,illustration3 ,portrait of ,leonardo da ,vinci1 after a woodcut published in ,lives of the ,painters1 by ,vasari4 ,the ,latin inscription reads ,,lionardo ,,da ,,vinci ,,pitt4 ,e ,,scvltor ,,fior4 ,leonardo da ,vinci1 ,painter ,sculptor of ,florence4 ,immortals of ,science ,,leonardo ,,da ,,vinci ,pathfinder of ,science ,henry ,s4 ,gillette ,,pictures ,,by ,,the ,,author ,franklin ,watts1 ,inc41 #ege ,lexington ,avenue ,new ,york #bb1 ,new ,york ,to my wife ,trudy ,,first ,,printing ,library of ,congress ,catalog ,card ,number3 #fb-hdbf ,copyright #aifb by ,franklin ,watts1 ,inc4 ,manufactured in the ,united ,states of ,america ,,designed ,,by ,,bernard ,,klein ,,author',s ,,note ,it is natural that1 within the confines of these few pages1 many facets of ,leonardo's extraordinary personality will be missing4 ,that he was an artist1 a man of letters1 a poet and a philosopher are well known4 ,that he was also a man of humor1 as well as a prophet whose vision extended far beyond his times1 are facts that ,i have also tried to include in this biography4 ,there are many gaps in our knowledge of his life1 and these ,i have sometimes filled with my own imagination to give some continuity to his story4 ,little is known of his early days1 his period of travels after leaving ,milan and his years in ,rome4 ,there is1 too1 a certain mystery in his relations to those around him1 since our descriptions of him derive mostly from his often cryptic1 personal notes and from biographers who wrote of him many years after he had died4 ,this book is about ,leonardo the scientist1 and to fully write of his many accomplishments would require an encyclopedic mind4 ,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 other1 more fully documented books--and1 above all1 in the notebooks that ,leonardo himself wrote4 --,h4 ,s4 ,g4 ,rome1 ,august #aifa ,contents #a ,the ,shield #a #b ,florence #i #c ,a ,studio of ,his ,own #bj #d ,years of ,frustration #bh #e ,milan #cg #f ,the ,monument #di #g ,success #fj #h ,the ,french #gc #i ,cesare ,borgia #hf #aj ,shattered ,hopes #ih #aa ,the ,return to ,milan #aad #ab ,rome #abi #ac ,the ,last ,years #adg #ad ,mankind's ,debt to ,leonardo #aei ,significant ,dates in ,leonardo's ,life #afb ,index #afd #a ,the ,shield ,dusk was beginning to gather in the valley at the foot of ,monte ,albano as young ,leonardo turned toward home4 ,stopping by a rushing stream to wash the dust of the day's explorations from his face1 he laid aside his cap and his leather pouch and plunged his hands into the cold mountain water4 ,he felt the force of the current and watched the whirl and flow of bubbles around his bare arms4 ,there was the same feeling1 he thought1 to the flow of air he had experienced blowing around the rocky crags of the mountains4 ,this evening1 however1 there was no time to sit awhile and think4 ,he was in a hurry to get home4 ,hastily scooping the water in his cupped palms1 he splashed it over his head and face1 then shaking the water from his hair he rose and picked up his cap4 ,he took a satisfied look in his pouch1 slung it over his shoulder and headed down the stony trail to the village of ,vinci4 ,vinci was a small hill town situated on a spur of ,monte ,albano4 ,its castle and the bell tower above the houses seemed like sentinels guarding the slopes of vineyards and olive groves spreading down into the valley4 ,leonardo da ,vinci1 which means 8,leonardo from the town of ,vinci10 thought about his home4 ,he knew that he had been born in ,anchiano1 near ,vinci1 on ,april #ae of the year #adeb1 to a peasant girl named ,caterina4 ,at the age of five1 he had been sent for by his natural father1 ,piero da ,vinci1 to come and live at his family's house in ,vinci1 a comfortable and roomy place with a spacious garden4 ,piero1 five years before1 had married ,albiera di ,giovanni ,amadori1 a girl of sixteen4 ,they had had no children of their own1 and ,leonardo was welcomed into the home with affection by his young stepmother4 ,when ,leonardo was about eleven1 young ,albiera died1 leaving a darkened and saddened house4 ,two years later his father married another girl by the name of ,francesca ,lanfredini4 ,although laughter and song soon replaced the grief1 ,leonardo never forgot the love of his first stepmother4 ,also in the house lived ,antonio1 his grandfather1 who was eighty-five1 his grandmother1 his uncle ,allessandro ,amadori and family1 and1 best of all1 his uncle ,francesco4 ,the da ,vincis1 who could trace their beginnings in the town back to the thirteenth century1 had always been respected lawyers and landowners4 ,because ,uncle ,francesco was neither a lawyer nor a great landowner1 the people of the town said he did nothing2 but he tended the family vineyards1 and1 to the delight of ,leonardo1 he raised his own silkworms4 ,as ,leonardo entered the main gate1 he noticed that the oil lamps were being lit above the stalls of the marketplace1 and the lively confusion of the last hours of business was in full swing4 ,people nodded and smiled to him1 for as a boy of fifteen he was already a striking figure4 ,he was tall with long1 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 church4 ,the music of his lute1 the sound of his voice1 and the gentleness of his person were such that all hearts and doors were open to him4 ,tonight1 however1 ,leonardo avoided the usual invitations to stop and chat4 ,his father would be back from ,florence2 he had been going there more and more frequently as his fame as a lawyer grew4 ,now ,leonardo was thinking that he had almost finished the assignment his father1 half jokingly1 had given him many weeks ago--so many weeks ago that he was sure his father had forgotten about it4 ,at that time a peasant1 whose skill in providing fish and game for the table of ,piero's big household was greatly appreciated1 had asked a favor of him4 ,this man had a round1 wooden shield cut from a fig tree and he had asked ,piero to have a design painted on it for him in ,florence4 ,piero1 who had noticed the sketches his son was making of plants1 rock formations1 and scenes in his wanderings about the countryside1 decided to test his son's ability and gave the shield to the boy4 ,in the secrecy of his room1 into which no one was allowed1 ,leonardo had smoothed and prepared the wood1 and on it he was painting a monster4 ,scrambling over rocks1 through streams1 and into caves1 ,leonardo had been in the habit of gathering all manner of creeping and crawling life4 ,patiently he would bring these home in his leather pouch and carefully study and draw them4 ,maggots1 bats1 butterflies1 locusts1 and snakes added to the confusion of the boy's already cluttered room4 ,everywhere he went he collected the things that aroused his curiosity2 and as a result1 his room was always filled with rocks1 dried plants1 flowers1 the skeletons of small animals--and his pages of notations and drawings4 ,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 imagination1 for each feature was a duplicate of a reality in nature4 ,unobserved1 ,leonardo reached the privacy of his room and emptied this day's collection on a table beside the shield4 ,he lit a candle and examined his catch--a lizard and a large grasshopper4 ,these would complete his picture2 and1 the most extraordinary find of the day--a fossil seashell found high on the slopes of a mountain6 ,how did it get there8 ,was it a result of the flood about which his religion had taught him8 ,had an immense wave deposited this ancient sea-life high on the ,albano mountains8 ,looking more closely he saw that it was a type of sea-snail and in almost perfect preservation4 ,this he would have to think about and examine later4 ,now1 however1 the picture must be completed1 for he hoped to surprise his father in the morning4 ,but just then1 ,leonardo heard the family stirring below and his father calling him to dinner4 ,reluctantly he left his table1 made himself presentable and went downstairs4 8,ah1 ,leonardo10 his father said when he appeared in the family dining room4 8,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 true80 8,yes1 ,papa--but ,i'm not doing badly40 8,signor ,benedetto might agree1 at least in your mathematics4 ,he tells me you ask him questions that often make him stop and think4 ,but ,leonardo1 you have other subjects--,latin1 reading1 and writing--as well as arithmetic4 ,you mustn't neglect the others1 my boy4 ,but come--let us eat40 ,together they sat down with the rest of the family--a large1 prosperous1 and happy gathering4 ,when dinner was over ,leonardo made hurried excuses to all the family1 protesting that he was too tired to sing1 and escaped back into his room4 ,for a long time he worked1 unaware that the house was growing quieter4 ,finally he laid down his brushes and his maul stick1 pushed his chair back and smiled a triumphant smile4 ,the shield was finished4 ,tomorrow he would ask his father in to look at it4 ,conscious now that everybody had gone to bed1 ,leonardo blew out his candle and opened the shutters4 ,the night sky was a panoply of stars and only here and there was the dark loneliness of the valley relieved by pinpoints of light4 ,leonardo leaned his head against the window frame and stared at the blue infinity above him4 ,what exactly were the stars8 ,did all of them move around the earth8 ,what was the haze that obscured the horizon ever so faintly8 ,what was that sea-snail doing in the mountains8 ,why8 ,how8 ,the next morning ,leonardo found his father and ,uncle ,francesco in the garden deep in conversation about their vineyards and olive groves4 8,papa1 ,i have a surprise for you up in my room--can you come now80 8,yes1 ,leonardo4 ,what is it you have found now--not a better way to raise my grapes1 ,i'll wager60 ,the elder da ,vinci put his arm around the boy's shoulder and went with him up to the door of his room4 8,wait here1 ,papa1 until ,i say to come in40 ,leonardo unlocked his door1 lifted the cloth from the shield standing on the easel and opened the shutter just a trifle so that a soft light filled the room4 8,papa--you can come in now40 ,piero entered--he had long forgotten the round piece of wood--and suddenly he froze in the middle of the room4 8,have mercy on me60 he said when he saw the horrible fire-breathing creature4 ,in the dimness of the room1 the monster and the murky cave from which it was emerging were terribly real4 ,piero actually started to back out of the room in fright1 when ,leonardo laid a hand on his shoulder4 8,papa1 this work has served its purpose2 take it away1 then1 for it has produced the intended effect40 ,the shield was the talk of the house2 it was set up and marveled at4 ,as for ,piero1 he resolved to take it with him to ,florence secretly and sell it1 giving his peasant friend some cheap substitute that he would buy in the marketplace4 ,so1 a few days later1 ,leonardo's father saddled his horse and had the shield wrapped and packed in his saddlebag4 ,also1 unknown to his son1 he took some of the boy's drawings4 ,piero had now realized that ,leonardo might have a rare talent4 ,moreover1 he was planning to move to ,florence with his family so that he could be nearer to the ,badia1 or the law offices of the city1 for whom he had been frequently employed4 ,there1 thought ,piero1 ,leonardo's talent could be developed under the best of teachers4 ,it was many days before ,leonardo's father returned2 when he did1 he gathered his family together and it was obvious to all that he had exciting news4 ,first1 ,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 ,badia4 ,it was a handsome office centrally located opposite the palace of the ,podest1 or chief magistrate4 ,then1 turning to ,leonardo1 he said3 8,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 apprentice4 ,what do you think of that80 ,leonardo was stunned4 ,verrochio1 the great artist and sculptor6 ,florence6 ,the city-state whose power and influence had spread far beyond her own walls4 ,now he would study in earnest2 now he would find the answers to his never-ending questions4 ,he embraced his father and could say nothing4 #b ,florence ,the ,italy of ,medieval and ,renaissance days was not a unified country as it is today4 ,it was1 of course1 part of the ,holy ,roman ,empire1 but the main governing forces in the land were in the city-states1 of which ,florence was one of the most powerful4 ,a city-state was much more than a city--it was almost a kingdom in itself4 ,each had its own army1 and very often there were large-scale wars between such city-states as ,milan1 ,naples1 ,rome1 ,venice--and of course ,florence4 ,the ,italians of those days considered themselves citizens--not of ,italy as a whole--but of their particular cities2 people coming from other cities were looked upon as 8foreigners10 even though they looked the same1 wore the same style of clothing1 and spoke the same language6 ,all the power1 influence1 and ideas of this period in history were concentrated within the city-states4 ,a man might be a very fine artist1 engineer1 or philosopher1 but unless he managed to bring his work to the attention of the ruler of one of the cities1 he was likely to remain in obscurity4 ,thus it was that ,piero da ,vinci1 knowing that his son would have to have a powerful patron if he was to succeed at all1 brought ,leonardo to ,florence4 ,in #adfg1 when the da ,vinci family entered ,florence1 the city had been under the rule of the ,medici family for some thirty-three years4 ,as it was in most of these city-states1 the head of the ruling family--at this time ,piero de' ,medici--was in charge of the government of ,florence and the surrounding countryside4 ,but ,piero was fifty-one years old and ailing1 and he had only two years of life left at the time of ,leonardo's arrival4 ,none of this was in ,leonardo's mind as he rode with his father through one of the great1 guarded gates of the city4 ,he was thinking1 not of politics1 but of the fabulous sights that awaited him in this rich center of commerce and activity4 ,the narrow streets of the city were so crowded that is was necessary for the da ,vinci family1 together with their servants and the donkeys laden with household effects1 to go single file4 ,leonardo rode behind his father1 shouting questions1 and1 at the same time1 turning his head from side to side so as not to miss a thing4 ,brought up in the solitude of mountains and valleys1 and accustomed to the quiet life of a village1 the boy of fifteen was overwhelmed with the excitement of the city4 ,illustration3 ,leonardo rode behind his father1 turning his head from side to side so as not to miss a thing4 ,the party was now making its way past the booths of hundreds of shops1 past magnificent palaces built by wealthy merchants1 and across squares filled with the produce from hundreds of farms4 ,every now and then1 ,leonardo caught a glimpse of the cathedral dome1 one of the architectural marvels of its day4 ,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 city4 ,this palace still stands and today it is called the ,palazzo ,vecchio or ,old ,palace4 ,but now these sights were lost to view in the midst of the narrow streets1 other churches1 flags1 and the lines of washing that seemed to hang everywhere4 ,frequently1 ,piero's party was pressed against a wall as a procession shoved its way through a street4 ,sometimes it was by armed horsemen escorting a rich banker to some appointment2 other times it was a file of cowled monks observing some saint's day and carrying huge wax candles before them4 ,after they had crossed the magnificent square of the ,signoria1 in front of the ,palace of the same name1 ,piero leaned down from his horse and asked a blacksmith where ,verrochio's studio might be4 ,the man shouted above the din of clanging hammers3 8,everybody knows that shop1 ,signor--it's down that street and to the right6 ,you can't miss it--ask anybody60 ,the man was right1 for the workshop of ,verrochio was not hard to find4 ,verrochio was considered one of ,florence's finest artists and everybody knew of him4 ,he was a short1 broad-shouldered man of thirty-two with a round face1 shrewd eyes1 a thin mouth and dark curly hair that reached almost to his shoulders4 ,in his workshop were two other apprentices--young ,pietro ,perugino1 who was six years older than ,leonardo1 and ,lorenzo di ,credi1 a boy of eight4 ,they all lived in the house together and1 after ,leonardo was shown where he would sleep and had put away the few things he had brought with him from ,vinci1 he was taken to the place where he would work4 ,verrochio1 whose real name was ,andrea di ,michele di ,francesco de' ,cioni1 had taken the name of his teacher1 a renowned goldsmith1 as was the custom in the shops at that time4 ,verrochio himself was a skilled goldsmith4 ,but to be an artist and to have your own workshop in the year #adfg meant being a specialist in many things4 ,into ,verrochio's place came a great variety of artistic work--painting pictures1 sculpting and architecture1 goldsmithing1 designing and making armor1 creating decorated furniture1 designing mechanical toys1 and even preparing stage scenery4 ,verrochio1 of course1 would attend to the greater creative tasks1 while his apprentices did the chores of grinding colors1 preparing panels for painting1 making armatures for his sculpture1 hewing to size the marble for a statue1 preparing molds for casting1 building models for a new palace or church--in fact1 all the countless number of preparations to the finished work4 ,sometimes1 if an apprentice showed extraordinary talent1 he would be allowed to work on the finished painting or assist with the final strokes of the chisel4 ,verrochio was a busy man and a successful artisan4 ,to further his own ambitions1 he was now absorbed in the perfecting of mathematical perspective and the study of geometry4 ,the curious ,leonardo had come to the right man4 ,in ,verrochio's workshop1 where so many crafts were learned at the same time1 his powers of observation were able to develop2 his hunger to know about mathematics was fed4 ,in ,verrochio1 ,leonardo found a teacher who would encourage these investigations and urge him to study a wide variety of subjects4 ,leonardo now felt his lack of a fuller education4 ,he started to borrow mathematics textbooks and to seek out men who could teach him what he needed to know4 ,after each day's work was over1 ,leonardo would continue on into the night1 catching up on his neglected studies and discovering for himself new areas of thought such as anatomy1 movement and weight1 botany1 and another subject which was to occupy much of his later years--hydraulics1 or the useful application of water power4 ,in these early years1 ,leonardo commenced his famous ,notes4 ,he had developed his own 8secret0 writing in his childhood at ,vinci4 ,these notes--consisting of observations1 proportions1 and reminders to himself--were inscribed on his drawings4 ,they were1 however1 unreadable to the eye--until held up to a mirror4 ,leonardo was lefthanded and could write fluently in this strange manner4 ,it could have been for many reasons that he did so--perhaps from a natural desire for secrecy1 perhaps for reasons of safety from possible enemies4 ,in those days1 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 career4 ,leonardo was popular in ,florence4 ,he traveled with the young men of the town1 and his handsome appearance and enormous strength 7he could bend a horseshoe in his hands7 made him a welcome figure in many houses4 ,he continued to play the lute and the lyre4 ,he wrote poetry1 composed his own music1 and sang with a pleasing voice4 ,his blue eyes were kind and his manner gentle4 ,he always avoided arguments and competition when he could4 ,when he walked through the marketplace and came upon the caged birds1 he would buy them--just to set them free4 ,indeed1 his love of animals had become so great that he no longer ate meat4 ,during these years in ,verrochio's service1 ,leonardo grew in stature as an artist and rapidly developed into a scientist of promise4 ,he amazed his master when he painted an angel in an altarpiece that had been assigned to ,verrochio4 ,he painted it in the new oil colors recently acquired from the ,flemish painters4 ,so astounded was ,verrochio with its grace that the master vowed he would never lift a brush again if a 8mere child0 could so surpass him4 ,in this picture there is a tuft of grass beside a kneeling figure1 also painted by ,leonardo1 which indicates by its careful attention to detail the amount of research he did before committing it to canvas4 ,in other paintings he made beautiful drawings of a lily and studies of animals and crabs1 giving a hint of what was to come4 ,for1 in these preparatory works1 ,leonardo could not be satisfied until he had thoroughly studied the characteristics of plants and animals in general4 ,later in life1 he was to become more and more absorbed in these researches until they occupied the greater part of his time4 ,in #adfi1 when ,leonardo had been in ,florence only two short years1 ,piero de' ,medici died and was succeeded by his son1 the mighty ,lorenzo de' ,medici--or ,lorenzo the ,magnificent1 as he was often called4 ,now the city of ,florence felt itself under the control of a man who really knew how to use power4 ,lorenzo was ,florence2 nothing happened without his making it happen1 and he became one of the most prominent patrons of art and scholarship in all of ,italy4 ,if ,leonardo was to make any headway in ,florence1 he would have to make himself noticed by this new ,medici ruler4 ,but ,leonardo was not yet worrying about how to make himself a success4 ,a young man of seventeen and still an apprentice of ,verrochio1 ,leonardo continued to meet new friends with new ideas4 ,it was at about this time that he met ,benedetto ,aritmetico1 a prominent scholar and mathematician4 ,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 devices4 ,at any rate1 during these months ,leonardo was walking the streets of ,florence1 wandering into shops and mills1 making careful observations of all the various methods of manufacturing4 ,the more he saw1 the more he thought to himself that one man could do the work of many--if only he had the proper machine4 ,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 tools4 ,in addition1 the particular problems in the engagement of joints fascinated ,leonardo1 leading him on to the study of more general problems such as the transmission of power by gears and the strength of materials4 ,he also spent long hours studying geometrical theories and reading ,greek and ,latin classical works4 ,laboriously1 he translated these into his own formulas and made comments about them in his notebooks4 ,he attended the lectures of ,john ,argyropoulos1 a ,greek1 who talked of the ,aristotelian theories of natural history1 and who had translated ,aristotle's ,physics4 ,the study of physics opened to ,leonardo a whole new world of ideas4 ,he experimented with cogwheels1 and with the improvement of ways to lift weights4 ,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 drag2 he also tested the natural power of one body to set another in motion4 ,this bench with its rollers and weights was similar in principle to the one used by the ,french physicist ,a4 ,c4 ,coulomb almost three centuries later4 ,leonardo was indeed growing into a man of genius4 ,now everything from the stars to the flight of an insect occupied his thoughts4 ,at the same time1 he continued his studies of drawing and painting4 ,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 memory4 ,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 read4 ,this brought him into frequent conflict with the astrologers1 the alchemists and even the ,church4 ,the astrologers were men who told fortunes by the movements of the stars4 ,the alchemists1 with their knowledge of chemistry1 pretended to be able to talk with ghosts and to tell the future4 ,these men ,leonardo held in contempt4 ,although he was a devoutly religious man1 ,leonardo objected to many attitudes of the ,church which he considered outmoded and which stood in the way of scientific progress2 because of these objections1 he was frequently called a pagan4 ,in this same year of #adfi1 ,leonardo met the aging ,paolo del ,pozzo ,toscanelli4 ,toscanelli was a famous physician1 philosopher and mathematician who1 just the previous year1 had marked off on the cathedral floor the famous meridian line for determining the dates of the various ,church holidays4 ,the old man and the boy became not only the famous teacher and ardent pupil1 but close friends4 ,one evening at ,toscanelli's house1 the old man showed young ,leonardo a globe of the world4 ,much of it was marked 8unknown10 but ,toscanelli had filled in some areas from his own careful calculations and from the stories told him by sailors and travelers4 ,visions of distant lands1 remote mountain ranges and vast oceans filled ,leonardo's imagination as ,toscanelli spoke4 ,then ,toscanelli tapped the globe to the westward of ,spain1 saying3 8,here will be found a quicker route to ,india than the world has ever known before40 ,then1 turning to ,leonardo he murmured1 8,you will see it happen1 my boy1 in your lifetime40 ,one by one1 ,leonardo's childhood questions were being answered4 ,toscanelli told him much about the stars1 the fossils of creatures long disappeared from the world1 and how he believed the earth's early formation took place4 ,he also taught the boy the art of drawing a map4 ,not only did ,toscanelli greatly influence ,leonardo1 but the course of history as well4 ,ten years after ,toscanelli had died1 ,christopher ,columbus1 struggling westward over the ,atlantic ,ocean1 was using a map that old ,toscanelli had sent him1 carefully notated with all his accumulated wisdom4 ,leonardo1 in keeping with his own philosophy1 tested all this knowledge with experiments of his own4 ,because astronomical instruments were rare1 crude1 and costly1 ,leonardo borrowed them where he could and later set about making his own4 ,he went on to experiment with time measurements1 devising the first example of the application of a pendulum to regulate a clock2 by means of two springs1 it measured the minutes as well as the hours4 ,so for the next three years ,leonardo worked in ,verrochio's studio and continued his studies and experiments4 ,in #adgb ,leonardo's name was inscribed in the ,red ,book of the ,painters of ,florence1 which was the official guild1 or artists' union of that time4 ,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 ,st4 ,luke1 the patron saint of all painters4 ,although his father now had a spacious apartment in a house on one of the main squares of ,florence1 ,leonardo continued to live with ,verrochio4 ,in fact1 he stayed on past his formal training period for about four more years1 grateful to the kindly man for the food and bed he offered4 #c ,a ,studio of ,his ,own ,on ,sunday1 ,april #bf1 #adgh1 the bells of the cathedral were ringing loudly over ,florence1 almost drowning out the noise of the crowds in the street4 ,shutters were being thrown open and people were shouting excited questions at each other4 ,distantly at first1 but growing in volume1 was another sound--an ugly one--the sound of an approaching1 angry mob4 ,leonardo1 holding a roll of drawings closer under his arm1 stopped and listened4 ,suddenly the questioning voices stopped4 ,the bells continued ringing and now the angry shouts of the mob could be heard4 8,lorenzo is dead6 ,giuliano is dead6 ,death to traitors6 ,pazzi6 ,pazzi60 8,on to the ,palace of the ,signoria6 ,they've captured the ,archbishop6 ,he's a prisoner there60 8,get a ram and we'll break the door down60 ,the people in the street were caught up in the surging mass4 ,already soldiers of the ,medici were spreading out through the city4 ,cobblestones were ripped from the street1 and swords1 knives1 and clubs were being brandished in the air4 ,leonardo1 backed against a wall of a house1 was soon left in an almost deserted street4 ,still holding the drawings1 he made his way carefully back to his studio4 ,as it turned out1 ,lorenzo was not dead at all4 ,it was on this ,sunday that the ,pazzi conspiracy had broken out in ,florence4 ,in the cathedral1 the ailing ,giuliano de' ,medici1 brother of ,lorenzo1 was killed by assassins4 ,lorenzo himself escaped with only a scratched arm4 ,the ,pazzi family were rival bankers of the ,medicis and had joined in this plot with ,girolamo ,riario1 a relative of ,pope ,sixtus ,,iv1 and ,francesco ,salviati1 a long-time enemy of ,lorenzo4 ,a hired professional thug completed the members of the conspiracy4 ,girolamo ,riario hated the ,medicis because they refused him money for his own ambitions1 and the ,pope opposed ,lorenzo because ,lorenzo was supporting raids against papal territory4 ,as for ,archbishop ,salviati1 he had for years nursed a personal hatred for ,lorenzo4 ,illustration3 ,leonardo1 backed against a wall1 was soon left in an almost deserted street4 ,when the assassination attempt failed1 the ,archbishop and ,francesco de' ,pazzi fled to the ,palace of the ,signoria for protection4 ,however1 the members of the ,council of ,florence1 who were meeting1 then became suspicious and bolted the doors after them4 ,both men were later killed by the ,medici followers and their bodies were hung from the barred windows of the ,palace4 ,in the terror of the days afterward1 eighty victims lost their lives4 ,the ,pazzi conspiracy also had an effect on ,leonardo's future1 as we shall see later on4 ,leonardo had been on his way to the ,palace that morning4 ,he had been given his first painting assignment1 or commission1 the previous ,january4 ,this was to paint an altarpiece for the chapel of ,san ,bernardo in the ,palace1 and just the month before he had received the sum of twenty-five florins as a partial payment4 ,some time before ,january of #adgh1 ,leonardo had left ,verrochio and had found a place of his own4 ,the commission had come to ,leonardo through the influence of his father1 who was now one of the leading notaries1 or lawyers1 of the city4 ,though still poor1 ,leonardo could now devote this new independence to his widening fields of study4 ,leonardo's studio was like his childhood room in one respect--it was still filled with all the different things that had aroused his curiosity4 ,books were everywhere--on his tables and shelves and piled on the floor--books by ,ptolemy1 ,pliny1 and ,strabo on geography and natural history1 by ,aristotle on physics1 even one by ,guido1 a tenth-century monk1 who has been called the father of modern music4 ,in addition1 there were books on arithmetic1 agriculture1 geometry1 grammar1 philosophy1 fables1 poetry and even one containing jokes4 ,a map of the world hung on the wall1 together with his drawings2 and1 scattered throughout the whole studio were the plants1 fossils1 rocks and animal skeletons he was still collecting from his trips into the country4 ,there was also a huge table extending down the middle of ,leonardo's studio upon which were many drawings and instruments for working geometrical problems4 ,his easel near the window supported a painting--a study for his commission in the ,palazzo4 ,and on his desk was a confusion of papers containing notes all written in his 8secret0 writing4 ,at twenty-six ,leonardo was deep in the study of mechanical law1 geometry1 and botany4 ,for example1 he had observed the rings in trees and their relationship to the age of the trees4 ,in mechanics1 he was absorbed in drawing models of a 8variable speed drive40 ,by meshing three cogged wheels of different diameters to a common lantern wheel1 ,leonardo saw that different speeds of rotation could be obtained at the same time4 ,this same principle is used in the gear shift of modern automobiles4 ,about mechanics ,leonardo wrote that it was 8the paradise of the mathematical sciences because by means of it one comes to the fruit of mathematics40 ,now1 too1 he was starting to write about his observations on the flight of birds1 the formations of clouds and the behavior of smoke in the air4 ,he compared the flying of birds to the swimming of fish in the sea1 and the flow of air to the flow of water4 ,two hundred years before ,newton1 ,leonardo would define the principles of aerodynamic reciprocity1 as contained in ,newton's ,third ,law of ,motion4 ,at this time1 ,leonardo had an idea for making the ,arno river navigable all the way from ,florence to ,pisa by the addition of canals1 thus giving ,florence an outlet to the sea4 ,he also had thoughts for the improvement of irrigation in order to make use of land that did not have enough water4 ,nothing that ,leonardo saw in his day's activities was too small to pass unnoticed and unquestioned4 ,the flight of a butterfly1 the stratification of rock in a cliffside1 the shape of a mighty cumulus cloud1 the turning of a carriage wheel on a bumpy road1 the play of muscles in a farmer's back1 the curling of water around a rock in a stream--all of these aroused ,leonardo's curiosity4 ,continually1 he studied these things and painstakingly drew them and wrote about them in his notebooks4 ,unfortunately1 ,leonardo's painting commission for the ,palace of the ,signoria was never completed4 ,by the end of the year #adgh1 the ,pope1 angered by the killing of the ,archbishop during the ,pazzi conspiracy1 had declared war on the ,republic of ,florence4 ,ferdinand1 the ,king of ,naples1 was persuaded to help in this war against ,florence and the ,medicis4 ,as the papal forces were approaching the fortresses on the ,florentine hills1 the ,council of ,florence discontinued ,leonardo's commission in order to conserve money for the defense of the city4 ,disappointed though he was1 ,leonardo did not allow this setback to discourage him4 ,from a page of drawings in the ,uffizi ,gallery of ,florence on which are sketched various arms and war materials1 we learn that he turned from his artistic to his mechanical skills and began designing engines of war4 ,besides being a ,florentine concerned with the defense of his city1 ,leonardo was eager to gain an appointment with ,lorenzo as military engineer to make up for the painting commission he had just lost4 ,also1 as the fifteenth century was a turning point in the methods of waging war1 ,leonardo was attracted to all the mechanical possibilities of the new artillery4 ,before then soldiers had used spears1 bows and arrows1 and stone-throwing catapults1 among other primitive methods4 ,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 cradle4 ,the military appointment that ,leonardo hoped for didn't come4 ,unfortunately for the ,medicis1 the war with the papal forces was being lost4 ,one by one1 the fortresses under siege surrendered2 more and more of the ,florentine troops were fleeing4 ,leonardo continued the work on his military machines for1 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 design1 he still wanted official recognition for his inventions from ,lorenzo de' ,medici4 ,during these weeks late in the year of #adgi1 ,leonardo conceived many ingenious devices to wage war4 ,besides the small artillery piece1 he designed a bombard1 or rock-throwing cannon1 which did not recoil when it was fired4 ,this was followed by a light gun arranged in three tiers of barrels1 mounted so that while one tier was fired1 the second was being loaded and the third was cooling 7a forerunner of the modern machine gun74 ,another was a device to repel enemy ladders4 ,it consisted of a horizontal beam laid parallel to the top of a fortress wall2 the beam could be pushed outward by one man or several men using a system of pulleys4 ,illustration3 ,leonardo's design for a machine gun4 ,it had thirty-three barrels in three banks of eleven each4 ,while one bank was fired1 one cooled and the other was reloaded4 ,unfortunately for ,leonardo1 just as he was ready to show these inventions to ,lorenzo de' ,medici1 the last fortress outside ,florence surrendered and a three-month truce followed4 ,lorenzo himself went to ,naples and persuaded ,king ,ferdinand to withdraw from the war4 ,by #adhj1 peace returned once again to ,florence4 ,as for the ,medicis1 military machines no longer interested them4 ,greatly disappointed at not having his inventions used--or even looked at--,leonardo began to search about for new fields of creative activity4 #d ,years ,of ,frustration ,the old monk spread the papers out before him on the table4 8,master ,leonardo10 he said1 8these are the terms of the commission4 ,we at the monastery wish to have an altarpiece painted for our chapel4 ,your father has recommended you1 and1 as you know1 he is our lawyer4 ,of course your reputation has already reached our ears1 and we are satisfied in our choice40 ,the year was #adhj4 ,the monk represented the monastery of ,san ,donato a ,scopeto near the ,porta ,romana1 just outside ,florence4 ,leonardo shook his head slowly at the terms of the commission4 ,the painting had to be completed in thirty months at the most4 ,moreover1 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 use4 ,nevertheless1 it was an opportunity1 and ,leonardo needed work4 ,since the papal war had ended1 he had not received any commissions--and his skill at military engineering was still too unknown to have won him recognition4 ,although ,lorenzo de' ,medici was a great supporter of the arts and sciences1 he had not granted ,leonardo any of his patronage4 ,in ,lorenzo's court were many men with much book-learning but little talent4 ,they guarded their positions jealously and kept the way to ,lorenzo barred to any applicant whom they did not like4 ,of them1 ,leonardo wrote in his notes3 8,they strut about puffed up and pompous1 decked out and adorned1 not with their own labors1 but by those of others1 and they will not even allow me my own4 ,and if they despise me who am an inventor1 how much more blame be given to themselves1 who are not inventors but trumpeters and reciters of the work of others80 ,in accepting the commission to paint the altarpiece1 ,leonardo hoped to attract attention to himself4 ,perhaps then ,lorenzo might welcome him to his court and grant him patronage4 ,so1 with his usual thoroughness1 ,leonardo set about the task of preparing an ,adoration of the ,magi--a favorite subject of that time4 ,this was to be a picture of the ,holy ,family surrounded by the three wise men from the ,east1 shepherds and animals1 old and young1 rich and poor1 paying their adoration to the ,christ child4 ,since he wanted his subjects perfect in every detail1 ,leonardo set about drawing countless youths1 old men1 sheep1 oxen1 horses1 and donkeys4 ,in a separate drawing for the background1 he worked out with mathematical mastery the problems of perspective1 that is1 drawing objects to make them appear three-dimensional and either close or far away in space4 ,in addition1 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 subject4 ,illustration3 ,leonardo's hygrometer4 ,among these sketches that ,leonardo made for his 8,adoration of the ,magi0 is a page on which appears an inspiration for one of his greatest masterpieces--a drawing of the 8,last ,supper40 ,and on this same page is another drawing--one of a hygrometer4 ,a hygrometer is an instrument for measuring the amount of moisture in the air4 ,leonardo's design consists of a simple1 graded disk with a balanced pointer1 weighted at one end with sand and at the other with a sponge or some salt4 ,as the sponge or salt absorbed the moisture in the air1 the added weight was indicated on the graded disk1 thus measuring the amount of humidity4 ,leonardo's researches for the altar painting took him almost a year4 ,although the monks began to grumble at his slowness1 ,leonardo would not be hurried4 ,he was determined to produce a painting that was perfect in all respects4 ,to quiet their impatience ,leonardo did odd jobs for them in the cloister4 ,he repainted their old clock and for this extra work they advanced him some much-needed money4 ,in ,march of #adha ,leonardo was ready to begin the actual drawing for the altarpiece4 ,as he progressed with the composition1 the monks crowded around with exclamations of delight4 ,so different was it from all the other ,adoration pictures they had ever seen1 that the monks sent ,leonardo some sacks of corn as a token of their appreciation4 ,one day1 ,leonardo was walking slowly toward the monastery over the ,ponte ,vecchio--the ,old ,bridge--across the ,arno ,river4 ,he made his way slowly up the hill past the construction for the new ,pitti ,palace4 ,the morning was hot and the farmers moving into the city with their heavily laden carts were short-tempered4 ,leonardo stood to one side as he watched a pair of oxen straining to haul a wagon up a rise in the road4 ,their owner1 his shirt unbuttoned to the waist1 was shouting angrily1 lashing the animals with his leather-thonged whip4 ,it was a cruel sight and ,leonardo turned away4 ,from some experiments he had been making1 ,leonardo realized that the poor animals were struggling not only with the hill1 but the drag of friction on the creaking axle4 ,this drag could be eased1 he thought to himself1 by simply resting the axle in two sets of roller-bearings attached to the bottom of the cart near each wheel4 ,in his mind he formed the plan for such a model as he made his way to the monastery4 ,the drawing of the altarpiece was nearing completion4 ,the monks were fascinated by the spectacle of the ,adoration appearing before their eyes4 ,the soft1 umber outlines deepened with gray1 the ochre highlighting the central figures charmed them and they sent another gift to ,leonardo's house--a cask of ,tuscan red wine4 ,as it turned out1 ,leonardo never finished this altarpiece4 ,it is not known why4 ,but the drawing for it can be seen today in the ,uffizi ,gallery in ,florence just as ,leonardo left it4 ,it is certain1 however1 that ,leonardo was far from idle during this time4 ,he drew the design for eliminating the friction of a turning axle by mounting the axle in roller-bearings4 ,he experimented with1 and solved the problem of1 transmitting motion to revolving machine parts by friction--the possible forerunner of our modern friction clutch4 ,another device1 found in modern automobiles--the differential--was also drawn by ,leonardo4 ,this idea provided for the difference in speed between the two drive wheels when rounding a curve4 ,leonardo also drew the first known plans for a self-propelled vehicle--an 8automobile40 ,it was designed to operate by a system of elastic springs wound by hand by the person on the vehicle2 the 8car0 was then supposed to run the short distance allowed it by the unwinding of the springs4 ,in addition1 ,leonardo continued designing machines for both offensive and defensive military action4 ,one of these was a breech-loading cannon1 together with the first known projectiles that took into consideration better penetration through the air and greater stability in their trajectory4 ,indeed1 these very much resembled present-day aerial bombs1 with pointed noses and stabilizing fins4 ,as the months passed1 however1 ,leonardo began to feel that his time and talents were being wasted in ,florence4 ,although the monks and friends of the monastery were pleased with the work he was doing1 other artists were being called to greater tasks in ,rome4 ,for example1 ,domenico di ,tommaso del ,ghirlandaio1 ,sandro ,botticelli1 and even ,leonardo's fellow student1 ,pietro ,perugino1 had left ,florence to work in the chapel of ,pope ,sixtus ,,iv in ,rome--known to us as the ,sistine ,chapel4 ,now1 too1 it was becoming clear that ,lorenzo and his court had no time for this solitary genius whose ideas stretched beyond his age4 ,so ,leonardo looked about him4 ,he was thirty years old and the walls of ,florence seemed to bind his spirit4 ,to what city could he go where his talents would be put to fruitful use8 ,rome seemed to hold out no hope1 for no one had offered him a position there4 ,but ,leonardo remembered that there had been a visitor to the ,medicis from another city in recent months4 ,this man was ,ludovico ,sforza1 the ruling prince of ,milan1 the great city-state of the north4 ,ludovico1 who was also called 8,il ,moro0 7the ,moor7 because of his dark complexion1 was seeking the friendship and alliance of the ,medicis4 ,he was fascinated with the art and culture of ,florence and sought to gather to his own court of ,milan as many artists1 scientists1 philosophers1 and musicians as he could4 ,perhaps1 thought ,leonardo1 his future lay in ,milan4 ,so he began collecting his countless drawings1 diagrams of machines and instruments of war1 his notes1 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 ,ludovico4 ,then he sat down to write a letter to that nobleman4 ,in it he set forth in ten numbered paragraphs his qualifications as military and naval engineer1 architect1 and hydraulics expert4 ,almost as an afterthought to the tenth item1 he wrote3 8,i can carry out sculpture in marble1 bronze1 or clay1 and also ,i can do in painting whatever may be done1 as well as any other1 be he who he may40 ,when he had finished the letter1 ,leonardo took out a strange instrument4 ,it was a lyre of silver in the shape of a horse's head4 ,he had designed it himself1 and now with an air of peace1 he commenced to play4 ,its rich tone was sweet to hear and the music was his own composition4 ,leonardo had also designed other instruments--lyres1 lutes1 viols1 and a kind of zither4 ,he had perfected the single-stringed monochord of ,pythagoras1 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 string4 ,in addition1 he introduced stops or small pistons in the holes of wooden reed instruments2 and1 he had even invented a set of mechanical chords by using a wheel of reeds which plucked a set of strings as it was turned4 ,his skill as a musician1 composer1 and singer was well known among his friends and his bass voice had retained the pureness of his boyhood4 ,as it happened1 news of ,leonardo's silver lyre had reached ,lorenzo de' ,medici4 ,all ,leonardo's paintings1 all his designs for cannons and fortifications1 all his inventions for commercial machinery had failed to interest ,lorenzo--yet this single musical oddity excited the ruler's curiosity4 ,leonardo was summoned to the ,medici palace4 ,lorenzo was enchanted both by the instrument and ,leonardo's musical talent4 ,when ,leonardo had finished playing1 ,lorenzo1 surrounded by members of his court1 applauded and said1 8,it would please us if ,master ,leonardo da ,vinci would present us with this beautiful instrument so that we1 in turn1 could make a gift of it to ,his ,highness1 ,ludovico ,sforza1 of ,milan40 ,leonardo bowed and replied1 8,your ,grace's request is my pleasure4 ,moreover1 ,sire1 it would further that pleasure to bear the gift myself to ,his ,excellency in ,milan40 ,the idea delighted ,lorenzo4 ,he immediately directed that ,leonardo be given a letter to ,ludovico and that every protection be given ,leonardo for his journey4 ,leonardo1 with the silver lyre and the letter of recommendation1 hurried home to make his final preparations4 ,he called on a friend and pupil1 young ,atalante ,migliorotti1 to accompany him4 ,toward the end of #adhb or the beginning of #adhc1 with the letter to ,ludovico folded in a leather pouch1 ,leonardo and ,atalante mounted their horses and left ,florence for the long journey to ,milan4 #e ,milan ,milan at this time was one of the greatest and wealthiest city-states in all ,europe4 ,its battlements and the spires of its mighty cathedral rose impressively from the lush plain of ,lombardy4 ,towering over the city in the distance were the snow-capped peaks of the ,alps4 ,groves of mulberry trees for the production of its famous silk industry and vast stretches of rice paddies extended far into the surrounding countryside4 ,leonardo and ,atalante rode along the embankment of one of the many canals4 ,the sight of the city hastened their pace although the journey had been a long one4 ,frequently on the trip ,leonardo had stopped to make notes4 ,riding over the mountains and ravines surrounding ,florence he had drawn some of the rushing streams and the stratifications of exposed cliffs4 ,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 waterwheels4 ,leonardo was excited by this new city and by his prospects at the court of ,ludovico4 ,on the way to his lodgings1 he also noticed that ,milan was a great center of arms manufacture4 ,shop after shop displayed its wares of swords1 spears1 shields1 armor for man and horse1 and signs advertising foundries for the making of cannon4 ,perhaps here he might find an outlet for his military inventions4 ,in the inn where he and ,atalante stayed1 ,leonardo overheard the current political rumors4 ,all around him was talk of the war4 ,girolamo ,riario was again in the field1 and ,ludovico's ally1 ,alfonso of ,calabria1 had just been defeated by the ,venetians in a bloody battle at ,campo ,morto4 ,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 engineer4 ,he would minimize the bronze monument1 his music1 and his painting1 and instead1 he would stress his skills in the inventions of war4 ,when ,leonardo appeared before ,ludovico1 he was a handsome young man of thirty-one4 ,tall and strong1 he was dressed not according to fashion1 but simply--almost severely4 ,his hair hung in curls on his shoulders and his auburn mustache and neatly trimmed beard accented his ruddy complexion and deep-set blue eyes4 ,indeed1 he presented a striking contrast to the nobleman seated before him4 ,il ,moro1 with his dark skin and straight black hair1 his richly embroidered doublet with its broad sleeves and the heavy gold chains across his thick chest1 was the exact opposite of ,leonardo4 ,ludovico set aside ,leonardo's letter1 rose from his chair1 and walked to the heavy table on which ,leonardo had spread out his drawings4 ,plans for all manner of war machines were there--those that ,leonardo had designed for ,lorenzo de' ,medici without success1 together with many new additions4 ,for example1 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 8rotatory rocket0 when it was actually invented in #ahdf4 ,leonardo also explained to ,ludovico his idea for 8poison gas0 bombs containing sulfur3 the fumes of these bombs would 8produce stupor10 and they could be used both on land and sea1 together with masks to protect those who were using them4 ,shrapnel shells1 hand grenades1 and javelins that burst into flame when they struck their objectives--these and many more were among his ideas4 ,but perhaps the most unusual to ,ludovico's eyes was the design for an armored vehicle4 ,it was shaped like a giant turtle1 with overlapping sheets of reinforced wood so that enemy shells would bounce off its surface4 ,the armor was pierced by loopholes for the breech-loading cannon and there was an opening at the top for ventilation4 ,power for the vehicle was supplied by eight men inside turning cranks which in turn were cogged to other wheels1 setting in motion the four drive wheels4 ,this of course was the forerunner of the tank and the armored car used in modern warfare4 ,illustration3 ,forerunner of the tank or armored car1 as conceived by ,leonardo4 ,motion was supposed to be supplied by four cogged wheels turned by manpower4 ,sheets of reinforced wood were supposed to serve as 8armor0 against enemy projectiles4 ,in addition1 ,leonardo laid before ,ludovico all manner of cannons and designs for tunneling under the enemy's defenses4 ,actually1 with respect to warfare itself1 ,leonardo called it a most brutal 8madness02 however1 he recognized the necessity of being prepared4 ,in his notebook1 he wrote1 8,when besieged by ambitious tyrants ,i find a means of offense and defense in order to preserve the chief gift of nature1 which is liberty40 ,ludovico was very much interested in the things ,leonardo had showed him4 ,although he was a man of limited imagination and was not able to grasp the scope of ,leonardo's proposals1 he was nevertheless involved in a war4 ,since ,ludovico's aging military engineer was to be replaced1 ,leonardo left the forbidding castle of the ,sforzas with high hopes of getting the position4 ,in the meantime1 he was commissioned to paint the portrait of a young girl from a noble family in ,milan4 ,at the same time1 he began the bronze equestrian statue of ,ludovico's father1 ,francesco ,sforza4 ,for this work1 he began an intensive study of horses4 ,since hunting was the popular sport at the court of the ,sforzas1 ,ludovico owned a stable of the finest ,arabian horses1 and here ,leonardo commenced his drawings4 ,again1 his research for a work of art led him beyond just making preparatory sketches4 ,his studies developed into notes1 and his notes into a planned book on the anatomy of the horse4 ,during these months of waiting for the appointment as military engineer1 ,leonardo furthered his experiments with cannon4 ,in the course of these experiments1 he came across a power that would later revolutionize all industry--steam4 ,he devised--although he attributed the original idea to ,archimedes--a water vessel connected to a copper tube which was heated by a fire4 ,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 force4 ,leonardo experimented with steam in other ways4 ,he built an apparatus for measuring the transformation of water into vapor4 ,it consisted of a metal box in which was a thin animal bladder partly filled with water4 ,resting on the top of the bladder was a flat lid attached by a cord hung from two pulleys to a counterweight on the outside4 ,as the water was heated1 the steam in the bladder pushed up the lid4 ,as the lid rose both the volume and the pressure could be measured4 ,there were distillation experiments with various condensers1 one in particular that anticipated the modern condenser of ,leibig1 introducing double walls that formed a complete jacket for cooling with water in continual circulation4 ,not content with having an idle moment1 ,leonardo again turned to searching out books that he had not read and trying to fill the gaps in his education4 ,he became especially interested in the ,german philosopher1 ,cardinal ,cusanus4 ,cusanus1 like himself1 had been influenced by ,toscanelli and was a man devoted to the natural sciences4 ,leonardo also studied the philosophy of ,aristotle and the writings of ,st4 ,augustine4 ,throughout his life ,leonardo believed in an active mind for1 as 8iron rusts from disuse1 stagnant water loses its purity and in cold weather becomes frozen1 even so does inaction sap the vigor of the mind40 ,unfortunately1 the post of military engineer went to a man named ,ambrogio ,ferrari4 ,the extent and variety of ,leonardo's proposals were too great for ,ludovico to trust4 ,he did not believe that one man could possibly bring all those ideas into being4 ,ferrari1 on the other hand1 was a military engineer only1 and a man who was content with the customary methods of warfare4 ,furthermore1 ,ludovico had at last decided that peaceful negotiations would gain him more than fighting4 ,thus ,leonardo's chance of recognition was again postponed4 ,meanwhile1 the money that ,leonardo had brought with him from ,florence was almost gone4 ,he had been forced to move from his apartment to a single room and now he was barely able to live from day to day4 ,although the court of ,ludovico ,sforza was one of the richest in the world1 artists were frequently treated as servants2 often they were the last to be paid for their services4 ,also1 ,leonardo was a foreigner in the city1 which meant he was regarded with suspicion4 ,because of these reasons1 ,leonardo finally decided to do what the ,milanese artists did--they banded together in groups sharing work and costs4 ,leonardo had met a young artist of twenty-eight1 ,giovanni ,ambrogio de ,predis1 at the court of ,ludovico4 ,ambrogio was court painter to the ,sforza family and had achieved some success4 ,ambrogio recognized in the handsome stranger from ,florence1 however1 the touch of genius1 and he realized that his own talents would be furthered by learning from ,leonardo4 ,the two young men decided to pool their abilities4 ,ambrogio offered both lodging and a studio2 and1 in association with his two half-brothers1 one a woodcarver1 another a miniaturist1 and his elder brother1 a minter of coins1 they would not lack for commissions4 ,commissions weren't long in coming4 ,on ,april #be1 #adhc1 a contract was signed between ,bartolommeo degli ,scarlione1 a prior of the ,fraternity of the ,immaculate ,conception1 and ,ambrogio and ,leonardo for an altarpiece4 ,the fee was two hundred ducats1 with a promise of more if it were delivered on time and was satisfactory to the ,fraternity4 ,delivery date was to be ,december #h1 #adhd4 ,ambrogio was to paint the altar wings and ,leonardo the center piece--a picture of the ,blessed ,virgin and ,child4 ,but when the painting was finished1 it was not according to the instructions set forth in the contract4 ,leonardo had too independent a mind to be bound by conformity4 ,nor was it completed on time4 ,indeed1 for twenty years the quarrel between the ,fraternity and the painters went on4 ,after ten years1 ,ludovico was asked to intervene for the money owed2 after he failed1 another ten years went by and the ,king of ,france himself was finally asked to settle the dispute4 ,leonardo wanted his one hundred ducats and the ,fraternity offered twenty-five4 ,eventually1 a secret agreement was arrived at and the painting was restored to ,leonardo and ,ambrogio4 ,leonardo's painting1 the masterpiece entitled the 8,virgin of the ,rocks10 now hangs in the museum of the ,louvre in ,paris4 ,the day this contract was signed1 ,leonardo walked back through the city to ,ambrogio's studio near the ,ticino gate4 ,he was low in spirits from reading the petty instructions of the contract1 and1 in this mood1 he became aware of the city streets and crowds about him4 ,the noise1 the confusion1 the smells--yes1 the smells were the worst4 ,garbage1 filth1 and dust were in heaps where the last rainwater had left them and they buzzed with flies4 ,moreover the houses were jammed together and shopkeepers crowded their wares to the edges of the streets1 leaving just enough room for the occasional horseman to get through4 ,latrines were only for the better houses2 here1 the streets1 alleys and even open doorways were toilets4 ,people flung their scraps out of the window and at night in the poorly lit streets could be heard the scurrying of rats4 ,leonardo stopped1 thinking half aloud3 8,two levels4 ,streets running one above the other--one for pedestrians and one for carts and horses4 ,yes1 and cutting through the whole city a system of canals to carry the city's waste to a river or to the sea4 ,why not even ten cities of1 say1 five thousand houses in each--say1 no more than thirty thousand people to a city80 ,intent now on his thoughts he hurried to his home1 his mind busy with his visions of new cities4 ,during the years #adhd and #adhe the bubonic plague swept ,italy--the same dreaded ,black ,death so prevalent in medieval times4 ,milan was one of the cities most severely stricken4 ,every courtyard became a hospital and the streets were deserted except for the rumbling carts picking up the dead4 ,on the roads from the city were lines of refugees fleeing to the country4 ,surrounding cities that had not been infected manned their fortress walls as in wartime to keep the fleeing populations out4 ,ludovico at first tried to protect ,milan from the spread of the disease2 then1 frightened1 he and his court fled4 ,even the ruler's official documents had to be 8disinfected0 by perfume and then held for a period of time before he would allow them near him4 ,leonardo1 sensing opportunity1 drew out his plans for his new cities4 ,canals running through them were to be used for barges and the underground conduits greatly resembled those of modern sewage systems4 ,paths were to have gutters for the adequate drainage of the streets4 ,public toilets were to be installed4 ,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 roofs4 ,the widths of the streets were to be in proportion to the heights of the houses--light and air would circulate freely4 ,two levels would be connected by graceful ramps--the lower level for the commercial traffic and the upper level for the pedestrians4 ,where stairs were used they were designed so one could ascend or descend without one person seeing the other4 ,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 waste4 ,illustration3 ,the results of the bubonic plague in ,italy1 #adhd-he4 ,streets were deserted except for the carts picking up the dead4 ,these sweeping plans ,leonardo laid before ,ludovico when the epidemic had subsided4 ,but ,ludovico1 once his fear was overcome1 brushed them aside as impossible dreams4 ,so ,leonardo returned to the commission for the ,fraternity and the designs for the bronze monument of ,francesco ,sforza4 ,these jobs kept ,leonardo from brooding about his rejections4 ,often1 too1 ,leonardo worked with ,bernardino de ,predis1 the elder brother of ,ambrogio4 ,bernardino was a minter of coins4 ,as ,leonardo watched him at the laborious task of first cutting disks from ingots and then hammering the design into the hot metal1 he suggested to ,bernardino an easier method1 then used in ,germany4 ,this was to prepare smooth ribbons of metal of the desired thickness and with a punch1 impress the design into the ribbon at the necessary intervals and then1 punch out the coin4 ,leonardo went on to improve this system by designing precise punches for both faces of the coin4 ,a single machine then cut out and stamped the coins1 using a falling weight raised by little winches4 ,this machine was later destined for the ,vatican mint in ,rome4 ,on ,march #bf1 #adhe an event occurred in ,milan that was viewed with mingled fear1 superstition1 curiosity and excitement4 ,there was a total eclipse of the sun4 ,to some1 coming as it did so soon after the plague1 it was a judgment of ,god2 to others1 it was regarded as an omen--a sign for astrologers to use for predicting the future4 ,but to ,leonardo the eclipse was a moment of great scientific importance4 ,at this time in history1 the ,ptolemaic1 or geocentric theory of the universe was the popular belief4 ,this theory taught that the earth is fixed and the sun and moon revolve around it4 ,leonardo himself had believed this theory for a long time4 ,as he grew older1 however1 he read and heard discussions of the heliocentric theory4 ,this theory proposed that the sun is fixed and the earth and stars move around it4 ,now1 as he watched the eclipse1 his doubts of the ,ptolemaic concept were renewed and he resolved to make experiments of his own4 ,the new theory was so daring for his times1 however1 that it would be many years before he became convinced of its truth4 ,later that night1 deep in thought over the experience of the day1 he noted down his observations of the eclipse and his doubts of the medieval concept of the heavens4 ,the ,church believed the earth was the fixed center of the universe4 ,scholars and scientists supported the belief of ,aristotle in the four elements1 earth1 water1 air1 and fire--but something was wrong4 ,what were the planets--what was the moon8 ,he picked up his pen and on a clean sheet of paper he wrote1 8,make glasses in order to see the moon large40 #f ,the ,monument ,during this time1 ,leonardo had been struggling with the design for the bronze equestrian statue4 ,drawing after drawing lay scattered on his studio floor4 ,lately1 however1 a daring plan for this statue had come to him4 ,it was to be a huge bronze warrior1 ,francesco ,sforza1 mounted on a rearing horse4 ,weighing perhaps a hundred thousand pounds1 it was to be cast in sections in five furnaces--a fitting monument to the power of the ,sforza family4 ,but there still remained a big problem to be solved3 how could he balance the plunging horse and man on just the two rear legs of the horse8 ,meanwhile1 ,leonardo had another problem to work on--a wooden model of the ,milan cathedral4 ,he had entered his name with the cathedral authorities as a competitor in the design and construction of the cathedral's dome4 ,many architects had been brought in and had failed1 partly because of the antagonism of the ,milanese workmen to foreign craftsmen1 and partly because the committee found it difficult to decide what designs it liked4 ,leonardo had sent them a letter outlining his own recommendations and had drawn many pages of possible plans4 ,he put forward his knowledge of various building materials1 his understanding of classical architecture1 and his wish to keep his own ideas in harmony with the ,gothic tradition of the cathedral itself4 ,often he would make a point of walking about the city1 observing the different constructions under way and drawing up plans to shorten the labor by mechanical means4 ,in ,july of #adhg ,leonardo received a payment from the cathedral authorities for the wooden model he had submitted4 ,still1 however1 no final decision had been reached4 ,now1 as ,leonardo looked at the model in his studio1 he felt the urge to improve it further--to make it more perfect4 ,yet he held his impatience in check and decided he would wait a little longer4 ,instead1 he decided to work on some of his ideas for construction devices4 ,he had already made many drawings1 but they could be improved1 he thought1 and he began to make calculations4 ,among these notes and drawings was an improvement on a device for the raising of columns4 ,it was a mobile windlass with a transmission gear for transporting and erecting columns and obelisks4 ,another device was an earth drill resembling a modern corkscrew with double handle bars4 ,the upper bar1 when turned1 drilled the screw into the earth while the lower bar--when turned the opposite way--carried the dirt up and out4 ,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 directions4 ,other labor-saving devices that ,leonardo designed were an automatic pile driver1 the weight of which was raised by a winch and tripped automatically at its height to fall on the piling2 a lift for raising iron bells to bell towers2 and a machine for boring tree trunks to make pipes for carrying water4 ,in the fall of #adhh1 ,leonardo was interrupted by a summons from ,ludovico1 who wanted him to design and build the decorations for the forthcoming marriage of his nephew1 young ,duke ,gian ,galeazzo ,sforza1 to ,isabella of ,aragon1 granddaughter of the ,king of ,naples4 ,he worked on this steadily until the wedding ceremony in ,february of the following year4 ,when the day arrived1 the street from the cathedral to the grim castle was trimmed with flags and banners of the two royal houses4 ,the inner courtyards of the castle were transformed into delicate arbors of laurel boughs4 ,yet it was the evening's reception and entertainment which were to be the climax and to them ,leonardo had brought all his mechanical skill4 ,however1 the announcement of the death of the bride's mother cut short the celebration and1 after the bride and groom had left for ,pavia1 the wedding party soon dispersed4 ,disappointed that his decorations had not been fully appreciated1 ,leonardo returned to his studio and the problem of the monument4 ,he was still struggling with the problem of balancing the rearing horse4 ,and1 indeed1 a solution was soon found4 ,by placing a fallen soldier with his arm upraised in protection under the forefeet of the horse1 ,leonardo could balance the enormous weight and provide for the proper casting of the molten bronze4 ,finally1 ,leonardo made a small wax model of the proposed statue and showed it to ,ludovico4 ,the nobleman was impressed by its originality4 ,most of the ideas contributed by other sculptors were mere variations of what had already been done many times4 ,also1 the other plans called for bronze of not more than two thousand pounds1 while ,leonardo envisioned a statue fifty times that size6 ,ludovico awarded the commission to ,leonardo4 ,leonardo was to work on this commission for ten years and it was destined never to be immortalized in bronze1 for reasons that will be explained later4 ,his energies1 as usual1 were poured into many schemes4 ,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 horse4 ,but the one subject1 which he began to study in this period and which would occupy the remainder of his life1 was the study of human anatomy4 ,so ,leonardo1 in the midst of all his other activities1 wrote in his notes1 8,on the second day of ,april #adhi the book entitled ,of the ,human ,figure40 ,the sources of anatomical study up to ,leonardo's day had been the ,greeks--,hippocrates and ,galen--and the ,arab--,avicenna4 ,books on this subject were few1 and the anatomical diagrams were crude and inaccurate4 ,galen1 for example1 had based his studies on the dissection of monkeys4 ,renaissance anatomists had explained his errors by pointing out that man had probably changed since ,galen's time4 ,the ,church had stepped in during the fourteenth century with an edict that was interpreted as a prohibition against dissection of the human body4 ,in ,italy1 however1 there were some dissections4 ,they could only use1 for this purpose1 the bodies of criminals1 slaves1 and people of foreign birth4 ,in ,florence1 anatomy was studied by the artists1 and ,leonardo had undoubtedly watched ,pollaiuolo at work on a corpse that that artist had dissected4 ,in #adhi ,leonardo1 from the results of his own investigation1 produced drawings of the skull and backbone whose careful attention to detail are--even today--classics in art and anatomy4 ,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 bones4 ,he drew the lachrymal 7tear7 canal1 and he was the first to show the cavity in the superior maxillary bone--not discovered again until #afea1 by ,highmore--now named 8the antrum of ,highmore40 ,he was the first to demonstrate the double curvature of the spine and its accompanying vertebrae1 the inclination of the sacrum1 the shape of the rib cage1 and the true position of the pelvis4 ,he planned a whole series of books that would include from head to foot and from inside to outside every section of the human apparatus4 ,meanwhile he had been working on the monument1 redesigning it to conform to the practical needs of casting4 ,now it had reached an even grander scale--a colossus that would require two hundred thousand pounds of bronze6 ,he recorded in his notes the very day that this work was started1 8,on the twenty-third day of ,april #adij ,i commenced this book and recommenced the horse40 ,the 8horse10 of course1 was the monument and 8this book0 referred to still another subject which had grown out of his studies of anatomy and perspective4 ,the title of the proposed book was to be ,light and ,shade4 ,it would include the subject of optics or the mechanism of the eye1 the problems of reflection and refraction and it would lead him eventually to a re-examination of his studies of the sun and moon4 ,in ,leonardo's day1 and even for a long while afterwards1 the popular belief of vision was one that had originally been put forth by the ,platonic school and expanded by ,euclid and ,ptolemy4 ,this belief was that the eye sent forth rays that brought back the image to the soul4 ,leonardo1 in his younger days1 had believed in the same theory4 ,not content with what had been written on the subject1 however1 he began to experiment for himself4 ,these experiments led him to an examination of the eye itself4 ,he noted the various parts of the eye--the optic foramen or opening1 the pigment layer1 and the iris4 ,these were already known by the ,arabs4 ,leonardo discovered1 however1 the crystalline area of the eye4 ,he explained binocular vision1 or three-dimensional images1 by correctly noting the positions of the two eyes in the head4 ,he described the variations in the diameter of the pupil according to the surrounding light4 ,further experiments with light brought him to the conclusion that light and images are received by the eye4 ,he took a piece of paper1 for example1 and pierced it with a small hole4 ,with this he looked at the source of light4 ,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 again4 ,he established that light travels in straight lines4 ,he constructed the first 8camera obscura0--a box with a small hole in it4 ,inside the box an object was placed near the hole and behind that a lighted candle4 ,when the box was closed the image of the object was cast on the wall4 ,leonardo was already acquainted with lenses1 and he placed a magnifying lens over the hole to create an enlarged image4 ,illustration3 ,leonardo's 8camera obscura0 which he used for projecting an image of an object on a wall or screen4 ,he also demonstrated various laws relative to optical illusion1 such as irradiation--when a metal rod is made red-hot at one end1 that end seems thicker than the other4 ,a brightly lit object seems larger than one exactly like it that is dimly lit2 a dark object placed against a light background seems smaller than it is2 a light object seems larger than its real size when placed against a dark background2 and the illusion of a light swung in a circle appears as a complete circle of light4 ,many years before ,newton1 ,leonardo described the experiment of breaking up a ray of white light into the solar spectrum4 ,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 later6 ,he stated the law of reflection--that is1 that the angle of reflection is always equal to the angle of incidence4 ,about this time ,leonardo left the studio of ,ambrogio de ,predis and moved into the ,sforza ,castle4 ,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 locked4 ,to his growing list of work1 ,leonardo now had to add the preparations for the delayed wedding reception of ,ludovico's nephew1 ,gian ,galeazzo ,sforza4 ,on a cold winter evening of ,january #adij the guests assembled again4 ,silks1 satins and gold brocade1 diamonds1 rubies and pearls glittered in the brilliant lights4 ,princes of the ,church mingled with ambassadors of foreign lands4 ,music and perfume filled the air and as the party quieted down the entertainment began4 ,there were dances in gay costumes4 ,poetry was recited that flattered the bride and groom4 ,there were allegorical processions4 ,the jokes and antics of the court jester made the audience laugh4 ,then1 at midnight1 the curtain that hung from wall to wall at the end of the ballroom was raised4 ,applause and cries of delight greeted the spectacle4 ,the rising curtain revealed a room in which there was a hemisphere surrounded by the signs of the zodiac and the planets4 ,while the planets in their niches flickered with concealed lights and the signs of the zodiac glowed1 lines were spoken in honor of the house of ,sforza to the accompaniment of a choir4 ,the ancient gods swept down from the heavens1 and the ,virtues and ,graces moved across the scene with nymphs waving lanterns4 ,the music drowned out the sound of the mechanism4 ,this was the kind of mechanics that ,ludovico could understand and appreciate4 ,the success of this entertainment so pleased ,ludovico that ,leonardo was encouraged to present another amusing idea4 ,this one was an 8alarm clock0 and it utilized what we call today the mechanical relay principle4 ,when a small power is suddenly switched over1 the power is reinforced4 ,the 8alarm0 clock worked by placing a shallow basin of water at one end of a tubed lever4 ,at the other end was another empty basin4 ,water was led drop by drop into the second basin and as this slowly filled the increasing weight lowered the lever4 ,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 feet4 ,leonardo decided to withdraw from the competition for the cathedral dome4 ,although the cathedral authorities were pleased with his design1 they could not decide to whom the commission should be awarded4 ,in the summer of #adij ,ludovico was called upon to settle the issue and he decided in favor of ,antonio ,amadeo from ,milan4 ,but the work that ,leonardo had done so impressed ,ludovico that he sent him to ,pavia in company with an architect from ,siena1 ,francesco di ,giorgio ,martini1 to inspect the work on the cathedral of that city4 ,leonardo1 who had his own workshop and apprentices now1 took along one of them1 ,marco d',oggionno1 a young boy of twenty4 ,in ,pavia one of the greatest libraries in all of ,italy was in the ducal palace4 ,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 chains4 ,one book that he records in his notes was written in the thirteenth century by ,witelo1 a ,polish scholar1 who wrote extensively on perspective4 ,leonardo1 by the necessity of his art1 had solved many problems in perspective4 ,he had invented a pair of proportional compasses1 the forerunners of those used today for the transfer of a drawing from one scale to duplicate the same drawing in a larger scale4 ,leonardo had also designed in very careful detail a parabolic compass for drawing a parabola in one continuous movement4 ,he now determined to write his own book on perspective and1 as the subject was so close to his studies of the eye1 he would entitle it ,introduction to ,perspective1 or the ,function of the ,eye4 ,leonardo submitted a number of plans for the completion of the cathedral to the authorities in ,pavia and then returned to ,milan4 ,he worked through the rest of the summer on the equestrian statue and at the same time he continued to expand his notes on anatomy1 light and shade1 and perspective4 ,late on a cold ,december night in #adij1 ,leonardo lit his lamp4 ,this was a very special lamp that he had invented4 ,it had already created a great deal of comment4 ,it was so unusual1 he had received an order from the court for another which he made with a richly carved pedestal4 ,candles1 torches1 and oil lamps1 the only methods of artificial illumination in those days1 were poor substitutes for light4 ,they flickered1 smoked1 went out1 and frequently caused damage with their hot drippings4 ,as a side result of his experiments in light1 ,leonardo had put a glass cylinder in the middle of a larger glass globe4 ,a wick in olive oil was placed in the cylinder and the outside globe was then filled with water4 ,the result was a bright1 steady light magnified by the water in the globe4 ,he sat down by the small fire and arranged his papers in front of him4 ,then1 with a glance at his lamp1 he picked up his goose-quill pen and wrote1 8,no substance can be comprehended without light and shade2 light and shade are caused by light40 #g ,success ,it was ,january of #adia1 and a light snow had fallen in ,milan1 edging with white all the roofs1 the massive spires of the cathedral and the red battlements of the ,sforza castle4 ,soon ,ludovico was to be married to ,beatrice d',este of the ducal house of ,ferrara4 ,once more the streets of ,milan echoed to the carpenters' hammers4 ,messengers rode to and from the castle and endless carts full of provisions pushed through the crowded city4 ,guests began to arrive from all the allied courts of ,italy with their bodyguards and servants4 ,the rooms of the castle1 the palaces of the nobles1 and even the inns were filling with the royal processions4 ,leonardo was again summoned by the court to prepare the decorations1 the costumes for the masquerades1 and the arena for the jousting tournaments4 ,an invitation had been sent to all the friendly courts to attend these contests-at-arms4 ,so1 accompanying each new party's arrival was a band of armored knights1 their breast-plates1 helmets1 and shields glistening in the winter sun4 ,leonardo enjoyed designing mechanical toys and entertaining the guests with them4 ,one of these was a mechanical drum4 ,ordinarily most of the entertainment began with normal drum rolls1 but ,leonardo's rolls were made on a kind of wheelbarrow4 ,on it was mounted an enormous drum4 ,when the 8wheelbarrow0 was pushed1 it put into motion a cogged wheel geared to the axle4 ,this wheel in turn was geared to two rotary cylinders with pegs mounted around the top4 ,the pegs moved against five drumsticks on either side of the drum and thumped out a rhythm according to the position of the pegs4 ,ludovico's marriage to ,beatrice d',este1 a girl of little more than fifteen years1 further isolated ,leonardo from the court4 ,being almost a child1 ,beatrice loved parties and festivities1 and she surrounded herself with people who catered to her frivolous whims4 ,as a result so serious a man as ,leonardo was forced into the background of the court life4 ,he was called upon more and more to act as stage-designer while his more important work went unnoticed4 ,because these entertainments were easy for ,leonardo to design1 they did give him more time to work on his giant equestrian monument of ,francesco ,sforza4 ,working one day on the scaffolding surrounding the clay figure of his statue1 ,leonardo heard a knock at his studio door4 8,come in10 he shouted as he climbed down4 8,the door's open40 ,three peasants cautiously entered the room and quickly took off their caps4 ,one of them was holding a carefully wrapped bundle4 8,master ,leonardo1 we have brought you some shells we found on a ridge of ,monferrato4 ,remember1 you asked us to bring anything we found that was unusual80 8,yes1 ,pietro4 ,thank you4 ,put them here on the table40 ,leonardo opened the bundle4 ,he smiled when he saw the shells4 ,he remembered how1 as a young boy1 he had found seashells like these high in the mountains4 ,leonardo questioned ,pietro and his companions as to where they had been found and under what circumstances4 ,he gave them some coins and1 when they had gone1 he looked among his growing collection of notes and drawings on the shelves4 ,it took some time for him to find what he wanted1 for the pages were in such confusion4 ,finally1 he sat down at the table with several of the sheets and1 putting the seashells in front of him1 he began to make notes4 ,the shells were fossil shells but1 thought ,leonardo1 their presence on the high mountains of ,lombardy could hardly be attributed to the great flood as described in the ,bible4 ,in his notes1 ,leonardo cited the case of the cockle which1 out of water1 is like the snail4 ,it makes a furrow in the sand and can travel in this furrow about three to four yards a day4 ,by such means1 he calculated1 it could not possibly have reached ,monferrato from the ,adriatic in forty days 7which was supposed to have been the duration of the flood7--a distance of #bej miles4 ,nor were these simply dead shells deposited by the waves--for the living creatures are recognized by being in pairs1 and these in front of him had certainly been traveling in pairs4 ,consequently1 they could have been left there only when they were alive and the mountains were covered by the primeval oceans4 ,moreover1 ,leonardo also described how living matter in prehistoric times fell into the mud and died1 and how this mud1 as the waters receded and years had passed1 was changed into rock forming a mold about the fossil--literally making a cast of its original living appearance4 ,by such deductive reasoning and the testing of the evidence before him against the common beliefs1 ,leonardo struggled to free the minds of men from medieval superstitions and beliefs4 ,indeed1 these medieval superstitions existed everywhere4 ,astrologers1 or men who told fortunes by the position of the stars at a given moment2 and necromancers1 those who by tricks of magic claimed to be able to talk to departed spirits--these men profited from the ignorant4 ,the ,church1 with its preaching of devils and hells1 provided the background against which these fakers flourished4 ,ludovico ,sforza was himself a believer in such things4 ,his own physician and astrologer was a man by the name of ,ambrogio da ,rosate1 who had such influence over the court that he was given a post in the ,university of ,pavia1 and his fame was so great that he was called upon to predict the future of ,pope ,innocent ,,viii6 ,leonardo's dislike of these men was intense4 ,he scorned the supernatural and asked men to look about them at the real world and the real heavens4 ,observation and experiment--these were ,leonardo's key words4 ,but he was a lonely figure in his thinking--like a man awake while the rest of the world slept4 ,at last the full-size model of the ,sforza monument was nearing completion4 ,ludovico had ordered it ready for exhibition in the courtyard of the castle for yet another marriage festival that was soon to take place4 ,this time it was the marriage of his niece ,bianca ,maria to ,maximilian ,i of ,germany4 ,leonardo and his assistants were busy with the finishing touches on the monument1 and with building a wagon on which to carry it from the studio to the courtyard4 ,during these last months ,leonardo had had to struggle with all kinds of heavy loads4 ,already he had improved on pulleys by inventing a new kind of tackle1 and he also had utilized many kinds of levers4 ,one of his simpler discoveries for raising heavy weights was a jack which1 in appearance and principle1 was the forerunner of our own automobile jack4 ,in #adic when the clay model of the ,sforza monument was completed1 it was put on the cart and wheeled to its place of exhibition where a curtain was thrown around it4 ,again ,milan was the host to a gathering of noble courts1 and this time ,ludovico outdid himself in the display of luxury4 ,tapestries hung from the buildings and rich carpets were laid down the steps of the cathedral4 ,everything that ,milan had to show was on exhibition--even a crocodile4 ,but the most impressive sight of all was the unveiling of ,leonardo's colossal statue4 ,it rose in majesty against the red walls of the castle4 ,the name of ,leonardo da ,vinci was suddenly on everyone's lips4 ,as the word of his artistic achievement spread from city to city1 messages of praise came pouring in4 ,and1 for a while the years of frustration and failure to gain recognition melted away4 ,leonardo at forty-one had at last achieved some success4 ,now there was a breathing spell1 and ,leonardo returned to some of his own projects4 ,for a long time he had continued his observations of his two favorite elements--air and water4 ,to him they were related in their movements4 ,the birds flying in the currents of air and the fish swimming in the flow of water seemed very similar to him4 ,he had already designed various instruments to tell him about the direction of wind and its velocity1 and he had also commenced to analyze the wing structure of birds and bats4 ,to soar through the air like a bird was an ancient dream of man1 yet for ,leonardo it had become a passion4 ,ceaselessly1 he sketched the flights of birds1 the flutterings of butterflies and analyzed their flying patterns4 ,but to ,leonardo1 understanding the dynamics1 or motion1 of air was the most important thing4 ,he built an anemoscope1 an instrument like a weather-vane for telling the direction of the wind2 and1 he also constructed several types of anemometers for measuring the velocity or force of the wind4 ,one of these latter consisted of a thin rectangle of metal hanging straight down in front of an upward-curving wooden arc4 ,this arc was marked off in units of measurement4 ,when the wind blew1 it pushed the thin rectangle up the arc2 thus1 by noting at which gradation it stopped1 ,leonardo could tell the velocity4 ,in addition1 ,leonardo at this time constructed a device which has been compared to the modern instrument used for testing the weight-carrying capacity of airplane wings4 ,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 lever4 ,this wing in turn was mounted on a plank that was in weight equal to that of a human being4 ,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 together4 ,another device resembling those found in airplanes today that ,leonardo constructed was an inclination gauge4 ,he made this by suspending a heavy ball on a cord within a glass bell4 ,this ball was then supposed to guide the flyer by telling him whether he was flying level1 diagonally1 up1 or down4 ,illustration3 ,one of ,leonardo's anemometers4 ,the wind blew against the strip of metal1 pushing it up the curved gauge and thereby measuring the force of the wind4 ,illustration3 ,leonardo's inclination gauge1 designed to guide a man in flight4 ,the ball in the glass cylinder was supposed to tell a 8flyer0 whether or not he was flying level or tipped4 ,to ,leonardo1 water was also a phenomenon that from his youth never failed to excite his curiosity4 ,the use of water power to run machines1 to irrigate fields and to carry boats inland was a subject that he never ceased investigating4 ,out of his experiments at this time he constructed a device for raising water to high levels4 ,it was based on the geometric spiral of ,archimedes4 ,he took a piece of gut1 inflated it1 and let it dry4 ,then1 covering it with a coat of wax to make it waterproof1 he wound it around a thin staff in a spiral4 ,he put one end in a stream and attached it by gears to a cogged water wheel2 this set the long screw to turning1 and he was able to raise water from a low level to any height he desired4 ,with a multiple system of these screws he could raise water in continuous circulation to the reservoirs on the highest towers4 ,in the year #adid1 ,king ,charles ,,viii of ,france crossed the ,alps at the head of an army of twenty-five thousand men4 ,now ,ludovico1 by a series of diplomatic maneuvers1 had allied himself with ,charles and had1 by secret negotiation1 actually invited the invasion4 ,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 ,italy4 ,outwardly ,charles was asserting his rights to the ,kingdom of ,naples1 but inwardly he dreamt of leading a crusade against the infidels in the ,holy ,land4 ,at the same time young ,gian ,galeazzo ,sforza1 ,duke of ,milan1 was dying4 ,ludovico desired this title for himself2 however1 until ,galeazzo was out of the way1 he could not have it4 ,there were ugly rumors that young ,sforza had been poisoned4 ,moreover1 in #adid1 the ,medicis--another powerful obstacle--were expelled from ,florence1 and a republic was established4 ,soon young ,gian ,galeazzo died1 leaving a son1 ,francesco4 ,this son was the rightful heir to the ,dukedom of ,milan but ,ludovico usurped the boy's claim and declared himself ,duke of ,milan4 ,now ,ludovico was in a position to await the impending battle between ,charles and the ,pope4 ,with such military and political ambitions in mind1 ,duke ,ludovico now assigned ,leonardo the task of reviewing ,milan's defenses4 ,again ,leonardo submitted to ,ludovico his plans for strengthening fortresses and designs for new ones4 ,the great architect ,bramante was also assigned the task of seeing to the city's defenses1 and for some time the two brilliant men worked together4 ,then1 in the spring of #adid1 ,leonardo was sent to ,vigevano where ,ludovico's young wife was staying4 ,this town was also the birthplace of ,ludovico1 and ,leonardo was given the job of designing and building a small summer house and garden there for ,beatrice4 ,in addition1 ,leonardo built a kind of 8air conditioner0 for her bedroom4 ,it consisted of a large waterwheel that cooled the air circulated into her room4 ,although this ancient device had long been known to the ,greeks and ,romans1 ,leonardo was the one who succeeded in perfecting it4 ,during this time ,leonardo's highly original mind was also at work on other devices4 ,one of these was an odometer1 an instrument for measuring the distance traversed by a vehicle4 ,dials1 turned by a system of gears attached to the wheel of a wheelbarrow1 measured the distance traveled as the barrow was pushed along the ground4 ,in addition1 ,leonardo conceived a kind of odometer to be used at sea2 this consisted essentially of a spinner that was towed by a ship which registered its speed4 ,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 water6 ,in the meantime1 ,charles ,,viii of ,france had marched through ,rome and entered ,naples4 ,the conquest was without opposition4 ,charles was then crowned ,king of ,naples and all ,italy was at his feet4 ,yet his triumph was a short one4 ,ludovico1 having used the king to get rid of his enemies1 now plotted against the king himself4 ,he formed an alliance with the ,pope1 ,venice1 ,spain1 and the ,german emperor4 ,charles1 faced with this league1 hastily beat a retreat to ,france4 ,fighting his way to the border1 he there signed a peace treaty4 ,thus ,ludovico had swept ,italy clean of all opposition and was now the most powerful prince in the land4 ,yet ,ludovico was quick to realize that his position could only be held by force and he set about strengthening himself and his allies4 ,to provide for more cannons1 a hundred and fifty thousand tons of bronze were sent to manufacturing works in ,ferrara4 ,this1 however1 included the very bronze ,leonardo needed for the casting of his equestrian statue1 and this is why the statue was never cast4 ,years of ,leonardo's work now seemed to vanish overnight4 ,ludovico also needed large sums of money to secure friends in high places and ,leonardo's own payments were suddenly dropped4 ,forced again to worry about paying for his daily bread and for his household and apprentices1 he wrote letters to ,ludovico complaining of his lack of funds and asking for money that was owed him for work done4 ,he looked about for other commissions1 but none were available4 ,moreover1 because he was still court painter to ,ludovico1 he was ordered to paint the decorations of some rooms in the castle4 ,but this was more than ,leonardo could take--he walked off the job without finishing it4 ,despite all of these misfortunes1 ,leonardo continued struggling with the problems of flight4 ,he kept working out the proportions of wing span to the weight of the load4 ,indeed1 he had already started designs for a flying machine4 ,he had chosen a room which was the highest in one of the towers of the castle and which had access to a roof4 ,leonardo's plans for a flying machine were a secret1 and1 with the exception of an assistant1 no one knew about them4 ,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 model4 ,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 parachute4 ,it was a pyramid-shaped 8tent of linen0 twenty-four feet broad and twenty-four feet high1 and it is believed to have been successfully tried out from a tower especially constructed for that purpose4 ,since ,leonardo was no longer working for ,ludovico1 he lived more simply than ever4 ,he made regular lists of his expenses down to the last penny4 ,his habits were frugal although he always kept himself neat4 ,his meals were spare2 he drank a little wine at meals and never ate meat4 ,to his pupils and apprentices1 he recommended regular habits such as not sleeping during midday1 eating only when hungry and chewing well1 exercising moderately1 and sleeping well covered4 ,yet1 even though ,leonardo lived cheaply1 he was now greatly in need of money4 ,swallowing his pride1 he wrote to ,ludovico1 placing himself at the duke's service once again4 ,his absence from court1 he said1 had been necessary so that he could earn a living4 ,in this and other ways1 ,leonardo attempted to heal the break between them4 ,it turned out that ,ludovico was glad to have ,leonardo back4 ,perhaps mindful of the fame that the model of the equestrian monument had brought the house of ,sforza1 he now commissioned ,leonardo to paint a picture4 ,the ,dominican monastery of ,santa ,maria delle ,grazie was the nearest church to the ,sforza castle and a favorite retreat of ,ludovico4 ,here he used to walk in the quiet garden while the white-robed monks silently went about their chores4 ,in gratitude for the peace he found there1 ,ludovico had had the refectory rebuilt and on the back wall1 a crucifixion scene had been painted by ,montorfano1 a ,lombard4 ,but the front wall was given to ,leonardo4 ,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 world4 #h ,the ,french ,the noonday sun was baking the deserted streets of ,milan as ,leonardo hurried across the drawbridge of the castle4 ,the guard dozing in the entrance arch started to his feet1 but when he saw who it was he sat down again1 muttering about a madman4 ,taking the shortest way1 ,leonardo arrived at the monastery gate and pulled on the bellcord4 ,when the gate opened ,leonardo brushed past the startled monk and made directly for the scaffolding in the refectory4 ,he looked at his almost completed painting for a moment1 took a brush and mixed a color swiftly on the large palette4 ,then he climbed the scaffolding and very quickly applied three or four strokes4 ,with this he sighed and smiled4 ,then1 just as abruptly1 he put away his brushes and1 without a backward glance1 he left1 making his way back to the castle in the hot sun4 ,for three years1 ,leonardo had been working this way on the 8,last ,supper40 ,sometimes he would work from dawn to dusk forgetting to eat2 other times1 he would stay away for days and then run back just to add a touch4 ,once he arrived and1 with his arms folded across his chest1 he stood in front of it for two hours just studying what he had done4 ,now1 in #adih1 the painting was nearing completion and the only faces still left blank were those of ,christ and ,judas4 ,leonardo had drawn hundreds of sketches1 taking his models wherever he found them--once he sketched a man just for his hands4 ,now that his name had become well known he always had an audience while he worked4 ,his pupils1 the monks1 visiting nobility1 church officials1 and frequently ,ludovico himself watched him as he painted the 8,last ,supper40 ,but ,leonardo1 as usual1 was involved in many different tasks4 ,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 castle4 ,mindful1 too1 of the uncertainty of court patronage1 he was designing commercial machinery1 hoping thereby to secure an income outside the court4 ,among the most notable of these were an olive press1 an automatic file-cutter1 a hydraulic saw1 and a needle sharpener4 ,this latter was a forerunner of modern sharpeners with their mass-production methods4 ,with it1 ,leonardo dreamt of sharpening four hundred needles at a time1 or forty thousand an hour so that in twelve hours one person could sharpen four hundred and eighty thousand needles6 ,the needles were arranged successively on a moving belt of leather and brought against a rotating grindstone4 ,this grindstone was set in such a way that the needles were sharpened into curvilinear points rather than the usual triangular points4 ,in his travels to ,vigevano and other parts of the countryside around ,milan1 ,leonardo had studied flour mills4 ,he had talked with the workmen1 asked the prices of grain1 and noted the time that it took to do the milling4 ,then he made calculations on ways to cut down the time1 and1 in fact1 redesigned the entire mill4 ,he mounted twelve cylindrical millstones in rows of four on one side of a canal and another twelve on the other side4 ,in the canal were hydraulic wheels or paddlewheels4 ,each wheel was attached to a rod that ran underneath four millstones4 ,geared to the one rod were four grinding levers to the stones above4 ,in this way it was possible to have twenty-four millstones operating at the same time4 ,but most fascinating to ,leonardo now was the construction of his flying machine4 ,his first models involved the principle of an air-screw mounted on a platform on which a man stood4 ,but where would the necessary power come from to lift his machine from the ground8 ,at first he thought of operating his air-screw by means of a steel spring coiled around a drum1 but this he apparently abandoned4 ,later1 however1 ,leonardo did design another model on this principle which has been called the forerunner of the modern helicopter4 ,it was to be operated by four men standing on a platform4 ,each man would hold a bar which wound a spring-driven mechanism1 much as in a modern clockworks4 ,the air-screw was a broad blade spiraling about a vertical shaft--the ancestor of the modern propeller4 ,the model that ,leonardo wanted to construct now1 however1 was of a different principle4 ,instead of an air-screw he substituted a pair of wings fashioned after those of the birds4 ,there was still a platform on which the flyer stood and two springs were still the essential 8motor0 to raise and lower the wings4 ,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 updraft4 ,it was necessary to return to his study of the air and its currents4 ,with all of this activity in mechanical devices ,leonardo had reawakened his interest in mathematics4 ,during this time he was introduced to a man at ,ludovico's court who became his friend and collaborator4 ,he was a ,franciscan monk named ,fra ,luca ,pacioli who had been appointed a professor of mathematics by ,ludovico4 ,he1 too1 came from ,florence1 and in #adif1 when he met ,leonardo1 he was forty-six years old and the author of ,summa di ,arithmetica1 the first printed scientific work of his time4 ,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 book4 ,as ,leonardo had already made a study of human proportions1 the association with ,pacioli was of benefit to them both4 ,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 outstretched1 his legs together and then apart1 inscribed within a square and a circle4 ,it was made to illustrate a passage from ,vitruvius on the proportions of a human figure and demonstrated1 among other things1 8the span of a man's outstretched arms is equal to his height40 ,moreover1 ,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 methods4 ,pacioli also helped ,leonardo with his arithmetic1 a subject that ,leonardo had neglected in his impatience to study geometry4 ,the association also helped to free him further from the cobwebs of medieval beliefs4 ,for ,pacioli1 the friendship with ,leonardo was a revelation4 ,although ,pacioli was a learned mathematician1 ,leonardo demonstrated to him that the application of his science encompassed all sciences--even art--for ,leonardo later wrote1 8,let no one read me who is not a mathematician44440 ,legend relates that ,leonardo became so absorbed in his studies that the prior of the monastery complained to ,ludovico that the 8,last ,supper10 although nearly completed1 still lacked the faces of ,christ and ,judas4 ,ludovico summoned ,leonardo to court and laid the complaint before him4 ,leonardo1 however1 was quick to reply4 8,the good prior is an esteemed man1 your ,grace1 but he is a monk and not a painter4 ,little does he know that ,i spend at least two hours a day on my painting40 8,but ,master1 he says he never sees you there1 so how do you explain these two hours a day80 8,excellency1 the figure of ,judas must be of incomparable evil4 ,every day ,i search for this face in the criminal quarter1 and every day ,i fail to find the evil that ,i am looking for4 ,if ,i cannot find this man1 however1 ,i can use the head of the prior--it would do admirably1 but ,i have hesitated for fear of hurting his feelings40 ,ludovico slapped his knees and roared with laughter4 ,there were no more complaints4 ,finally1 in #adih1 the scaffolding was removed from the painting and ,leonardo's masterpiece was revealed4 ,the twelve apostles grouped at the table are shown each responding in his own way to the words of ,christ1 8,one of you shall betray me40 ,again hundreds flocked to see this latest marvel of ,leonardo's4 ,its striking influence was felt by generations of painters4 ,even now1 more than four hundred and fifty years later1 the world still comes to stand before the genius of ,leonardo da ,vinci in the refectory of ,santa ,maria delle ,grazie4 ,the clouds of war were gathering again over ,italy4 ,in ,april of #adih1 ,charles ,,viii of ,france died and his successor was ,louis of ,orleans1 who became ,louis ,,xii4 ,the new ,king of ,france laid claim to the ,dukedom of ,milan1 and ,ludovico again tried to form an alliance against him4 ,but the years of juggling enemy against enemy and friend against friend were now coming to an end4 ,no one trusted ,il ,moro any more1 and suddenly he realized that he was to be alone in this new fight4 ,after nearly twenty years of power sustained by powerful alliances1 ,ludovico was forced to turn to his own people of ,lombardy4 ,frantically he tried to correct the injustices of years4 ,the people had been cruelly taxed to support the extravagances of the ,sforza court1 and1 in addition1 they had been badly treated by petty government officials4 ,ludovico now sought to repay the past miseries of his people and to rally them to his support4 ,in such a spirit he remembered his court painter1 ,leonardo da ,vinci1 and gave him a vineyard and considerable piece of land not far from the ,porta ,vercellina4 ,now1 for the first time in his life1 ,leonardo knew financial security4 ,with the income from the vineyard1 and in the peace of his estate1 he was left free to follow his own researches4 ,he took no notice that his 8peace0 was surrounded by the threat of war4 ,indeed1 he remained aloof from politics and court intrigues as much as was possible for a man living in the midst of such chaotic times4 ,leonardo now had the opportunity to follow up an early interest--the study of plants4 ,he made many beautiful drawings2 no plant was too small to catch his eye4 ,his notes on botany began to grow4 ,with his genius for observation and analysis of nature1 ,leonardo made some extraordinary discoveries of botanical laws entirely unknown before his time4 ,he wrote of the phenomenon of heliotropism1 or the movement of plants toward or away from the sunlight4 ,in addition1 he described the phenomenon known as geotropism1 or the growth of plants according to gravitational law1 as for example1 roots growing downward and shoots growing upward4 ,he also defined the laws of phyllotaxis1 which describe the system or order of leaf arrangement on a plant's stem4 ,that is1 leaves are arranged spirally around a stem so that the third leaf above grows out over the third leaf below on one type of plant2 or1 on another type1 the two third leaves are over the two third leaves below4 ,the same natural laws apply to the branches of plants as well2 they occur so that every leaf and branch can receive sufficient air and light4 ,amazingly enough1 these laws1 which ,leonardo described so completely1 were not rediscovered until almost two centuries later6 ,leonardo went even further in his botanical studies4 ,he experimented with gourds1 planting them in various aqueous solutions2 this anticipated modern methods of growing plants in chemicals4 ,he also tested the actions of arsenic and mercury poisons in plants4 ,he reproduced the shape and form of leaves by pressing them on paper coated with lampblack1 a method that was not used again until the nineteenth century4 ,carefully noted1 too1 in his writings was the rising of sap from the roots to the branches by capillary action2 this1 too1 was not rediscovered until much later--in the eighteenth century4 ,leonardo also extracted oils and essences from flowers and studied the influences of altitude on the development of vegetation4 ,indeed ,leonardo's very approaches to a systematic classification of plants were the forerunners of modern methods of classifying4 ,in the seclusion of his own home1 as he continued his studies of geometry with ,pacioli1 ,leonardo again turned to his observations of the heavens4 ,on the roof of his house he had set up a small observatory for watching the sky at night4 ,often he looked at the stars through a pinhole in a sheet of paper4 ,leonardo did this to stop the 8twinkling0 of the stars which he recognized as an optical illusion4 ,moreover1 by looking at the stars in this manner1 he noticed that some were larger than others1 and imagined to himself how our own earth might look from them4 ,would we not be but another 8star0 in a vast collection of stars8 ,and if that were true--how could the earth be the center of the universe8 ,by the same imaginary reasoning1 he speculated on how we must look to someone on the moon4 ,realizing that the moonlight on earth faintly illuminates the dark side of the earth1 he reasoned that then there must be an 8earthlight0 doing the same on the moon4 ,thus he was the first to explain the dim reflected light on the dark side of the moon4 ,moreover1 ,leonardo is known to have looked at the moon through a convex lens1 and perhaps even a form of telescope4 ,indeed1 he had built telescopic-type tubes with lenses in them and had written directions for their use4 ,it seems certain that at about this time ,leonardo became convinced of the heliocentric theory1 the theory that states the sun is the center of our universe4 ,on a sheet of mathematical notes ,leonardo wrote in large letters1 8the sun does not move40 ,during this time he continued to seek out books on astronomy4 ,leonardo was familiar with ,aristotle's ,meteorology1 ,archimedes' ,on the ,center of ,gravity1 and with ,problems in ,aristotle's ,books of the ,sky and the ,world1 a work by ,albert of ,saxony4 ,this last book ,leonardo had to read with the help of a ,latin dictionary1 because his ,latin was not good4 ,he had already read ,plutarch1 who had defined the moon as a solid4 ,plutarch had written further that the 8spots0 on the moon were the result of shadows cast by irregularities on its surface4 ,this theory1 that was apparently abandoned during the ,middle ,ages1 supported the conclusions that ,leonardo had reached by his own observations4 ,but he still struggled against a mistaken idea of his own4 ,for a long while he maintained that there were seas and waters upon the moon which accounted for the sunlight being reflected so brilliantly4 ,meanwhile1 in ,july of #adii1 the ,french army had reached ,lombardy4 ,ludovico was now in a state of desperation4 ,he tried to appeal to the people of ,milan1 explaining that their heavy taxes had been due to the constant threats from abroad4 ,but1 however hard he tried to arouse their sense of loyalty to him1 the public of ,milan turned a deaf ear4 ,they had not forgotten how ,ludovico had allied himself with ,charles ,,viii--a foreign king6 ,ludovico now had to put his trust in his army commander1 ,galeazzo da ,sanseverino1 despite warnings that this was a man of doubtful loyalty4 ,moreover1 to make matters worse1 ,louis ,,xii had succeeded in forming an alliance against ,ludovico2 and1 among his allies was a powerful cardinal1 son of ,pope ,alexander ,,vi--the notorious ,cesare ,borgia4 ,from a note on a page of designs for supplying and heating a bath we know that ,leonardo continued his quiet life1 only vaguely disturbed by the political upheaval taking place around him4 ,his note reads1 8,on the first day of ,august #adii ,i wrote here of movement and weight40 ,he had made many experiments and calculations concerning the movement and weight of objects4 ,he had drawn1 for example1 the flight of an arrow to describe motion through air and although he wrote no specific formula1 he marked the three stages of its trajectory--the initial push1 the slowing and the steeper downward path as the arrow's momentum was overcome by the resistance of the air4 ,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 wrote1 8every weight tends to fall toward the center by the shortest way40 ,a diagram of this period is probably the first scientific graph4 ,leonardo had experimented with two balls dropped from a height4 ,first he dropped them together and then one after the other4 ,in attempting to solve the mathematical problems presented by these falling bodies he drew a graph of vertical and horizontal lines4 ,the times it took for the balls to fall were marked on the horizontal lines and the distances on the vertical lines--thus1 he could trace their relationship4 ,but this peaceful time of productive work was running out for ,leonardo4 ,ludovico's commander1 ,galeazzo1 had yielded the fortress of ,alessandria to the ,french at the first battle4 ,ludovico himself had sent his sons and his treasure to his brother1 ,cardinal ,ascanio1 in ,germany4 ,when he saw that his cause was lost1 he turned the ,sforza castle over to ,bernardino da ,corte1 a trusted commander1 making certain that it was fully supplied with arms and food4 ,then in sorrow1 ,ludovico ,sforza1 ,duke of ,milan1 left his city for the last time as ruler of ,lombardy4 ,the gates of ,milan were opened to the ,french in ,october of #adii1 and ,bernardino da ,corte surrendered the ,sforza castle4 ,french soldiers now occupied ,milan as conquerors and the people of the city were in a state of confusion4 ,those who could made their peace with the ,french2 but others1 who had been supporters of ,ludovico1 fled to avoid arrest4 ,leonardo1 who would be suspect to the ,french1 packed up his few possessions--although he did manage to retain his estate--and left1 together with ,pacioli and an apprentice1 for ,mantua4 ,illustration3 ,leonardo had to flee ,milan4 #i ,cesare ,borgia ,leonardo1 ,pacioli1 and ,salai1 the apprentice1 arrived in ,mantua in ,february of the year #aejj4 ,they were given refuge in the castle of ,isabella d',este1 who was the sister of ,beatrice1 and the wife of ,francesco ,gonzaga1 governor of ,mantua4 ,isabella was one of the eminent women of her time and attracted to her court the intellectual life of ,italy4 ,in ,leonardo she recognized the man of genius2 indeed1 she treated him as an equal1 putting her castle at his disposal4 ,she persuaded him to paint her portrait and ,leonardo commenced a preparatory drawing4 ,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 #adij to assume the post of court musician to ,isabella4 ,although ,leonardo had found a haven of peace in the political storm that raged about the city state of ,mantua1 he and ,pacioli took to the road again for reasons unknown4 ,isabella d',este1 who still wanted ,leonardo at her court1 sent many a letter and messenger in the following years to bring ,leonardo back--first to finish the portrait and then1 when that failed1 to sell to her any picture that ,leonardo wished to send4 ,strangely enough1 however1 ,leonardo seems to have turned his back upon the one sympathetic person he had met in a world of indifference4 ,the first1 warm breezes of spring were blowing over the lagoons of ,venice when ,leonardo and ,pacioli stepped ashore on the ,piazzetta1 or ,little ,square of ,san ,marco4 ,but the beauty of this jewel-like city rising from the sea was momentarily ignored by the two travelers for an angry1 frightened crowd had gathered about the ,doge's palace on the ,piazzetta4 ,the people of ,venice were fearful because their fleet had just suffered a crushing defeat by the ,turks4 ,this meant that their power at sea1 once supreme1 was now no more4 ,year by year1 moreover1 their possessions in the east had been slowly whittled away1 and now the city itself was threatened by invasion4 ,at this same time1 the ,venetian ambassador1 ,manenti1 hoping to make peace with the ,turks1 had been rudely rejected by them4 ,panic soon swept the city and rumors of the bloodthirsty infidel passed from person to person like the rush of an ugly wind4 ,barricades were put up and windows were barred4 ,in this charged atmosphere1 ,leonardo and ,pacioli sought out their lodgings4 ,soon after ,leonardo's arrival here--either because his reputation had preceded him or1 more likely1 because of ,fra ,luca ,pacioli's recommendations--he became directly involved with the defenses of ,venice4 ,immediately he was sent on an inspection trip of the city's existing defenses1 especially those inland from where an invasion would probably come4 ,when he had seen them1 he recommended a system of defenses along the ,isonzo river near the present border of ,yugoslavia1 using the river itself to the disadvantage of the enemy4 ,he also made suggestions for the improvement of forts1 and even drew up plans for a completely new type--a circular fort4 ,this consisted of a central1 circular fort surrounded by two belts of fortresses each separated by a moat4 ,in the outside moat were four semicircular outposts4 ,communication was by underground galleries4 ,the total absence of superstructure and projecting balconies was a new idea for the times4 ,another new defense idea was to station in the moat itself a low1 thick tower almost completely submerged1 defended by a thin opening near the waterline4 ,it was reached from the main fort by an underground passage and the gunsmoke was removed by vents4 ,according to ,leonardo no enemy could conceal himself in any part of the defenses and not be seen from such an outpost4 ,leonardo's most unusual scheme for defending ,venice1 however1 was his idea of approaching an enemy fleet under the water and then putting holes in the hulls of their ships4 ,actually1 the idea of diving was not a new one4 ,aristotle had written of diving and diving bells1 and certainly the stories of pearl fishers in the ,orient were well known in the ,renaissance4 ,but ,leonardo designed a diver's suit closely resembling those used today4 ,this consisted of a complete suit of leather with helmet and eyepieces2 it was made airtight by spirals of steel at the joints4 ,he then added a bladder for holding air which fastened inside the suit at the diver's chest4 ,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 discovery4 ,he wrote1 8444 and this ,i do not publish or divulge1 on account of the evil nature of man1 who would practice assassinations at the bottom of the seas44440 ,leonardo felt the same way about a 8submarine0 that he presented to the ,councilors and ,tribunal of ,venice4 ,this resembled a turtle's shell with a raised bump on the center which was the 8periscope40 ,when submerged the water probably rose to an area just around the 8periscope10 but1 again1 the information about its air-supply is missing and the only reference to it is a reminder to close the 8l--40 ,in addition1 he invented a system of screws mounted in tongs with the borer in the middle for putting holes in the bottoms of enemy ships1 and at the same time he thought of a defense against such an attack by designing the defending vessels with double hulls4 ,among ,leonardo's other maritime devices were designs for boats that could dredge canals1 harbors1 and lagoons4 ,what was the result of all these plans8 ,we do not know4 ,whether any one of them was used against the ,turks is a mystery4 ,at any rate1 ,leonardo and ,pacioli left ,venice that same spring and arrived in ,florence in ,april of #aejj4 ,one of the purposes of ,leonardo's journey was to visit his father who was now living on ,via ,ghibellina with his fourth wife4 ,leonardo was now forty-eight4 ,still tall and straight with the strength of his youth1 his face prematurely aged and his hair thinning back from his high forehead1 ,leonardo was more than ever an outstanding looking man4 ,he still scorned fashionable clothes and dressed according to his own comfort which made him even more noticeable among the crowd4 ,his deep-set eyes with their direct and penetrating glance1 framed by his full1 reddish beard1 never missed a thing1 although he now wore spectacles at his work4 ,now that he was back in ,florence1 ,leonardo needed lodgings and a job4 ,he had banked his small savings1 and he did not want to touch that4 ,his father's house with the five children of his present wife plus the sons from his previous marriages was too full to accommodate ,leonardo4 ,moreover1 the relationship between ,piero and ,leonardo was polite but distant1 as ,piero preferred the children of his later marriages4 ,luckily1 the place to live and the commission ,leonardo needed presented themselves at the same time4 ,the ,church of the ,annunciation of the ,servite ,order of ,monks needed an altarpiece1 and1 as ,leonardo's fame was great1 they offered him and his apprentice quarters in the monastery4 ,here1 in the solitude of a monastic cell1 ,leonardo was able to return to his own researches4 ,his long association with ,fra ,luca ,pacioli continued as they worked together on ,pacioli's edition of ,euclid's ,elements4 ,at the same time1 with his absorption in geometry1 ,leonardo commenced his studies of the transformation of solids2 that is1 changing the shape of something to another shape without diminishing or increasing its substance4 ,in his preoccupation with geometry1 ,leonardo had apparently done little about the commission which the ,servite monks had given him4 ,he finally yielded to their complaints1 however1 and commenced to draw the preliminary study for the subject1 which was 8,st4 ,anne with the ,virgin and ,child40 ,again his knowledge of geometry is most apparent in the finely constructed composition1 every gesture of which is as plotted as a geometric exercise4 ,in ,april of #aeja1 the drawing was finished2 it caused an immediate sensation throughout ,florence4 ,for two days the public was allowed to pass in front of it4 ,but now a change was taking place in ,leonardo4 ,he was no longer content with simply painting4 ,his highly original researches for pictures had slowly grown to the point where the research was more important than painting4 ,in a sense the scientist had taken the brush from the artist4 ,in two letters from ,isabella d',este's emissary in ,florence we learn1 8,he is entirely wrapped up in geometry and has no patience for painting40 ,this excerpt from a letter dated ,april #h1 #aeja1 was followed six days later by another which said in part1 8,in brief1 his mathematical experiments have made painting so distasteful to him that he cannot even bear to take up a brush40 ,a few months after the completion of the ,st4 ,anne drawing1 ,leonardo received a letter signed by ,cesare ,borgia1 ,duke of ,valentinois4 ,leonardo frowned and thought back to his last days in ,milan4 ,when ,king ,louis ,,xii of ,france had entered the city1 he had summoned the painter of the 8,last ,supper0 to an audience4 ,the king had been generous in his praise and had tried to persuade ,leonardo to remain4 ,at that same audience had also been ,cesare ,borgia1 an ally of the ,french4 ,leonardo remembered the man now--the dark hair and eyes1 the black1 arched eyebrows1 and the face marked by some old disease4 ,he was a powerful-chested1 thin-hipped man who had originally been made a cardinal by his father1 ,pope ,alexander ,,vi4 ,but the attractions of secular power soon persuaded him to abandon this title4 ,with the enthusiastic help of his father1 ,borgia had fought1 murdered1 and deceived his way to a formidable position of authority in these last years4 ,leonardo1 in the seclusion of the monastery1 had lately heard that ,borgia's army had even been at the gates of ,florence4 ,the letter addressed to ,leonardo was an offer to assume the post of ,architect and ,military ,engineer to ,his ,excellency1 ,cesare ,borgia4 ,he thought of ,ludovico ,sforza--defeated and captured at the battle of ,novara just a year ago as he attempted to regain his dukedom4 ,now the duke was a prisoner at ,loches in ,touraine2 ,leonardo had written of him1 8,the duke lost his ,state1 his personal possessions and his liberty1 and none of his enterprises have been completed40 ,and ,leonardo also thought of his equestrian monument still standing in the castle being used for target practice by the ,french archers4 ,like the duke1 nothing of his own had been completed either4 ,perhaps this ,borgia offer was an opportunity4 ,leonardo decided to accept it4 ,in ,may of #aejb1 after having presented himself to ,cesare ,borgia in ,rome1 ,leonardo began his hectic travels through ,tuscany and ,umbria4 ,he was to inspect the fortresses and cities of ,cesare's new conquests there1 and to make whatever recommendations he felt necessary for their improvements4 ,arriving in ,piombino1 he at once set down a project for draining the marshes and reclaiming the land4 ,also1 while he was here1 he spent hours by the sea watching the waves curl in from the ,adriatic and studying the crash of water over the beaches4 ,moving on to ,arrezzo1 he drew up the first in a series of remarkable maps for the army of ,vitellozzo which1 with the backing of ,cesare ,borgia1 was marching against ,florence4 ,these maps are bird's-eye views of ,tuscany and ,umbria1 and somewhat resemble modern aerial photographs4 ,drawn from ,leonardo's own observations1 the green mountains stand1 according to their height1 in relief1 with the roads winding over them and down through the valleys4 ,the streams and their tributaries are in blue and even the villages and cities are drawn with great exactitude4 ,indeed ,leonardo had learned his lessons from old ,toscanelli well1 and he was one of the first to bring the art of cartography to such perfection4 ,in ,july and ,august ,leonardo was in ,urbino and ,pesaro1 and by the #hth of ,august he had reached ,rimini4 ,here he strengthened the fortifications and then rode quickly on to ,cesena4 ,between ,cesena1 capital of the ,romagna1 and ,porto ,cesanatico1 he spent from the middle of ,august to ,september planning a canal between the two1 redesigning government buildings1 and drawing up a new quarter to be built for the city of ,cesena4 ,at this time he constructed an instrument for telling him the speed of water currents in a stream4 ,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 bed4 ,in the meantime1 ,florence1 alarmed at the growing power of ,cesare ,borgia1 appealed to ,charles d',amboise1 ,regent of ,milan for ,france1 to come to her aid4 ,charles responded in the absence of the ,french ,king and helped to protect ,florence4 ,the enemies of ,cesare took advantage of this to form an alliance1 and soon ,cesare was being forced back from his newly won possessions4 ,cesare himself then hastened to ,milan1 and there he suddenly came face to face again with ,louis1 the ,king of ,france1 who was on his way to ,naples4 ,borgia1 who could exert great charm and influence when he wished1 persuaded the king that1 all rumors to the contrary1 he1 ,cesare1 was fighting the enemies of ,france4 ,again he won over the ,french1 which greatly strengthened his position4 ,then1 from ,pavia1 he issued a decree placing every facility possible at ,leonardo's disposal4 ,in addition1 he instructed all officials to help ,leonardo in every matter1 referring to him as 8our highly esteemed court architect40 ,while ,leonardo was in ,porto ,cesanatico1 a delegation from ,bayzid ,,ii1 ,sultan of ,turkey1 paid a visit to ,cesare ,borgia4 ,among other things the delegation was looking for an engineer to build a bridge between ,constantinople and ,pera to replace a temporary wooden structure4 ,leonardo designed for them a single-arched bridge with double ramps at either end 7looking very much like a present-day 8thruway0 entrance74 ,he provided that it should be approximately twelve hundred feet long1 eighty feet wide1 and one hundred and forty feet above the water4 ,illustration3 ,da ,vinci's proposed bridge from ,constantinople 7,istanbul7 to ,pera4 ,looking very much like a modern 8thruway0 entrance1 it was to have double ramps on both sides4 ,in his travels through the countryside1 ,leonardo could not help but notice how primitive the mills were4 ,feeling how strongly the wind blew in from the sea1 he designed a windmill with a roof that turned with the sails4 ,for the mechanism inside he devised a band brake--a semicircle of wood into which the large cogwheel of the mill was forced4 ,this mill resembles the 8,dutch0 mills of the ,netherlands and was among the first of its type to be brought into existence4 ,in the fall ,leonardo was at ,imola4 ,there he created another of his beautifully rendered maps4 ,he drew this with the help of a magnetic compass of his own invention4 ,it consisted of a board with an arc on it and a compass needle1 and was probably the first magnetic needle on a horizontal axis4 ,this time the map was of the city itself1 the walls1 the castle and the principal buildings all touched with color and the river winding through the fields4 ,drawn in the shape of a circle1 it resembles a view through a telescope from directly above4 ,in ,imola1 too1 he met ,niccol ,machiavelli1 the famous historian and political scientist1 who was an emissary from the ,signoria1 the ,council which now governed ,florence4 ,these two men became friends and1 later1 collaborators in ,leonardo's scheme to make the ,arno river navigable to the sea4 ,at this time ,cesare ,borgia1 having achieved great success in his military campaigns and confident of his conquests1 decided to return to ,rome4 ,with the disbanding of ,borgia's headquarters at ,imola1 ,leonardo's duties were finished4 ,together with his new friend ,niccol ,machiavelli and two other ,florentines1 he left ,imola and the service of ,cesare ,borgia to return to ,florence4 ,in ,january of #aejc1 a mathematician named ,giovanni ,battista ,danti attempted a flight in a machine that he had designed4 ,this flight was part of the entertainment at a wedding reception in ,perugia4 ,danti climbed into his apparatus on top of the tower of ,st4 ,mary of the ,virgin4 ,it was pushed off into the air1 hovered a few seconds1 then began slowly drifting toward the ground4 ,but suddenly1 one of its wings hit a building projection and it crashed4 ,danti was carried away with a broken leg4 ,the news of the event traveled quickly to ,florence4 ,when ,leonardo heard about it1 he eagerly questioned all those who had either seen it or had heard it described first hand4 ,danti's attempted flight excited ,leonardo for now he realized that he was no longer alone in his search4 ,with a sense of urgency he returned to the problems of flying4 ,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 sky4 #aj ,shattered ,hopes ,before ,leonardo could return to the problem of flight1 however1 he was again faced with the necessity of supporting himself and his growing household4 ,the small fees he received for taking on apprentices hardly covered the cost of housing and feeding them4 ,moreover1 the equipment he had to buy for his scientific researches added further to his strained budget4 ,so1 when a servant from ,francesco del ,giocondo1 a rich ,florentine merchant1 presented himself at the gate with the request that ,leonardo accept a commission to paint ,francesco's wife1 ,leonardo was only too glad to accept4 ,the name of ,francesco's wife was ,madonna ,lisa1 or ,mona ,lisa for short4 ,leonardo painted her portrait on and off for the next three years4 ,thus1 what started as a minor commission ended as the one painting--in addition to the 8,last ,supper0--that most people today associate with the name of ,leonardo da ,vinci4 ,having secured this work1 ,leonardo turned back to his studies of birds in flight and the nature of air4 ,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 glider4 ,he proposed to write a treatise on the nature of birds' flight1 and1 with his usual thoroughness1 he began to weigh1 dissect1 and reconstruct various types of birds and their wing structure4 ,he realized that one of the main difficulties of gliding was maintaining balance1 or1 more accurately1 maintaining the center of gravity4 ,from previous observations ,leonardo had noted that man is capable of making the same motions that a bird does4 ,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 standing4 ,consequently he began to redesign his machine making use of man's arms and legs to operate or 8flap0 the wings instead of standing him on a platform4 ,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 body4 ,he could manipulate the flight by handles that were connected to the flexible1 outer parts of the wings4 ,these wings were designed from the webbed wings of the bat4 ,surprisingly enough1 this device closely resembled the experimental gliders used by ,otto ,lilienthal almost four centuries later in ,germany4 ,leonardo was now approaching other solutions to pure flight when further hostilities interrupted his work4 ,florence and ,pisa were in bitter rivalry1 and their struggle had assumed the proportions of a major war4 ,the ,florentine army was now practically at the gates of ,pisa4 ,niccol ,machiavelli urged the ,signoria to enlist the help of ,leonardo da ,vinci1 who might be able to think of an immediate plan for destroying ,pisa and her army4 ,never one to think in terms of an immediate battle or a temporary success1 ,leonardo put forth a daring and sweeping plan that would forever reduce the power of ,pisa4 ,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 ,pisa4 ,in this way1 ,pisa would lose her water supply and her opening to the sea4 ,the plan met with immediate approval and by the end of ,july #aejc1 ,leonardo was sent out to survey the entire course of the river4 ,he was accompanied by ,giovanni 8the ,piper10 a man who was frequently employed on minor engineering projects and who was the official player of the pipes to the city of ,florence4 ,giovanni was also the father of ,benvenuto ,cellini1 who became the most famous goldsmith of the ,renaissance4 ,as they made their way to ,pisa1 ,leonardo made some more of his extraordinary maps of the area1 paying particular attention to the course of the ,arno and its tributaries4 ,these maps later inspired him to plan a whole series showing the main watersheds of ,italy4 ,when he rode into the ,florentine camp drawn up before ,pisa1 ,leonardo designed from his observations and maps1 a dam on the ,arno to regulate the course of the river4 ,this bird's-eye view map is a marvel of exactness4 ,it shows the flow of the river hitting the dam with its swirling backwash and overflow4 ,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 eyes4 ,one of the main problems in regulating the ,arno was its tendency to continually be shifting its bed by the deposits of new sediment1 and ,leonardo realized it would be a long time before this project could be completed4 ,when he returned to ,florence he presented to the ,signoria1 as part of his survey1 various machines to hasten the excavation of the ,arno4 ,he had designed a crane that would assist in the digging out of two different levels at the same time4 ,he also submitted the results of his calculations on the saving of muscular energy by the use of such machines4 ,in addition1 ,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 ditch4 ,as if this were not enough1 he had invented a practical method of piling as a foundation for the lock-basins to protect them against the dangers of erosion4 ,a separate map of this period on the flow of rivers in general was intended to relate to his treatise on the nature of water4 ,in this treatise is the first outline of the fundamental principles of hydrodynamics1 as for example3 ,the velocity of a current increases with the slope and decreases with the winding of the riverbed4 ,the volume of a river is in proportion to the width of its bed1 the slope and the depth of the water being equal4 ,the slope and width being equal1 the speed of the current is greatest in the deepest part of the river4 ,the excavation force increases at the narrowest section of the river4 ,because of the grumbling of the military commanders at what they considered a waste of time1 ,machiavelli had to intervene with the ,signoria before ,leonardo was sent out again with documents of authority to continue with his plans4 ,he spent well into the fall surveying the ,arno and in ,october he was back in ,florence4 ,meanwhile the fighting between ,pisa and ,florence had been lessened by two political changes4 ,in ,august ,pope ,alexander ,,vi had died and his son ,cesare ,borgia became seriously ill4 ,the ,republic of ,florence was now free of its most dangerous enemies--the ,borgias4 ,the city relaxed in its new security and the hostilities between ,florence and ,pisa died down to an uneasy armed watch4 ,leonardo quickly took advantage of the situation to present an early dream of his to the ,signoria4 ,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 mills1 lumber yards1 forges and other commercial interests in utilizing the water power that would be available from his project4 ,piero ,soderini1 the governor of the city-state of ,florence1 was impressed and thought of the glory it would bring to ,florence and himself4 ,he told ,leonardo he would present it to the ,signoria4 ,leonardo now plunged into a winter of great activity4 ,forced to draw from his savings1 he had rejoined the guild of painters in ,october of #aejc1 and then applied for the commission of painting the murals in the council chamber of the ,palace of the ,signoria4 ,it had been planned to decorate this great hall with scenes commemorating famous ,florentine victories1 and ,leonardo chose the battle of ,anghiari where the soldiers of ,florence defeated the ,milanese in #addj4 ,in addition to working on the 8,mona ,lisa0 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 geology4 ,leonardo1 while investigating the course of the upper ,arno1 had come across much evidence that the land there had at one time been completely under water4 ,various types of ancient ocean life and vegetation lay scattered in layers along the ridges of the mountains1 and these ,leonardo collected and brought back to his studio4 ,he wrote1 8above the plains of ,italy where now birds fly in flocks1 fishes were wont to wander in large shoals40 ,he reread ,ptolemy1 the ancient ,greek geographer ,strabo1 and even ,sir ,john ,mandeville1 an ,english author of travel books1 in his quest for knowledge of distant places4 ,he talked to travelers1 sailors1 and wrote to friends to send him information about the countries they had seen or lived in4 ,strabo1 in particular1 had set forth the doctrine that the earth's transformation had taken place by the forces of volcanoes and water1 but the wisdom of these early men had been obscured by the closed minds of the ,middle ,ages4 ,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 scholars4 ,for example1 the ,church believed in the great flood1 as described in the ,bible1 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 records4 ,to this latter ,leonardo responded1 8444 sufficient for us is the testimony of things produced in the salt waters and now found again in the high mountains far from the seas40 ,but ,leonardo's conception of the evolution of the earth was mistaken in one respect4 ,he regarded the earth as organic--living--and the flow of water he believed to be like the flow of blood in man4 ,indeed1 according to ,leonardo1 all living creatures were reflections of a living1 breathing earth4 ,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 error4 ,it had been the idea that the earth was the center of the universe which supported ,leonardo's theory of an organic earth4 ,yet after years of observation and study he abandoned this theory and1 with the eye of a man centuries ahead of his time1 he wrote in his notes1 8,the moon has every month a winter and a summer4 ,and it has greater colds and greater heats and its equinoxes are colder than ours40 ,he went further and identified the elements existing on the moon such as 8water1 air1 and fire10 and described them and their functions as being like those on our own earth4 ,in so doing he recognized the existence of the moon as a solid in space1 reflecting the light of the sun--one of many 8stars0 in a universe4 ,with his acceptance of this concept he realized that the earth could not be organic4 ,in ,may of #aejd1 the ,signoria complained to ,leonardo that there had been no progress on the proposed paintings for their council chamber1 even though he had already been partially paid for them4 ,accordingly1 he was forced to sign a document that he must be finished by ,february of next year or refund all monies paid him4 ,as was his custom he had made many preliminary drawings4 ,although he was well acquainted with horses he had again researched their anatomy and actions4 ,pages of rearing1 frightened horses and men in combat covered his studio tables4 ,on one of these pages there are sketches of the heads of a lion1 some horses and a man--all with fierce expressions on their faces4 ,here ,leonardo hinted at the comparative anatomy of expression in man and animal that ,darwin was to write about almost four hundred years later4 ,but the paintings could wait1 for now the ,arno ,river was in spring flood4 ,the time had arrived to make the first attempts at diverting the river into its new course4 ,leonardo was again in the field supervising the work4 ,there had been much opposition to ,leonardo's canal from both the army captains and the ,signoria4 ,it was called a whim and a crazy idea1 but ,piero ,soderini and ,niccol ,machiavelli were stubborn in their defense of ,leonardo's plan and they overcame all opposition to it4 ,and indeed1 the raising of the sluice gates was successful and the ,arno actually flowed into its new bed4 ,the tensions in the camp and in the ,council of ,florence were eased4 ,the only sad person was ,leonardo1 for he had just learned of the death of his father4 ,leonardo felt the loss deeply4 ,outwardly1 however1 he only acknowledged the death of his father at a distance4 ,not only had ,leonardo and his father drifted apart over the years1 ,piero left nothing to ,leonardo in his will4 ,his father's other children quarreled among themselves over what money he did leave4 ,leonardo's one friend in the family was ,uncle ,francesco1 who was still living in ,vinci4 ,when he heard of his brother's will1 ,francesco made out a will of his own and left everything to the nephew he loved--,leonardo4 ,after having successfully diverted the ,arno river1 it was now necessary for ,leonardo to return to the painting commissioned by the ,signoria for its council chamber4 ,but recently1 ,leonardo had suffered a rebuff in this work4 ,originally he had been given the whole room to do but now the opposite wall had been assigned to another man--,michelangelo ,buonarroti4 ,leonardo had first met the young ,michelangelo when he helped to judge the best location for ,michelangelo's monumental statue of ,david4 ,the two men were opposites in every way4 ,leonardo1 fifty-two years old1 carefully dressed1 cool and detached1 was a man whose every action was the result of a thoughtful and analytical mind4 ,michelangelo1 twenty-six years old1 his clothes rumpled and covered with marble dust1 was passionate and moody--an impulsive youth totally dedicated to art4 ,they did not like each other1 and now ,leonardo was forced into a rivalry for which he had no heart4 ,the duel between these two giants of art aroused the whole of ,florence and there was a constant stream of people watching them at work4 ,michelangelo was given a studio in the hospital of ,sant' ,onofrio and ,leonardo was working in the ,papal ,chamber in ,santa ,maria ,novella4 ,among the many people who came to watch ,leonardo was a young man of nineteen4 ,he was already a pupil of ,perugino and the experience of meeting and learning from ,leonardo was to influence him the rest of his life4 ,his name was ,raffaello ,sanzio--one of the great ,renaissance painters of ,italy and known to us by the name of ,raphael4 ,while ,leonardo worked at ,santa ,maria ,novella he had the opportunity of continuing his studies in anatomy4 ,dissections at that time were novelties and when one was performed the doors were thrown open to the public4 ,leonardo must have attended the public dissections at the ,church of ,santa ,croce4 ,now at ,santa ,maria ,novella there was a hospital1 and here ,leonardo was able to continue his own dissections without interruption4 ,in a cool room below the hospital where bodies were kept ,leonardo worked late into the night4 ,by the flickering lights of candles and in the silence of the world about him he studied1 drew1 and wrote in his notes of the wonders of the human body4 ,illustration3 ,in a cool room below the hospital1 ,leonardo worked late into the night4 ,he performed autopsies on people who had died natural deaths--a special permission granted to him by the monks of the church1 and among these autopsies are the first written reports of some of the diseases that are the causes of death4 ,arteriosclerosis1 or stony growths in the blood vessels1 and pulmonary tuberculosis1 a nut-like growth in the lung1 are among the discoveries ,leonardo made in his lonely searches1 although he did not use these medical names for them4 ,above all ,leonardo was attracted to the function of the muscles1 especially those in the arms and legs4 ,so faithfully1 in fact1 did he record the origin and insertion of all the various muscles that these drawings can be used as anatomical models today4 ,moreover1 he believed that a good drawing was worth pages of words describing human anatomy4 ,the muscles were rendered as cords so as to better understand their function4 ,he described this function as one of pulling instead of pushing and he noted that for every muscle there is an opposing muscle4 ,when one contracts the other expands4 ,for example1 when you tighten the biceps in your arm you can feel the looseness of the triceps1 the muscle on the opposite side4 ,as the end of the summer of #aejd approached1 ,leonardo's dream of the canal from ,florence to the sea was destroyed4 ,the summer had been hot and without rain4 ,the water in the canal dried up and the ,arno river returned to its original course4 ,all the old arguments against the plan were revived4 ,the ,florentine army captains rebelled against the job of defending a useless project4 ,again ,soderini and ,machiavelli intervened4 ,after heated debates in the ,council of ,eighty1 which had been called into special session1 ,machiavelli himself was sent out to oversee the work4 ,it was brought almost to completion when in late ,october disaster struck4 ,the rains that had failed to come in summer fell from the heavens in great cloudbursts4 ,storm after storm swept the valleys4 ,the workmen left and the soldiers were recalled4 ,the ,pisan army rushed in to fill up the diggings and one final storm washed away the dream to nothing but eroded mounds of dirt4 ,leonardo buried his disappointment in other work4 ,when the drawing for the ,battle of ,anghiari was ready for transfer to the wall of the council chamber1 he had a special scaffolding made of his own invention which worked on the principle of a pair of scissors standing on end1 with a long platform on top4 ,as the legs were spread the scaffolding was lowered and when they were pinched together it was raised4 ,the wall had been prepared with a special mixture which he hoped would bring out the brilliance of his tempera colors4 ,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 begun4 ,during the winter months ,leonardo would relax from his work on the huge painting and his dissections to roam the country around ,florence4 ,he visited the slaughterhouses where the animals were killed and prepared for market4 ,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 cold4 ,he made a glass model of the aorta 7the main artery leading from the heart7 of an ox with which he could experiment on the flow of the blood4 ,he intended to add to it a glass tube for one of the semilunar valves of the heart4 ,he also experimented with a frog1 dissecting its brain1 heart1 and entrails and noted that it ceased to twitch only when the spinal cord was severed4 ,in his notes1 he wrote1 8,the frog instantly dies when the spinal cord is pierced2 and previous to this it lived without head1 without heart or any bowels or intestines or skin2 and here therefore it would seem lies the foundation of movement and life40 ,he was of course searching for the reasons that muscles moved and from where the impulses originated4 ,one of ,leonardo's favorite places to visit was ,fiesole where his uncle ,allessandro ,amadori lived4 ,uncle ,allessandro was the brother of ,leonardo's first stepmother and1 since he had loved her so much1 he likewise felt an affection for ,allessandro4 ,at ,fiesole1 which rises over ,florence in a steep ascent1 ,leonardo could watch the birds circling in the air below him4 ,on these lofty heights1 he would unfold his drawings of flying machines4 ,leonardo had progressed now to a point where an actual flight was all that was left4 ,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 bird4 ,he had noted that the tail of a bird acts as a rudder1 a stabilizer and a brake when landing4 ,but ,leonardo's most recent design was one that was called an ornithopter4 ,it consisted of a wooden frame1 two huge wings like a bat's1 a series of ropes and pulleys and a windlass1 all planned with the lightest of materials4 ,the flyer1 lying prone in the frame1 his feet in leather stirrups connected to the wings by pulleys1 would move his feet up and down to flap the wings while1 at the same time1 he operated the windlass with his arms in order to guide the machine4 ,soon he hoped to build this machine and try it out4 ,meanwhile1 ,leonardo returned to his painting in the council chamber with impatience1 for spring was approaching and the time to finally realize his dream of flying would be at hand4 ,aside from an assistant who had tested the pedals and windlass1 no one knew of his plan to actually put his machine in the air4 ,illustration3 ,the ornithopter1 one of ,leonardo's designs for a 8flying machine40 ,by pumping his feet in the stirrups1 the flyer could flap the device's wings4 ,weeks passed and the painting was almost finished4 ,the huge wall was covered with plunging horses and embattled soldiers4 ,the colors were brilliant on the special mixture he had prepared for the wall--but they were not drying as they should have4 ,something was wrong4 ,to speed the drying process1 ,leonardo had a special fire built in the room that directed the heat onto the painting4 ,spectators were allowed to watch as the waves of hot air rose against the wall4 ,then--disaster began slowly with a small trickle of paint from the top6 ,before anybody could put out the fire1 the great figures and horses slowly melted down the wall in shiny1 sticky streaks of color4 ,leonardo fled the room in an agony of shame4 ,with his own friends discouraged1 the ,signoria hostile1 and the friends of ,michelangelo triumphant1 ,leonardo went back to ,fiesole4 ,he went back with his secret dream of flight4 ,the world would soon forget the ,battle of ,anghiari--but the conquest of the air1 if he could achieve it1 would live forever4 ,in the spring of #aejf1 from the slopes of ,monte ,cecero near ,fiesole1 legend tells us that a great bird sailed into the air and disappeared4 ,no one knows whether ,leonardo actually flew his machine or not but ,girolamo ,cardano1 the son of a friend of ,leonardo1 wrote1 long after ,leonardo had died1 8,leonardo da ,vinci also attempted to fly1 but he failed4 ,he was a fine painter40 ,another dream had been shattered4 #aa ,the ,return to ,milan ,leonardo felt his fifty-four years that spring day in #aejf4 ,the bitterness of his failures and the frustration of his dreams added considerably to the weight of his years4 ,all morning he had wasted in argument with ,soderini and the ,signoria4 ,if it had not been for the letter from ,charles d',amboise1 ,viceroy of the ,king of ,france for ,milan1 he would have felt like a beggar4 ,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 ,sforza4 ,but the authority of the letter had finally won a grudging consent from ,soderini4 ,leonardo looked about him to see if he had forgotten anything and slowly climbed onto his horse4 ,he nodded to ,salai1 his apprentice1 looked back to see if his servant had the pack-horses ready1 and started down the street leading the small procession4 ,he was going back to ,milan4 ,leonardo took out the letter and reread it4 ,the words were respectful and admiring--and in ,french4 ,they requested the presence of 8,matre ,leonard de ,vinci0 at the court of ,charles d',amboise1 for purposes of painting and other 8diverse projects0 for the ,king of ,france4 ,the letter restored a measure of confidence to ,leonardo's self-respect4 ,before ,leonardo left1 ,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 return4 ,it was signed1 notarized and dated ,may #cj1 #aejf4 ,nevertheless1 ,leonardo had decided to accept the ,french envoy's offer2 moreover1 he looked forward to the prospect of returning to his vineyard at ,porta ,vercellina and the understanding of a sympathetic patron4 ,indeed1 ,charles d',amboise turned out to be more than sympathetic4 ,he recognized ,leonardo as a great artist2 but even more1 he was one of the few patrons who could appreciate the magnitude of ,leonardo's scientific and mechanical genius4 ,in the court of ,charles1 ,leonardo once more enjoyed a time of peace and an assured income4 ,the ,french ,vice-,chancellor of ,milan1 ,geffroy ,carles1 who was second in command1 was also a distinguished scholar and a patron of the arts and natural sciences4 ,with the admiration and support of these two men and especially with the distant backing of ,king ,louis ,,xii of ,france1 ,leonardo's dismal memories of ,florence began to fade4 ,leonardo's three months' allotted absence from ,florence1 however1 were soon past and a letter arrived from ,soderini demanding either ,leonardo's return or a forfeiture of the one hundred and fifty florins deposit4 ,now a tug-of-war developed between the ,viceroy of ,milan and the governor of ,florence over ,leonardo4 ,the ,signoria reminded ,charles that ,leonardo had his work to complete1 while ,charles d',amboise and ,geffroy ,carles demanded an extension of time4 ,one month more was granted4 ,more letters were exchanged until the affair became so heated that the ,king of ,france himself intervened4 ,in ,january of #aejg the ,french ,king informed ,soderini and the ,signoria that ,leonardo was 8not to move from ,milan until our arrival40 ,since ,florence at this time was under the protection of the ,french1 such final authority silenced the ,signoria4 ,shortly afterwards ,leonardo discharged his obligation to the ,signoria by relinquishing the one hundred and fifty florins1 and he at last became free from the demands of his native city4 ,on ,may #bd1 #aejg ,king ,louis ,,xii re-entered ,milan with all the splendor and color that ,france and the ,dukedom of ,milan could confer upon their ruler4 ,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 ,france4 ,with such pomp and display in ,milan1 ,leonardo was soon back at his old occupation of designing pageants and tournaments4 ,while some of the people from the days of the ,sforzas returned1 not many remembered ,duke ,ludovico1 who was slowly dying in a ,french dungeon4 ,among the people that ,leonardo now met1 there appeared ,francesco de' ,melzi1 a noble from an old ,milanese family1 who entered ,leonardo's life at this time as a pupil4 ,soon the young man became like a son to ,leonardo4 ,of handsome appearance1 he had the sensitivity to appreciate the essential loneliness of ,leonardo and so1 almost without realizing it1 he filled a gap in ,leonardo's life that was to last until the end of his days4 ,yet1 as ,franceso de' ,melzi opened one door of ,leonardo's life another door closed4 ,he received word that his beloved uncle ,francesco had died at ,vinci and that he had become the heir to his uncle's property4 ,no sooner had this news been delivered when ,leonardo was notified that ,giuliano1 a son of ,piero1 and now a lawyer in his own right1 was contesting the will4 ,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 rights4 ,wisely1 ,leonardo had armed himself with letters from his new1 influential patrons and even one from ,king ,louis himself recommending1 8444 we request that you will cause this dispute to be settled in the best and briefest delivery of justice44440 ,in ,august of that same year--#aejg--;,charles d',amboise added his personal letter suggesting that the king could not spare ,leonardo too long from the court at ,milan4 ,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 case4 ,he went to stay with a sculptor friend1 ,giovanni ,rustici1 a man of thirty-five and also an ex-student of ,verrochio4 ,they lived in a house lent to ,rustici by a wealthy scholar and patron named ,piero ,martelli4 ,leonardo soon found that he and ,rustici had much in common4 ,rustici1 too1 collected the odds and ends of his journeys into the country4 ,flying about the house were a tame eagle and a raven1 while1 at dinner1 a pet porcupine begged for food4 ,rustici1 however1 was a believer in alchemy and magic4 ,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 gold1 or to call upon the spirits to predict the future4 ,leonardo settled into the life of the house very quickly and even helped his friend on an important sculpture commission4 ,this was a group composition of ,st4 ,john between the ,pharisee and the ,levite for over the doors of the baptistry4 ,he also started to gather together his scattered notes on all the subjects that he had written about1 going through them making corrections and erasing the repetitions4 ,possibly ,leonardo was considering the publication of all his material for he wrote1 8,begun at ,florence in the house of ,piero di ,braccio ,martelli1 on the #bbnd day of ,march1 #aejh4 ,this will be a collection without order1 made up of many sheets which ,i have copied here1 hoping afterwards to arrange them in order in their proper places according to the subjects of which they treat44440 ,this 8collection without order0 of almost forty years extended into practically all branches of human knowledge1 founded on years of observation and experiment4 ,indeed1 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 mankind4 ,in addition1 ,leonardo returned to his studies of anatomy and comparative anatomy4 ,for this latter he made many beautiful drawings of the legs of animals as compared to those of man4 ,with them1 ,leonardo tried to indicate man's place in the natural order of the world4 ,he pointed out that our physical bodies are basically the same as those of animals1 and that the muscular and organic differences are those of function only4 ,for example1 bird and man have the same chest muscles1 called the pectoralis4 ,but the bird1 in order to fly1 has developed these into powerful instruments of motion4 ,man1 on the other hand1 has learned to stand and move in an upright position4 ,he has developed the muscles of the back1 called the erectores spinae1 and those of the buttocks to hold him erect4 ,leonardo intended to enlarge upon his studies of comparative anatomy to include all living creatures1 even the insects4 ,meanwhile1 the ,viceroy of ,milan was becoming impatient for ,leonardo's return4 ,the judgment against his half-brothers had been settled in ,leonardo's favor1 and he hastened back to ,milan4 ,by the summer of #aejh he was once more in the routine of the court's activities4 ,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 living4 ,with these steady payments ,leonardo now had the leisure and support to pursue his own multitude of interests4 ,as his notes began to take shape and he thought of printing them1 it was natural for the inventive ,leonardo to design his own printing press4 ,it is one of the earliest such designs on record4 ,because the carrying bed which held the type and the paper was automatically adjusted to the handlebar1 the press could be operated by one man4 ,besides his notes ,leonardo also considered printing a work by ,roger ,bacon1 the thirteenth century ,english scientist4 ,this project for printing his own books1 however1 was never realized by ,leonardo4 ,lately1 he had received a commission which took him back in memory to the days of ,ludovico4 ,the subject was ,marshal ,gian ,giacomo ,trivulzio1 a soldier-of-fortune4 ,originally this man was a loyal commander of ,galeazzo ,sforza's but when ,ludovico came to power he had had ,trivulzio banished from ,milan4 ,embittered1 ,trivulzio had become a stubborn enemy of ,ludovico from that time on1 serving under any banner that marched against the house of ,sforza4 ,a stocky1 square-faced man1 his body was covered with the scars of many battles4 ,he had been fighting with the ,french ever since the time ,ludovico had betrayed ,charles ,,viii4 ,trivulzio had seen the great monument that ,leonardo had modeled and1 although it was riddled by ,french arrows and damaged by wind and rain1 the ,marshal was impressed and wished for a similar memorial to himself4 ,leonardo set to work immediately4 ,his past experience with the ,sforza monument was now to his advantage4 ,this time there was no need for experimenting4 ,he knew how much material he needed and the approximate cost of everything including the casting4 ,he submitted an estimate of three thousand and forty--six ducats for the completed work1 one hundred of which would go to ,leonardo4 ,the sum was acceptable to ,trivulzio and ,leonardo began his preliminary studies4 ,as he gathered the material for this new equestrian statue1 ,leonardo and the ,french ,viceroy ,charles d',amboise became interested in the further canalization of the plains of ,lombardy4 ,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 locks4 ,leonardo started another survey of the area4 ,in his imagination1 he envisioned a vast hydraulic engineering project4 ,on ,september #ab1 #aejh ,leonardo announced in his notes the beginning of a book on the nature of water4 ,he had decided to separate this book from the one on hydraulics because it was necessary to separate theory and practice4 ,his pages treating the science of hydraulics1 or the practical applications of water power1 had reached to 8forty books of benefits40 ,by the spring of #aeji he had expanded his notes on the nature of water to include the greatest wave to the smallest raindrop4 ,concerning the practical applications of water power1 ,leonardo put forth many designs for new locks4 ,he introduced new methods of raising the gates by windlasses and chains which could easily be set in motion by one man4 ,but most important is ,leonardo's discovery of the use of centrifugal force for draining marshes--the ancestor of the centrifugal pump4 ,when you rapidly rotate a stick in a pail of water1 the water spins in a spiral rising on the sides1 and1 if you rotate the stick fast enough it bares the bottom of the pail4 ,when you remove the stick suddenly1 the water continues to whirl as it slowly subsides4 ,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 away4 ,the centrifugal pump was also used with a hydraulic screw which converted water power to mechanical power4 ,the force of a stream of water was injected into the base of a vertical cylinder4 ,in the base of this cylinder was a six-bladed propeller mounted on a vertical shaft4 ,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 above4 ,the turning propeller revolved the vertical shaft4 ,this shaft1 emerging from the top of the cylinder1 turned a cogged wheel4 ,this wheel was joined to another cogged wheel mounted on a horizontal shaft1 thus providing the mechanical power4 ,not only is this the forerunner of the turbine1 but the use of the propeller1 itself1 for propulsion in water1 was a new idea not to be thought of again until the eighteenth century4 ,for certain types of hydraulic pumps he conceived of the cone-headed mitre valve still in use today4 ,leonardo1 besides studying the practical applications of water power1 explored the very nature of water itself4 ,in his proposed books on this subject he intended to examine why clouds and fog form1 why rain falls and the raindrop itself--even how the raindrop is held together4 ,he understood the nature of capillary attraction1 which holds the raindrop together1 and his notes show us that he was exploring the science of hydrostatics which relates to the pressure and equilibrium of liquids in general4 ,now that ,leonardo had a steady income and the relief from meeting painting commissions by fixed dates1 he was free to explore his other favorite avenues of knowledge4 ,it seemed that his ever-active mind could never stop roaming over the whole field of scientific knowledge4 ,he continued with his early interests--the nature and movement of air1 astronomy and geometry4 ,he was also still concerned with movement and weight1 for he set down in his notes1 8,the thing which moves will be so much the more difficult to stop as it is of greater weight40 ,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 inertia4 ,for example1 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 it4 ,illustration3 ,da ,vinci's cone-headed mitre valve for use in a hydraulic pump4 ,on a note dated ,april #bh1 #aeji he wrote1 8,having for a long time sought to square the angle of two curved sides 444 ,i have solved the proposition at ten o'clock on the evening of ,sunday40 ,as always1 ,leonardo was deeply involved in the study of mathematics4 ,too deep perhaps to recognize the new rumblings of war4 ,louis ,,xii1 still pursuing his campaign in northern ,italy1 had again arrived in ,milan amid the salutes of the ,french artillery4 ,following his personal banner of a gold porcupine on a white field1 he had come back prepared to do battle with the ,venetians whose power1 as it diminished in the east1 was extending westward into ,italy4 ,alarmed at this ,venetian expansion1 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 threat4 ,charles d',amboise1 the ,french ,viceroy1 had already taken to the field and at the castle of ,cassano1 overlooking the ,adda river near ,milan1 he awaited the arrival of his king4 ,by the end of ,may1 ,leonardo was in the saddle once more4 ,surrounded by the best knights of ,france and the nobles of ,milan1 he personally accompanied the ,french ,king as military engineer to the meeting with the ,viceroy of ,milan at ,cassano4 ,during the next three months1 through the battles and defeat of the ,venetians at ,aquadello where sixteen thousand dead were left on the field1 and the siege of ,caravaggio and the capture of ,peschiera1 ,leonardo served as military consultant and map maker4 ,more than ever his eye was attracted to the possibilities of utilizing the many rivers they crossed both for warfare and commerce4 ,he envisioned making the ,adda river navigable from ,milan to ,lake ,como4 ,during this time1 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 vehicles4 ,by ,july1 ,leonardo had returned with the king and the ,french army to ,milan4 ,here was planned a great celebration of the ,french victory over the ,venetians4 ,in front of the cathedral1 to the delight of the hundreds of spectators1 ,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 out4 ,after the festivities ,leonardo returned to his everyday work4 ,in time1 he had a thriving workshop and as he became more and more preoccupied with his scientific explorations1 his art commissions were turned over to his assistants4 ,he did continue1 however1 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 anatomy4 ,this renewed interest in anatomy led him to attend a lecture in the winter of #aeji4 ,the lecturer was ,marcantonio della ,torre1 a young man in his late twenties and one of the best-known anatomists of the times4 ,he had been a professor at the ,university of ,padua1 but this city had fallen into the hands of the ,venetians4 ,marcantonio was forced to flee ,padua and had settled at ,pavia4 ,the two men1 when they met1 recognized in each other a devotion to science and they began a professional collaboration that grew into a friendship4 ,leonardo now developed his anatomy studies to the point where he is today recognized as the foremost medical anatomist of the ,renaissance4 ,returning to his dissections1 ,leonardo now proceeded to explore the heart and system of veins in the human body4 ,his drawings of the heart are nearly perfect4 ,indeed1 he was probably the first to discover the endocardium membrane that sheathes the valves and sinews of the heart4 ,also1 he pictured and described the moderator band1 8the first cause of the motion of the heart40 ,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 century4 ,further1 ,leonardo was the first to accurately draw a representation of the foetus1 or unborn child1 in the womb of its mother1 writing in his notes that1 8we conclude therefore1 that a single soul governs the bodies and nourishes the two40 ,in addition1 he drew a remarkable picture of the female figure and for the first time accurately placed her organic structure4 ,in his notes1 he also pointed the way to the laws governing metabolism when he wrote1 8,the body of anything whatsoever that receives nourishment continually dies and is continually renewed44440 ,by pouring wax into a hole in the skull he made the first casts of the ventricles of the brain4 ,several hundred years were to pass before this method was rediscovered4 ,as ,leonardo's work progressed1 his admiration for the complexity of the human body grew4 ,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 being4 ,indeed1 these drawings and notes represent the sum of many1 many dissections2 moreover1 ,leonardo had to work under conditions that placed many obstacles in his path--the crude lights and instruments1 the difficulties of obtaining corpses and1 above all1 the opposition of the superstitious and ignorant4 ,the following year ,leonardo entered in his notes1 8,this winter of the year #aeaj ,i look to finish all this anatomy40 ,and yet1 however sincerely he might express such a wish1 ,leonardo was a person who was literally never 8finished40 ,the scientific and artistic tasks he had chosen for himself were clearly beyond the limits of any one man4 ,besides1 the pressures of the outside world were once more threatening the peace and quiet of his home and work4 ,pope ,julius ,,ii became increasingly fearful of the ,french victories over the ,venetians4 ,secretly1 he concluded a peace with ,venice and1 allying himself with his former enemy1 he now turned against the ,french4 ,when the conflict continued1 ,charles d',amboise1 the patron of ,leonardo1 was killed at the battle of ,correggio4 ,he was replaced by a new ,french ,viceroy1 ,gaston de ,foix4 ,although the ,pope now hired ,swiss mercenaries1 this invasion from the ,north was defeated by the young ,gaston4 ,not to be outdone1 the ,pope then brought in ,spanish troops4 ,in the ensuing bloody battle at ,ravenna1 the ,french completely defeated the armies of the ,pope and ,spain1 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' ,medici6 ,although the ,french were victorious1 they lost their brilliant young leader1 ,gaston de ,foix1 and with him they lost their heart4 ,as a result1 they were soon disorganized4 ,the ,pope's armies renewed their attacks1 and the ,french began a long retreat4 ,once again the plague infested ,milan and ,leonardo's friend1 ,marcantonio della ,torre1 died of it4 ,after some futile attempts at recovery1 the ,french fled across the ,alps and with them went ,marshal ,trivulzio4 ,milan was left temporarily under the martial rule of the ,swiss1 and ,leonardo with only his few apprentices was left again without a patron4 ,tired and prematurely old at sixty-one1 ,leonardo resignedly gathered his possessions together once more and with ,francesco de' ,melzi and four of his loyal pupils1 he turned his back on ,milan for the last time4 ,the date was ,september #bi1 #aeac4 ,their destination was ,rome4 #ab ,rome 8,name80 8,leonardo da ,vinci40 8,where from and where are you staying80 8,we are coming from ,milan by way of ,florence4 ,i have quarters being prepared for me at the ,belvedere in the ,vatican--by order of the ,pope4 ,now1 young man1 let us pass40 ,the guard at the ,porta del ,popolo changed his manner4 ,he dropped his halberd and motioned to the other guards to let the riders through4 ,he touched his helmet roughly and with a grin he said1 8,i'm sorry1 ,sire--but you know how it is4 ,all these people--there's bound to be them that we don't want here4 ,go ahead1 your ,excellency4 ,make way there60 ,with these words he laid his spear against a jostling group of broad-hatted pilgrims blocking the entrance to the city of ,rome4 ,leonardo heeled his horse and with ,francesco de' ,melzi at his side1 followed by his servant and students1 pushed past the crowd at the gate4 ,to the left rose the ,pincio hill with its stately pines where1 in the days of ,imperial ,rome1 ,lucullus had walked in his gardens4 ,but ,leonardo had no time to look about4 ,it was a damp ,december day1 and rain threatened from the gray skies4 ,he was tired1 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 long1 graying hair on his shoulders4 ,they made their way through the crowded1 noisy city4 ,they crossed the ,tiber and rode past ,castel' ,sant' ,angelo1 the papal fortress built on the tomb of ,emperor ,hadrian4 ,after another inspection by the ,swiss guards in beribboned uniforms of white1 green and gold under their shining breastplates1 they entered the walls of the ,vatican4 ,that evening after he had settled himself in the ,belvedere apartments and dinner had been eaten1 ,leonardo1 gazing into the embers of the fire1 looked back over his new stroke of fortune4 ,the ,medicis had returned to power4 ,pope ,julius ,,ii had died1 and ,giovanni de' ,medici1 son of ,lorenzo1 had become ,pope ,leo ,x at the age of thirty-seven4 ,with his election to the head of the ,christian world1 the ,republic of ,florence became a city of the ,medicis once more and ,leonardo had received an appointment in ,rome4 ,giuliano de' ,medici1 ,pope ,leo's favorite younger brother1 in his new rise to power and wealth1 became ,leonardo's patron4 ,the two must have met sometime during the ,medici's exile4 ,leonardo was given the apartments in the ,vatican and a salary of thirty-three ducats 7approximately eighty-five dollars7 a month and a workshop was fitted for him and his pupils4 ,he was also assigned an exclusive ,german assistant named ,georg4 ,the ,pope's court in the ,vatican was like the ,medici court in the ,florence of ,leonardo's youth--multiplied by hundreds4 ,leo ,x saw himself as the center of the artistic world1 and being a man of luxurious tastes with the wealth of the church behind him1 the ,vatican was soon filled with a mixture of the wise and foolish4 ,pompous classic-quoters1 third-rate poets and clowns mixed with the world's scholars and statesmen4 ,the two greatest artists were ,bramante1 the architect and friend of ,leonardo's first years in ,milan1 and ,bramante's pupil ,raphael1 the painter4 ,bramante was busy building the new church of ,st4 ,peter's and1 as the architect of this favorite project of the ,popes1 he was sole master of the ,roman art world4 ,raphael1 as his protege1 was the recipient of the better painting commissions in ,rome4 ,the elderly ,bramante and the thirty-year-old assistant were a famous pair in the ,rome of #aeac4 ,equally as famous1 however1 was ,michelangelo2 he was still living in ,rome1 but was without patronage after ,julius ,,ii's death4 ,leonardo's old rival had scored his triumph with his extraordinary paintings in the ,sistine ,chapel4 ,although the young ,raphael1 who owed so much to the example of ,leonardo1 now rode through the streets as a wealthy nobleman1 ,leonardo himself received no great commissions4 ,while ,pope ,leo was indulgent of his brother's whims he himself had no use for this tall1 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 zoo4 ,in reality1 ,leonardo's patron1 ,giuliano de' ,medici was a weak man4 ,he played at being a patron but1 like his brother the ,pope1 he lacked the force and decision of his famous father ,lorenzo4 ,nevertheless1 he did give ,leonardo one small commission for a picture4 ,immediately ,leonardo1 excited by the exotic plants in the ,vatican gardens1 commenced to experiment with them to find a resin to make a varnish with which to cover the future painting4 ,pope ,leo made fun of him exclaiming1 to the delight of his court1 8,this man will never get anything done1 he thinks of the end before the beginning40 ,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 eyes4 ,leonardo also suffered the humiliations of a man who did not conform to the fashions of his day4 ,his knowledge of ,latin1 for example1 was weak and although he could read it with the help of a dictionary he could not speak it4 ,and1 among the people who surrounded the ,pope1 ,latin was the only language allowed4 ,prizes of great sums of money and important positions were often granted on the strength of an improvised speech in ,latin 7with many quotations from the classical authors7 or a flattering ,latin verse4 ,faced with such setbacks and ridicule1 ,leonardo--not surprisingly--began to withdraw into himself4 ,and yet1 ,leonardo refused to remain idle--he had to work4 ,the need for mirrors in the vast halls and rooms of the papal palace was great4 ,leonardo turned his mechanical skill to redesigning and improving methods of making them1 and even inventing his own machines for the grinding of the glass4 ,also1 for ,giuliano1 who dabbled in alchemy and magic1 he made distorting mirrors and burning lenses4 ,in addition1 ,leonardo invented a machine which could be run hydraulically for producing long strips of copper of equal width for use in soldering the mirrors4 ,but1 with the making of these mirrors1 ,leonardo began to run into trouble with his ,german assistant1 ,georg4 ,the boy was a loafer2 he spoke little ,italian and took every opportunity to spend his days with his countrymen in the ,swiss guard4 ,leonardo tried to alter the situation by suggesting that the boy have his meals with him at his worktable1 thus giving ,georg a better chance to learn the language4 ,this however did not appeal to him4 ,then1 because ,leonardo's inventions were so extraordinary1 he began to give away the secrets of their mechanisms to ,johannes the mirror-maker1 another ,german1 who had been replaced by ,leonardo in the favors of ,giuliano4 ,this naturally made ,johannes jealous of ,leonardo4 ,georg gossiped1 too1 and told stories about the old1 eccentric man who lived like a miser in the midst of all the luxury and who drew crazy circles on pages of paper4 ,these 8crazy circles0 were geometric exercises that had fascinated ,leonardo from the time he had wandered across ,italy with ,fra ,luca ,pacioli4 ,pacioli's book ,de ,divina ,proportione1 containing sixty illustrations from designs of ,leonardo1 had been published in ,venice in #aeji4 ,leonardo intended to entitle these geometric exercises ,de ,ludo ,geometrico4 ,in geometry a lune is a crescent-shaped figure bounded by two intersecting arcs of circles on a plane or a sphere4 ,leonardo drew pages of these lunes and then proceeded to transform their curvilinear figures into squares of equal area4 ,he also reviewed ,archimedes' method of squaring a circle and developed it into a variety of ways for cubing spheres and cylinders4 ,he returned as well to formulating theories of friction4 ,he wrote in his notes1 8the tallest wheel is the easiest to pull0--for example1 a big wheel turning at the same speed as a smaller one has less friction to overcome because it makes less revolutions4 ,his experiments in friction predated men like ,amontons and ,coulomb by two and three centuries4 ,he established a formula for the building arch which he described as 8a strength caused by two weaknesses0--if one half of an arch is removed1 the other half collapses4 ,they support and give strength to each other4 ,in addition1 ,leonardo determined1 before ,galileo1 the center of gravity of any pyramid and of a tetrahedral1 or four-sided body4 ,as the days went by and he waited for commissions to come1 ,leonardo took to wandering about the streets of ,rome4 ,he stood in the half-buried ,forum of the ,caesars surrounded by grazing sheep and grunting pigs4 ,wooden shacks where crude cartwheels were made and where the marble from the ancient temples was cut and sold1 were built against the sides of crumbling ruins4 ,the old triumphal arches1 now overgrown with creepers1 were boarded into towers and cattle were penned between the shafts of columns that once supported the grandeur of temple roofs4 ,here and there a classical scholar would be sketching or writing from the worn1 ,latin inscriptions on a marble slab tilted crazily from the ground where it had fallen hundreds of years ago4 ,goats wandered on the ,palatine hill1 once the home of ,emperors1 and the great baths of the ,emperor ,diocletian were now a deer park and a hunting ground for royalty4 ,during the course of these wanderings1 ,leonardo became interested in the primitive methods of carpentry4 ,such things as screws1 for example1 were rare4 ,those that were used were either made of wood or1 if of metal1 by goldsmiths laboriously making each one by hand1 soldering wire around a pin and another wire into the hole to hold the screw4 ,sometimes they were made by filing pieces of metal individually4 ,all these methods were time-consuming and costly4 ,leonardo had thought of this problem before1 and now he concentrated on perfecting his ideas about it4 ,previously1 he had thought of casting the metal in wooden molds and then turning the metal on thread-cutters4 ,the designs he finally drew in careful detail1 however1 are essentially the methods used today4 ,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 perform4 ,he also drew designs for a mechanical plane and a machine for drawing wire that worked by water power4 ,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 him4 ,true1 he received his thirty-three ducats a month1 but ,michelangelo had been paid three thousand for his work in the ,sistine ,chapel1 while ,raphael had earned twelve thousand for each room he painted in the ,vatican4 ,illustration3 ,leonardo became interested in various methods of carpentry4 ,thus ,leonardo drifted farther and farther away from his painting4 ,this1 in itself1 caused people to talk in the papal city4 ,for he had earned fame as a painter1 but his passion for science was regarded as strange and whimsical4 ,occasionally1 he did receive a small commission from the workshop of ,raphael1 yet these were like the crumbs from a rich man's table4 ,even the toys ,leonardo made at this period for the amusement of his patrons were looked upon as somewhat weird4 ,for example1 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 guest4 ,once he caught a curious lizard in the garden and spent hours putting scales all over the tiny body1 attached to it a little beard and horns1 then let it out from a box at a banquet4 ,the guests jumped back with fear and the women became hysterical4 ,one of ,leonardo's jokes that has been passed down in accounts of his life at this period must have created quite a sensation4 ,he showed the company the cleaned entrails of a sheep resting on the palm of his hand4 ,after telling them to wait and watch he took the entrails in another room and with a bellows inflated them with warm air4 ,as the entrails filled with air they expanded and extended4 ,they crept into the room where the company waited4 ,slowly they grew and grew until they began to fill the room4 ,the guests overturned their chairs in their hurry to get out of the way of this shapeless1 translucent creature4 ,then ,leonardo appeared1 the air-filled entrails giving way before him1 and said3 8,sires1 this is but an example and symbol of virtue4 ,as you can see1 the smallest virtue is capable of the greatest growth40 ,the guests laughed1 but it was an uncomfortable laugh4 ,thus another story was added to the legend of ,leonardo as an odd old man4 ,leonardo1 whose work--particularly his anatomical studies--had constantly been interrupted by the fortunes of war1 had found another hospital in ,rome where he could continue these studies4 ,this time it was his intention to write a treatise on speech4 ,he dissected and drew the anatomy of the larynx 7the voice box71 the vocal cords and the trachea 7the air passage to the lungs71 and all the muscles that control the movements of the tongue and the lips4 ,if you pronounce each letter of the alphabet you will feel these muscles of the lips1 especially with the letters 8o10 8p10 and 8f40 ,carefully he noted how the air vibrations from the trachea form themselves into vowels and consonants1 and he drew the membrane which1 when air is pressed against it1 makes the sound 8aah40 ,at this same time he was also busy finishing a treatise on painting which he had begun when he was working on the 8,last ,supper0 for ,ludovico ,sforza4 ,but it was for his knowledge of military engineering that he was sent to the city of ,parma by the ,pope on ,september #be1 #aead4 ,here he stayed at the ,bell ,inn while examining the fortifications and other defenses of the city4 ,leonardo's patron1 ,giuliano de' ,medici1 had been appointed governor of this particular area and1 since ,pope ,leo ,x was fearful of two powerful countries1 ,france and ,spain1 he was preparing the papal territory against possible invasion4 ,another fear of the ,pope--and indeed of everybody in ,rome--was malaria1 the disease carried by the mosquitoes that bred in the ,pontine marshes west and southwest of the city4 ,at that time1 however1 no one knew the cause was mosquitoes2 rather1 they thought it was the bad air from the marshes4 ,as ,leonardo had already been effective in draining the pestilential marshes of ,piombino for ,cesare ,borgia and1 later1 those around ,milan for ,charles d',amboise1 he was assigned the same task for the ,pontine marshes4 ,he surveyed the entire area to the sea and made another extraordinary aerial type map4 ,his recommendations included draining the entire area1 enlarging and regulating the ,martino river and cutting an extra outlet from the river ,livoli to the sea4 ,these plans were adopted some years later and parts of the marshes were drained successfully1 yielding new land for the cultivation of crops4 ,by ,december of #aead ,leonardo had finished his treatise on speech and1 possibly in an effort to attract the attention of the ,pope1 he submitted it to the ,privy-,chamberlain1 ,battista dell',aquila4 ,as ,pope ,leo was surrounded by an army of secretaries and assistants who passed on everything submitted1 this manuscript with its beautiful drawings was mislaid and lost and only a few notes and sketches remain4 ,the continual discouragement of his life in ,rome was offset by a visit from his half-brother1 ,giuliano1 around ,christmas4 ,leonardo was held in esteem by his family despite the quarrel over his father's and his uncle ,francesco's will1 and his half-brothers were pleased to tell of their famous relative who lived in the ,belvedere as guest of the ,medicis4 ,yet they knew little of ,leonardo's scientific dreams and his lack of recognition in the papal city4 ,often1 ,leonardo's greatest comfort was to return to his notes4 ,the challenge of geometry and the mysteries of the movement of air and water kept him from brooding about his lonely life4 ,francesco de' ,melzi1 ,leonardo's young friend1 had more and more taken over the practical responsibilities of his everyday life4 ,except for his workshop1 where the troublesome ,georg worked at the making of mirrors1 and an occasional small commission for a painting1 ,leonardo was free to study4 ,in addition to his geometrical investigations1 ,leonardo now experimented with the science of statics 7objects that are stationary71 and dynamics 7objects in motion74 ,one of his most important discoveries in the science of mechanics came about during this period4 ,concerning the division of weight1 he wrote1 8,there are three conditions of gravity of which the one is its simple natural gravity1 the second is its accidental gravity1 the third the friction produced by it4 ,but the natural weight is in itself unchangeable1 the accidental which is joined to it is of infinite force1 and the friction varies according to the places wherein it occurs1 namely rough or smooth places40 ,thus he realized and formulated what composes the movement of an object4 ,he found that movement is the result of separate forces acting upon the object from different directions1 as for example1 the initial push1 the pull of gravity and the resistance of friction4 ,and1 before ,galileo1 ,leonardo further experimented with objects dropped from a height4 ,as the result of repeated experiments1 he noted that the fall was being affected by the earth's rotation4 ,that is1 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 century4 ,he also became fascinated with spiral motion1 such as is found in a spinning top or in a whirlpool of water4 ,because of his interest in hydrodynamics1 or the movement of water1 he began to sketch imaginary 8,deluge compositions40 ,these were drawings showing the world--probably inspired by the ,bible--in a chaos of wind and floods4 ,they were based on his years of scientific research4 ,indeed1 his drawings of actual whirlpools are still among the greatest of his scientific art4 ,today1 with all the latest technical aids1 such as dusting a whirlpool with powdered rosin and then photographing it1 an accurate three-dimensional picture is impossible4 ,yet ,leonardo1 by sheer observation and analysis coupled with his genius for drawing1 could reproduce the complicated shape of whirling water4 ,in the relatedness of his explorations of water1 air and movement1 and weight1 he worked out the similarity between the laws of equilibrium controlling solids and liquids4 ,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 them4 ,far into the night ,leonardo worked on his papers4 ,he tired more easily now1 and his eyes had grown weaker4 ,to provide the increase in light that his failing eyesight demanded1 he had improved on his original oil lamp by making the wick rise as the oil was burned away1 and he had extra lamps fitted to the ceiling4 ,on ,january #i1 #aeae ,leonardo wrote in his notes1 8,il ,magnifico ,giuliano de' ,medici set out on the ninth day of ,january #aeae at daybreak from ,rome1 to go and marry a wife in ,savoy4 ,and on that day came the news of the death of the ,king of ,france 7,louis ,,xii740 ,this meant that his new patron had left and his old patron had died4 ,leonardo's note was a sad one and perhaps he felt1 in the departure of his patron1 more alone than ever in the crowded life of the ,vatican4 ,giuliano1 on the urging of his brother1 was marrying ,philiberta of ,savoy1 in an effort to strengthen the prestige of the ,medici4 ,louis ,,xii1 before he died1 had formed a league against ,spain1 and with the marriage of the ,pope's brother to a noble house of ,france1 the league would be strengthened by keeping the ,pope on the side of ,france4 ,actually ,pope ,leo was playing both sides1 for at the time he was also friendly with ,spain4 ,shortly after ,giuliano's departure from ,rome1 ,leonardo fell ill1 presumably from a mild heart attack complicated by a touch of malarial fever4 ,the doctor had been called4 ,it was a warning1 the doctor told ,francesco de' ,melzi1 and ,leonardo must remain quiet for quite awhile4 ,by the end of the winter ,leonardo was back on his feet and apparently feeling completely well again4 ,giuliano himself had fallen ill about the same time and the news that he had recovered and was finally returning to ,rome cheered ,leonardo4 ,he sat down and wrote a long letter to his patron expressing his joy4 ,this letter also included a long list of complaints against ,georg and ,johannes4 ,georg was now using his room in ,leonardo's apartment to do work for others4 ,he lied to ,leonardo and flew into such a rage when he was questioned that no one could go near him4 ,moreover1 ,johannes1 the mirror-maker1 was now moving back into the ,vatican and turning out mirrors for everyone1 even using ,georg's room as his own workroom4 ,johannes boasted of his skill and told everybody that ,leonardo did not know what he was doing4 ,thus1 it was not surprising that ,leonardo1 in his long complaint1 was taking out the anger and frustration he felt against all the injustices of his life in ,rome4 ,but by summer ,leonardo was again employed as a military engineer4 ,francis ,i had succeeded to the throne of ,france4 ,the new ,french ,king was anxious to secure his lost title to the ,dukedom of ,milan and was preparing another invasion of ,italy4 ,pope ,leo ,x1 still trying to play both sides at once1 was making secret agreements with ,francis while at the same time joining the ,king of ,spain1 ,milan1 ,genoa1 and the ,swiss in an alliance against ,france4 ,consequently1 he sent ,leonardo out to inspect the fortifications of ,civitavecchia1 a city on the ,tyrrhenian coast not too far from ,rome4 ,when1 in ,august1 ,francis ,i crossed into ,italy with an army of thirty-five thousand men including ,marshal ,trivulzio1 the ,pope ordered his brother1 ,giuliano1 to take command of the papal forces4 ,on the way to assume this command1 ,giuliano fell ill and collapsed4 ,his sickness this time was soon to be fatal4 ,leonardo returned to ,rome with his survey of ,civitavecchia1 where he immediately learned of his patron's latest illness4 ,perhaps realizing that ,giuliano was fatally ill1 ,leonardo made a desperate effort to gain the recognition he felt should be his4 ,he entered the competition for a new faade of ,san ,lorenzo in ,florence4 ,among the other competitors was ,michelangelo1 his younger and yet oldest rival4 ,in ,october of #aeae1 ,francis ,i had recaptured ,milan and by ,christmas was in ,rome4 ,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 ,france4 ,certainly it is known that he attended ,francis' court in ,rome4 ,leonardo's name was well respected in ,french circles and1 as ,francis had already admired the pictures by ,leonardo1 the meeting was a happy occasion for them both4 ,indeed1 the recognition that ,leonardo had sought in his native land was never as great as that accorded to him by the ,french4 ,as ,francis ,i prepared to leave for ,france in ,january he must have offered ,leonardo a position at his court4 ,while he still hoped that ,giuliano de' ,medici would recover from his illness and return to ,rome1 ,francis' offer gave him support in the knowledge that he had a powerful1 new friend4 ,march of #aeaf brought the first of three events that were to change the course of ,leonardo's last years4 ,giuliano de' ,medici died1 leaving ,leonardo not only without a patron1 but without a friend in the ,vatican4 ,now sixty-four years old1 he was reluctant to leave his comfortable quarters in the ,belvedere with its workshop and pleasant gardens4 ,besides1 deep within himself1 he felt that ,rome could still offer him the fame that had always escaped him4 ,spring ripened into summer and the second event occurred4 ,the competition for the new faade of ,san ,lorenzo in ,florence was won by ,michelangelo4 ,to ,leonardo the news was a blow4 ,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 ,pope4 ,the third event was the sum of many small events4 ,georg and his friend ,johannes1 in their jealousy1 had spread much gossip about ,leonardo in court circles4 ,they now took advantage of ,giuliano's death to circulate stories about ,leonardo's dissections of bodies in the hospital4 ,these were added to vicious gossip that ,leonardo was pro-,french4 ,this news eventually reached ,pope ,leo ,x4 ,the ,pope himself was perfectly aware of the practice of dissection and1 personally1 he had turned his eyes the other way4 ,however1 as dissection was contrary to ,church doctrine1 an official complaint to the head of the ,church could not be ignored4 ,the ,pope used it as an excuse to be rid of this tiresome old man whom he had tolerated only for his brother's sake4 ,leonardo was abandoned4 ,the year #aeaf was drawing to a close4 ,leonardo had decided to seek the patronage offered him by ,francis ,i4 ,so he and ,francesco de' ,melzi1 his loyal young friend1 left ,rome for the long journey into ,france4 ,as he left his native land for the last time1 ,leonardo looked back over his years--from the silver lute that had sent him to ,milan1 to the death of ,giuliano1 to the final rejection of ,pope ,leo ,x4 ,remembering how ,lorenzo de' ,medici had sent him to ,ludovico so many years before1 ,leonardo thought to himself with great sadness1 8,the ,medici created and destroyed me40 #ac ,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 lawn4 ,the click of the mallets and balls was mingled with the shouts and laughter of the young people4 ,it was late afternoon in ,may and although the sun was warm the breeze from the west was chilly4 ,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 see4 ,swallows were swooping low over the banks below and the wind carried their shrilling cries up to him4 ,the forested islands and sandbars interrupted the steady flow of the river and ,leonardo could see the reflections sway in the current4 ,he had been studying the river but he realized that his aging eyes were not up to the task of concentrating for long4 ,the wind made them water1 so he turned away and started back to his home4 ,there was much that was familiar in the castle at ,amboise4 ,the thick1 high walls and round towers and especially the graceful1 lacy spires of the king's residence brought back much that he had known in his native land4 ,the gardens had been planted by ,italians--there were orange trees and even a mulberry tree from his beloved plains of ,lombardy4 ,the king's residence and chapel had been constructed and the decorations carved in stone by ,italian artisans4 ,leonardo could stop and talk in his native tongue with many of the men employed by the king4 ,since the time of ,charles ,,viii1 the ,french had brought in the latest ,renaissance styles from ,italy4 ,leonardo's steps took him back from the castle grounds and down a path with a hand-railing4 ,the steep roofs of the town of ,amboise with their chimneys could be seen below him4 ,the path led to a small manor house1 like a miniature castle with sharp spires and lacy1 carved-stone gables that was set in green lawns and gravel paths4 ,the ,manoir de ,cloux1 as ,leonardo's house was called1 had been a hunting lodge for ,francis ,i1 but when ,leonardo had arrived he gave the house to ,leonardo for his home4 ,francis1 in his admiration for this great man1 also gave him seven hundred crowns a year1 together with a pension of four hundred for ,francesco de' ,melzi4 ,illustration3 ,leonardo at ,chateau d',amboise on the ,loire4 ,the long journey from ,rome had left ,leonardo tired and weak and he had fallen ill again shortly after his arrival4 ,this time the attack was more serious and had left him with his right hand permanently crippled4 ,he looked at it now as he opened the door to his room4 8,another warning10 he thought1 8and there's still so much to do40 ,the young1 robust ,king ,francis was everywhere at once4 ,he gloried in knightly tournaments1 hunts1 and sports of all kinds4 ,always restless1 he might appear at any place unannounced4 ,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 nobles4 ,with a great jingling of spurs he would bound up the stairs of the manor house calling for ,leonardo4 ,he delighted in long talks with the old man1 and would listen respectfully as ,leonardo1 his deep-set eyes brooding over his notes1 would demonstrate some scientific point on a blank sheet of paper4 ,at this time1 ,leonardo was engaged on three projects which demanded his immediate attention4 ,one was the entertainment for a banquet that ,francis was giving for his sister1 ,marguerite de ,valois1 and her husband4 ,another was a new design for the king's castle at ,amboise1 and the third was a design for making a navigable waterway from ,amboise to ,romorantin4 ,although these three projects were the main ones that occupied ,leonardo's time1 there was always the supervising of his pupils' painting on the walls in the little chapel of the manor house1 his own work on a painting of ,st4 ,john the ,baptist1 and the continual ordering and revising of his notes4 ,the banquet took place in ,october of #aeag1 and the mechanical lion ,leonardo had made was an immediate success4 ,it 8walked0 by means of a spring motor1 into the hall1 opening and closing its fierce mouth while swaying its head from side to side4 ,with a wand that he had been given1 ,francis ,i stepped down from his seat and tapped the lion three times4 ,the toy fell apart and from it a cascade of white lilies poured out at the king's feet4 ,also at this time there was a distinguished guest at the castle of ,amboise4 ,he was a fellow-countryman of ,leonardo and his name was ,cardinal ,luigi d',aragona4 ,with him was his secretary ,antonio de' ,beatis4 ,as ,leonardo was now a famous member of ,king ,francis' court1 the cardinal paid him a visit accompanied by ,antonio4 ,the extraordinary anatomy drawings and all his notes were shown to the cardinal2 he and his secretary were deeply impressed4 ,they were also surprised to learn that ,leonardo had never been accorded the same recognition by his own countrymen4 ,antonio de' ,beatis wrote home that 8,this gentleman has written a treatise on anatomy1 showing by illustrations the members1 muscles1 nerves1 veins1 joints1 intestines and whatever else is to discuss in the bodies of men and women1 in a way that has never yet been done by anyone else4 ,all this we have seen with our own eyes2 and he said that he had dissected more than thirty bodies1 both of men and women of all ages4 ,he has also written of the nature of water1 and of divers machines1 and of other matters which he has set down in an endless number of volumes1 all in the vulgar tongue meaning ,italian not ,latin1 which1 if they be published1 will be profitable and delightful40 ,by now ,leonardo had accumulated thousands of pages of notes1 and they lay stacked in all manner of chests and boxes4 ,often now1 as ,leonardo surveyed the work of his lifetime1 he realized that he would never see the day of their publication4 ,time was slipping through his fingers4 ,already summer had come and gone and now the sharp winds of fall were lifting the leaves from the ground in dancing whirls4 ,fortunately these were years of peace and for the first time in a long while the people were free of wars4 ,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 ,italy6 ,leonardo1 old and ailing as he was1 had surveyed parts of the rivers ,loire and ,cher1 braving the rough roads and crude accommodations4 ,in addition1 ,leonardo had designed a castle for ,francis ,i's widowed mother in ,romorantin4 ,this castle was never built1 but many of the ideas that ,leonardo had incorporated in its design were used in the gigantic and magnificent castle of ,chambord4 ,also1 at ,francis' request1 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 ,leonardo4 ,in ,february of #aeag1 a son had been born to ,queen ,claude and ,francis ,i4 ,the king decided to postpone the baptism of the dauphin 7the title given to the eldest son of a ,french ,king7 until ,may of the following year4 ,at that time there would be a double celebration at ,amboise1 for a nephew of ,pope ,leo ,x1 the young ,lorenzo de' ,medici1 was being married to ,madelaine d',auvergne4 ,as usual1 ,leonardo was given the assignment of preparing the festivities4 ,although he was fond of preparing these entertainments1 ,leonardo now felt the pressure of time2 for indeed1 the interruptions of this eager young king were sometimes a hardship4 ,he felt that his years were drawing to an end4 ,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 endurance4 ,as ,leonardo was sketching one day from the window of his room where he could see the castle walls and the chapel of ,saint-,hubert1 he set aside the drawing for a moment to write a memorandum to himself4 8,write of the quality of time as distinct from its mathematical divisions40 ,was this extraordinary man sensing the road down which ,einstein--in his studies of relativity--was to travel hundreds of years later8 ,spring arrived again and with it came the first wild flowers and roses1 the songs of the birds in the woods and the blossoming of the chestnut trees4 ,the time for the double celebration came1 too1 and ,leonardo was seen busily preparing the decorations and mechanical delights for the large crowds already assembling4 ,in addition to the tournaments-at-arms that so delighted the king1 there was to be a mock battle with a besieged city1 and for this ,leonardo had had constructed imposing castle walls of wood with a backdrop of a city's spires and towers4 ,the party lasted for weeks1 and the climax was performed on the lawns of ,leonardo's house where a great ballroom had been set up4 ,here he repeated an earlier success1 the one that had so enchanted ,ludovico's guests so many years ago in the ,sforza castle at ,milan4 ,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 choir1 while the sun and moon shone in their own lights4 ,this display ended the festivities4 ,it was already late ,june and ,leonardo was anxious to return to his plans for the water route to ,italy4 ,there was the area near ,sologne which1 when flooded1 would make the surrounding countryside a marshland4 ,this would have to be drained by the same method as he had planned for the ,piombino and the ,pontine marshes4 ,francis ,i was interested1 too1 in the improvements ,leonardo had suggested for his own castle1 and he would have to talk with the castle superintendent about them4 ,as always1 there seemed to be so many things to do1 to plan1 to work on4 ,then ,leonardo wrote in his notes3 8,on the #bdth of ,june1 the day of ,st4 ,john1 #aeah1 at ,amboise1 in the palace of ,cloux44440 and underneath1 8,i will continue--0 8,i will continue--0 ,it was almost a note of defiance against the obstacles of advancing age and sickness and the interruptions of the practical world4 ,the sound of jingling spurs and bridle chains and the snorting of many horses announced another surprise visit from the young king4 ,leonardo could hear him below shouting something to ,battista1 the servant who had come to ,amboise with ,leonardo4 ,now1 as usual1 ,francis was running up the stairs with all the energy of youth shouting for 8le matre0 7the master74 ,resignedly and with patient humor1 ,leonardo stepped out to greet the king4 ,the gold chains around ,francis' thick neck and over his broad chest glinted in the semi-light of the hall1 and he was holding his plumed hat at his side and mopping his forehead with a dainty embroidered handkerchief4 8,master ,leonardo6 ,we are going on a tour of the river and ,i want you to look at the place that ,i told you about4 ,where ,i want to put that bridge4 ,you remember80 8,sire1 give me but a moment to gather some material together40 ,a chest was made ready and soon ,leonardo was at the door1 calling to ,francesco and ,battista to help him into the saddle of his horse1 while the king's servants hoisted the chest onto one of the carts already piled high with tents and provisions4 ,when ,francis was restless--which was often--a 8tour0 could mean many hours or many days of travel4 ,wagons were always kept ready with all the equipment for a long journey and ,leonardo1 himself1 had learned to accept these sudden whims and kept chests of his own ready for any such trip4 ,now1 as always1 the king kept his horse reined back out of regard for this tall1 stooped man with the long beard and simple clothes4 ,yet when ,leonardo returned from this 8tour0 he realized that he could no longer make such trips4 ,the hardships of sleeping in tents1 riding over the hot roads1 and the necessary work involved in surveying the possible sites for a bridge had left him almost exhausted4 ,he had made one suggestion1 however1 and that was to build houses that could be carried and then assembled with a few wooden locking devices1 then just as quickly taken down and moved to the next place4 ,they could also be left standing where the country people could use them while the court was away4 ,indeed1 such structures would seem to be the ancestors of our own prefabricated houses4 ,the winter of #aeai was a bitter one4 ,when the cold fog spread over the valley shrouding the bare trees it chilled the big1 white-washed rooms of ,cloux4 ,the wind blew down from the north sending blasts down the chimneys and scattering ashes and sparks4 ,leonardo1 huddled against the huge fireplace with its roof projecting into the room1 pulled his black cloak lined in soft leather around him and reminded himself to include it in his will for ,mathurine1 the faithful domestic who cooked for him and took care of his house4 ,the aged ,leonardo1 who had observed and analyzed so much of man and nature1 knew now that his own days were numbered4 ,when the first1 pale sunlight of ,march shone through the small leaded-glass windows of his house1 he applied to the king for permission to make out his own will4 ,french law demanded that the property of any foreigner dying in ,france went to the ,crown4 ,the permission was granted1 and on ,april #bc1 #aeai1 ,guillaume ,boureau1 the ,royal ,notary of ,amboise was summoned with witnesses4 ,to his half-brothers in ,florence ,leonardo left his property at ,fiesole and four hundred ducats4 ,to his faithful friend and companion1 ,francesco de' ,melzi1 nobleman of ,milan1 ,leonardo willed his notes1 drawings1 and paintings4 ,battista was given the income that ,louis ,,xii had granted ,leonardo from the tolls of the canal at ,san ,cristoforo near ,milan4 ,mathurine was granted the 8good black cloth1 trimmed with leather0 and two ducats4 ,moreover1 ,leonardo outlined in detail the plans for his own funeral1 right down to the use of ten pounds of candles4 ,too weak now to stand any more1 ,leonardo was confined to his big four-poster bed with the canopy4 ,from it he could see the tracery of the ,chapel of ,saint-,hubert against the pale1 foreign sky through the little window in the corner4 ,the vicar of the church of ,saint-,denis was called1 with two priests and two ,franciscan friars1 and ,leonardo received the last sacraments at his bedside4 ,an entry in his notes reads1 8,while ,i thought ,i was learning to live1 ,i have been learning how to die40 ,but death was not easy for him4 ,with tears rolling down his sunken cheeks for 8his wasted life10 he died on ,may #b1 #aeai--;fighting even this final interruption to all his work4 ,king ,francis ,i1 who was at ,st4 ,germain-en-,laye with his court1 wept when the news was brought to him4 ,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 death4 ,he wrote1 in part1 8,he was to me the best of fathers1 and it is impossible for me to express the grief that his death has caused me4 ,until the day when my body is laid under the ground1 ,i shall experience perpetual sorrow1 and not without reason1 for he daily showed me the most devoted and warmest affection40 ,and in a closing paragraph ,francesco added these words3 8,his loss is a grief to everyone1 for it is not in the power of nature to reproduce another such man40 #ad ,mankind's ,debt to ,leonardo ,when ,leonardo died his notebooks began their separate journeys into obscurity4 ,they traveled to different lands and became parts of widely disparate collections4 ,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 realized4 ,as the manuscripts and drawings were brought to light1 translated and published1 the extraordinary scope of ,leonardo's scientific explorations was revealed4 ,mathematician1 anatomist1 botanist1 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 study4 ,because of the universality of ,leonardo's scientific thought he has been frequently mentioned as the forerunner of such men as ,galileo ,galilei1 ,sir ,isaac ,newton1 ,james ,watt1 ,francis ,bacon and ,william ,harvey4 ,although ,leonardo cannot be credited with the actual discoveries that these men made1 his methods of investigation pointed the way down the paths that they would follow4 ,the key to ,leonardo's methods lies in a quotation from his notes on vision4 ,he wrote of vision as saper vedere--8to know how to see0--and he referred to the eye as 8the window of the soul40 ,again and again1 he stressed the importance of observation and personal experience4 ,although he himself was well read1 he emphasized that 8science comes by observation not by authority40 ,his supreme talent for drawing underlines his credo and is inseparable from his science4 ,what he saw in the natural world about him needed investigating4 ,the results of these investigations were transformed into drawings as the most certain method for passing this knowledge along to others4 ,the best example of this attitude is represented by his anatomical studies4 ,to merely draw the living figure in front of him was not sufficient--it was imperative to know what he was drawing4 ,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 understand4 ,what ,walter ,pater wrote of the ,renaissance--8in many things great rather by what it designed or aspired to than by what it actually achieved0--could be a summation of ,leonardo's own lifetime of effort in science4 ,he labored to bring mankind from the morass of medieval superstitions onto the firm ground of natural facts4 ,with an insatiable curiosity ,leonardo attempted the impossible task of encompassing all knowledge4 ,thus he established his right to immortality--for it was an attempt that shone like a beacon in a world dark with ignorance4 ,significant ,dates in ,leonardo's ,life #adeb ,april #ae4 ,birth of ,leonardo4 #adfg ,commences apprenticeship with ,verrochio in ,florence4 #adgh ,commissioned for altarpiece in the ,palace of the ,signoria4 #adha ,commissioned to paint an altarpiece for ,convent of ,san ,donato4 #adhb-hc787 ,leonardo leaves ,florence for the court of ,ludovico ,sforza in ,milan4 #adhc ,begins equestrian monument of ,francesco ,sforza for ,ludovico4 #adhd-hf ,plague in ,milan4 #adij ,april #bc4 ,recommences equestrian monument and starts book on light and shade4 #adif ,meets with ,fra ,luca ,pacioli1 professor of mathematics4 #adih ,the ,last ,supper completed4 #adii ,apr4 ,land awarded to ,leonardo near ,porta ,vercellina4 ,oct4 ,french occupy ,milan4 ,dec4 ,leonardo leaves ,milan with ,pacioli4 #aejj ,leonardo arrives in ,mantua4 ,travels to ,venice and returns to ,florence4 #aejb ,in the service of ,cesare ,borgia4 #aejc ,returns to ,florence1 commences work on a canal to sea4 #aejd ,begins the painting of battle of ,anghiari4 ,father dies4 ,attempt at flight 7874 #aejf ,may4 ,leaves ,florence for ,milan at summons of ,charles d',amboise1 ,french military governor4 #aejg ,sept4 ,goes to 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