for the removal of waste. - - [Illustration: _The results of the bubonic plague in Italy, 1484-85. - Streets were deserted except for the carts picking up the dead._] - -These sweeping plans Leonardo laid before Ludovico when the epidemic had -subsided. But Ludovico, once his fear was overcome, brushed them aside -as impossible dreams. - -So Leonardo returned to the commission for the Fraternity and the -designs for the bronze monument of Francesco Sforza. These jobs kept -Leonardo from brooding about his rejections. - -Often, too, Leonardo worked with Bernardino de Predis, the elder brother -of Ambrogio. Bernardino was a minter of coins. As Leonardo watched him -at the laborious task of first cutting disks from ingots and then -hammering the design into the hot metal, he suggested to Bernardino an -easier method, then used in Germany. This was to prepare smooth ribbons -of metal of the desired thickness and with a punch, impress the design -into the ribbon at the necessary intervals and then, punch out the coin. -Leonardo went on to improve this system by designing precise punches for -both faces of the coin. A single machine then cut out and stamped the -coins, using a falling weight raised by little winches. This machine was -later destined for the Vatican mint in Rome. - -On March 26, 1485 an event occurred in Milan that was viewed with -mingled fear, superstition, curiosity and excitement. There was a total -eclipse of the sun. To some, coming as it did so soon after the plague, -it was a judgment of God; to others, it was regarded as an omen--a sign -for astrologers to use for predicting the future. - -But to Leonardo the eclipse was a moment of great scientific importance. -At this time in history, the Ptolemaic, or geocentric theory of the -universe was the popular belief. This theory taught that the earth is -fixed and the sun and moon revolve around it. Leonardo himself had -believed this theory for a long time. As he grew older, however, he read -and heard discussions of the heliocentric theory. This theory proposed -that the sun is fixed and the earth and stars move around it. Now, as he -watched the eclipse, his doubts of the Ptolemaic concept were renewed -and he resolved to make experiments of his own. The new theory was so -daring for his times, however, that it would be many years before he -became convinced of its truth. - -Later that night, deep in thought over the experience of the day, he -noted down his observations of the eclipse and his doubts of the -medieval concept of the heavens. The Church believed the earth was the -fixed center of the universe. Scholars and scientists supported the -belief of Aristotle in the four elements, earth, water, air, and -fire--but something was wrong. What were the planets--what was the moon? -He picked up his pen and on a clean sheet of paper he wrote, "Make -glasses in order to see the moon large." - - - - - 6 - _The Monument_ - - -During this time, Leonardo had been struggling with the design for the -bronze equestrian statue. Drawing after drawing lay scattered on his -studio floor. Lately, however, a daring plan for this statue had come to -him. It was to be a huge bronze warrior, Francesco Sforza, mounted on a -rearing horse. Weighing perhaps a hundred thousand pounds, it was to be -cast in sections in five furnaces--a fitting monument to the power of -the Sforza family. But there still remained a big problem to be solved: -how could he balance the plunging horse and man on just the two rear -legs of the horse? - -Meanwhile, Leonardo had another problem to work on--a wooden model of -the Milan cathedral. He had entered his name with the cathedral -authorities as a competitor in the design and construction of the -cathedral's dome. Many architects had been brought in and had failed, -partly because of the antagonism of the Milanese workmen to foreign -craftsmen, and partly because the committee found it difficult to decide -what designs it liked. Leonardo had sent them a letter outlining his own -recommendations and had drawn many pages of possible plans. He put -forward his knowledge of various building materials, his understanding -of classical architecture, and his wish to keep his own ideas in harmony -with the Gothic tradition of the cathedral itself. Often he would make a -point of walking about the city, observing the different constructions -under way and drawing up plans to shorten the labor by mechanical means. - -In July of 1487 Leonardo received a payment from the cathedral -authorities for the wooden model he had submitted. Still, however, no -final decision had been reached. Now, as Leonardo looked at the model in -his studio, he felt the urge to improve it further--to make it more -perfect. Yet he held his impatience in check and decided he would wait a -little longer. Instead, he decided to work on some of his ideas for -construction devices. He had already made many drawings, but they could -be improved, he thought, and he began to make calculations. - -Among these notes and drawings was an improvement on a device for the -raising of columns. It was a mobile windlass with a transmission gear -for transporting and erecting columns and obelisks. Another device was -an earth drill resembling a modern corkscrew with double handle bars. -The upper bar, when turned, drilled the screw into the earth while the -lower bar--when turned the opposite way--carried the dirt up and out. -Also there was a double crane mounted on a circular trolley which -carried the dirt of excavation up and then the crane was moved around on -its trolley so the dirt could be unloaded in different directions. - -Other labor-saving devices that Leonardo designed were an automatic pile -driver, the weight of which was raised by a winch and tripped -automatically at its height to fall on the piling; a lift for raising -iron bells to bell towers; and a machine for boring tree trunks to make -pipes for carrying water. - -In the fall of 1488, Leonardo was interrupted by a summons from -Ludovico, who wanted him to design and build the decorations for the -forthcoming marriage of his nephew, young Duke Gian Galeazzo Sforza, to -Isabella of Aragon, granddaughter of the King of Naples. He worked on -this steadily until the wedding ceremony in February of the following -year. When the day arrived, the street from the cathedral to the grim -castle was trimmed with flags and banners of the two royal houses. The -inner courtyards of the castle were transformed into delicate arbors of -laurel boughs. Yet it was the evening's reception and entertainment -which were to be the climax and to them Leonardo had brought all his -mechanical skill. However, the announcement of the death of the bride's -mother cut short the celebration and, after the bride and groom had left -for Pavia, the wedding party soon dispersed. Disappointed that his -decorations had not been fully appreciated, Leonardo returned to his -studio and the problem of the monument. - -He was still struggling with the problem of balancing the rearing horse. -And, indeed, a solution was soon found. By placing a fallen soldier with -his arm upraised in protection under the forefeet of the horse, Leonardo -could balance the enormous weight and provide for the proper casting of -the molten bronze. - -Finally, Leonardo made a small wax model of the proposed statue and -showed it to Ludovico. The nobleman was impressed by its originality. -Most of the ideas contributed by other sculptors were mere variations of -what had already been done many times. Also, the other plans called for -bronze of not more than two thousand pounds, while Leonardo envisioned a -statue fifty times that size! Ludovico awarded the commission to -Leonardo. - -Leonardo was to work on this commission for ten years and it was -destined never to be immortalized in bronze, for reasons that will be -explained later. His energies, as usual, were poured into many schemes. -Growing out of his work on the monument he planned one book on the -subject of casting in bronze and another on the anatomy of the horse. -But the one subject, which he began to study in this period and which -would occupy the remainder of his life, was the study of human anatomy. -So Leonardo, in the midst of all his other activities, wrote in his -notes, "On the second day of April 1489 the book entitled _Of the Human -Figure_." - -The sources of anatomical study up to Leonardo's day had been the -Greeks--Hippocrates and Galen--and the Arab--Avicenna. Books on this -subject were few, and the anatomical diagrams were crude and inaccurate. -Galen, for example, had based his studies on the dissection of monkeys. -Renaissance anatomists had explained his errors by pointing out that man -had probably changed since Galen's time. The Church had stepped in -during the fourteenth century with an edict that was interpreted as a -prohibition against dissection of the human body. In Italy, however, -there were some dissections. They could only use, for this purpose, the -bodies of criminals, slaves, and people of foreign birth. In Florence, -anatomy was studied by the artists, and Leonardo had undoubtedly watched -Pollaiuolo at work on a corpse that that artist had dissected. - -In 1489 Leonardo, from the results of his own investigation, produced -drawings of the skull and backbone whose careful attention to detail -are--even today--classics in art and anatomy. With infinite patience and -with a saw of his own invention he had halved a skull and drew for the -first time with accuracy the curves of the frontal and sphenoid bones. -He drew the lachrymal (tear) canal, and he was the first to show the -cavity in the superior maxillary bone--not discovered again until 1651, -by Highmore--now named "the antrum of Highmore." He was the first to -demonstrate the double curvature of the spine and its accompanying -vertebrae, the inclination of the sacrum, the shape of the rib cage, and -the true position of the pelvis. He planned a whole series of books that -would include from head to foot and from inside to outside every section -of the human apparatus. - -Meanwhile he had been working on the monument, redesigning it to conform -to the practical needs of casting. Now it had reached an even grander -scale--a colossus that would require two hundred thousand pounds of -bronze! He recorded in his notes the very day that this work was -started, "On the twenty-third day of April 1490 I commenced this book -and recommenced the horse." The "horse," of course, was the monument and -"this book" referred to still another subject which had grown out of his -studies of anatomy and perspective. - -The title of the proposed book was to be _Light and Shade_. It would -include the subject of optics or the mechanism of the eye, the problems -of reflection and refraction and it would lead him eventually to a -re-examination of his studies of the sun and moon. - -In Leonardo's day, and even for a long while afterwards, the popular -belief of vision was one that had originally been put forth by the -Platonic school and expanded by Euclid and Ptolemy. This belief was that -the eye sent forth rays that brought back the image to the soul. -Leonardo, in his younger days, had believed in the same theory. Not -content with what had been written on the subject, however, he began to -experiment for himself. - -These experiments led him to an examination of the eye itself. He noted -the various parts of the eye--the optic foramen or opening, the pigment -layer, and the iris. These were already known by the Arabs. Leonardo -discovered, however, the crystalline area of the eye. He explained -binocular vision, or three-dimensional images, by correctly noting the -positions of the two eyes in the head. He described the variations in -the diameter of the pupil according to the surrounding light. Further -experiments with light brought him to the conclusion that light and -images are received by the eye. He took a piece of paper, for example, -and pierced it with a small hole. With this he looked at the source of -light. He noted the cone shape of the rays funneling into the tiny hole -and then when the paper was held next to a white wall he noted that the -rays spread out again. He established that light travels in straight -lines. He constructed the first "camera obscura"--a box with a small -hole in it. Inside the box an object was placed near the hole and behind -that a lighted candle. When the box was closed the image of the object -was cast on the wall. Leonardo was already acquainted with lenses, and -he placed a magnifying lens over the hole to create an enlarged image. - - [Illustration: _Leonardo's "camera obscura" which he used for - projecting an image of an object on a wall or screen._] - -He also demonstrated various laws relative to optical illusion, such as -irradiation--when a metal rod is made red-hot at one end, that end seems -thicker than the other. A brightly lit object seems larger than one -exactly like it that is dimly lit; a dark object placed against a light -background seems smaller than it is; a light object seems larger than -its real size when placed against a dark background; and the illusion of -a light swung in a circle appears as a complete circle of light. - -Many years before Newton, Leonardo described the experiment of breaking -up a ray of white light into the solar spectrum. Also he compared two -sources of light and measured their intensity by the depth of their -shadows accompanied by a drawing that was the forerunner of Rumford's -photometer three centuries later! He stated the law of reflection--that -is, that the angle of reflection is always equal to the angle of -incidence. - - -About this time Leonardo left the studio of Ambrogio de Predis and moved -into the Sforza Castle. Ludovico had put at his disposal a studio in the -Corte Vecchia and the use of a room in one of the towers--which Leonardo -always kept locked. To his growing list of work, Leonardo now had to add -the preparations for the delayed wedding reception of Ludovico's nephew, -Gian Galeazzo Sforza. - -On a cold winter evening of January 1490 the guests assembled again. -Silks, satins and gold brocade, diamonds, rubies and pearls glittered in -the brilliant lights. Princes of the Church mingled with ambassadors of -foreign lands. Music and perfume filled the air and as the party quieted -down the entertainment began. There were dances in gay costumes. Poetry -was recited that flattered the bride and groom. There were allegorical -processions. The jokes and antics of the court jester made the audience -laugh. - -Then, at midnight, the curtain that hung from wall to wall at the end of -the ballroom was raised. Applause and cries of delight greeted the -spectacle. The rising curtain revealed a room in which there was a -hemisphere surrounded by the signs of the zodiac and the planets. While -the planets in their niches flickered with concealed lights and the -signs of the zodiac glowed, lines were spoken in honor of the house of -Sforza to the accompaniment of a choir. The ancient gods swept down from -the heavens, and the Virtues and Graces moved across the scene with -nymphs waving lanterns. The music drowned out the sound of the -mechanism. This was the kind of mechanics that Ludovico could understand -and appreciate. - -The success of this entertainment so pleased Ludovico that Leonardo was -encouraged to present another amusing idea. This one was an "alarm -clock" and it utilized what we call today the mechanical relay -principle. When a small power is suddenly switched over, the power is -reinforced. The "alarm" clock worked by placing a shallow basin of water -at one end of a tubed lever. At the other end was another empty basin. -Water was led drop by drop into the second basin and as this slowly -filled the increasing weight lowered the lever. The shallow basin of -water at the first end was suddenly emptied and the immediate switch in -weight flipped the lever up and this in turn pushed up the sleeper's -feet. - - -Leonardo decided to withdraw from the competition for the cathedral -dome. Although the cathedral authorities were pleased with his design, -they could not decide to whom the commission should be awarded. In the -summer of 1490 Ludovico was called upon to settle the issue and he -decided in favor of Antonio Amadeo from Milan. But the work that -Leonardo had done so impressed Ludovico that he sent him to Pavia in -company with an architect from Siena, Francesco di Giorgio Martini, to -inspect the work on the cathedral of that city. Leonardo, who had his -own workshop and apprentices now, took along one of them, Marco -d'Oggionno, a young boy of twenty. - -In Pavia one of the greatest libraries in all of Italy was in the ducal -palace. Here Leonardo wandered among shelves of books and illuminated -manuscripts bound in rich velvets and gold-embossed leather all bound to -their places with silver chains. One book that he records in his notes -was written in the thirteenth century by Witelo, a Polish scholar, who -wrote extensively on perspective. Leonardo, by the necessity of his art, -had solved many problems in perspective. He had invented a pair of -proportional compasses, the forerunners of those used today for the -transfer of a drawing from one scale to duplicate the same drawing in a -larger scale. Leonardo had also designed in very careful detail a -parabolic compass for drawing a parabola in one continuous movement. He -now determined to write his own book on perspective and, as the subject -was so close to his studies of the eye, he would entitle it -_Introduction to Perspective, or the Function of the Eye_. - -Leonardo submitted a number of plans for the completion of the cathedral -to the authorities in Pavia and then returned to Milan. He worked -through the rest of the summer on the equestrian statue and at the same -time he continued to expand his notes on anatomy, light and shade, and -perspective. - -Late on a cold December night in 1490, Leonardo lit his lamp. This was a -very special lamp that he had invented. It had already created a great -deal of comment. It was so unusual, he had received an order from the -court for another which he made with a richly carved pedestal. Candles, -torches, and oil lamps, the only methods of artificial illumination in -those days, were poor substitutes for light. They flickered, smoked, -went out, and frequently caused damage with their hot drippings. As a -side result of his experiments in light, Leonardo had put a glass -cylinder in the middle of a larger glass globe. A wick in olive oil was -placed in the cylinder and the outside globe was then filled with water. -The result was a bright, steady light magnified by the water in the -globe. - -He sat down by the small fire and arranged his papers in front of him. -Then, with a glance at his lamp, he picked up his goose-quill pen and -wrote, "No substance can be comprehended without light and shade; light -and shade are caused by light." - - - - - 7 - _Success_ - - -It was January of 1491, and a light snow had fallen in Milan, edging -with white all the roofs, the massive spires of the cathedral and the -red battlements of the Sforza castle. Soon Ludovico was to be married to -Beatrice d'Este of the ducal house of Ferrara. - -Once more the streets of Milan echoed to the carpenters' hammers. -Messengers rode to and from the castle and endless carts full of -provisions pushed through the crowded city. Guests began to arrive from -all the allied courts of Italy with their bodyguards and servants. The -rooms of the castle, the palaces of the nobles, and even the inns were -filling with the royal processions. - -Leonardo was again summoned by the court to prepare the decorations, the -costumes for the masquerades, and the arena for the jousting -tournaments. An invitation had been sent to all the friendly courts to -attend these contests-at-arms. So, accompanying each new party's arrival -was a band of armored knights, their breast-plates, helmets, and shields -glistening in the winter sun. - -Leonardo enjoyed designing mechanical toys and entertaining the guests -with them. One of these was a mechanical drum. Ordinarily most of the -entertainment began with normal drum rolls, but Leonardo's rolls were -made on a kind of wheelbarrow. On it was mounted an enormous drum. When -the "wheelbarrow" was pushed, it put into motion a cogged wheel geared -to the axle. This wheel in turn was geared to two rotary cylinders with -pegs mounted around the top. The pegs moved against five drumsticks on -either side of the drum and thumped out a rhythm according to the -position of the pegs. - -Ludovico's marriage to Beatrice d'Este, a girl of little more than -fifteen years, further isolated Leonardo from the court. Being almost a -child, Beatrice loved parties and festivities, and she surrounded -herself with people who catered to her frivolous whims. As a result so -serious a man as Leonardo was forced into the background of the court -life. He was called upon more and more to act as stage-designer while -his more important work went unnoticed. Because these entertainments -were easy for Leonardo to design, they did give him more time to work on -his giant equestrian monument of Francesco Sforza. Working one day on -the scaffolding surrounding the clay figure of his statue, Leonardo -heard a knock at his studio door. - -"Come in," he shouted as he climbed down. "The door's open." - -Three peasants cautiously entered the room and quickly took off their -caps. One of them was holding a carefully wrapped bundle. - -"Master Leonardo, we have brought you some shells we found on a ridge of -Monferrato. Remember, you asked us to bring anything we found that was -unusual?" - -"Yes, Pietro. Thank you. Put them here on the table." - -Leonardo opened the bundle. He smiled when he saw the shells. He -remembered how, as a young boy, he had found seashells like these high -in the mountains. Leonardo questioned Pietro and his companions as to -where they had been found and under what circumstances. He gave them -some coins and, when they had gone, he looked among his growing -collection of notes and drawings on the shelves. It took some time for -him to find what he wanted, for the pages were in such confusion. -Finally, he sat down at the table with several of the sheets and, -putting the seashells in front of him, he began to make notes. - -The shells were fossil shells but, thought Leonardo, their presence on -the high mountains of Lombardy could hardly be attributed to the great -flood as described in the Bible. In his notes, Leonardo cited the case -of the cockle which, out of water, is like the snail. It makes a furrow -in the sand and can travel in this furrow about three to four yards a -day. By such means, he calculated, it could not possibly have reached -Monferrato from the Adriatic in forty days (which was supposed to have -been the duration of the flood)--a distance of 250 miles. Nor were these -simply dead shells deposited by the waves--for the living creatures are -recognized by being in pairs, and these in front of him had certainly -been traveling in pairs. Consequently, they could have been left there -only when they were alive and the mountains were covered by the primeval -oceans. Moreover, Leonardo also described how living matter in -prehistoric times fell into the mud and died, and how this mud, as the -waters receded and years had passed, was changed into rock forming a -mold about the fossil--literally making a cast of its original living -appearance. - -By such deductive reasoning and the testing of the evidence before him -against the common beliefs, Leonardo struggled to free the minds of men -from medieval superstitions and beliefs. Indeed, these medieval -superstitions existed everywhere. Astrologers, or men who told fortunes -by the position of the stars at a given moment; and necromancers, those -who by tricks of magic claimed to be able to talk to departed -spirits--these men profited from the ignorant. The Church, with its -preaching of devils and hells, provided the background against which -these fakers flourished. - -Ludovico Sforza was himself a believer in such things. His own physician -and astrologer was a man by the name of Ambrogio da Rosate, who had such -influence over the court that he was given a post in the University of -Pavia, and his fame was so great that he was called upon to predict the -future of Pope Innocent VIII! Leonardo's dislike of these men was -intense. He scorned the supernatural and asked men to look about them at -the real world and the real heavens. Observation and experiment--these -were Leonardo's key words. But he was a lonely figure in his -thinking--like a man awake while the rest of the world slept. - -At last the full-size model of the Sforza monument was nearing -completion. Ludovico had ordered it ready for exhibition in the -courtyard of the castle for yet another marriage festival that was soon -to take place. This time it was the marriage of his niece Bianca Maria -to Maximilian I of Germany. Leonardo and his assistants were busy with -the finishing touches on the monument, and with building a wagon on -which to carry it from the studio to the courtyard. - -During these last months Leonardo had had to struggle with all kinds of -heavy loads. Already he had improved on pulleys by inventing a new kind -of tackle, and he also had utilized many kinds of levers. One of his -simpler discoveries for raising heavy weights was a jack which, in -appearance and principle, was the forerunner of our own automobile jack. - -In 1493 when the clay model of the Sforza monument was completed, it was -put on the cart and wheeled to its place of exhibition where a curtain -was thrown around it. Again Milan was the host to a gathering of noble -courts, and this time Ludovico outdid himself in the display of luxury. -Tapestries hung from the buildings and rich carpets were laid down the -steps of the cathedral. Everything that Milan had to show was on -exhibition--even a crocodile. - -But the most impressive sight of all was the unveiling of Leonardo's -colossal statue. It rose in majesty against the red walls of the castle. -The name of Leonardo da Vinci was suddenly on everyone's lips. As the -word of his artistic achievement spread from city to city, messages of -praise came pouring in. And, for a while the years of frustration and -failure to gain recognition melted away. Leonardo at forty-one had at -last achieved some success. - -Now there was a breathing spell, and Leonardo returned to some of his -own projects. For a long time he had continued his observations of his -two favorite elements--air and water. To him they were related in their -movements. The birds flying in the currents of air and the fish swimming -in the flow of water seemed very similar to him. He had already designed -various instruments to tell him about the direction of wind and its -velocity, and he had also commenced to analyze the wing structure of -birds and bats. To soar through the air like a bird was an ancient dream -of man, yet for Leonardo it had become a passion. Ceaselessly, he -sketched the flights of birds, the flutterings of butterflies and -analyzed their flying patterns. - -But to Leonardo, understanding the _dynamics_, or motion, of air was the -most important thing. He built an _anemoscope_, an instrument like a -weather-vane for telling the direction of the wind; and, he also -constructed several types of _anemometers_ for measuring the velocity or -force of the wind. One of these latter consisted of a thin rectangle of -metal hanging straight down in front of an upward-curving wooden arc. -This arc was marked off in units of measurement. When the wind blew, it -pushed the thin rectangle up the arc; thus, by noting at which gradation -it stopped, Leonardo could tell the velocity. - -In addition, Leonardo at this time constructed a device which has been -compared to the modern instrument used for testing the weight-carrying -capacity of airplane wings. He fashioned a wing resembling a bird's wing -and attached it to a lever so that it would be possible to lower the -wing by pushing rapidly down on the lever. This wing in turn was mounted -on a plank that was in weight equal to that of a human being. He then -calculated that two wings of this kind would have to be about twelve -meters wide and twelve meters long to raise a man and his machine -together. Another device resembling those found in airplanes today that -Leonardo constructed was an inclination gauge. He made this by -suspending a heavy ball on a cord within a glass bell. This ball was -then supposed to guide the flyer by telling him whether he was flying -level, diagonally, up, or down. - - [Illustration: _One of Leonardo's anemometers. The wind blew against - the strip of metal, pushing it up the curved gauge and thereby - measuring the force of the wind._] - - [Illustration: _Leonardo's inclination gauge, designed to guide a - man in flight. The ball in the glass cylinder was supposed to tell a - "flyer" whether or not he was flying level or tipped._] - -To Leonardo, water was also a phenomenon that from his youth never -failed to excite his curiosity. The use of water power to run machines, -to irrigate fields and to carry boats inland was a subject that he never -ceased investigating. Out of his experiments at this time he constructed -a device for raising water to high levels. It was based on the geometric -spiral of Archimedes. He took a piece of gut, inflated it, and let it -dry. Then, covering it with a coat of wax to make it waterproof, he -wound it around a thin staff in a spiral. He put one end in a stream and -attached it by gears to a cogged water wheel; this set the long screw to -turning, and he was able to raise water from a low level to any height -he desired. With a multiple system of these screws he could raise water -in continuous circulation to the reservoirs on the highest towers. - - -In the year 1494, King Charles VIII of France crossed the Alps at the -head of an army of twenty-five thousand men. Now Ludovico, by a series -of diplomatic maneuvers, had allied himself with Charles and had, by -secret negotiation, actually invited the invasion. By such an alliance -he hoped to use Charles' army to overcome the forces of the Pope which -stood in the path of Ludovico's ambition to become the most powerful -ruler in Italy. Outwardly Charles was asserting his rights to the -Kingdom of Naples, but inwardly he dreamt of leading a crusade against -the infidels in the Holy Land. At the same time young Gian Galeazzo -Sforza, Duke of Milan, was dying. Ludovico desired this title for -himself; however, until Galeazzo was out of the way, he could not have -it. There were ugly rumors that young Sforza had been poisoned. -Moreover, in 1494, the Medicis--another powerful obstacle--were expelled -from Florence, and a republic was established. - -Soon young Gian Galeazzo died, leaving a son, Francesco. This son was -the rightful heir to the Dukedom of Milan but Ludovico usurped the boy's -claim and declared himself Duke of Milan. Now Ludovico was in a position -to await the impending battle between Charles and the Pope. - -With such military and political ambitions in mind, Duke Ludovico now -assigned Leonardo the task of reviewing Milan's defenses. Again Leonardo -submitted to Ludovico his plans for strengthening fortresses and designs -for new ones. The great architect Bramante was also assigned the task of -seeing to the city's defenses, and for some time the two brilliant men -worked together. - -Then, in the spring of 1494, Leonardo was sent to Vigevano where -Ludovico's young wife was staying. This town was also the birthplace of -Ludovico, and Leonardo was given the job of designing and building a -small summer house and garden there for Beatrice. In addition, Leonardo -built a kind of "air conditioner" for her bedroom. It consisted of a -large waterwheel that cooled the air circulated into her room. Although -this ancient device had long been known to the Greeks and Romans, -Leonardo was the one who succeeded in perfecting it. - -During this time Leonardo's highly original mind was also at work on -other devices. One of these was an _odometer_, an instrument for -measuring the distance traversed by a vehicle. Dials, turned by a system -of gears attached to the wheel of a wheelbarrow, measured the distance -traveled as the barrow was pushed along the ground. In addition, -Leonardo conceived a kind of odometer to be used at sea; this consisted -essentially of a spinner that was towed by a ship which registered its -speed. Leonardo even invented an automatic spit operated by metal vanes -mounted in the chimney that revolved with the pressure of the hot air -rising from the fire--and a pair of large floating shoes for walking on -water! - -In the meantime, Charles VIII of France had marched through Rome and -entered Naples. The conquest was without opposition. Charles was then -crowned King of Naples and all Italy was at his feet. Yet his triumph -was a short one. Ludovico, having used the king to get rid of his -enemies, now plotted against the king himself. He formed an alliance -with the Pope, Venice, Spain, and the German emperor. Charles, faced -with this league, hastily beat a retreat to France. Fighting his way to -the border, he there signed a peace treaty. Thus Ludovico had swept -Italy clean of all opposition and was now the most powerful prince in -the land. - -Yet Ludovico was quick to realize that his position could only be held -by force and he set about strengthening himself and his allies. To -provide for more cannons, a hundred and fifty thousand tons of bronze -were sent to manufacturing works in Ferrara. This, however, included the -very bronze Leonardo needed for the casting of his equestrian statue, -and this is why the statue was never cast. Years of Leonardo's work now -seemed to vanish overnight. Ludovico also needed large sums of money to -secure friends in high places and Leonardo's own payments were suddenly -dropped. Forced again to worry about paying for his daily bread and for -his household and apprentices, he wrote letters to Ludovico complaining -of his lack of funds and asking for money that was owed him for work -done. He looked about for other commissions, but none were available. -Moreover, because he was still court painter to Ludovico, he was ordered -to paint the decorations of some rooms in the castle. But this was more -than Leonardo could take--he walked off the job without finishing it. - -Despite all of these misfortunes, Leonardo continued struggling with the -problems of flight. He kept working out the proportions of wing span to -the weight of the load. Indeed, he had already started designs for a -flying machine. He had chosen a room which was the highest in one of the -towers of the castle and which had access to a roof. Leonardo's plans -for a flying machine were a secret, and, with the exception of an -assistant, no one knew about them. He made sure that he could not be -seen by the workmen on the dome of the cathedral and proceeded to block -off his room with beams which he planned to use as supports for his -model. - -He had thought at first that any attempted flight should take place over -water in order to cushion a possible crash--but as his plans progressed -he designed a parachute. It was a pyramid-shaped "tent of linen" -twenty-four feet broad and twenty-four feet high, and it is believed to -have been successfully tried out from a tower especially constructed for -that purpose. - -Since Leonardo was no longer working for Ludovico, he lived more simply -than ever. He made regular lists of his expenses down to the last penny. -His habits were frugal although he always kept himself neat. His meals -were spare; he drank a little wine at meals and never ate meat. To his -pupils and apprentices, he recommended regular habits such as not -sleeping during midday, eating only when hungry and chewing well, -exercising moderately, and sleeping well covered. - -Yet, even though Leonardo lived cheaply, he was now greatly in need of -money. Swallowing his pride, he wrote to Ludovico, placing himself at -the duke's service once again. His absence from court, he said, had been -necessary so that he could earn a living. In this and other ways, -Leonardo attempted to heal the break between them. - -It turned out that Ludovico was glad to have Leonardo back. Perhaps -mindful of the fame that the model of the equestrian monument had -brought the house of Sforza, he now commissioned Leonardo to paint a -picture. The Dominican monastery of Santa Maria delle Grazie was the -nearest church to the Sforza castle and a favorite retreat of Ludovico. -Here he used to walk in the quiet garden while the white-robed monks -silently went about their chores. In gratitude for the peace he found -there, Ludovico had had the refectory rebuilt and on the back wall, a -crucifixion scene had been painted by Montorfano, a Lombard. But the -front wall was given to Leonardo. On this Leonardo decided to paint a -picture of the Last Supper--the painting that has since become one of -the best known in the world. - - - - - 8 - _The French_ - - -The noonday sun was baking the deserted streets of Milan as Leonardo -hurried across the drawbridge of the castle. The guard dozing in the -entrance arch started to his feet, but when he saw who it was he sat -down again, muttering about a madman. Taking the shortest way, Leonardo -arrived at the monastery gate and pulled on the bellcord. When the gate -opened Leonardo brushed past the startled monk and made directly for the -scaffolding in the refectory. He looked at his almost completed painting -for a moment, took a brush and mixed a color swiftly on the large -palette. Then he climbed the scaffolding and very quickly applied three -or four strokes. With this he sighed and smiled. Then, just as abruptly, -he put away his brushes and, without a backward glance, he left, making -his way back to the castle in the hot sun. - -For three years, Leonardo had been working this way on the "Last -Supper." - -Sometimes he would work from dawn to dusk forgetting to eat; other -times, he would stay away for days and then run back just to add a -touch. Once he arrived and, with his arms folded across his chest, he -stood in front of it for two hours just studying what he had done. - -Now, in 1498, the painting was nearing completion and the only faces -still left blank were those of Christ and Judas. Leonardo had drawn -hundreds of sketches, taking his models wherever he found them--once he -sketched a man just for his hands. Now that his name had become well -known he always had an audience while he worked. His pupils, the monks, -visiting nobility, church officials, and frequently Ludovico himself -watched him as he painted the "Last Supper." - -But Leonardo, as usual, was involved in many different tasks. He was -supervising the installation of a hydraulic pump over seventy feet high -beside a stream which would use the power of the stream itself to pump -water into the castle. Mindful, too, of the uncertainty of court -patronage, he was designing commercial machinery, hoping thereby to -secure an income outside the court. Among the most notable of these were -an olive press, an automatic file-cutter, a hydraulic saw, and a needle -sharpener. This latter was a forerunner of modern sharpeners with their -mass-production methods. With it, Leonardo dreamt of sharpening four -hundred needles at a time, or forty thousand an hour so that in twelve -hours one person could sharpen four hundred and eighty thousand needles! -The needles were arranged successively on a moving belt of leather and -brought against a rotating grindstone. This grindstone was set in such a -way that the needles were sharpened into curvilinear points rather than -the usual triangular points. - -In his travels to Vigevano and other parts of the countryside around -Milan, Leonardo had studied flour mills. He had talked with the workmen, -asked the prices of grain, and noted the time that it took to do the -milling. Then he made calculations on ways to cut down the time, and, in -fact, redesigned the entire mill. He mounted twelve cylindrical -millstones in rows of four on one side of a canal and another twelve on -the other side. In the canal were hydraulic wheels or paddlewheels. Each -wheel was attached to a rod that ran underneath four millstones. Geared -to the one rod were four grinding levers to the stones above. In this -way it was possible to have twenty-four millstones operating at the same -time. - -But most fascinating to Leonardo now was the construction of his flying -machine. His first models involved the principle of an air-screw mounted -on a platform on which a man stood. But where would the necessary power -come from to lift his machine from the ground? At first he thought of -operating his air-screw by means of a steel spring coiled around a drum, -but this he apparently abandoned. Later, however, Leonardo did design -another model on this principle which has been called the forerunner of -the modern helicopter. It was to be operated by four men standing on a -platform. Each man would hold a bar which wound a spring-driven -mechanism, much as in a modern clockworks. The air-screw was a broad -blade spiraling about a vertical shaft--the ancestor of the modern -propeller. - -The model that Leonardo wanted to construct now, however, was of a -different principle. Instead of an air-screw he substituted a pair of -wings fashioned after those of the birds. There was still a platform on -which the flyer stood and two springs were still the essential "motor" -to raise and lower the wings. But as Leonardo worked on his apparatus he -began to realize that it would be too much at the mercy of a sudden gust -of wind or a violent updraft. It was necessary to return to his study of -the air and its currents. - -With all of this activity in mechanical devices Leonardo had reawakened -his interest in mathematics. During this time he was introduced to a man -at Ludovico's court who became his friend and collaborator. He was a -Franciscan monk named Fra Luca Pacioli who had been appointed a -professor of mathematics by Ludovico. He, too, came from Florence, and -in 1496, when he met Leonardo, he was forty-six years old and the author -of _Summa di Arithmetica_, the first printed scientific work of his -time. Pacioli was now at work on a book of geometry to be entitled _De -Divina Proportione_ and he enlisted Leonardo's aid in drawing the plates -for his book. As Leonardo had already made a study of human proportions, -the association with Pacioli was of benefit to them both. Among -Leonardo's best known drawings of human proportion is a beautifully -rendered figure-study of a standing man with his arms at his sides and -then outstretched, his legs together and then apart, inscribed within a -square and a circle. It was made to illustrate a passage from Vitruvius -on the proportions of a human figure and demonstrated, among other -things, "the span of a man's outstretched arms is equal to his height." - -Moreover, Leonardo found with Pacioli confirmation of many of his own -observations and experiments and in turn Pacioli gave to Leonardo a -confidence in his own methods. Pacioli also helped Leonardo with his -arithmetic, a subject that Leonardo had neglected in his impatience to -study geometry. The association also helped to free him further from the -cobwebs of medieval beliefs. For Pacioli, the friendship with Leonardo -was a revelation. Although Pacioli was a learned mathematician, Leonardo -demonstrated to him that the application of his science encompassed -_all_ sciences--even art--for Leonardo later wrote, "Let no one read me -who is not a mathematician...." - -Legend relates that Leonardo became so absorbed in his studies that the -prior of the monastery complained to Ludovico that the "Last Supper," -although nearly completed, still lacked the faces of Christ and Judas. -Ludovico summoned Leonardo to court and laid the complaint before him. -Leonardo, however, was quick to reply. - -"The good prior is an esteemed man, your Grace, but he is a monk and not -a painter. Little does he know that I spend at least two hours a day on -my painting." - -"But Master, he says he never sees you there, so how do you explain -these two hours a day?" - -"Excellency, the figure of Judas must be of incomparable evil. Every day -I search for this face in the criminal quarter, and every day I fail to -find the evil that I am looking for. If I cannot find this man, however, -I can use the head of the prior--it would do admirably, but I have -hesitated for fear of hurting his feelings." - -Ludovico slapped his knees and roared with laughter. There were no more -complaints. - -Finally, in 1498, the scaffolding was removed from the painting and -Leonardo's masterpiece was revealed. The twelve apostles grouped at the -table are shown each responding in his own way to the words of Christ, -"One of you shall betray me." Again hundreds flocked to see this latest -marvel of Leonardo's. Its striking influence was felt by generations of -painters. Even now, more than four hundred and fifty years later, the -world still comes to stand before the genius of Leonardo da Vinci in the -refectory of Santa Maria delle Grazie. - - -The clouds of war were gathering again over Italy. In April of 1498, -Charles VIII of France died and his successor was Louis of Orleans, who -became Louis XII. The new King of France laid claim to the Dukedom of -Milan, and Ludovico again tried to form an alliance against him. But the -years of juggling enemy against enemy and friend against friend were now -coming to an end. No one trusted Il Moro any more, and suddenly he -realized that he was to be alone in this new fight. After nearly twenty -years of power sustained by powerful alliances, Ludovico was forced to -turn to his own people of Lombardy. Frantically he tried to correct the -injustices of years. The people had been cruelly taxed to support the -extravagances of the Sforza court, and, in addition, they had been badly -treated by petty government officials. Ludovico now sought to repay the -past miseries of his people and to rally them to his support. In such a -spirit he remembered his court painter, Leonardo da Vinci, and gave him -a vineyard and considerable piece of land not far from the Porta -Vercellina. - -Now, for the first time in his life, Leonardo knew financial security. -With the income from the vineyard, and in the peace of his estate, he -was left free to follow his own researches. He took no notice that his -"peace" was surrounded by the threat of war. Indeed, he remained aloof -from politics and court intrigues as much as was possible for a man -living in the midst of such chaotic times. - -Leonardo now had the opportunity to follow up an early interest--the -study of plants. He made many beautiful drawings; no plant was too small -to catch his eye. His notes on botany began to grow. With his genius for -observation and analysis of nature, Leonardo made some extraordinary -discoveries of botanical laws entirely unknown before his time. He wrote -of the phenomenon of _heliotropism_, or the movement of plants toward or -away from the sunlight. In addition, he described the phenomenon known -as _geotropism_, or the growth of plants according to gravitational law, -as for example, roots growing downward and shoots growing upward. He -also defined the laws of phyllotaxis, which describe the system or order -of leaf arrangement on a plant's stem. That is, leaves are arranged -spirally around a stem so that the third leaf above grows out over the -third leaf below on one type of plant; or, on another type, the two -third leaves are over the two third leaves below. The same natural laws -apply to the branches of plants as well; they occur so that every leaf -and branch can receive sufficient air and light. Amazingly enough, these -laws, which Leonardo described so completely, were not rediscovered -until almost two centuries later! - -Leonardo went even further in his botanical studies. He experimented -with gourds, planting them in various aqueous solutions; this -anticipated modern methods of growing plants in chemicals. He also -tested the actions of arsenic and mercury poisons in plants. He -reproduced the shape and form of leaves by pressing them on paper coated -with lampblack, a method that was not used again until the nineteenth -century. Carefully noted, too, in his writings was the rising of sap -from the roots to the branches by capillary action; this, too, was not -rediscovered until much later--in the eighteenth century. Leonardo also -extracted oils and essences from flowers and studied the influences of -altitude on the development of vegetation. Indeed Leonardo's very -approaches to a systematic classification of plants were the forerunners -of modern methods of classifying. - -In the seclusion of his own home, as he continued his studies of -geometry with Pacioli, Leonardo again turned to his observations of the -heavens. On the roof of his house he had set up a small observatory for -watching the sky at night. Often he looked at the stars through a -pinhole in a sheet of paper. Leonardo did this to stop the "twinkling" -of the stars which he recognized as an optical illusion. Moreover, by -looking at the stars in this manner, he noticed that some were larger -than others, and imagined to himself how our own earth might look from -them. Would we not be but another "star" in a vast collection of stars? -And if that were true--how could the earth be the center of the -universe? By the same imaginary reasoning, he speculated on how we must -look to someone on the moon. Realizing that the moonlight on earth -faintly illuminates the dark side of the earth, he reasoned that then -there must be an "earthlight" doing the same on the moon. Thus he was -the first to explain the dim reflected light on the dark side of the -moon. Moreover, Leonardo is known to have looked at the moon through a -convex lens, and perhaps even a form of telescope. Indeed, he had built -telescopic-type tubes with lenses in them and had written directions for -their use. It seems certain that at about this time Leonardo became -convinced of the heliocentric theory, the theory that states the sun is -the center of our universe. On a sheet of mathematical notes Leonardo -wrote in large letters, "the sun does not move." - -During this time he continued to seek out books on astronomy. Leonardo -was familiar with Aristotle's _Meteorology_, Archimedes' _On the Center -of Gravity_, and with _Problems in Aristotle's Books of the Sky and the -World_, a work by Albert of Saxony. This last book Leonardo had to read -with the help of a Latin dictionary, because his Latin was not good. He -had already read Plutarch, who had defined the moon as a solid. Plutarch -had written further that the "spots" on the moon were the result of -shadows cast by irregularities on its surface. This theory, that was -apparently abandoned during the Middle Ages, supported the conclusions -that Leonardo had reached by his own observations. But he still -struggled against a mistaken idea of his own. For a long while he -maintained that there were seas and waters upon the moon which accounted -for the sunlight being reflected so brilliantly. - -Meanwhile, in July of 1499, the French army had reached Lombardy. -Ludovico was now in a state of desperation. He tried to appeal to the -people of Milan, explaining that their heavy taxes had been due to the -constant threats from abroad. But, however hard he tried to arouse their -sense of loyalty to him, the public of Milan turned a deaf ear. They had -not forgotten how Ludovico had allied himself with Charles VIII--a -foreign king! Ludovico now had to put his trust in his army commander, -Galeazzo da Sanseverino, despite warnings that this was a man of -doubtful loyalty. Moreover, to make matters worse, Louis XII had -succeeded in forming an alliance against Ludovico; and, among his allies -was a powerful cardinal, son of Pope Alexander VI--the notorious Cesare -Borgia. - -From a note on a page of designs for supplying and heating a bath we -know that Leonardo continued his quiet life, only vaguely disturbed by -the political upheaval taking place around him. His note reads, "On the -first day of August 1499 I wrote here of movement and weight." He had -made many experiments and calculations concerning the movement and -weight of objects. He had drawn, for example, the flight of an arrow to -describe motion through air and although he wrote no specific formula, -he marked the three stages of its trajectory--the initial push, the -slowing and the steeper downward path as the arrow's momentum was -overcome by the resistance of the air. He also defined the law of -movement on an inclined plane and he arrived at the root principle of -Newton's law of gravitation when he wrote, "every weight tends to fall -toward the center by the shortest way." - -A diagram of this period is probably the first scientific graph. -Leonardo had experimented with two balls dropped from a height. First he -dropped them together and then one after the other. In attempting to -solve the mathematical problems presented by these falling bodies he -drew a graph of vertical and horizontal lines. The times it took for the -balls to fall were marked on the horizontal lines and the distances on -the vertical lines--thus, he could trace their relationship. - -But this peaceful time of productive work was running out for Leonardo. -Ludovico's commander, Galeazzo, had yielded the fortress of Alessandria -to the French at the first battle. Ludovico himself had sent his sons -and his treasure to his brother, Cardinal Ascanio, in Germany. When he -saw that his cause was lost, he turned the Sforza castle over to -Bernardino da Corte, a trusted commander, making certain that it was -fully supplied with arms and food. Then in sorrow, Ludovico Sforza, Duke -of Milan, left his city for the last time as ruler of Lombardy. The -gates of Milan were opened to the French in October of 1499, and -Bernardino da Corte surrendered the Sforza castle. - -French soldiers now occupied Milan as conquerors and the people of the -city were in a state of confusion. Those who could made their peace with -the French; but others, who had been supporters of Ludovico, fled to -avoid arrest. Leonardo, who would be suspect to the French, packed up -his few possessions--although he did manage to retain his estate--and -left, together with Pacioli and an apprentice, for Mantua. - - [Illustration: _Leonardo had to flee Milan._] - - - - - 9 - _Cesare Borgia_ - - -Leonardo, Pacioli, and Salai, the apprentice, arrived in Mantua in -February of the year 1500. They were given refuge in the castle of -Isabella d'Este, who was the sister of Beatrice, and the wife of -Francesco Gonzaga, governor of Mantua. Isabella was one of the eminent -women of her time and attracted to her court the intellectual life of -Italy. In Leonardo she recognized the man of genius; indeed, she treated -him as an equal, putting her castle at his disposal. She persuaded him -to paint her portrait and Leonardo commenced a preparatory drawing. - -In the evenings at the castle there were discussions and music and here -Leonardo again met his pupil and companion on the trip from Florence so -many years ago--Atalante Migliorotti who had left Milan in 1490 to -assume the post of court musician to Isabella. - -Although Leonardo had found a haven of peace in the political storm that -raged about the city state of Mantua, he and Pacioli took to the road -again for reasons unknown. Isabella d'Este, who still wanted Leonardo at -her court, sent many a letter and messenger in the following years to -bring Leonardo back--first to finish the portrait and then, when that -failed, to sell to her any picture that Leonardo wished to send. -Strangely enough, however, Leonardo seems to have turned his back upon -the one sympathetic person he had met in a world of indifference. - - -The first, warm breezes of spring were blowing over the lagoons of -Venice when Leonardo and Pacioli stepped ashore on the Piazzetta, or -Little Square of San Marco. But the beauty of this jewel-like city -rising from the sea was momentarily ignored by the two travelers for an -angry, frightened crowd had gathered about the Doge's palace on the -Piazzetta. - -The people of Venice were fearful because their fleet had just suffered -a crushing defeat by the Turks. This meant that their power at sea, once -supreme, was now no more. Year by year, moreover, their possessions in -the east had been slowly whittled away, and now the city itself was -threatened by invasion. At this same time, the Venetian ambassador, -Manenti, hoping to make peace with the Turks, had been rudely rejected -by them. Panic soon swept the city and rumors of the bloodthirsty -infidel passed from person to person like the rush of an ugly wind. -Barricades were put up and windows were barred. In this charged -atmosphere, Leonardo and Pacioli sought out their lodgings. - -Soon after Leonardo's arrival here--either because his reputation had -preceded him or, more likely, because of Fra Luca Pacioli's -recommendations--he became directly involved with the defenses of -Venice. Immediately he was sent on an inspection trip of the city's -existing defenses, especially those inland from where an invasion would -probably come. When he had seen them, he recommended a system of -defenses along the Isonzo river near the present border of Yugoslavia, -using the river itself to the disadvantage of the enemy. He also made -suggestions for the improvement of forts, and even drew up plans for a -completely new type--a circular fort. This consisted of a central, -circular fort surrounded by two belts of fortresses each separated by a -moat. In the outside moat were four semicircular outposts. Communication -was by underground galleries. The total absence of superstructure and -projecting balconies was a new idea for the times. Another new defense -idea was to station in the moat itself a low, thick tower almost -completely submerged, defended by a thin opening near the waterline. It -was reached from the main fort by an underground passage and the -gunsmoke was removed by vents. According to Leonardo no enemy could -conceal himself in any part of the defenses and not be seen from such an -outpost. - -Leonardo's most unusual scheme for defending Venice, however, was his -idea of approaching an enemy fleet under the water and then putting -holes in the hulls of their ships. Actually, the idea of diving was not -a new one. Aristotle had written of diving and diving bells, and -certainly the stories of pearl fishers in the Orient were well known in -the Renaissance. But Leonardo designed a diver's suit closely resembling -those used today. This consisted of a complete suit of leather with -helmet and eyepieces; it was made airtight by spirals of steel at the -joints. He then added a bladder for holding air which fastened inside -the suit at the diver's chest. It is possible that Leonardo also -invented an air chamber that could be used by the diver while under -water--but he was very secretive about this invention for fear of how -men might abuse such a discovery. He wrote, "... and this I do not -publish or divulge, on account of the evil nature of man, who would -practice assassinations at the bottom of the seas...." - -Leonardo felt the same way about a "submarine" that he presented to the -Councilors and Tribunal of Venice. This resembled a turtle's shell with -a raised bump on the center which was the "periscope." When submerged -the water probably rose to an area just around the "periscope," but, -again, the information about its air-supply is missing and the only -reference to it is a reminder to close the "l--." In addition, he -invented a system of screws mounted in tongs with the borer in the -middle for putting holes in the bottoms of enemy ships, and at the same -time he thought of a defense against such an attack by designing the -defending vessels with double hulls. - -Among Leonardo's other maritime devices were designs for boats that -could dredge canals, harbors, and lagoons. What was the result of all -these plans? We do not know. Whether any one of them was used against -the Turks is a mystery. - -At any rate, Leonardo and Pacioli left Venice that same spring and -arrived in Florence in April of 1500. One of the purposes of Leonardo's -journey was to visit his father who was now living on Via Ghibellina -with his fourth wife. Leonardo was now forty-eight. Still tall and -straight with the strength of his youth, his face prematurely aged and -his hair thinning back from his high forehead, Leonardo was more than -ever an outstanding looking man. He still scorned fashionable clothes -and dressed according to his own comfort which made him even more -noticeable among the crowd. His deep-set eyes with their direct and -penetrating glance, framed by his full, reddish beard, never missed a -thing, although he now wore spectacles at his work. - -Now that he was back in Florence, Leonardo needed lodgings and a job. He -had banked his small savings, and he did not want to touch that. His -father's house with the five children of his present wife plus the sons -from his previous marriages was too full to accommodate Leonardo. -Moreover, the relationship between Piero and Leonardo was polite but -distant, as Piero preferred the children of his later marriages. - -Luckily, the place to live and the commission Leonardo needed presented -themselves at the same time. The Church of the Annunciation of the -Servite Order of Monks needed an altarpiece, and, as Leonardo's fame was -great, they offered him and his apprentice quarters in the monastery. -Here, in the solitude of a monastic cell, Leonardo was able to return to -his own researches. His long association with Fra Luca Pacioli continued -as they worked together on Pacioli's edition of Euclid's _Elements_. At -the same time, with his absorption in geometry, Leonardo commenced his -studies of the transformation of solids; that is, changing the shape of -something to another shape without diminishing or increasing its -substance. - -In his preoccupation with geometry, Leonardo had apparently done little -about the commission which the Servite monks had given him. He finally -yielded to their complaints, however, and commenced to draw the -preliminary study for the subject, which was "St. Anne with the Virgin -and Child." Again his knowledge of geometry is most apparent in the -finely constructed composition, every gesture of which is as plotted as -a geometric exercise. In April of 1501, the drawing was finished; it -caused an immediate sensation throughout Florence. For two days the -public was allowed to pass in front of it. - -But now a change was taking place in Leonardo. He was no longer content -with simply painting. His highly original researches for pictures had -slowly grown to the point where the research was more important than -painting. In a sense the scientist had taken the brush from the artist. -In two letters from Isabella d'Este's emissary in Florence we learn, "He -is entirely wrapped up in geometry and has no patience for painting." -This excerpt from a letter dated April 8, 1501, was followed six days -later by another which said in part, "In brief, his mathematical -experiments have made painting so distasteful to him that he cannot even -bear to take up a brush." - - -A few months after the completion of the St. Anne drawing, Leonardo -received a letter signed by Cesare Borgia, Duke of Valentinois. Leonardo -frowned and thought back to his last days in Milan. When King Louis XII -of France had entered the city, he had summoned the painter of the "Last -Supper" to an audience. The king had been generous in his praise and had -tried to persuade Leonardo to remain. At that same audience had also -been Cesare Borgia, an ally of the French. Leonardo remembered the man -now--the dark hair and eyes, the black, arched eyebrows, and the face -marked by some old disease. He was a powerful-chested, thin-hipped man -who had originally been made a cardinal by his father, Pope Alexander -VI. But the attractions of secular power soon persuaded him to abandon -this title. With the enthusiastic help of his father, Borgia had fought, -murdered, and deceived his way to a formidable position of authority in -these last years. Leonardo, in the seclusion of the monastery, had -lately heard that Borgia's army had even been at the gates of Florence. - -The letter addressed to Leonardo was an offer to assume the post of -Architect and Military Engineer to His Excellency, Cesare Borgia. He -thought of Ludovico Sforza--defeated and captured at the battle of -Novara just a year ago as he attempted to regain his dukedom. Now the -duke was a prisoner at Loches in Touraine; Leonardo had written of him, -"The duke lost his State, his personal possessions and his liberty, and -none of his enterprises have been completed." And Leonardo also thought -of his equestrian monument still standing in the castle being used for -target practice by the French archers. Like the duke, nothing of his own -had been completed either. Perhaps this Borgia offer was an opportunity. -Leonardo decided to accept it. - -In May of 1502, after having presented himself to Cesare Borgia in Rome, -Leonardo began his hectic travels through Tuscany and Umbria. He was to -inspect the fortresses and cities of Cesare's new conquests there, and -to make whatever recommendations he felt necessary for their -improvements. Arriving in Piombino, he at once set down a project for -draining the marshes and reclaiming the land. Also, while he was here, -he spent hours by the sea watching the waves curl in from the Adriatic -and studying the crash of water over the beaches. Moving on to Arrezzo, -he drew up the first in a series of remarkable maps for the army of -Vitellozzo which, with the backing of Cesare Borgia, was marching -against Florence. These maps are bird's-eye views of Tuscany and Umbria, -and somewhat resemble modern aerial photographs. Drawn from Leonardo's -own observations, the green mountains stand, according to their height, -in relief, with the roads winding over them and down through the -valleys. The streams and their tributaries are in blue and even the -villages and cities are drawn with great exactitude. Indeed Leonardo had -learned his lessons from old Toscanelli well, and he was one of the -first to bring the art of cartography to such perfection. - -In July and August Leonardo was in Urbino and Pesaro, and by the 8th of -August he had reached Rimini. Here he strengthened the fortifications -and then rode quickly on to Cesena. Between Cesena, capital of the -Romagna, and Porto Cesanatico, he spent from the middle of August to -September planning a canal between the two, redesigning government -buildings, and drawing up a new quarter to be built for the city of -Cesena. At this time he constructed an instrument for telling him the -speed of water currents in a stream. It told him whether the flow was -swifter at the surface or at the bottom or on one side or the other of -the stream's bed. - -In the meantime, Florence, alarmed at the growing power of Cesare -Borgia, appealed to Charles d'Amboise, Regent of Milan for France, to -come to her aid. Charles responded in the absence of the French King and -helped to protect Florence. The enemies of Cesare took advantage of this -to form an alliance, and soon Cesare was being forced back from his -newly won possessions. Cesare himself then hastened to Milan, and there -he suddenly came face to face again with Louis, the King of France, who -was on his way to Naples. Borgia, who could exert great charm and -influence when he wished, persuaded the king that, all rumors to the -contrary, he, Cesare, was fighting the enemies of France. Again he won -over the French, which greatly strengthened his position. Then, from -Pavia, he issued a decree placing every facility possible at Leonardo's -disposal. In addition, he instructed all officials to help Leonardo in -every matter, referring to him as "our highly esteemed court architect." - -While Leonardo was in Porto Cesanatico, a delegation from Bayzid II, -Sultan of Turkey, paid a visit to Cesare Borgia. Among other things the -delegation was looking for an engineer to build a bridge between -Constantinople and Pera to replace a temporary wooden structure. -Leonardo designed for them a single-arched bridge with double ramps at -either end (looking very much like a present-day "thruway" entrance). He -provided that it should be approximately twelve hundred feet long, -eighty feet wide, and one hundred and forty feet above the water. - - [Illustration: _Da Vinci's proposed bridge from Constantinople - (Istanbul) to Pera. Looking very much like a modern "thruway" - entrance, it was to have double ramps on both sides._] - -In his travels through the countryside, Leonardo could not help but -notice how primitive the mills were. Feeling how strongly the wind blew -in from the sea, he designed a windmill with a roof that turned with the -sails. For the mechanism inside he devised a band brake--a semicircle of -wood into which the large cogwheel of the mill was forced. This mill -resembles the "Dutch" mills of the Netherlands and was among the first -of its type to be brought into existence. - -In the fall Leonardo was at Imola. There he created another of his -beautifully rendered maps. He drew this with the help of a magnetic -compass of his own invention. It consisted of a board with an arc on it -and a compass needle, and was probably the first magnetic needle on a -horizontal axis. This time the map was of the city itself, the walls, -the castle and the principal buildings all touched with color and the -river winding through the fields. Drawn in the shape of a circle, it -resembles a view through a telescope from directly above. In Imola, too, -he met Niccolò Machiavelli, the famous historian and political -scientist, who was an emissary from the Signoria, the Council which now -governed Florence. These two men became friends and, later, -collaborators in Leonardo's scheme to make the Arno river navigable to -the sea. - -At this time Cesare Borgia, having achieved great success in his -military campaigns and confident of his conquests, decided to return to -Rome. With the disbanding of Borgia's headquarters at Imola, Leonardo's -duties were finished. Together with his new friend Niccolò Machiavelli -and two other Florentines, he left Imola and the service of Cesare -Borgia to return to Florence. - -In January of 1503, a mathematician named Giovanni Battista Danti -attempted a flight in a machine that he had designed. This flight was -part of the entertainment at a wedding reception in Perugia. Danti -climbed into his apparatus on top of the tower of St. Mary of the -Virgin. It was pushed off into the air, hovered a few seconds, then -began slowly drifting toward the ground. But suddenly, one of its wings -hit a building projection and it crashed. Danti was carried away with a -broken leg. - -The news of the event traveled quickly to Florence. - -When Leonardo heard about it, he eagerly questioned all those who had -either seen it or had heard it described first hand. Danti's attempted -flight excited Leonardo for now he realized that he was no longer alone -in his search. With a sense of urgency he returned to the problems of -flying. He felt now that the solution to flight might be in the swift -gusts of air through the ravines and the spread wings of the eagle -drifting high in the sky. - - - - - 10 - _Shattered Hopes_ - - -Before Leonardo could return to the problem of flight, however, he was -again faced with the necessity of supporting himself and his growing -household. The small fees he received for taking on apprentices hardly -covered the cost of housing and feeding them. Moreover, the equipment he -had to buy for his scientific researches added further to his strained -budget. So, when a servant from Francesco del Giocondo, a rich -Florentine merchant, presented himself at the gate with the request that -Leonardo accept a commission to paint Francesco's wife, Leonardo was -only too glad to accept. The name of Francesco's wife was Madonna Lisa, -or Mona Lisa for short. Leonardo painted her portrait on and off for the -next three years. Thus, what started as a minor commission ended as the -one painting--in addition to the "Last Supper"--that most people today -associate with the name of Leonardo da Vinci. - -Having secured this work, Leonardo turned back to his studies of birds -in flight and the nature of air. The soaring wings of eagles and hawks -and the way they rode the currents with hardly a dip of their spread -wings guided Leonardo's thinking from pure mechanics to machines that -act more on the principle of the glider. He proposed to write a treatise -on the nature of birds' flight, and, with his usual thoroughness, he -began to weigh, dissect, and reconstruct various types of birds and -their wing structure. He realized that one of the main difficulties of -gliding was maintaining balance, or, more accurately, maintaining the -center of gravity. From previous observations Leonardo had noted that -man is capable of making the same motions that a bird does. He had also -measured the strength of a man's legs and had calculated that man has -twice the power in his leg muscles that he needs for standing. -Consequently he began to redesign his machine making use of man's arms -and legs to operate or "flap" the wings instead of standing him on a -platform. - -The first of Leonardo's new designs was a sort of harness apparatus -strapped across the shoulders of the flyer who was supposed to be able -to keep himself balanced by moving the lower part of his body. He could -manipulate the flight by handles that were connected to the flexible, -outer parts of the wings. These wings were designed from the webbed -wings of the bat. Surprisingly enough, this device closely resembled the -experimental gliders used by Otto Lilienthal almost four centuries later -in Germany. - -Leonardo was now approaching other solutions to pure flight when further -hostilities interrupted his work. Florence and Pisa were in bitter -rivalry, and their struggle had assumed the proportions of a major war. -The Florentine army was now practically at the gates of Pisa. Niccolò -Machiavelli urged the Signoria to enlist the help of Leonardo da Vinci, -who might be able to think of an immediate plan for destroying Pisa and -her army. Never one to think in terms of an immediate battle or a -temporary success, Leonardo put forth a daring and sweeping plan that -would forever reduce the power of Pisa. The plan was as simple as it was -monumental--divert the Arno river from its course into two canals that -would empty into the sea at Leghorn south of Pisa. In this way, Pisa -would lose her water supply and her opening to the sea. - -The plan met with immediate approval and by the end of July 1503, -Leonardo was sent out to survey the entire course of the river. He was -accompanied by Giovanni "the Piper," a man who was frequently employed -on minor engineering projects and who was the official player of the -pipes to the city of Florence. Giovanni was also the father of Benvenuto -Cellini, who became the most famous goldsmith of the Renaissance. As -they made their way to Pisa, Leonardo made some more of his -extraordinary maps of the area, paying particular attention to the -course of the Arno and its tributaries. These maps later inspired him to -plan a whole series showing the main watersheds of Italy. - -When he rode into the Florentine camp drawn up before Pisa, Leonardo -designed from his observations and maps, a dam on the Arno to regulate -the course of the river. This bird's-eye view map is a marvel of -exactness. It shows the flow of the river hitting the dam with its -swirling backwash and overflow. Leonardo's knowledge of the movement of -water was so great and his craftsmanship in drawing so fine that the -water in this map seems to flow before one's eyes. One of the main -problems in regulating the Arno was its tendency to continually be -shifting its bed by the deposits of new sediment, and Leonardo realized -it would be a long time before this project could be completed. - -When he returned to Florence he presented to the Signoria, as part of -his survey, various machines to hasten the excavation of the Arno. He -had designed a crane that would assist in the digging out of two -different levels at the same time. He also submitted the results of his -calculations on the saving of muscular energy by the use of such -machines. In addition, Leonardo proposed to use the water in the canals -for irrigation purposes and had even calculated what the volume and -velocity of a jet of water would be if projected from an opening in the -bottom of the canal wall into an irrigation ditch. As if this were not -enough, he had invented a practical method of piling as a foundation for -the lock-basins to protect them against the dangers of erosion. - -A separate map of this period on the flow of rivers in general was -intended to relate to his treatise on the nature of water. In this -treatise is the first outline of the fundamental principles of -hydrodynamics, as for example: - -The velocity of a current increases with the slope and decreases with -the winding of the riverbed. - -The volume of a river is in proportion to the width of its bed, the -slope and the depth of the water being equal. - -The slope and width being equal, the speed of the current is greatest in -the deepest part of the river. - -The excavation force increases at the narrowest section of the river. - - -Because of the grumbling of the military commanders at what they -considered a waste of time, Machiavelli had to intervene with the -Signoria before Leonardo was sent out again with documents of authority -to continue with his plans. He spent well into the fall surveying the -Arno and in October he was back in Florence. - -Meanwhile the fighting between Pisa and Florence had been lessened by -two political changes. In August Pope Alexander VI had died and his son -Cesare Borgia became seriously ill. The Republic of Florence was now -free of its most dangerous enemies--the Borgias. The city relaxed in its -new security and the hostilities between Florence and Pisa died down to -an uneasy armed watch. - -Leonardo quickly took advantage of the situation to present an early -dream of his to the Signoria. He again put forth his idea of a -commercial canal to the sea and made mention of the great advantages -there would be for all the mills, lumber yards, forges and other -commercial interests in utilizing the water power that would be -available from his project. Piero Soderini, the governor of the -city-state of Florence, was impressed and thought of the glory it would -bring to Florence and himself. He told Leonardo he would present it to -the Signoria. - -Leonardo now plunged into a winter of great activity. Forced to draw -from his savings, he had rejoined the guild of painters in October of -1503, and then applied for the commission of painting the murals in the -council chamber of the Palace of the Signoria. It had been planned to -decorate this great hall with scenes commemorating famous Florentine -victories, and Leonardo chose the battle of Anghiari where the soldiers -of Florence defeated the Milanese in 1440. In addition to working on the -"Mona Lisa" and continuing with the canal project--for which he was now -designing great suction pumps to lift rivers from one level to -another--he turned again to astronomy and geology. - -Leonardo, while investigating the course of the upper Arno, had come -across much evidence that the land there had at one time been completely -under water. Various types of ancient ocean life and vegetation lay -scattered in layers along the ridges of the mountains, and these -Leonardo collected and brought back to his studio. He wrote, "above the -plains of Italy where now birds fly in flocks, fishes were wont to -wander in large shoals." He reread Ptolemy, the ancient Greek geographer -Strabo, and even Sir John Mandeville, an English author of travel books, -in his quest for knowledge of distant places. He talked to travelers, -sailors, and wrote to friends to send him information about the -countries they had seen or lived in. Strabo, in particular, had set -forth the doctrine that the earth's transformation had taken place by -the forces of volcanoes and water, but the wisdom of these early men had -been obscured by the closed minds of the Middle Ages. - -Even in his own time of reawakening knowledge--the Renaissance--Leonardo -had to contend with the combined superstition of the Church and the -ignorance of misguided scholars. For example, the Church believed in the -great flood, as described in the Bible, and the scholars claimed that if -what Leonardo said were true--that the earth was the result of an -evolutionary process--there would have been written records. To this -latter Leonardo responded, "... sufficient for us is the testimony of -things produced in the salt waters and now found again in the high -mountains far from the seas." But Leonardo's conception of the evolution -of the earth was mistaken in one respect. He regarded the earth as -organic--living--and the flow of water he believed to be like the flow -of blood in man. Indeed, according to Leonardo, all living creatures -were reflections of a living, breathing earth. It was only when he again -turned his eyes inquiringly toward the moon and the laws of the universe -that he began to realize his error. - -It had been the idea that the earth was the center of the universe which -supported Leonardo's theory of an organic earth. Yet after years of -observation and study he abandoned this theory and, with the eye of a -man centuries ahead of his time, he wrote in his notes, "The moon has -every month a winter and a summer. And it has greater colds and greater -heats and its equinoxes are colder than ours." He went further and -identified the elements existing on the moon such as "water, air, and -fire," and described them and their functions as being like those on our -own earth. In so doing he recognized the existence of the moon as a -solid in space, reflecting the light of the sun--one of many "stars" in -a universe. With his acceptance of this concept he realized that the -earth could not be organic. - - -In May of 1504, the Signoria complained to Leonardo that there had been -no progress on the proposed paintings for their council chamber, even -though he had already been partially paid for them. Accordingly, he was -forced to sign a document that he must be finished by February of next -year or refund all monies paid him. As was his custom he had made many -preliminary drawings. Although he was well acquainted with horses he had -again researched their anatomy and actions. Pages of rearing, frightened -horses and men in combat covered his studio tables. On one of these -pages there are sketches of the heads of a lion, some horses and a -man--all with fierce expressions on their faces. Here Leonardo hinted at -the comparative anatomy of expression in man and animal that Darwin was -to write about almost four hundred years later. - -But the paintings could wait, for now the Arno River was in spring -flood. The time had arrived to make the first attempts at diverting the -river into its new course. Leonardo was again in the field supervising -the work. There had been much opposition to Leonardo's canal from both -the army captains and the Signoria. It was called a whim and a crazy -idea, but Piero Soderini and Niccolò Machiavelli were stubborn in their -defense of Leonardo's plan and they overcame all opposition to it. And -indeed, the raising of the sluice gates was successful and the Arno -actually flowed into its new bed. The tensions in the camp and in the -Council of Florence were eased. The only sad person was Leonardo, for he -had just learned of the death of his father. - -Leonardo felt the loss deeply. Outwardly, however, he only acknowledged -the death of his father at a distance. Not only had Leonardo and his -father drifted apart over the years, Piero left nothing to Leonardo in -his will. His father's other children quarreled among themselves over -what money he did leave. Leonardo's one friend in the family was Uncle -Francesco, who was still living in Vinci. When he heard of his brother's -will, Francesco made out a will of his own and left everything to the -nephew he loved--Leonardo. - -After having successfully diverted the Arno river, it was now necessary -for Leonardo to return to the painting commissioned by the Signoria for -its council chamber. But recently, Leonardo had suffered a rebuff in -this work. Originally he had been given the whole room to do but now the -opposite wall had been assigned to another man--Michelangelo Buonarroti. -Leonardo had first met the young Michelangelo when he helped to judge -the best location for Michelangelo's monumental statue of David. The two -men were opposites in every way. Leonardo, fifty-two years old, -carefully dressed, cool and detached, was a man whose every action was -the result of a thoughtful and analytical mind. Michelangelo, twenty-six -years old, his clothes rumpled and covered with marble dust, was -passionate and moody--an impulsive youth totally dedicated to art. They -did not like each other, and now Leonardo was forced into a rivalry for -which he had no heart. - -The duel between these two giants of art aroused the whole of Florence -and there was a constant stream of people watching them at work. -Michelangelo was given a studio in the hospital of Sant' Onofrio and -Leonardo was working in the Papal Chamber in Santa Maria Novella. Among -the many people who came to watch Leonardo was a young man of nineteen. -He was already a pupil of Perugino and the experience of meeting and -learning from Leonardo was to influence him the rest of his life. His -name was Raffaello Sanzio--one of the great Renaissance painters of -Italy and known to us by the name of Raphael. - -While Leonardo worked at Santa Maria Novella he had the opportunity of -continuing his studies in anatomy. Dissections at that time were -novelties and when one was performed the doors were thrown open to the -public. Leonardo must have attended the public dissections at the Church -of Santa Croce. Now at Santa Maria Novella there was a hospital, and -here Leonardo was able to continue his own dissections without -interruption. In a cool room below the hospital where bodies were kept -Leonardo worked late into the night. By the flickering lights of candles -and in the silence of the world about him he studied, drew, and wrote in -his notes of the wonders of the human body. - - [Illustration: _In a cool room below the hospital, Leonardo worked - late into the night._] - -He performed autopsies on people who had died natural deaths--a special -permission granted to him by the monks of the church, and among these -autopsies are the first written reports of some of the diseases that are -the causes of death. Arteriosclerosis, or stony growths in the blood -vessels, and pulmonary tuberculosis, a nut-like growth in the lung, are -among the discoveries Leonardo made in his lonely searches, although he -did not use these medical names for them. - -Above all Leonardo was attracted to the function of the muscles, -especially those in the arms and legs. So faithfully, in fact, did he -record the origin and insertion of all the various muscles that these -drawings can be used as anatomical models today. Moreover, he believed -that a good drawing was worth pages of words describing human anatomy. -The muscles were rendered as cords so as to better understand their -function. He described this function as one of pulling instead of -pushing and he noted that for every muscle there is an opposing muscle. -When one contracts the other expands. For example, when you tighten the -biceps in your arm you can feel the looseness of the triceps, the muscle -on the opposite side. - - -As the end of the summer of 1504 approached, Leonardo's dream of the -canal from Florence to the sea was destroyed. The summer had been hot -and without rain. The water in the canal dried up and the Arno river -returned to its original course. All the old arguments against the plan -were revived. The Florentine army captains rebelled against the job of -defending a useless project. Again Soderini and Machiavelli intervened. -After heated debates in the Council of Eighty, which had been called -into special session, Machiavelli himself was sent out to oversee the -work. It was brought almost to completion when in late October disaster -struck. The rains that had failed to come in summer fell from the -heavens in great cloudbursts. Storm after storm swept the valleys. The -workmen left and the soldiers were recalled. The Pisan army rushed in to -fill up the diggings and one final storm washed away the dream to -nothing but eroded mounds of dirt. - -Leonardo buried his disappointment in other work. When the drawing for -the Battle of Anghiari was ready for transfer to the wall of the council -chamber, he had a special scaffolding made of his own invention which -worked on the principle of a pair of scissors standing on end, with a -long platform on top. As the legs were spread the scaffolding was -lowered and when they were pinched together it was raised. The wall had -been prepared with a special mixture which he hoped would bring out the -brilliance of his tempera colors. With several assistants who had been -assigned to him by the Signoria the violence of the Battle of Anghiari -was transferred to the wall and the actual painting was begun. - -During the winter months Leonardo would relax from his work on the huge -painting and his dissections to roam the country around Florence. He -visited the slaughterhouses where the animals were killed and prepared -for market. Here he was able to examine the hearts of animals just -slaughtered and to note that the heart retained its action until the -body was almost cold. He made a glass model of the aorta (the main -artery leading from the heart) of an ox with which he could experiment -on the flow of the blood. He intended to add to it a glass tube for one -of the semilunar valves of the heart. He also experimented with a frog, -dissecting its brain, heart, and entrails and noted that it ceased to -twitch only when the spinal cord was severed. In his notes, he wrote, -"The frog instantly dies when the spinal cord is pierced; and previous -to this it lived without head, without heart or any bowels or intestines -or skin; and here therefore it would seem lies the foundation of -movement and life." He was of course searching for the reasons that -muscles moved and from where the impulses originated. - -One of Leonardo's favorite places to visit was Fiesole where his uncle -Allessandro Amadori lived. Uncle Allessandro was the brother of -Leonardo's first stepmother and, since he had loved her so much, he -likewise felt an affection for Allessandro. At Fiesole, which rises over -Florence in a steep ascent, Leonardo could watch the birds circling in -the air below him. - -On these lofty heights, he would unfold his drawings of flying machines. -Leonardo had progressed now to a point where an actual flight was all -that was left. He had designed a sort of flying boat--a shell with wings -that moved up and down and he had introduced a tail like that of a bird. -He had noted that the tail of a bird acts as a rudder, a stabilizer and -a brake when landing. - -But Leonardo's most recent design was one that was called an -_ornithopter_. It consisted of a wooden frame, two huge wings like a -bat's, a series of ropes and pulleys and a windlass, all planned with -the lightest of materials. The flyer, lying prone in the frame, his feet -in leather stirrups connected to the wings by pulleys, would move his -feet up and down to flap the wings while, at the same time, he operated -the windlass with his arms in order to guide the machine. Soon he hoped -to build this machine and try it out. - -Meanwhile, Leonardo returned to his painting in the council chamber with -impatience, for spring was approaching and the time to finally realize -his dream of flying would be at hand. Aside from an assistant who had -tested the pedals and windlass, no one knew of his plan to actually put -his machine in the air. - - [Illustration: _The_ ornithopter, _one of Leonardo's designs for a - "flying machine." By pumping his feet in the stirrups, the flyer - could flap the device's wings._] - -Weeks passed and the painting was almost finished. The huge wall was -covered with plunging horses and embattled soldiers. The colors were -brilliant on the special mixture he had prepared for the wall--but they -were not drying as they should have. Something was wrong. To speed the -drying process, Leonardo had a special fire built in the room that -directed the heat onto the painting. Spectators were allowed to watch as -the waves of hot air rose against the wall. Then--disaster began slowly -with a small trickle of paint from the top! Before anybody could put out -the fire, the great figures and horses slowly melted down the wall in -shiny, sticky streaks of color. Leonardo fled the room in an agony of -shame. - -With his own friends discouraged, the Signoria hostile, and the friends -of Michelangelo triumphant, Leonardo went back to Fiesole. He went back -with his secret dream of flight. The world would soon forget the Battle -of Anghiari--but the conquest of the air, if he could achieve it, would -live forever. - -In the spring of 1506, from the slopes of Monte Cecero near Fiesole, -legend tells us that a great bird sailed into the air and disappeared. -No one knows whether Leonardo actually flew his machine or not but -Girolamo Cardano, the son of a friend of Leonardo, wrote, long after -Leonardo had died, "Leonardo da Vinci also attempted to fly, but he -failed. He was a fine painter." Another dream had been shattered. - - - - - 11 - _The Return to Milan_ - - -Leonardo felt his fifty-four years that spring day in 1506. The -bitterness of his failures and the frustration of his dreams added -considerably to the weight of his years. All morning he had wasted in -argument with Soderini and the Signoria. If it had not been for the -letter from Charles d'Amboise, Viceroy of the King of France for Milan, -he would have felt like a beggar. Charles d'Amboise had been appointed -military governor of Milan by Louis XII ever since the French had -conquered that city and captured Duke Ludovico Sforza. But the authority -of the letter had finally won a grudging consent from Soderini. Leonardo -looked about him to see if he had forgotten anything and slowly climbed -onto his horse. He nodded to Salai, his apprentice, looked back to see -if his servant had the pack-horses ready, and started down the street -leading the small procession. He was going back to Milan. - -Leonardo took out the letter and reread it. The words were respectful -and admiring--and in French. They requested the presence of "Maître -Leonard de Vinci" at the court of Charles d'Amboise, for purposes of -painting and other "diverse projects" for the King of France. The letter -restored a measure of confidence to Leonardo's self-respect. Before -Leonardo left, Soderini had made him sign a letter in which Leonardo -promised to return to Florence within three months and to leave a -deposit of one hundred and fifty florins which would be held against his -return. It was signed, notarized and dated May 30, 1506. Nevertheless, -Leonardo had decided to accept the French envoy's offer; moreover, he -looked forward to the prospect of returning to his vineyard at Porta -Vercellina and the understanding of a sympathetic patron. - -Indeed, Charles d'Amboise turned out to be more than sympathetic. He -recognized Leonardo as a great artist; but even more, he was one of the -few patrons who could appreciate the magnitude of Leonardo's scientific -and mechanical genius. In the court of Charles, Leonardo once more -enjoyed a time of peace and an assured income. The French -Vice-Chancellor of Milan, Geffroy Carles, who was second in command, was -also a distinguished scholar and a patron of the arts and natural -sciences. With the admiration and support of these two men and -especially with the distant backing of King Louis XII of France, -Leonardo's dismal memories of Florence began to fade. - -Leonardo's three months' allotted absence from Florence, however, were -soon past and a letter arrived from Soderini demanding either Leonardo's -return or a forfeiture of the one hundred and fifty florins deposit. Now -a tug-of-war developed between the Viceroy of Milan and the governor of -Florence over Leonardo. The Signoria reminded Charles that Leonardo had -his work to complete, while Charles d'Amboise and Geffroy Carles -demanded an extension of time. One month more was granted. More letters -were exchanged until the affair became so heated that the King of France -himself intervened. In January of 1507 the French King informed Soderini -and the Signoria that Leonardo was "not to move from Milan until our -arrival." Since Florence at this time was under the protection of the -French, such final authority silenced the Signoria. Shortly afterwards -Leonardo discharged his obligation to the Signoria by relinquishing the -one hundred and fifty florins, and he at last became free from the -demands of his native city. - -On May 24, 1507 King Louis XII re-entered Milan with all the splendor -and color that France and the Dukedom of Milan could confer upon their -ruler. Knights in armor and the ladies of the courts followed the king -who rode in flowing white and gold under a canopy of blue decorated with -the lilies of France. - -With such pomp and display in Milan, Leonardo was soon back at his old -occupation of designing pageants and tournaments. While some of the -people from the days of the Sforzas returned, not many remembered Duke -Ludovico, who was slowly dying in a French dungeon. Among the people -that Leonardo now met, there appeared Francesco de' Melzi, a noble from -an old Milanese family, who entered Leonardo's life at this time as a -pupil. Soon the young man became like a son to Leonardo. Of handsome -appearance, he had the sensitivity to appreciate the essential -loneliness of Leonardo and so, almost without realizing it, he filled a -gap in Leonardo's life that was to last until the end of his days. - -Yet, as Franceso de' Melzi opened one door of Leonardo's life another -door closed. He received word that his beloved uncle Francesco had died -at Vinci and that he had become the heir to his uncle's property. No -sooner had this news been delivered when Leonardo was notified that -Giuliano, a son of Piero, and now a lawyer in his own right, was -contesting the will. All the frustrations of his life in Florence now -rose to an angry pitch and he set out once again for Florence to fight -for his own rights. - -Wisely, Leonardo had armed himself with letters from his new, -influential patrons and even one from King Louis himself recommending, -"... we request that you will cause this dispute to be settled in the -best and briefest delivery of justice...." In August of that same -year--1507--Charles d'Amboise added his personal letter suggesting that -the king could not spare Leonardo too long from the court at Milan. - -It was with the title of Painter and Engineer to the King of France that -Leonardo rode back to Florence to await the outcome of the judges in his -case. He went to stay with a sculptor friend, Giovanni Rustici, a man of -thirty-five and also an ex-student of Verrochio. They lived in a house -lent to Rustici by a wealthy scholar and patron named Piero Martelli. - -Leonardo soon found that he and Rustici had much in common. Rustici, -too, collected the odds and ends of his journeys into the country. -Flying about the house were a tame eagle and a raven, while, at dinner, -a pet porcupine begged for food. Rustici, however, was a believer in -alchemy and magic. To practice these arts the young man devoted one room -to the strange mixtures which bubbled over flames as he attempted to -change base metals into gold, or to call upon the spirits to predict the -future. - -Leonardo settled into the life of the house very quickly and even helped -his friend on an important sculpture commission. This was a group -composition of St. John between the Pharisee and the Levite for over the -doors of the baptistry. He also started to gather together his scattered -notes on all the subjects that he had written about, going through them -making corrections and erasing the repetitions. Possibly Leonardo was -considering the publication of all his material for he wrote, "Begun at -Florence in the house of Piero di Braccio Martelli, on the 22nd day of -March, 1508. This will be a collection without order, made up of many -sheets which I have copied here, hoping afterwards to arrange them in -order in their proper places according to the subjects of which they -treat...." This "collection without order" of almost forty years -extended into practically all branches of human knowledge, founded on -years of observation and experiment. Indeed, it was the magnificent -effort of one extraordinary mind to push back the curtains of ignorance -in order to let the light of natural truth shine through to mankind. - -In addition, Leonardo returned to his studies of anatomy and comparative -anatomy. For this latter he made many beautiful drawings of the legs of -animals as compared to those of man. With them, Leonardo tried to -indicate man's place in the natural order of the world. He pointed out -that our physical bodies are basically the same as those of animals, and -that the muscular and organic differences are those of function only. -For example, bird and man have the same chest muscles, called the -pectoralis. But the bird, in order to fly, has developed these into -powerful instruments of motion. Man, on the other hand, has learned to -stand and move in an upright position. He has developed the muscles of -the back, called the erectores spinae, and those of the buttocks to hold -him erect. Leonardo intended to enlarge upon his studies of comparative -anatomy to include all living creatures, even the insects. - -Meanwhile, the Viceroy of Milan was becoming impatient for Leonardo's -return. The judgment against his half-brothers had been settled in -Leonardo's favor, and he hastened back to Milan. By the summer of 1508 -he was once more in the routine of the court's activities. King Louis -had granted Leonardo a regular allowance and it was the first time he -had enjoyed such a long freedom from the concerns of earning a living. -With these steady payments Leonardo now had the leisure and support to -pursue his own multitude of interests. - -As his notes began to take shape and he thought of printing them, it was -natural for the inventive Leonardo to design his own printing press. It -is one of the earliest such designs on record. Because the carrying bed -which held the type and the paper was automatically adjusted to the -handlebar, the press could be operated by one man. Besides his notes -Leonardo also considered printing a work by Roger Bacon, the thirteenth -century English scientist. - -This project for printing his own books, however, was never realized by -Leonardo. Lately, he had received a commission which took him back in -memory to the days of Ludovico. The subject was Marshal Gian Giacomo -Trivulzio, a soldier-of-fortune. Originally this man was a loyal -commander of Galeazzo Sforza's but when Ludovico came to power he had -had Trivulzio banished from Milan. Embittered, Trivulzio had become a -stubborn enemy of Ludovico from that time on, serving under any banner -that marched against the house of Sforza. A stocky, square-faced man, -his body was covered with the scars of many battles. He had been -fighting with the French ever since the time Ludovico had betrayed -Charles VIII. Trivulzio had seen the great monument that Leonardo had -modeled and, although it was riddled by French arrows and damaged by -wind and rain, the Marshal was impressed and wished for a similar -memorial to himself. - -Leonardo set to work immediately. His past experience with the Sforza -monument was now to his advantage. This time there was no need for -experimenting. He knew how much material he needed and the approximate -cost of everything including the casting. He submitted an estimate of -three thousand and forty--six ducats for the completed work, one hundred -of which would go to Leonardo. The sum was acceptable to Trivulzio and -Leonardo began his preliminary studies. - -As he gathered the material for this new equestrian statue, Leonardo and -the French Viceroy Charles d'Amboise became interested in the further -canalization of the plains of Lombardy. The use of canals and locks had -been in practice for roughly a hundred years and around Milan there were -already some fifty miles of canals and about twenty-five locks. Leonardo -started another survey of the area. In his imagination, he envisioned a -vast hydraulic engineering project. - -On September 12, 1508 Leonardo announced in his notes the beginning of a -book on the nature of water. He had decided to separate this book from -the one on hydraulics because it was necessary to separate theory and -practice. His pages treating the science of hydraulics, or the practical -applications of water power, had reached to "forty books of benefits." -By the spring of 1509 he had expanded his notes on the nature of water -to include the greatest wave to the smallest raindrop. - -Concerning the practical applications of water power, Leonardo put forth -many designs for new locks. He introduced new methods of raising the -gates by windlasses and chains which could easily be set in motion by -one man. But most important is Leonardo's discovery of the use of -centrifugal force for draining marshes--the ancestor of the centrifugal -pump. When you rapidly rotate a stick in a pail of water, the water -spins in a spiral rising on the sides, and, if you rotate the stick fast -enough it bares the bottom of the pail. When you remove the stick -suddenly, the water continues to whirl as it slowly subsides. - -This is basically the same principle Leonardo used to raise the water -from a marsh to a level above the sea so that it could be drained away. - -The centrifugal pump was also used with a hydraulic screw which -converted water power to mechanical power. The force of a stream of -water was injected into the base of a vertical cylinder. In the base of -this cylinder was a six-bladed propeller mounted on a vertical shaft. -The force of the water turned the screw and at the same time the water -was forced to rise in the cylinder to an outlet above. The turning -propeller revolved the vertical shaft. This shaft, emerging from the top -of the cylinder, turned a cogged wheel. This wheel was joined to another -cogged wheel mounted on a horizontal shaft, thus providing the -mechanical power. Not only is this the forerunner of the turbine, but -the use of the propeller, itself, for propulsion in water, was a new -idea not to be thought of again until the eighteenth century. For -certain types of hydraulic pumps he conceived of the cone-headed mitre -valve still in use today. - -Leonardo, besides studying the practical applications of water power, -explored the very nature of water itself. In his proposed books on this -subject he intended to examine why clouds and fog form, why rain falls -and the raindrop itself--even how the raindrop is held together. He -understood the nature of capillary attraction, which holds the raindrop -together, and his notes show us that he was exploring the science of -hydrostatics which relates to the pressure and equilibrium of liquids in -general. - -Now that Leonardo had a steady income and the relief from meeting -painting commissions by fixed dates, he was free to explore his other -favorite avenues of knowledge. It seemed that his ever-active mind could -never stop roaming over the whole field of scientific knowledge. He -continued with his early interests--the nature and movement of air, -astronomy and geometry. He was also still concerned with movement and -weight, for he set down in his notes, "The thing which moves will be so -much the more difficult to stop as it is of greater weight." This is a -hint at a principle formulated by Isaac Newton almost two hundred years -later in his First Law of Motion--the law concerning inertia. For -example, the motion of an arrow shot into the air maintains itself in -flight so long as the influence of the initial force is maintained in -it. - - [Illustration: _Da Vinci's cone-headed mitre valve for use in a - hydraulic pump._] - -On a note dated April 28, 1509 he wrote, "Having for a long time sought -to square the angle of two curved sides ... I have solved the -proposition at ten o'clock on the evening of Sunday." As always, -Leonardo was deeply involved in the study of mathematics. Too deep -perhaps to recognize the new rumblings of war. - -Louis XII, still pursuing his campaign in northern Italy, had again -arrived in Milan amid the salutes of the French artillery. Following his -personal banner of a gold porcupine on a white field, he had come back -prepared to do battle with the Venetians whose power, as it diminished -in the east, was extending westward into Italy. Alarmed at this Venetian -expansion, the French King had allied himself with Pope Julius II and -the powers of Europe to form the League of Cambrai to push back this -threat. Charles d'Amboise, the French Viceroy, had already taken to the -field and at the castle of Cassano, overlooking the Adda river near -Milan, he awaited the arrival of his king. - -By the end of May, Leonardo was in the saddle once more. Surrounded by -the best knights of France and the nobles of Milan, he personally -accompanied the French King as military engineer to the meeting with the -Viceroy of Milan at Cassano. - -During the next three months, through the battles and defeat of the -Venetians at Aquadello where sixteen thousand dead were left on the -field, and the siege of Caravaggio and the capture of Peschiera, -Leonardo served as military consultant and map maker. More than ever his -eye was attracted to the possibilities of utilizing the many rivers they -crossed both for warfare and commerce. He envisioned making the Adda -river navigable from Milan to Lake Como. During this time, he devised -not only a revolving bridge but even one of two layers in a single -span--the upper level for pedestrians and the lower one for vehicles. - -By July, Leonardo had returned with the king and the French army to -Milan. Here was planned a great celebration of the French victory over -the Venetians. In front of the cathedral, to the delight of the hundreds -of spectators, Leonardo devised a mechanical lion scaring a dragon out -of an artificial lake into the beak of a cock which picked the dragon's -eyes out. After the festivities Leonardo returned to his everyday work. -In time, he had a thriving workshop and as he became more and more -preoccupied with his scientific explorations, his art commissions were -turned over to his assistants. He did continue, however, to work on the -plans for Marshal Trivulzio's monument and in his preparatory work for -this assignment he expanded his notes and drawings of comparative -anatomy. - -This renewed interest in anatomy led him to attend a lecture in the -winter of 1509. The lecturer was Marcantonio della Torre, a young man in -his late twenties and one of the best-known anatomists of the times. He -had been a professor at the University of Padua, but this city had -fallen into the hands of the Venetians. Marcantonio was forced to flee -Padua and had settled at Pavia. The two men, when they met, recognized -in each other a devotion to science and they began a professional -collaboration that grew into a friendship. Leonardo now developed his -anatomy studies to the point where he is today recognized as the -foremost medical anatomist of the Renaissance. - -Returning to his dissections, Leonardo now proceeded to explore the -heart and system of veins in the human body. His drawings of the heart -are nearly perfect. Indeed, he was probably the first to discover the -endocardium membrane that sheathes the valves and sinews of the heart. -Also, he pictured and described the moderator band, "the first cause of -the motion of the heart." His work on this organ led him to the doorstep -of discovering the circulation of the blood--later to be carried out by -William Harvey in the seventeenth century. - -Further, Leonardo was the first to accurately draw a representation of -the _foetus_, or unborn child, in the womb of its mother, writing in his -notes that, "we conclude therefore, that a single soul governs the -bodies and nourishes the two." In addition, he drew a remarkable picture -of the female figure and for the first time accurately placed her -organic structure. In his notes, he also pointed the way to the laws -governing metabolism when he wrote, "The body of anything whatsoever -that receives nourishment continually dies and is continually -renewed...." By pouring wax into a hole in the skull he made the first -casts of the ventricles of the brain. Several hundred years were to pass -before this method was rediscovered. - -As Leonardo's work progressed, his admiration for the complexity of the -human body grew. Many times in the middle of explaining a section of -anatomy he inserted a sentence or two of wonder or praise at the -magnificent creation that is the human being. Indeed, these drawings and -notes represent the sum of many, many dissections; moreover, Leonardo -had to work under conditions that placed many obstacles in his path--the -crude lights and instruments, the difficulties of obtaining corpses and, -above all, the opposition of the superstitious and ignorant. - -The following year Leonardo entered in his notes, "This winter of the -year 1510 I look to finish all this anatomy." And yet, however sincerely -he might express such a wish, Leonardo was a person who was literally -never "finished." The scientific and artistic tasks he had chosen for -himself were clearly beyond the limits of any one man. Besides, the -pressures of the outside world were once more threatening the peace and -quiet of his home and work. - -Pope Julius II became increasingly fearful of the French victories over -the Venetians. Secretly, he concluded a peace with Venice and, allying -himself with his former enemy, he now turned against the French. When -the conflict continued, Charles d'Amboise, the patron of Leonardo, was -killed at the battle of Correggio. He was replaced by a new French -Viceroy, Gaston de Foix. Although the Pope now hired Swiss mercenaries, -this invasion from the North was defeated by the young Gaston. Not to be -outdone, the Pope then brought in Spanish troops. - -In the ensuing bloody battle at Ravenna, the French completely defeated -the armies of the Pope and Spain, despite their use of battle-cars armed -with razor-sharp sickles on their wheels--strangely like the early -inventions that Leonardo designed for Lorenzo de' Medici! Although the -French were victorious, they lost their brilliant young leader, Gaston -de Foix, and with him they lost their heart. As a result, they were soon -disorganized. The Pope's armies renewed their attacks, and the French -began a long retreat. - -Once again the plague infested Milan and Leonardo's friend, Marcantonio -della Torre, died of it. After some futile attempts at recovery, the -French fled across the Alps and with them went Marshal Trivulzio. Milan -was left temporarily under the martial rule of the Swiss, and Leonardo -with only his few apprentices was left again without a patron. - -Tired and prematurely old at sixty-one, Leonardo resignedly gathered his -possessions together once more and with Francesco de' Melzi and four of -his loyal pupils, he turned his back on Milan for the last time. The -date was September 29, 1513. Their destination was Rome. - - - - - 12 - _Rome_ - - -"Name?" - -"Leonardo da Vinci." - -"Where from and where are you staying?" - -"We are coming from Milan by way of Florence. I have quarters being -prepared for me at the Belvedere in the Vatican--by order of the Pope. -Now, young man, let us pass." - -The guard at the Porta del Popolo changed his manner. He dropped his -halberd and motioned to the other guards to let the riders through. He -touched his helmet roughly and with a grin he said, - -"I'm sorry, Sire--but you know how it is. All these people--there's -bound to be them that we don't want here. Go ahead, your Excellency. -Make way there!" - -With these words he laid his spear against a jostling group of -broad-hatted pilgrims blocking the entrance to the city of Rome. - -Leonardo heeled his horse and with Francesco de' Melzi at his side, -followed by his servant and students, pushed past the crowd at the gate. -To the left rose the Pincio hill with its stately pines where, in the -days of Imperial Rome, Lucullus had walked in his gardens. But Leonardo -had no time to look about. It was a damp December day, and rain -threatened from the gray skies. He was tired, and as Francesco glanced -at him he could see Leonardo pull his cape around him with a little -shiver as the chill wind stirred the long, graying hair on his -shoulders. They made their way through the crowded, noisy city. They -crossed the Tiber and rode past Castel' Sant' Angelo, the papal fortress -built on the tomb of Emperor Hadrian. After another inspection by the -Swiss guards in beribboned uniforms of white, green and gold under their -shining breastplates, they entered the walls of the Vatican. That -evening after he had settled himself in the Belvedere apartments and -dinner had been eaten, Leonardo, gazing into the embers of the fire, -looked back over his new stroke of fortune. - -The Medicis had returned to power. Pope Julius II had died, and Giovanni -de' Medici, son of Lorenzo, had become Pope Leo X at the age of -thirty-seven. With his election to the head of the Christian world, the -Republic of Florence became a city of the Medicis once more and Leonardo -had received an appointment in Rome. Giuliano de' Medici, Pope Leo's -favorite younger brother, in his new rise to power and wealth, became -Leonardo's patron. The two must have met sometime during the Medici's -exile. Leonardo was given the apartments in the Vatican and a salary of -thirty-three ducats (approximately eighty-five dollars) a month and a -workshop was fitted for him and his pupils. He was also assigned an -exclusive German assistant named Georg. - -The Pope's court in the Vatican was like the Medici court in the -Florence of Leonardo's youth--multiplied by hundreds. Leo X saw himself -as the center of the artistic world, and being a man of luxurious tastes -with the wealth of the church behind him, the Vatican was soon filled -with a mixture of the wise and foolish. Pompous classic-quoters, -third-rate poets and clowns mixed with the world's scholars and -statesmen. The two greatest artists were Bramante, the architect and -friend of Leonardo's first years in Milan, and Bramante's pupil Raphael, -the painter. - -Bramante was busy building the new church of St. Peter's and, as the -architect of this favorite project of the Popes, he was sole master of -the Roman art world. Raphael, as his protege, was the recipient of the -better painting commissions in Rome. The elderly Bramante and the -thirty-year-old assistant were a famous pair in the Rome of 1513. -Equally as famous, however, was Michelangelo; he was still living in -Rome, but was without patronage after Julius II's death. Leonardo's old -rival had scored his triumph with his extraordinary paintings in the -Sistine Chapel. - -Although the young Raphael, who owed so much to the example of Leonardo, -now rode through the streets as a wealthy nobleman, Leonardo himself -received no great commissions. While Pope Leo was indulgent of his -brother's whims he himself had no use for this tall, serious old man who -roamed the shaded walks of the Vatican poking at the strange plants in -the botanical garden or making drawings of the foreign animals in the -private zoo. In reality, Leonardo's patron, Giuliano de' Medici was a -weak man. He played at being a patron but, like his brother the Pope, he -lacked the force and decision of his famous father Lorenzo. -Nevertheless, he did give Leonardo one small commission for a picture. -Immediately Leonardo, excited by the exotic plants in the Vatican -gardens, commenced to experiment with them to find a resin to make a -varnish with which to cover the future painting. Pope Leo made fun of -him exclaiming, to the delight of his court, "This man will never get -anything done, he thinks of the end before the beginning." - -This ridicule by the Pope made Leonardo a joke to many in the circles of -the Vatican who were a little afraid of this strange man with the -searching eyes. Leonardo also suffered the humiliations of a man who did -not conform to the fashions of his day. His knowledge of Latin, for -example, was weak and although he could read it with the help of a -dictionary he could not speak it. And, among the people who surrounded -the Pope, Latin was the only language allowed. Prizes of great sums of -money and important positions were often granted on the strength of an -improvised speech in Latin (with many quotations from the classical -authors) or a flattering Latin verse. Faced with such setbacks and -ridicule, Leonardo--not surprisingly--began to withdraw into himself. - -And yet, Leonardo refused to remain idle--he had to work. The need for -mirrors in the vast halls and rooms of the papal palace was great. -Leonardo turned his mechanical skill to redesigning and improving -methods of making them, and even inventing his own machines for the -grinding of the glass. Also, for Giuliano, who dabbled in alchemy and -magic, he made distorting mirrors and burning lenses. In addition, -Leonardo invented a machine which could be run hydraulically for -producing long strips of copper of equal width for use in soldering the -mirrors. - -But, with the making of these mirrors, Leonardo began to run into -trouble with his German assistant, Georg. The boy was a loafer; he spoke -little Italian and took every opportunity to spend his days with his -countrymen in the Swiss guard. Leonardo tried to alter the situation by -suggesting that the boy have his meals with him at his worktable, thus -giving Georg a better chance to learn the language. This however did not -appeal to him. Then, because Leonardo's inventions were so -extraordinary, he began to give away the secrets of their mechanisms to -Johannes the mirror-maker, another German, who had been replaced by -Leonardo in the favors of Giuliano. This naturally made Johannes jealous -of Leonardo. Georg gossiped, too, and told stories about the old, -eccentric man who lived like a miser in the midst of all the luxury and -who drew crazy circles on pages of paper. - -These "crazy circles" were geometric exercises that had fascinated -Leonardo from the time he had wandered across Italy with Fra Luca -Pacioli. Pacioli's book _De Divina Proportione_, containing sixty -illustrations from designs of Leonardo, had been published in Venice in -1509. Leonardo intended to entitle these geometric exercises _De Ludo -Geometrico_. In geometry a lune is a crescent-shaped figure bounded by -two intersecting arcs of circles on a plane or a sphere. Leonardo drew -pages of these lunes and then proceeded to transform their curvilinear -figures into squares of equal area. He also reviewed Archimedes' method -of squaring a circle and developed it into a variety of ways for cubing -spheres and cylinders. - -He returned as well to formulating theories of friction. He wrote in his -notes, "the tallest wheel is the easiest to pull"--for example, a big -wheel turning at the same speed as a smaller one has less friction to -overcome because it makes less revolutions. His experiments in friction -predated men like Amontons and Coulomb by two and three centuries. He -established a formula for the building arch which he described as "a -strength caused by two weaknesses"--if one half of an arch is removed, -the other half collapses. They support and give strength to each other. -In addition, Leonardo determined, before Galileo, the center of gravity -of any pyramid and of a tetrahedral, or four-sided body. - -As the days went by and he waited for commissions to come, Leonardo took -to wandering about the streets of Rome. He stood in the half-buried -Forum of the Caesars surrounded by grazing sheep and grunting pigs. -Wooden shacks where crude cartwheels were made and where the marble from -the ancient temples was cut and sold, were built against the sides of -crumbling ruins. The old triumphal arches, now overgrown with creepers, -were boarded into towers and cattle were penned between the shafts of -columns that once supported the grandeur of temple roofs. Here and there -a classical scholar would be sketching or writing from the worn, Latin -inscriptions on a marble slab tilted crazily from the ground where it -had fallen hundreds of years ago. Goats wandered on the Palatine hill, -once the home of Emperors, and the great baths of the Emperor Diocletian -were now a deer park and a hunting ground for royalty. - -During the course of these wanderings, Leonardo became interested in the -primitive methods of carpentry. Such things as screws, for example, were -rare. Those that were used were either made of wood or, if of metal, by -goldsmiths laboriously making each one by hand, soldering wire around a -pin and another wire into the hole to hold the screw. Sometimes they -were made by filing pieces of metal individually. All these methods were -time-consuming and costly. - -Leonardo had thought of this problem before, and now he concentrated on -perfecting his ideas about it. Previously, he had thought of casting the -metal in wooden molds and then turning the metal on thread-cutters. The -designs he finally drew in careful detail, however, are essentially the -methods used today. The new machines did with a few turns of a handle -and adjustments of a few cogged wheels what it took one man many hours -to perform. He also drew designs for a mechanical plane and a machine -for drawing wire that worked by water power. - -Leonardo now lived and worked in the Belvedere of the Vatican--more a -man on exhibition than an active participant in the great artistic -activities taking place around him. True, he received his thirty-three -ducats a month, but Michelangelo had been paid three thousand for his -work in the Sistine Chapel, while Raphael had earned twelve thousand for -each room he painted in the Vatican. - - [Illustration: _Leonardo became interested in various methods of - carpentry._] - -Thus Leonardo drifted farther and farther away from his painting. This, -in itself, caused people to talk in the papal city. For he had earned -fame as a painter, but his passion for science was regarded as strange -and whimsical. Occasionally, he did receive a small commission from the -workshop of Raphael, yet these were like the crumbs from a rich man's -table. - -Even the toys Leonardo made at this period for the amusement of his -patrons were looked upon as somewhat weird. For example, he would take -small pieces of wax and mold them into strange little animals and then -inflate them so that they floated in the air in front of a startled -guest. Once he caught a curious lizard in the garden and spent hours -putting scales all over the tiny body, attached to it a little beard and -horns, then let it out from a box at a banquet. The guests jumped back -with fear and the women became hysterical. - -One of Leonardo's jokes that has been passed down in accounts of his -life at this period must have created quite a sensation. He showed the -company the cleaned entrails of a sheep resting on the palm of his hand. -After telling them to wait and watch he took the entrails in another -room and with a bellows inflated them with warm air. As the entrails -filled with air they expanded and extended. They crept into the room -where the company waited. Slowly they grew and grew until they began to -fill the room. The guests overturned their chairs in their hurry to get -out of the way of this shapeless, translucent creature. Then Leonardo -appeared, the air-filled entrails giving way before him, and said: - -"Sires, this is but an example and symbol of virtue. As you can see, the -smallest virtue is capable of the greatest growth." - -The guests laughed, but it was an uncomfortable laugh. Thus another -story was added to the legend of Leonardo as an odd old man. - -Leonardo, whose work--particularly his anatomical studies--had -constantly been interrupted by the fortunes of war, had found another -hospital in Rome where he could continue these studies. This time it was -his intention to write a treatise on speech. He dissected and drew the -anatomy of the larynx (the voice box), the vocal cords and the trachea -(the air passage to the lungs), and all the muscles that control the -movements of the tongue and the lips. If you pronounce each letter of -the alphabet you will feel these muscles of the lips, especially with -the letters "o," "p," and "f." Carefully he noted how the air vibrations -from the trachea form themselves into vowels and consonants, and he drew -the membrane which, when air is pressed against it, makes the sound -"aah." - -At this same time he was also busy finishing a treatise on painting -which he had begun when he was working on the "Last Supper" for Ludovico -Sforza. But it was for his knowledge of military engineering that he was -sent to the city of Parma by the Pope on September 25, 1514. Here he -stayed at the Bell Inn while examining the fortifications and other -defenses of the city. - -Leonardo's patron, Giuliano de' Medici, had been appointed governor of -this particular area and, since Pope Leo X was fearful of two powerful -countries, France and Spain, he was preparing the papal territory -against possible invasion. Another fear of the Pope--and indeed of -everybody in Rome--was malaria, the disease carried by the mosquitoes -that bred in the Pontine marshes west and southwest of the city. At that -time, however, no one knew the cause was mosquitoes; rather, they -thought it was the bad air from the marshes. - -As Leonardo had already been effective in draining the pestilential -marshes of Piombino for Cesare Borgia and, later, those around Milan for -Charles d'Amboise, he was assigned the same task for the Pontine -marshes. He surveyed the entire area to the sea and made another -extraordinary aerial type map. His recommendations included draining the -entire area, enlarging and regulating the Martino river and cutting an -extra outlet from the river Livoli to the sea. These plans were adopted -some years later and parts of the marshes were drained successfully, -yielding new land for the cultivation of crops. - -By December of 1514 Leonardo had finished his treatise on speech and, -possibly in an effort to attract the attention of the Pope, he submitted -it to the Privy-Chamberlain, Battista dell'Aquila. As Pope Leo was -surrounded by an army of secretaries and assistants who passed on -everything submitted, this manuscript with its beautiful drawings was -mislaid and lost and only a few notes and sketches remain. - -The continual discouragement of his life in Rome was offset by a visit -from his half-brother, Giuliano, around Christmas. Leonardo was held in -esteem by his family despite the quarrel over his father's and his uncle -Francesco's will, and his half-brothers were pleased to tell of their -famous relative who lived in the Belvedere as guest of the Medicis. Yet -they knew little of Leonardo's scientific dreams and his lack of -recognition in the papal city. - -Often, Leonardo's greatest comfort was to return to his notes. The -challenge of geometry and the mysteries of the movement of air and water -kept him from brooding about his lonely life. Francesco de' Melzi, -Leonardo's young friend, had more and more taken over the practical -responsibilities of his everyday life. Except for his workshop, where -the troublesome Georg worked at the making of mirrors, and an occasional -small commission for a painting, Leonardo was free to study. - -In addition to his geometrical investigations, Leonardo now experimented -with the science of _statics_ (objects that are stationary), and -_dynamics_ (objects in motion). One of his most important discoveries in -the science of mechanics came about during this period. Concerning the -division of weight, he wrote, "There are three conditions of gravity of -which the one is its simple natural gravity, the second is its -accidental gravity, the third the friction produced by it. But the -natural weight is in itself unchangeable, the accidental which is joined -to it is of infinite force, and the friction varies according to the -places wherein it occurs, namely rough or smooth places." Thus he -realized and formulated what composes the movement of an object. He -found that movement is the result of separate forces acting upon the -object from different directions, as for example, the initial push, the -pull of gravity and the resistance of friction. And, before Galileo, -Leonardo further experimented with objects dropped from a height. As the -result of repeated experiments, he noted that the fall was being -affected by the earth's rotation. That is, the object dropped always -fell in a slight eastward direction rather than vertically downward--a -fact later proved conclusively by Isaac Newton and Robert Hooke in the -next century. - -He also became fascinated with spiral motion, such as is found in a -spinning top or in a whirlpool of water. Because of his interest in -_hydrodynamics_, or the movement of water, he began to sketch imaginary -"Deluge compositions." These were drawings showing the world--probably -inspired by the Bible--in a chaos of wind and floods. They were based on -his years of scientific research. Indeed, his drawings of actual -whirlpools are still among the greatest of his scientific art. Today, -with all the latest technical aids, such as dusting a whirlpool with -powdered rosin and then photographing it, an accurate three-dimensional -picture is impossible. Yet Leonardo, by sheer observation and analysis -coupled with his genius for drawing, could reproduce the complicated -shape of whirling water. - -In the relatedness of his explorations of water, air and movement, and -weight, he worked out the similarity between the laws of equilibrium -controlling solids and liquids. The equation between the motive force -and resistance that makes for equilibrium or balance in solids can be -compared to the equation between the upward pressure of liquids and the -downward pressure exerted on them. - -Far into the night Leonardo worked on his papers. He tired more easily -now, and his eyes had grown weaker. To provide the increase in light -that his failing eyesight demanded, he had improved on his original oil -lamp by making the wick rise as the oil was burned away, and he had -extra lamps fitted to the ceiling. - -On January 9, 1515 Leonardo wrote in his notes, "Il Magnifico Giuliano -de' Medici set out on the ninth day of January 1515 at daybreak from -Rome, to go and marry a wife in Savoy. And on that day came the news of -the death of the King of France (Louis XII)." This meant that his new -patron had left and his old patron had died. Leonardo's note was a sad -one and perhaps he felt, in the departure of his patron, more alone than -ever in the crowded life of the Vatican. Giuliano, on the urging of his -brother, was marrying Philiberta of Savoy, in an effort to strengthen -the prestige of the Medici. Louis XII, before he died, had formed a -league against Spain, and with the marriage of the Pope's brother to a -noble house of France, the league would be strengthened by keeping the -Pope on the side of France. Actually Pope Leo was playing both sides, -for at the time he was also friendly with Spain. - - -Shortly after Giuliano's departure from Rome, Leonardo fell ill, -presumably from a mild heart attack complicated by a touch of malarial -fever. The doctor had been called. It was a warning, the doctor told -Francesco de' Melzi, and Leonardo must remain quiet for quite awhile. - -By the end of the winter Leonardo was back on his feet and apparently -feeling completely well again. Giuliano himself had fallen ill about the -same time and the news that he had recovered and was finally returning -to Rome cheered Leonardo. He sat down and wrote a long letter to his -patron expressing his joy. This letter also included a long list of -complaints against Georg and Johannes. Georg was now using his room in -Leonardo's apartment to do work for others. He lied to Leonardo and flew -into such a rage when he was questioned that no one could go near him. -Moreover, Johannes, the mirror-maker, was now moving back into the -Vatican and turning out mirrors for everyone, even using Georg's room as -his own workroom. Johannes boasted of his skill and told everybody that -Leonardo did not know what he was doing. Thus, it was not surprising -that Leonardo, in his long complaint, was taking out the anger and -frustration he felt against all the injustices of his life in Rome. - -But by summer Leonardo was again employed as a military engineer. -Francis I had succeeded to the throne of France. The new French King was -anxious to secure his lost title to the Dukedom of Milan and was -preparing another invasion of Italy. Pope Leo X, still trying to play -both sides at once, was making secret agreements with Francis while at -the same time joining the King of Spain, Milan, Genoa, and the Swiss in -an alliance against France. Consequently, he sent Leonardo out to -inspect the fortifications of Civitavecchia, a city on the Tyrrhenian -coast not too far from Rome. When, in August, Francis I crossed into -Italy with an army of thirty-five thousand men including Marshal -Trivulzio, the Pope ordered his brother, Giuliano, to take command of -the papal forces. On the way to assume this command, Giuliano fell ill -and collapsed. His sickness this time was soon to be fatal. - -Leonardo returned to Rome with his survey of Civitavecchia, where he -immediately learned of his patron's latest illness. Perhaps realizing -that Giuliano was fatally ill, Leonardo made a desperate effort to gain -the recognition he felt should be his. He entered the competition for a -new façade of San Lorenzo in Florence. Among the other competitors was -Michelangelo, his younger and yet oldest rival. - -In October of 1515, Francis I had recaptured Milan and by Christmas was -in Rome. Leonardo may have met the new King of France in Bologna where -Pope Leo X had personally traveled in order to settle a peace treaty -with France. Certainly it is known that he attended Francis' court in -Rome. Leonardo's name was well respected in French circles and, as -Francis had already admired the pictures by Leonardo, the meeting was a -happy occasion for them both. Indeed, the recognition that Leonardo had -sought in his native land was never as great as that accorded to him by -the French. - -As Francis I prepared to leave for France in January he must have -offered Leonardo a position at his court. While he still hoped that -Giuliano de' Medici would recover from his illness and return to Rome, -Francis' offer gave him support in the knowledge that he had a powerful, -new friend. - -March of 1516 brought the first of three events that were to change the -course of Leonardo's last years. Giuliano de' Medici died, leaving -Leonardo not only without a patron, but without a friend in the Vatican. -Now sixty-four years old, he was reluctant to leave his comfortable -quarters in the Belvedere with its workshop and pleasant gardens. -Besides, deep within himself, he felt that Rome could still offer him -the fame that had always escaped him. - -Spring ripened into summer and the second event occurred. The -competition for the new façade of San Lorenzo in Florence was won by -Michelangelo. To Leonardo the news was a blow. The success of his old -rival weakened his position in the Vatican even further and added to the -growing hostility he had felt in the people surrounding the Pope. - -The third event was the sum of many small events. Georg and his friend -Johannes, in their jealousy, had spread much gossip about Leonardo in -court circles. They now took advantage of Giuliano's death to circulate -stories about Leonardo's dissections of bodies in the hospital. These -were added to vicious gossip that Leonardo was pro-French. This news -eventually reached Pope Leo X. The Pope himself was perfectly aware of -the practice of dissection and, personally, he had turned his eyes the -other way. However, as dissection was contrary to Church doctrine, an -official complaint to the head of the Church could not be ignored. The -Pope used it as an excuse to be rid of this tiresome old man whom he had -tolerated only for his brother's sake. Leonardo was abandoned. - -The year 1516 was drawing to a close. Leonardo had decided to seek the -patronage offered him by Francis I. So he and Francesco de' Melzi, his -loyal young friend, left Rome for the long journey into France. As he -left his native land for the last time, Leonardo looked back over his -years--from the silver lute that had sent him to Milan, to the death of -Giuliano, to the final rejection of Pope Leo X. Remembering how Lorenzo -de' Medici had sent him to Ludovico so many years before, Leonardo -thought to himself with great sadness, "The Medici created and destroyed -me." - - - - - 13 - _The Last Years_ - - -Leonardo looked around from where he was leaning on the parapet of the -Chateau d'Amboise to watch a group of young lords and ladies playing -croquet on the emerald-green lawn. The click of the mallets and balls -was mingled with the shouts and laughter of the young people. It was -late afternoon in May and although the sun was warm the breeze from the -west was chilly. Leonardo looked down again from the sheer height of the -castle wall across the wide sweep of the Loire river and the valley -extending as far as the eye could see. Swallows were swooping low over -the banks below and the wind carried their shrilling cries up to him. -The forested islands and sandbars interrupted the steady flow of the -river and Leonardo could see the reflections sway in the current. He had -been studying the river but he realized that his aging eyes were not up -to the task of concentrating for long. The wind made them water, so he -turned away and started back to his home. - -There was much that was familiar in the castle at Amboise. The thick, -high walls and round towers and especially the graceful, lacy spires of -the king's residence brought back much that he had known in his native -land. The gardens had been planted by Italians--there were orange trees -and even a mulberry tree from his beloved plains of Lombardy. The king's -residence and chapel had been constructed and the decorations carved in -stone by Italian artisans. Leonardo could stop and talk in his native -tongue with many of the men employed by the king. Since the time of -Charles VIII, the French had brought in the latest Renaissance styles -from Italy. Leonardo's steps took him back from the castle grounds and -down a path with a hand-railing. The steep roofs of the town of Amboise -with their chimneys could be seen below him. The path led to a small -manor house, like a miniature castle with sharp spires and lacy, -carved-stone gables that was set in green lawns and gravel paths. - -The Manoir de Cloux, as Leonardo's house was called, had been a hunting -lodge for Francis I, but when Leonardo had arrived he gave the house to -Leonardo for his home. Francis, in his admiration for this great man, -also gave him seven hundred crowns a year, together with a pension of -four hundred for Francesco de' Melzi. - - [Illustration: _Leonardo at Chateau d'Amboise on the Loire._] - -The long journey from Rome had left Leonardo tired and weak and he had -fallen ill again shortly after his arrival. This time the attack was -more serious and had left him with his right hand permanently crippled. -He looked at it now as he opened the door to his room. "Another -warning," he thought, "and there's still so much to do." - -The young, robust King Francis was everywhere at once. He gloried in -knightly tournaments, hunts, and sports of all kinds. Always restless, -he might appear at any place unannounced. Frequently there would be a -clamor at the gates of Leonardo's home and the king would ride in with -one or two of his nobles. With a great jingling of spurs he would bound -up the stairs of the manor house calling for Leonardo. He delighted in -long talks with the old man, and would listen respectfully as Leonardo, -his deep-set eyes brooding over his notes, would demonstrate some -scientific point on a blank sheet of paper. - -At this time, Leonardo was engaged on three projects which demanded his -immediate attention. One was the entertainment for a banquet that -Francis was giving for his sister, Marguerite de Valois, and her -husband. Another was a new design for the king's castle at Amboise, and -the third was a design for making a navigable waterway from Amboise to -Romorantin. Although these three projects were the main ones that -occupied Leonardo's time, there was always the supervising of his -pupils' painting on the walls in the little chapel of the manor house, -his own work on a painting of St. John the Baptist, and the continual -ordering and revising of his notes. - -The banquet took place in October of 1517, and the mechanical lion -Leonardo had made was an immediate success. It "walked" by means of a -spring motor, into the hall, opening and closing its fierce mouth while -swaying its head from side to side. With a wand that he had been given, -Francis I stepped down from his seat and tapped the lion three times. -The toy fell apart and from it a cascade of white lilies poured out at -the king's feet. - -Also at this time there was a distinguished guest at the castle of -Amboise. He was a fellow-countryman of Leonardo and his name was -Cardinal Luigi d'Aragona. With him was his secretary Antonio de' Beatis. -As Leonardo was now a famous member of King Francis' court, the cardinal -paid him a visit accompanied by Antonio. The extraordinary anatomy -drawings and all his notes were shown to the cardinal; he and his -secretary were deeply impressed. They were also surprised to learn that -Leonardo had never been accorded the same recognition by his own -countrymen. Antonio de' Beatis wrote home that "This gentleman has -written a treatise on anatomy, showing by illustrations the members, -muscles, nerves, veins, joints, intestines and whatever else is to -discuss in the bodies of men and women, in a way that has never yet been -done by anyone else. All this we have seen with our own eyes; and he -said that he had dissected more than thirty bodies, both of men and -women of all ages. He has also written of the nature of water, and of -divers machines, and of other matters which he has set down in an -endless number of volumes, all in the vulgar tongue [meaning Italian not -Latin], which, if they be published, will be profitable and delightful." - -By now Leonardo had accumulated thousands of pages of notes, and they -lay stacked in all manner of chests and boxes. Often now, as Leonardo -surveyed the work of his lifetime, he realized that he would never see -the day of their publication. Time was slipping through his fingers. -Already summer had come and gone and now the sharp winds of fall were -lifting the leaves from the ground in dancing whirls. Fortunately these -were years of peace and for the first time in a long while the people -were free of wars. The scheme to canalize the waterway to Romorantin had -grown to a vast idea for making a thoroughfare of water from the Loire -river all the way down France to Lyons and then into Italy! Leonardo, -old and ailing as he was, had surveyed parts of the rivers Loire and -Cher, braving the rough roads and crude accommodations. - -In addition, Leonardo had designed a castle for Francis I's widowed -mother in Romorantin. This castle was never built, but many of the ideas -that Leonardo had incorporated in its design were used in the gigantic -and magnificent castle of Chambord. Also, at Francis' request, he had -reviewed the work being done at the castle in Blois and there is reason -to think that the beautiful outside stairwell that spirals from left to -right might have been designed by Leonardo. - -In February of 1517, a son had been born to Queen Claude and Francis I. -The king decided to postpone the baptism of the dauphin (the title given -to the eldest son of a French King) until May of the following year. At -that time there would be a double celebration at Amboise, for a nephew -of Pope Leo X, the young Lorenzo de' Medici, was being married to -Madelaine d'Auvergne. As usual, Leonardo was given the assignment of -preparing the festivities. Although he was fond of preparing these -entertainments, Leonardo now felt the pressure of time; for indeed, the -interruptions of this eager young king were sometimes a hardship. He -felt that his years were drawing to an end. His notes were unfinished -and his dreams of extending man's knowledge of his world and of himself -were hindered not only by such petty chores but also by the limits of -his own physical endurance. - -As Leonardo was sketching one day from the window of his room where he -could see the castle walls and the chapel of Saint-Hubert, he set aside -the drawing for a moment to write a memorandum to himself. "Write of the -quality of time as distinct from its mathematical divisions." Was this -extraordinary man sensing the road down which Einstein--in his studies -of relativity--was to travel hundreds of years later? - -Spring arrived again and with it came the first wild flowers and roses, -the songs of the birds in the woods and the blossoming of the chestnut -trees. The time for the double celebration came, too, and Leonardo was -seen busily preparing the decorations and mechanical delights for the -large crowds already assembling. In addition to the tournaments-at-arms -that so delighted the king, there was to be a mock battle with a -besieged city, and for this Leonardo had had constructed imposing castle -walls of wood with a backdrop of a city's spires and towers. The party -lasted for weeks, and the climax was performed on the lawns of -Leonardo's house where a great ballroom had been set up. Here he -repeated an earlier success, the one that had so enchanted Ludovico's -guests so many years ago in the Sforza castle at Milan. There was again -a dome over the ballroom across which the stars moved mechanically and -artificial figures representing various gods and goddesses spoke and -sang by means of a hidden choir, while the sun and moon shone in their -own lights. - -This display ended the festivities. It was already late June and -Leonardo was anxious to return to his plans for the water route to -Italy. There was the area near Sologne which, when flooded, would make -the surrounding countryside a marshland. This would have to be drained -by the same method as he had planned for the Piombino and the Pontine -marshes. Francis I was interested, too, in the improvements Leonardo had -suggested for his own castle, and he would have to talk with the castle -superintendent about them. As always, there seemed to be so many things -to do, to plan, to work on. Then Leonardo wrote in his notes: "On the -24th of June, the day of St. John, 1518, at Amboise, in the palace of -Cloux...." and underneath, "I will continue--" - -"_I will continue_--" It was almost a note of defiance against the -obstacles of advancing age and sickness and the interruptions of the -practical world. - - -The sound of jingling spurs and bridle chains and the snorting of many -horses announced another surprise visit from the young king. Leonardo -could hear him below shouting something to Battista, the servant who had -come to Amboise with Leonardo. Now, as usual, Francis was running up the -stairs with all the energy of youth shouting for "le maître" (the -master). Resignedly and with patient humor, Leonardo stepped out to -greet the king. The gold chains around Francis' thick neck and over his -broad chest glinted in the semi-light of the hall, and he was holding -his plumed hat at his side and mopping his forehead with a dainty -embroidered handkerchief. - -"Master Leonardo! We are going on a tour of the river and I want you to -look at the place that I told you about. Where I want to put that -bridge. You remember?" - -"Sire, give me but a moment to gather some material together." - -A chest was made ready and soon Leonardo was at the door, calling to -Francesco and Battista to help him into the saddle of his horse, while -the king's servants hoisted the chest onto one of the carts already -piled high with tents and provisions. - -When Francis was restless--which was often--a "tour" could mean many -hours or many days of travel. Wagons were always kept ready with all the -equipment for a long journey and Leonardo, himself, had learned to -accept these sudden whims and kept chests of his own ready for any such -trip. Now, as always, the king kept his horse reined back out of regard -for this tall, stooped man with the long beard and simple clothes. - -Yet when Leonardo returned from this "tour" he realized that he could no -longer make such trips. The hardships of sleeping in tents, riding over -the hot roads, and the necessary work involved in surveying the possible -sites for a bridge had left him almost exhausted. He had made one -suggestion, however, and that was to build houses that could be carried -and then assembled with a few wooden locking devices, then just as -quickly taken down and moved to the next place. They could also be left -standing where the country people could use them while the court was -away. Indeed, such structures would seem to be the ancestors of our own -prefabricated houses. - -The winter of 1519 was a bitter one. When the cold fog spread over the -valley shrouding the bare trees it chilled the big, white-washed rooms -of Cloux. The wind blew down from the north sending blasts down the -chimneys and scattering ashes and sparks. Leonardo, huddled against the -huge fireplace with its roof projecting into the room, pulled his black -cloak lined in soft leather around him and reminded himself to include -it in his will for Mathurine, the faithful domestic who cooked for him -and took care of his house. - -The aged Leonardo, who had observed and analyzed so much of man and -nature, knew now that his own days were numbered. When the first, pale -sunlight of March shone through the small leaded-glass windows of his -house, he applied to the king for permission to make out his own will. -French law demanded that the property of any foreigner dying in France -went to the Crown. The permission was granted, and on April 23, 1519, -Guillaume Boureau, the Royal Notary of Amboise was summoned with -witnesses. - -To his half-brothers in Florence Leonardo left his property at Fiesole -and four hundred ducats. To his faithful friend and companion, Francesco -de' Melzi, nobleman of Milan, Leonardo willed his notes, drawings, and -paintings. Battista was given the income that Louis XII had granted -Leonardo from the tolls of the canal at San Cristoforo near Milan. -Mathurine was granted the "good black cloth, trimmed with leather" and -two ducats. Moreover, Leonardo outlined in detail the plans for his own -funeral, right down to the use of ten pounds of candles. - -Too weak now to stand any more, Leonardo was confined to his big -four-poster bed with the canopy. From it he could see the tracery of the -Chapel of Saint-Hubert against the pale, foreign sky through the little -window in the corner. The vicar of the church of Saint-Denis was called, -with two priests and two Franciscan friars, and Leonardo received the -last sacraments at his bedside. - -An entry in his notes reads, "While I thought I was learning to live, I -have been learning how to die." But death was not easy for him. With -tears rolling down his sunken cheeks for "his wasted life," he died on -May 2, 1519--fighting even this final interruption to all his work. - -King Francis I, who was at St. Germain-en-Laye with his court, wept when -the news was brought to him. Francesco de' Melzi was so overcome with -grief that he waited until June before writing to the half-brothers of -Leonardo of the Master's death. He wrote, in part, "He was to me the -best of fathers, and it is impossible for me to express the grief that -his death has caused me. Until the day when my body is laid under the -ground, I shall experience perpetual sorrow, and not without reason, for -he daily showed me the most devoted and warmest affection." - -And in a closing paragraph Francesco added these words: "His loss is a -grief to everyone, for it is not in the power of nature to reproduce -another such man." - - - - - 14 - _Mankind's Debt to Leonardo_ - - -When Leonardo died his notebooks began their separate journeys into -obscurity. They traveled to different lands and became parts of widely -disparate collections. It has only been within the last fifty years that -efforts were made to bring them all together between the covers of one -volume--a dream that Leonardo himself entertained but never realized. As -the manuscripts and drawings were brought to light, translated and -published, the extraordinary scope of Leonardo's scientific explorations -was revealed. - -Mathematician, anatomist, botanist, astronomer and geologist form only -part of the long list of his accomplishments and give the clue to the -man who considered all the natural world within his province of study. -Because of the universality of Leonardo's scientific thought he has been -frequently mentioned as the forerunner of such men as Galileo Galilei, -Sir Isaac Newton, James Watt, Francis Bacon and William Harvey. Although -Leonardo cannot be credited with the actual discoveries that these men -made, his methods of investigation pointed the way down the paths that -they would follow. - -The key to Leonardo's methods lies in a quotation from his notes on -vision. He wrote of vision as _saper vedere_--"to know how to see"--and -he referred to the eye as "the window of the soul." Again and again, he -stressed the importance of observation and personal experience. Although -he himself was well read, he emphasized that "science comes by -observation not by authority." His supreme talent for drawing underlines -his credo and is inseparable from his science. What he saw in the -natural world about him needed investigating. The results of these -investigations were transformed into drawings as the most certain method -for passing this knowledge along to others. The best example of this -attitude is represented by his anatomical studies. To merely draw the -living figure in front of him was not sufficient--it was imperative to -know what he was drawing. He turned to the dissecting room and after -intensive study produced some of the finest anatomical drawings in the -world--and among the easiest for others to understand. - -What Walter Pater wrote of the Renaissance--"in many things great rather -by what it designed or aspired to than by what it actually -achieved"--could be a summation of Leonardo's own lifetime of effort in -science. He labored to bring mankind from the morass of medieval -superstitions onto the firm ground of natural facts. With an insatiable -curiosity Leonardo attempted the impossible task of encompassing all -knowledge. Thus he established his right to immortality--for it was an -attempt that shone like a beacon in a world dark with ignorance. - - - - - _Significant Dates in Leonardo's Life_ - - - 1452 April 15. Birth of Leonardo. - 1467 Commences apprenticeship with Verrochio in Florence. - 1478 Commissioned for altarpiece in the Palace of the - Signoria. - 1481 Commissioned to paint an altarpiece for Convent of San - Donato. - 1482-83(?) Leonardo leaves Florence for the court of Ludovico - Sforza in Milan. - 1483 Begins equestrian monument of Francesco Sforza for - Ludovico. - 1484-86 Plague in Milan. - 1490 April 23. Recommences equestrian monument and starts - book on light and shade. - 1496 Meets with Fra Luca Pacioli, professor of mathematics. - 1498 _The Last Supper_ completed. - 1499 Apr. Land awarded to Leonardo near Porta Vercellina. - Oct. French occupy Milan. Dec. Leonardo leaves Milan - with Pacioli. - 1500 Leonardo arrives in Mantua. Travels to Venice and - returns to Florence. - 1502 In the service of Cesare Borgia. - 1503 Returns to Florence, commences work on a canal to sea. - 1504 Begins the painting of battle of Anghiari. Father dies. - Attempt at flight (?). - 1506 May. Leaves Florence for Milan at summons of Charles - d'Amboise, French military governor. - 1507 Sept. Goes to Florence to settle father's will. - 1508 July. Returns to Milan. - 1511 Works with Marc Antonio della Torre on anatomical - research. - 1512 French lose Milan. - 1513 Leonardo leaves Milan for Rome. Serves Giuliano de' - Medici, brother of Pope Leo X. - 1516 Leonardo leaves Rome for France to serve King Francis I. - 1519 May 2. Death of Leonardo. - - - - - _Index_ - - - A - Abbaco, Benedetto dell', 5 - Adda river, 124 - "Adoration of the Magi," 29, 30 - Adriatic, the, 62, 93 - "Air conditioner," 69 - Air, study of, 65, 66, 99 - "Alarm clock," 57 - Albert of Saxony, 81 - Alessandria, fortress of, 83 - Alfonso of Calabria, 38 - Alps, the, 37, 67 - Amadeo, Antonio, 58 - Amadori, Albiera di Giovanni, 2 - Amadori, Alessandro, 3, 111 - Amboise, _see_ Chateau d'Amboise - Amontons, 134 - Anatomy, human, 52, 53, 107, 109, 119, 125-127, 138 - Anchiano, 2 - Anemometer, 65, 66 - Anemoscope, 65 - Anghiari, battle of, 103, 110, 113 - Aquadello, 124 - Aquila, Battista dell', 139 - Arabs, the, 54 - Archimedes, 41, 67, 81, 134 - Architecture, 50, 58 - Argyropoulos, John, 17 - Aristotle, 17, 23, 42, 48, 81, 89 - Arithmetic, 77 - Arithmetico, Benedetto, 16 - Armored vehicle, 39, 40 - Arno river, 25, 31, 96, 100-106, 109 - Arrezzo, 93 - Ascanio, Cardinal, 83 - Astronomy, 80-82, 104, 105 - Atlantic Ocean, 19 - "Automobile," 32, 33 - Autopsies, 107 - Avicenna, 53 - - - B - Bacon, Francis, 160 - Bacon, Roger, 120 - Badia, the, 7 - Battista, 155, 157 - Bayzid II, 94 - Beatis, Antonio de', 151 - Bianca Maria, 64 - Bible, the, 62, 104, 141 - Birds, flight of, 24, 65, 66, 76, 99, 119 - Black Death, _see_ Bubonic plague - Blois, 152 - Bologna, 144 - Bombard, 26 - Bombs, 39 - Borgia, Cesare, 82, 86-97, 102, 139 - Borgias, the, 102 - Botticelli, Sandro, 33 - Boureau, Guillaume, 156 - Bramante, 68, 131 - Bridge building, 95 - Bubonic plague, 45-47 - Buonarroti, Michelangelo, _see_ Michelangelo - - - C - "Camera obscura," 55 - Campo Morto, battle of, 38 - Cannon, 26, 33, 41 - Caravaggio, siege of, 124 - Cardano, Girolamo, 113 - Carles, Geffroy, 115, 116 - Carpentry, 135, 136 - Cassano, castle of, 124 - Castel' Sant' Angelo, 130 - Caterina, 2 - Cellini, Benvenuto, 100 - Centrifugal pump, 121, 122 - Cesena, 94 - Chambord, castle of, 152 - Charles d'Amboise, 94, 114-117, 121, 124, 127, 139 - Chateau d'Amboise, 147-156 - Cher river, 152 - Christ, 30, 74, 77, 78 - Church of the Annunciation of the Servite Order of Monks, 90 - Church, the, 18, 48, 53, 63, 104, 145 - Cioni, Andrea di Michele di Francesco de', _see_ Verrochio, Andrea - del - City Planning, 44, 45, 47 - City-states, 9, 10 - Civitavecchia, 143, 144 - Cloux, Manoir de, 148, 154, 156 - Coins, minting of, 47 - Collections, 4 - Columbus, Christopher, 19 - Constantinople, 95 - Corte, Bernardino da, 83 - Corte Vecchia, 56 - Coulomb, A. C., 17, 134 - Council of Eighty, 109 - Council of Florence, 23, 106 - Councilors and Tribunal of Venice, 89 - Credi, Lorenzo di, 13 - Cusanus, Cardinal, 42 - - - D - Dams, 101 - Danti, Giovanni Battista, 96, 97 - d'Aragona, Cardinal Luigi, 151 - Darwin, 105 - d'Auvergne, Madelaine, 153 - David, statue of, 106 - _De Ludo Geometrico_, 134 - d'Este, Beatrice, 60, 61, 69, 86 - d'Este, Isabella, 86, 87, 91 - Diocletian, Emperor, 135 - Diseases, 109 - Dissection, 53, 126, 145 - Diver's suit, 89 - Drawing, _see_ Painting - Drum, mechanical, 61 - Dynamics, 140 - - - E - Earth, the, 104, 105 - Eclipse of the sun, 48 - Einstein, 153 - Equilibrium, 141 - Euclid, 54, 91 - Eye, the, 54, 55 - - - F - Ferdinand, King of Naples, 25, 27 - Ferrara, 70 - Ferrari, Ambrogio, 42 - Fiesole, 111, 113, 156 - Flemish painters, 15 - Flight, - of arrow, 82, 83 - of birds, 24, 65, 66, 76, 99, 119 - problems of, 70, 71, 75, 76, 96-100, 111-113 - Florence, 7-19, 25-27, 32, 38, 53, 68, 93-96, 100-103 - Flying machine, 70, 71, 75, 76, 112 - Foix, Gaston de, 127 - Forts, 88 - Forum of the Caesars, 134 - Four elements, 48 - France, 67-69, 78, 82-84, 94, 114-120, 125, 127, 128, 139, - 142-145, 152 - Francis I, 143-145, 148-157 - Fraternity of the Immaculate Conception, 43, 44, 47 - Friction, 140, 141 - - - G - Galen, 52, 53 - Galileo, Galilei, 134, 141, 160 - Genoa, 143 - Geocentric theory, _see_ Ptolemaic theory - Geography, 18, 19 - Geology, 103, 104 - Geometry, 91, 134 - Georg, 131, 133, 140, 143, 145 - Geotropism, 79 - Germany, 47, 69 - Ghirlandaio, Domenico di Tommaso del, 33 - Giocondo, Francesco del, 98 - Giovanni "the Piper," 100 - Gonzaga, Francesco, 86 - Gothic tradition, 50 - Gravity, 140, 141 - Greeks, the, 69 - Guido, 23 - Guild, 19 - - - H - Hadrian, Emperor, 130 - Harvey, William, 126, 160 - Heavens, observation of, 80 - Heliocentric theory, 48, 81 - Heliotropism, 79 - Highmore, 53 - Hippocrates, 52 - Holy Roman Empire, 9 - Hooke, Robert, 141 - Horse, anatomy of the, 41 - Hydraulic pump, 74, 122, 123 - Hydraulics, 14 - Hydrodynamics, 141 - Hygrometer, 30, 31 - - - I - Imola, 95, 96 - Inclination gauge, 66, 67 - India, 18 - _Introduction to Perspective, or the Function of the Eye_, 58 - Inventions, 25-27, 38-40 - Irradiation, 55 - Irrigation, 101 - Isabella of Aragon, 51 - Isonzo river, 88 - Istanbul, _see_ Constantinople - - - J - Johannes, 133, 143, 145 - Judas, 74, 77, 78 - - - K - King Charles VIII, 67-69, 78, 82, 120, 148 - - - L - Lake Como, 125 - Lamps, 59 - Lanfredini, Francesca, 2, 7 - "Last Supper," 30, 72, 74, 77, 92, 99, 138 - League of Cambria, 124 - Leghorn, 100 - Leibig, 41 - Leonardo da Vinci, - and the Church, 18, 48, 104, 145 - birth of, 2 - death of, 157 - early years of, 1-8 - illness of, 142, 150 - moves to Florence, 10 - notebooks of, 25, 29, 140, 152, 159, 160 - Levite, 118 - _Light and Shade_, 54 - Lighting, 59 - Lilienthal, Otto, 100 - Livoli river, 139 - Loches, 92 - Loire river, 147, 149, 152 - Lombardy, 37, 62, 78, 82, 83, 121,148 - Louis XII (of Orleans), 78, 82, 92, 94, 114, 116, 119, 124, 142, - 157 - Louvre, the, 44 - Lucullus, 130 - Lyons, 152 - Lyre, silver, 34, 35 - - - M - Machiavelli, Niccolò, 96, 100, 102, 106, 109 - Machine gun, 27 - Machinery, improvement of, 16 - Madonna Lisa, _see_ Mona Lisa - Malaria, 139 - Mandeville, Sir John, 103 - Manenti, 88 - Mantua, 84, 86, 87 - Mapmaking, 19, 93, 95, 96, 100, 101 - Martelli, Piero, 118 - Martini, Francesco di Giorgio, 58 - Martino river, 139 - Mathurine, 156, 157 - Maximilian I, 64 - Medici, Giovanni de', 130 - Medici, Giuliano de', 21, 130, 132, 138-146 - Medici, Lorenzo de', 16, 21, 26, 27, 29, 35, 39, 127, 130, 132, - 146, 153 - Medici, Piero de', 10, 16 - Medicis, the, 10, 21, 23, 26, 27, 33, 34, 68, 130, 131, 140, 142, - 146 - Melzi, Francesco de', 117, 128, 130, 140, 142, 145, 150, 155, 157, - 158 - Michelangelo, 106, 107, 113, 131, 137, 144, 145 - Middle Ages, 81, 104 - Migliorotti, Atalante, 35-38, 87 - Milan, 9, 33-48, 60, 64, 68, 78, 82, 83, 85, 95, 114-128, 143, 144 - Milan cathedral, 50 - Military, - defenses, 88, 89 - machines, 25-27, 33, 38-40 - Millstones, 75 - Mitre valve, 123 - Mirrors, 133 - "Mona Lisa," 99, 103 - Monferrato, 62 - Monte Albano, 1, 2, 5 - Monte Cecero, 113 - Montorfano, 72 - Muscles, 109, 119 - Music, 34, 35 - - - N - Naples, 9, 27, 68, 69 - Needle sharpener, 75 - Netherlands, the, 95 - Newton, Isaac, 24, 56, 123, 141, 160 - Newton's First Law of Motion, 123 - Newton's law of gravitation, 83 - _Notes_, 14 - Novara, battle of, 92 - - - O - Odometer, 69 - Oggionno, Marco d', 58 - Orient, the, 89 - Ornithopter, 111, 112 - - - P - Pacioli, Fra Luca, 76, 77, 80, 84, 86-91, 133 - Padua, 125 - Painting, 4-7, 29-32, 43, 44, 71, 72, 91, 99, 105, 110, 112 - Palatine hill, 135 - Palazzo della Signoria, 12, 21-25, 103 - Palazzo Vecchio, 12 - Parachute, 71 - Paris, 44 - Parma, 138 - Pater, Walter, 161 - Pavia, 51, 58, 125 - Pazzi conspiracy, 21, 23, 25 - Pazzi, Francesco de', 23 - Pera, 95 - "Periscope," the, 89 - Perugia, 96 - Perugino, Pietro, 13, 33, 107 - Pesaro, 93 - Peschiera, 124 - Pharisee, 118 - Philiberta, 142 - Phyllotaxis, 79 - Physics, 17 - Piazzetta, the, 87 - Pincio hill, 130 - Piombino, 93, 139, 154 - Pisa, 25, 100-102, 110 - Pitti Palace, 31 - Plague, _see_ Bubonic plague - Plants, study of, 79, 80 - Platonic school, 54 - Pliny, 23 - Plutarch, 81 - Pollaiuolo, 53 - Ponte Vecchio, 31 - Pontine marshes, 139, 154 - Pope Alexander VI, 82, 92, 102 - Pope Innocent VIII, 63 - Pope Julius II, 124, 127, 128, 130, 131 - Pope Leo X, 130-132, 139, 142-146, 153 - Pope Sixtus IV, 21, 33 - Porta del Popolo, 129 - Porta Romana, 29 - Porta Vercellina, 79, 115 - Porto Cesanatico, 94 - Portugal, 26 - Predis, Bernardino de, 47 - Predis, Giovanni Ambrogio de, 43, 44, 47, 56 - Ptolemaic theory, 48 - Ptolemy, 23, 54, 103 - - - Q - Queen Claude, 152 - - - R - Raphael, 107, 131, 137 - Ravenna, battle of, 127 - Red Book of the Painters of Florence, 19 - Reflection, law of, 56 - Renaissance, 89, 104, 125, 161 - Riario, Girolamo, 21, 38 - Rimini, 93 - Rome, 9, 33, 47, 69, 128-146 - Romorantin, 150, 152 - Rosate, Ambrogio da, 63 - Rumford, 56 - Rustici, Giovanni, 118 - - - S - "St. Anne with the Virgin and Child," 91, 92 - St. Augustine, 42 - Saint-Denis church, 157 - St. Germain-en-Laye, 157 - Saint-Hubert, chapel of, 153, 157 - St. John, 118, 154 - St. John the Baptist, 151 - St. Luke, 19 - St. Mary of the Virgin, 96 - St. Peter's, church of, 131 - Salai, 86, 115 - Salviati, Francesco, 21 - San Bernardo, chapel of, 23 - San Cristoforo, 157 - San Donato a Scopeto, 29 - San Lorenzo, 144, 145 - San Marco, Little Square of, 87 - Sanseverino, Galeazzo da, 82, 83 - Sant' Onofrio, hospital, 107 - Santa Croce, church of, 107 - Santa Maria delle Grazie, 71, 78 - Santa Maria Novella, 107 - Sanzio, Raffaello, _see_ Raphael - Savoy, 142 - Scarlione, Bartolommeo degli, 43 - Sculpture, 41, 49, 52-54, 58-64, 118 - Sforza, Duke Gian Galeazzo, 51, 56, 68, 120 - Sforza, Francesco, 41, 47, 49, 61, 64 - Sforza, Francesco (child), 68 - Sforza, Ludovico, 33-47, 51, 52, 56, 57, 60-72, 76-79, 82-84, 92, - 115, 117, 120, 138, 146, 154 - Sforza monument, 49-59, 61, 64, 120 - Sforzas, the, 40, 56, 57, 71, 79, 83, 117, 120, 154 - Shells, 62, 63 - Signoria, the, 96, 100-106, 110, 114, 116 - Sistine Chapel, 33, 132, 137 - Soderini, Piero, 103, 106, 109, 114-116 - Sologne, 154 - Spain, 18, 69, 127, 139, 142, 143 - Statics, 140 - Steam, 41 - Strabo, 23, 103, 104 - Swiss, 127, 128, 143 - - - T - Ticino gate, 44 - Torre, Marcantonio della, 125, 128 - Toscanelli, Paolo del Pozzo, 18, 19, 42, 93 - Touraine, 92 - Trivulzio, Marshal Gian Giacomo, 120, 121, 125, 128, 143 - Turks, the, 87-90, 94 - Tuscany, 93 - Tyrrhenian coast, 143 - - - U - Uffizi Gallery, 25, 32 - University of Padua, 125 - University of Pavia, 63 - Urbino, 93 - - - V - Valentinois, Duke of, _see_ Borgia, Cesare - Valois, Marguerite de, 150 - Vatican, the, 47, 130-145 - Venice, 9, 69, 87-89, 124, 125, 127 - Verrochio, Andrea del, 7, 12-19, 23, 118 - Via Ghibellina, 90 - Vigevano, 68, 75 - Vinci, 2, 13 - Vinci, da, Giuliano, 117 - Vinci, da, Piero, 2-7, 10, 12, 90, 106, 117 - "Virgin of the Rocks," 44 - Vitellozzo, 93 - Vitruvius, 77 - - - W - Water, study of, 67, 101, 102, 121, 122 - Watt, James, 160 - Witelo, 58 - - - Y - Yugoslavia, 88 - - [Illustration: Endpaper, portraits of scientists] - - [Illustration: Endpaper, names of scientists] - - - - - Transcriber's Notes - - ---Silently corrected a few typos. - ---Retained publication information from the printed edition: this eBook - is public-domain in the country of publication. - ---In the text versions only, text in italics is delimited by - _underscores_. - - - - - - - -End of the Project Gutenberg EBook of Leonardo da Vinci, Pathfinder of -Science, by Henry Sampson Gillette - -*** END OF THIS PROJECT GUTENBERG EBOOK LEONARDO DA VINCI, PATHFINDER OF SCIENCE *** - -***** This file should be named 54827-8.txt or 54827-8.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/5/4/8/2/54827/ - -Produced by Stephen Hutcheson and the Online Distributed -Proofreading Team at http://www.pgdp.net - 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