painting commissions by fixed dates, he was free to explore his other
favorite avenues of knowledge. It seemed that his ever-active mind could
never stop roaming over the whole field of scientific knowledge. He
continued with his early interests—the nature and movement of air,
astronomy and geometry. He was also still concerned with movement and
weight, for he set down in his notes, “The thing which moves will be so
much the more difficult to stop as it is of greater weight.” This is a
hint at a principle formulated by Isaac Newton almost two hundred years
later in his First Law of Motion—the law concerning inertia. For
example, the motion of an arrow shot into the air maintains itself in
flight so long as the influence of the initial force is maintained in
it.
[Illustration: _Da Vinci’s cone-headed mitre valve for use in a
hydraulic pump._]
On a note dated April 28, 1509 he wrote, “Having for a long time sought
to square the angle of two curved sides ... I have solved the
proposition at ten o’clock on the evening of Sunday.” As always,
Leonardo was deeply involved in the study of mathematics. Too deep
perhaps to recognize the new rumblings of war.
Louis XII, still pursuing his campaign in northern Italy, had again
arrived in Milan amid the salutes of the French artillery. Following his
personal banner of a gold porcupine on a white field, he had come back
prepared to do battle with the Venetians whose power, as it diminished
in the east, was extending westward into Italy. Alarmed at this Venetian
expansion, the French King had allied himself with Pope Julius II and
the powers of Europe to form the League of Cambrai to push back this
threat. Charles d’Amboise, the French Viceroy, had already taken to the
field and at the castle of Cassano, overlooking the Adda river near
Milan, he awaited the arrival of his king.
By the end of May, Leonardo was in the saddle once more. Surrounded by
the best knights of France and the nobles of Milan, he personally
accompanied the French King as military engineer to the meeting with the
Viceroy of Milan at Cassano.
During the next three months, through the battles and defeat of the
Venetians at Aquadello where sixteen thousand dead were left on the
field, and the siege of Caravaggio and the capture of Peschiera,
Leonardo served as military consultant and map maker. More than ever his
eye was attracted to the possibilities of utilizing the many rivers they
crossed both for warfare and commerce. He envisioned making the Adda
river navigable from Milan to Lake Como. During this time, he devised
not only a revolving bridge but even one of two layers in a single
span—the upper level for pedestrians and the lower one for vehicles.
By July, Leonardo had returned with the king and the French army to
Milan. Here was planned a great celebration of the French victory over
the Venetians. In front of the cathedral, to the delight of the hundreds
of spectators, Leonardo devised a mechanical lion scaring a dragon out
of an artificial lake into the beak of a cock which picked the dragon’s
eyes out. After the festivities Leonardo returned to his everyday work.
In time, he had a thriving workshop and as he became more and more
preoccupied with his scientific explorations, his art commissions were
turned over to his assistants. He did continue, however, to work on the
plans for Marshal Trivulzio’s monument and in his preparatory work for
this assignment he expanded his notes and drawings of comparative
anatomy.
This renewed interest in anatomy led him to attend a lecture in the
winter of 1509. The lecturer was Marcantonio della Torre, a young man in
his late twenties and one of the best-known anatomists of the times. He
had been a professor at the University of Padua, but this city had
fallen into the hands of the Venetians. Marcantonio was forced to flee
Padua and had settled at Pavia. The two men, when they met, recognized
in each other a devotion to science and they began a professional
collaboration that grew into a friendship. Leonardo now developed his
anatomy studies to the point where he is today recognized as the
foremost medical anatomist of the Renaissance.
Returning to his dissections, Leonardo now proceeded to explore the
heart and system of veins in the human body. His drawings of the heart
are nearly perfect. Indeed, he was probably the first to discover the
endocardium membrane that sheathes the valves and sinews of the heart.
Also, he pictured and described the moderator band, “the first cause of
the motion of the heart.” His work on this organ led him to the doorstep
of discovering the circulation of the blood—later to be carried out by
William Harvey in the seventeenth century.
Further, Leonardo was the first to accurately draw a representation of
the _foetus_, or unborn child, in the womb of its mother, writing in his
notes that, “we conclude therefore, that a single soul governs the
bodies and nourishes the two.” In addition, he drew a remarkable picture
of the female figure and for the first time accurately placed her
organic structure. In his notes, he also pointed the way to the laws
governing metabolism when he wrote, “The body of anything whatsoever
that receives nourishment continually dies and is continually
renewed....” By pouring wax into a hole in the skull he made the first
casts of the ventricles of the brain. Several hundred years were to pass
before this method was rediscovered.
As Leonardo’s work progressed, his admiration for the complexity of the
human body grew. Many times in the middle of explaining a section of
anatomy he inserted a sentence or two of wonder or praise at the
magnificent creation that is the human being. Indeed, these drawings and
notes represent the sum of many, many dissections; moreover, Leonardo
had to work under conditions that placed many obstacles in his path—the
crude lights and instruments, the difficulties of obtaining corpses and,
above all, the opposition of the superstitious and ignorant.
The following year Leonardo entered in his notes, “This winter of the
year 1510 I look to finish all this anatomy.” And yet, however sincerely
he might express such a wish, Leonardo was a person who was literally
never “finished.” The scientific and artistic tasks he had chosen for
himself were clearly beyond the limits of any one man. Besides, the
pressures of the outside world were once more threatening the peace and
quiet of his home and work.
Pope Julius II became increasingly fearful of the French victories over
the Venetians. Secretly, he concluded a peace with Venice and, allying
himself with his former enemy, he now turned against the French. When
the conflict continued, Charles d’Amboise, the patron of Leonardo, was
killed at the battle of Correggio. He was replaced by a new French
Viceroy, Gaston de Foix. Although the Pope now hired Swiss mercenaries,
this invasion from the North was defeated by the young Gaston. Not to be
outdone, the Pope then brought in Spanish troops.
In the ensuing bloody battle at Ravenna, the French completely defeated
the armies of the Pope and Spain, despite their use of battle-cars armed
with razor-sharp sickles on their wheels—strangely like the early
inventions that Leonardo designed for Lorenzo de’ Medici! Although the
French were victorious, they lost their brilliant young leader, Gaston
de Foix, and with him they lost their heart. As a result, they were soon
disorganized. The Pope’s armies renewed their attacks, and the French
began a long retreat.
Once again the plague infested Milan and Leonardo’s friend, Marcantonio
della Torre, died of it. After some futile attempts at recovery, the
French fled across the Alps and with them went Marshal Trivulzio. Milan
was left temporarily under the martial rule of the Swiss, and Leonardo
with only his few apprentices was left again without a patron.
Tired and prematurely old at sixty-one, Leonardo resignedly gathered his
possessions together once more and with Francesco de’ Melzi and four of
his loyal pupils, he turned his back on Milan for the last time. The
date was September 29, 1513. Their destination was Rome.
12
_Rome_
“Name?”
“Leonardo da Vinci.”
“Where from and where are you staying?”
“We are coming from Milan by way of Florence. I have quarters being
prepared for me at the Belvedere in the Vatican—by order of the Pope.
Now, young man, let us pass.”
The guard at the Porta del Popolo changed his manner. He dropped his
halberd and motioned to the other guards to let the riders through. He
touched his helmet roughly and with a grin he said,
“I’m sorry, Sire—but you know how it is. All these people—there’s bound
to be them that we don’t want here. Go ahead, your Excellency. Make way
there!”
With these words he laid his spear against a jostling group of
broad-hatted pilgrims blocking the entrance to the city of Rome.
Leonardo heeled his horse and with Francesco de’ Melzi at his side,
followed by his servant and students, pushed past the crowd at the gate.
To the left rose the Pincio hill with its stately pines where, in the
days of Imperial Rome, Lucullus had walked in his gardens. But Leonardo
had no time to look about. It was a damp December day, and rain
threatened from the gray skies. He was tired, and as Francesco glanced
at him he could see Leonardo pull his cape around him with a little
shiver as the chill wind stirred the long, graying hair on his
shoulders. They made their way through the crowded, noisy city. They
crossed the Tiber and rode past Castel’ Sant’ Angelo, the papal fortress
built on the tomb of Emperor Hadrian. After another inspection by the
Swiss guards in beribboned uniforms of white, green and gold under their
shining breastplates, they entered the walls of the Vatican. That
evening after he had settled himself in the Belvedere apartments and
dinner had been eaten, Leonardo, gazing into the embers of the fire,
looked back over his new stroke of fortune.
The Medicis had returned to power. Pope Julius II had died, and Giovanni
de’ Medici, son of Lorenzo, had become Pope Leo X at the age of
thirty-seven. With his election to the head of the Christian world, the
Republic of Florence became a city of the Medicis once more and Leonardo
had received an appointment in Rome. Giuliano de’ Medici, Pope Leo’s
favorite younger brother, in his new rise to power and wealth, became
Leonardo’s patron. The two must have met sometime during the Medici’s
exile. Leonardo was given the apartments in the Vatican and a salary of
thirty-three ducats (approximately eighty-five dollars) a month and a
workshop was fitted for him and his pupils. He was also assigned an
exclusive German assistant named Georg.
The Pope’s court in the Vatican was like the Medici court in the
Florence of Leonardo’s youth—multiplied by hundreds. Leo X saw himself
as the center of the artistic world, and being a man of luxurious tastes
with the wealth of the church behind him, the Vatican was soon filled
with a mixture of the wise and foolish. Pompous classic-quoters,
third-rate poets and clowns mixed with the world’s scholars and
statesmen. The two greatest artists were Bramante, the architect and
friend of Leonardo’s first years in Milan, and Bramante’s pupil Raphael,
the painter.
Bramante was busy building the new church of St. Peter’s and, as the
architect of this favorite project of the Popes, he was sole master of
the Roman art world. Raphael, as his protege, was the recipient of the
better painting commissions in Rome. The elderly Bramante and the
thirty-year-old assistant were a famous pair in the Rome of 1513.
Equally as famous, however, was Michelangelo; he was still living in
Rome, but was without patronage after Julius II’s death. Leonardo’s old
rival had scored his triumph with his extraordinary paintings in the
Sistine Chapel.
Although the young Raphael, who owed so much to the example of Leonardo,
now rode through the streets as a wealthy nobleman, Leonardo himself
received no great commissions. While Pope Leo was indulgent of his
brother’s whims he himself had no use for this tall, serious old man who
roamed the shaded walks of the Vatican poking at the strange plants in
the botanical garden or making drawings of the foreign animals in the
private zoo. In reality, Leonardo’s patron, Giuliano de’ Medici was a
weak man. He played at being a patron but, like his brother the Pope, he
lacked the force and decision of his famous father Lorenzo.
Nevertheless, he did give Leonardo one small commission for a picture.
Immediately Leonardo, excited by the exotic plants in the Vatican
gardens, commenced to experiment with them to find a resin to make a
varnish with which to cover the future painting. Pope Leo made fun of
him exclaiming, to the delight of his court, “This man will never get
anything done, he thinks of the end before the beginning.”
This ridicule by the Pope made Leonardo a joke to many in the circles of
the Vatican who were a little afraid of this strange man with the
searching eyes. Leonardo also suffered the humiliations of a man who did
not conform to the fashions of his day. His knowledge of Latin, for
example, was weak and although he could read it with the help of a
dictionary he could not speak it. And, among the people who surrounded
the Pope, Latin was the only language allowed. Prizes of great sums of
money and important positions were often granted on the strength of an
improvised speech in Latin (with many quotations from the classical
authors) or a flattering Latin verse. Faced with such setbacks and
ridicule, Leonardo—not surprisingly—began to withdraw into himself.
And yet, Leonardo refused to remain idle—he had to work. The need for
mirrors in the vast halls and rooms of the papal palace was great.
Leonardo turned his mechanical skill to redesigning and improving
methods of making them, and even inventing his own machines for the
grinding of the glass. Also, for Giuliano, who dabbled in alchemy and
magic, he made distorting mirrors and burning lenses. In addition,
Leonardo invented a machine which could be run hydraulically for
producing long strips of copper of equal width for use in soldering the
mirrors.
But, with the making of these mirrors, Leonardo began to run into
trouble with his German assistant, Georg. The boy was a loafer; he spoke
little Italian and took every opportunity to spend his days with his
countrymen in the Swiss guard. Leonardo tried to alter the situation by
suggesting that the boy have his meals with him at his worktable, thus
giving Georg a better chance to learn the language. This however did not
appeal to him. Then, because Leonardo’s inventions were so
extraordinary, he began to give away the secrets of their mechanisms to
Johannes the mirror-maker, another German, who had been replaced by
Leonardo in the favors of Giuliano. This naturally made Johannes jealous
of Leonardo. Georg gossiped, too, and told stories about the old,
eccentric man who lived like a miser in the midst of all the luxury and
who drew crazy circles on pages of paper.
These “crazy circles” were geometric exercises that had fascinated
Leonardo from the time he had wandered across Italy with Fra Luca
Pacioli. Pacioli’s book _De Divina Proportione_, containing sixty
illustrations from designs of Leonardo, had been published in Venice in
1509. Leonardo intended to entitle these geometric exercises _De Ludo
Geometrico_. In geometry a lune is a crescent-shaped figure bounded by
two intersecting arcs of circles on a plane or a sphere. Leonardo drew
pages of these lunes and then proceeded to transform their curvilinear
figures into squares of equal area. He also reviewed Archimedes’ method
of squaring a circle and developed it into a variety of ways for cubing
spheres and cylinders.
He returned as well to formulating theories of friction. He wrote in his
notes, “the tallest wheel is the easiest to pull”—for example, a big
wheel turning at the same speed as a smaller one has less friction to
overcome because it makes less revolutions. His experiments in friction
predated men like Amontons and Coulomb by two and three centuries. He
established a formula for the building arch which he described as “a
strength caused by two weaknesses”—if one half of an arch is removed,
the other half collapses. They support and give strength to each other.
In addition, Leonardo determined, before Galileo, the center of gravity
of any pyramid and of a tetrahedral, or four-sided body.
As the days went by and he waited for commissions to come, Leonardo took
to wandering about the streets of Rome. He stood in the half-buried
Forum of the Caesars surrounded by grazing sheep and grunting pigs.
Wooden shacks where crude cartwheels were made and where the marble from
the ancient temples was cut and sold, were built against the sides of
crumbling ruins. The old triumphal arches, now overgrown with creepers,
were boarded into towers and cattle were penned between the shafts of
columns that once supported the grandeur of temple roofs. Here and there
a classical scholar would be sketching or writing from the worn, Latin
inscriptions on a marble slab tilted crazily from the ground where it
had fallen hundreds of years ago. Goats wandered on the Palatine hill,
once the home of Emperors, and the great baths of the Emperor Diocletian
were now a deer park and a hunting ground for royalty.
During the course of these wanderings, Leonardo became interested in the
primitive methods of carpentry. Such things as screws, for example, were
rare. Those that were used were either made of wood or, if of metal, by
goldsmiths laboriously making each one by hand, soldering wire around a
pin and another wire into the hole to hold the screw. Sometimes they
were made by filing pieces of metal individually. All these methods were
time-consuming and costly.
Leonardo had thought of this problem before, and now he concentrated on
perfecting his ideas about it. Previously, he had thought of casting the
metal in wooden molds and then turning the metal on thread-cutters. The
designs he finally drew in careful detail, however, are essentially the
methods used today. The new machines did with a few turns of a handle
and adjustments of a few cogged wheels what it took one man many hours
to perform. He also drew designs for a mechanical plane and a machine
for drawing wire that worked by water power.
Leonardo now lived and worked in the Belvedere of the Vatican—more a man
on exhibition than an active participant in the great artistic
activities taking place around him. True, he received his thirty-three
ducats a month, but Michelangelo had been paid three thousand for his
work in the Sistine Chapel, while Raphael had earned twelve thousand for
each room he painted in the Vatican.
[Illustration: _Leonardo became interested in various methods of
carpentry._]
Thus Leonardo drifted farther and farther away from his painting. This,
in itself, caused people to talk in the papal city. For he had earned
fame as a painter, but his passion for science was regarded as strange
and whimsical. Occasionally, he did receive a small commission from the
workshop of Raphael, yet these were like the crumbs from a rich man’s
table.
Even the toys Leonardo made at this period for the amusement of his
patrons were looked upon as somewhat weird. For example, he would take
small pieces of wax and mold them into strange little animals and then
inflate them so that they floated in the air in front of a startled
guest. Once he caught a curious lizard in the garden and spent hours
putting scales all over the tiny body, attached to it a little beard and
horns, then let it out from a box at a banquet. The guests jumped back
with fear and the women became hysterical.
One of Leonardo’s jokes that has been passed down in accounts of his
life at this period must have created quite a sensation. He showed the
company the cleaned entrails of a sheep resting on the palm of his hand.
After telling them to wait and watch he took the entrails in another
room and with a bellows inflated them with warm air. As the entrails
filled with air they expanded and extended. They crept into the room
where the company waited. Slowly they grew and grew until they began to
fill the room. The guests overturned their chairs in their hurry to get
out of the way of this shapeless, translucent creature. Then Leonardo
appeared, the air-filled entrails giving way before him, and said:
“Sires, this is but an example and symbol of virtue. As you can see, the
smallest virtue is capable of the greatest growth.”
The guests laughed, but it was an uncomfortable laugh. Thus another
story was added to the legend of Leonardo as an odd old man.
Leonardo, whose work—particularly his anatomical studies—had constantly
been interrupted by the fortunes of war, had found another hospital in
Rome where he could continue these studies. This time it was his
intention to write a treatise on speech. He dissected and drew the
anatomy of the larynx (the voice box), the vocal cords and the trachea
(the air passage to the lungs), and all the muscles that control the
movements of the tongue and the lips. If you pronounce each letter of
the alphabet you will feel these muscles of the lips, especially with
the letters “o,” “p,” and “f.” Carefully he noted how the air vibrations
from the trachea form themselves into vowels and consonants, and he drew
the membrane which, when air is pressed against it, makes the sound
“aah.”
At this same time he was also busy finishing a treatise on painting
which he had begun when he was working on the “Last Supper” for Ludovico
Sforza. But it was for his knowledge of military engineering that he was
sent to the city of Parma by the Pope on September 25, 1514. Here he
stayed at the Bell Inn while examining the fortifications and other
defenses of the city.
Leonardo’s patron, Giuliano de’ Medici, had been appointed governor of
this particular area and, since Pope Leo X was fearful of two powerful
countries, France and Spain, he was preparing the papal territory
against possible invasion. Another fear of the Pope—and indeed of
everybody in Rome—was malaria, the disease carried by the mosquitoes
that bred in the Pontine marshes west and southwest of the city. At that
time, however, no one knew the cause was mosquitoes; rather, they
thought it was the bad air from the marshes.
As Leonardo had already been effective in draining the pestilential
marshes of Piombino for Cesare Borgia and, later, those around Milan for
Charles d’Amboise, he was assigned the same task for the Pontine
marshes. He surveyed the entire area to the sea and made another
extraordinary aerial type map. His recommendations included draining the
entire area, enlarging and regulating the Martino river and cutting an
extra outlet from the river Livoli to the sea. These plans were adopted
some years later and parts of the marshes were drained successfully,
yielding new land for the cultivation of crops.
By December of 1514 Leonardo had finished his treatise on speech and,
possibly in an effort to attract the attention of the Pope, he submitted
it to the Privy-Chamberlain, Battista dell’Aquila. As Pope Leo was
surrounded by an army of secretaries and assistants who passed on
everything submitted, this manuscript with its beautiful drawings was
mislaid and lost and only a few notes and sketches remain.
The continual discouragement of his life in Rome was offset by a visit
from his half-brother, Giuliano, around Christmas. Leonardo was held in
esteem by his family despite the quarrel over his father’s and his uncle
Francesco’s will, and his half-brothers were pleased to tell of their
famous relative who lived in the Belvedere as guest of the Medicis. Yet
they knew little of Leonardo’s scientific dreams and his lack of
recognition in the papal city.
Often, Leonardo’s greatest comfort was to return to his notes. The
challenge of geometry and the mysteries of the movement of air and water
kept him from brooding about his lonely life. Francesco de’ Melzi,
Leonardo’s young friend, had more and more taken over the practical
responsibilities of his everyday life. Except for his workshop, where
the troublesome Georg worked at the making of mirrors, and an occasional
small commission for a painting, Leonardo was free to study.