flood. The time had arrived to make the first attempts at diverting the
river into its new course. Leonardo was again in the field supervising
the work. There had been much opposition to Leonardo’s canal from both
the army captains and the Signoria. It was called a whim and a crazy
idea, but Piero Soderini and Niccolò Machiavelli were stubborn in their
defense of Leonardo’s plan and they overcame all opposition to it. And
indeed, the raising of the sluice gates was successful and the Arno
actually flowed into its new bed. The tensions in the camp and in the
Council of Florence were eased. The only sad person was Leonardo, for he
had just learned of the death of his father.
Leonardo felt the loss deeply. Outwardly, however, he only acknowledged
the death of his father at a distance. Not only had Leonardo and his
father drifted apart over the years, Piero left nothing to Leonardo in
his will. His father’s other children quarreled among themselves over
what money he did leave. Leonardo’s one friend in the family was Uncle
Francesco, who was still living in Vinci. When he heard of his brother’s
will, Francesco made out a will of his own and left everything to the
nephew he loved—Leonardo.
After having successfully diverted the Arno river, it was now necessary
for Leonardo to return to the painting commissioned by the Signoria for
its council chamber. But recently, Leonardo had suffered a rebuff in
this work. Originally he had been given the whole room to do but now the
opposite wall had been assigned to another man—Michelangelo Buonarroti.
Leonardo had first met the young Michelangelo when he helped to judge
the best location for Michelangelo’s monumental statue of David. The two
men were opposites in every way. Leonardo, fifty-two years old,
carefully dressed, cool and detached, was a man whose every action was
the result of a thoughtful and analytical mind. Michelangelo, twenty-six
years old, his clothes rumpled and covered with marble dust, was
passionate and moody—an impulsive youth totally dedicated to art. They
did not like each other, and now Leonardo was forced into a rivalry for
which he had no heart.
The duel between these two giants of art aroused the whole of Florence
and there was a constant stream of people watching them at work.
Michelangelo was given a studio in the hospital of Sant’ Onofrio and
Leonardo was working in the Papal Chamber in Santa Maria Novella. Among
the many people who came to watch Leonardo was a young man of nineteen.
He was already a pupil of Perugino and the experience of meeting and
learning from Leonardo was to influence him the rest of his life. His
name was Raffaello Sanzio—one of the great Renaissance painters of Italy
and known to us by the name of Raphael.
While Leonardo worked at Santa Maria Novella he had the opportunity of
continuing his studies in anatomy. Dissections at that time were
novelties and when one was performed the doors were thrown open to the
public. Leonardo must have attended the public dissections at the Church
of Santa Croce. Now at Santa Maria Novella there was a hospital, and
here Leonardo was able to continue his own dissections without
interruption. In a cool room below the hospital where bodies were kept
Leonardo worked late into the night. By the flickering lights of candles
and in the silence of the world about him he studied, drew, and wrote in
his notes of the wonders of the human body.
[Illustration: _In a cool room below the hospital, Leonardo worked
late into the night._]
He performed autopsies on people who had died natural deaths—a special
permission granted to him by the monks of the church, and among these
autopsies are the first written reports of some of the diseases that are
the causes of death. Arteriosclerosis, or stony growths in the blood
vessels, and pulmonary tuberculosis, a nut-like growth in the lung, are
among the discoveries Leonardo made in his lonely searches, although he
did not use these medical names for them.
Above all Leonardo was attracted to the function of the muscles,
especially those in the arms and legs. So faithfully, in fact, did he
record the origin and insertion of all the various muscles that these
drawings can be used as anatomical models today. Moreover, he believed
that a good drawing was worth pages of words describing human anatomy.
The muscles were rendered as cords so as to better understand their
function. He described this function as one of pulling instead of
pushing and he noted that for every muscle there is an opposing muscle.
When one contracts the other expands. For example, when you tighten the
biceps in your arm you can feel the looseness of the triceps, the muscle
on the opposite side.
As the end of the summer of 1504 approached, Leonardo’s dream of the
canal from Florence to the sea was destroyed. The summer had been hot
and without rain. The water in the canal dried up and the Arno river
returned to its original course. All the old arguments against the plan
were revived. The Florentine army captains rebelled against the job of
defending a useless project. Again Soderini and Machiavelli intervened.
After heated debates in the Council of Eighty, which had been called
into special session, Machiavelli himself was sent out to oversee the
work. It was brought almost to completion when in late October disaster
struck. The rains that had failed to come in summer fell from the
heavens in great cloudbursts. Storm after storm swept the valleys. The
workmen left and the soldiers were recalled. The Pisan army rushed in to
fill up the diggings and one final storm washed away the dream to
nothing but eroded mounds of dirt.
Leonardo buried his disappointment in other work. When the drawing for
the Battle of Anghiari was ready for transfer to the wall of the council
chamber, he had a special scaffolding made of his own invention which
worked on the principle of a pair of scissors standing on end, with a
long platform on top. As the legs were spread the scaffolding was
lowered and when they were pinched together it was raised. The wall had
been prepared with a special mixture which he hoped would bring out the
brilliance of his tempera colors. With several assistants who had been
assigned to him by the Signoria the violence of the Battle of Anghiari
was transferred to the wall and the actual painting was begun.
During the winter months Leonardo would relax from his work on the huge
painting and his dissections to roam the country around Florence. He
visited the slaughterhouses where the animals were killed and prepared
for market. Here he was able to examine the hearts of animals just
slaughtered and to note that the heart retained its action until the
body was almost cold. He made a glass model of the aorta (the main
artery leading from the heart) of an ox with which he could experiment
on the flow of the blood. He intended to add to it a glass tube for one
of the semilunar valves of the heart. He also experimented with a frog,
dissecting its brain, heart, and entrails and noted that it ceased to
twitch only when the spinal cord was severed. In his notes, he wrote,
“The frog instantly dies when the spinal cord is pierced; and previous
to this it lived without head, without heart or any bowels or intestines
or skin; and here therefore it would seem lies the foundation of
movement and life.” He was of course searching for the reasons that
muscles moved and from where the impulses originated.
One of Leonardo’s favorite places to visit was Fiesole where his uncle
Allessandro Amadori lived. Uncle Allessandro was the brother of
Leonardo’s first stepmother and, since he had loved her so much, he
likewise felt an affection for Allessandro. At Fiesole, which rises over
Florence in a steep ascent, Leonardo could watch the birds circling in
the air below him.
On these lofty heights, he would unfold his drawings of flying machines.
Leonardo had progressed now to a point where an actual flight was all
that was left. He had designed a sort of flying boat—a shell with wings
that moved up and down and he had introduced a tail like that of a bird.
He had noted that the tail of a bird acts as a rudder, a stabilizer and
a brake when landing.
But Leonardo’s most recent design was one that was called an
_ornithopter_. It consisted of a wooden frame, two huge wings like a
bat’s, a series of ropes and pulleys and a windlass, all planned with
the lightest of materials. The flyer, lying prone in the frame, his feet
in leather stirrups connected to the wings by pulleys, would move his
feet up and down to flap the wings while, at the same time, he operated
the windlass with his arms in order to guide the machine. Soon he hoped
to build this machine and try it out.
Meanwhile, Leonardo returned to his painting in the council chamber with
impatience, for spring was approaching and the time to finally realize
his dream of flying would be at hand. Aside from an assistant who had
tested the pedals and windlass, no one knew of his plan to actually put
his machine in the air.
[Illustration: _The_ ornithopter, _one of Leonardo’s designs for a
“flying machine.” By pumping his feet in the stirrups, the flyer
could flap the device’s wings._]
Weeks passed and the painting was almost finished. The huge wall was
covered with plunging horses and embattled soldiers. The colors were
brilliant on the special mixture he had prepared for the wall—but they
were not drying as they should have. Something was wrong. To speed the
drying process, Leonardo had a special fire built in the room that
directed the heat onto the painting. Spectators were allowed to watch as
the waves of hot air rose against the wall. Then—disaster began slowly
with a small trickle of paint from the top! Before anybody could put out
the fire, the great figures and horses slowly melted down the wall in
shiny, sticky streaks of color. Leonardo fled the room in an agony of
shame.
With his own friends discouraged, the Signoria hostile, and the friends
of Michelangelo triumphant, Leonardo went back to Fiesole. He went back
with his secret dream of flight. The world would soon forget the Battle
of Anghiari—but the conquest of the air, if he could achieve it, would
live forever.
In the spring of 1506, from the slopes of Monte Cecero near Fiesole,
legend tells us that a great bird sailed into the air and disappeared.
No one knows whether Leonardo actually flew his machine or not but
Girolamo Cardano, the son of a friend of Leonardo, wrote, long after
Leonardo had died, “Leonardo da Vinci also attempted to fly, but he
failed. He was a fine painter.” Another dream had been shattered.
11
_The Return to Milan_
Leonardo felt his fifty-four years that spring day in 1506. The
bitterness of his failures and the frustration of his dreams added
considerably to the weight of his years. All morning he had wasted in
argument with Soderini and the Signoria. If it had not been for the
letter from Charles d’Amboise, Viceroy of the King of France for Milan,
he would have felt like a beggar. Charles d’Amboise had been appointed
military governor of Milan by Louis XII ever since the French had
conquered that city and captured Duke Ludovico Sforza. But the authority
of the letter had finally won a grudging consent from Soderini. Leonardo
looked about him to see if he had forgotten anything and slowly climbed
onto his horse. He nodded to Salai, his apprentice, looked back to see
if his servant had the pack-horses ready, and started down the street
leading the small procession. He was going back to Milan.
Leonardo took out the letter and reread it. The words were respectful
and admiring—and in French. They requested the presence of “Maître
Leonard de Vinci” at the court of Charles d’Amboise, for purposes of
painting and other “diverse projects” for the King of France. The letter
restored a measure of confidence to Leonardo’s self-respect. Before
Leonardo left, Soderini had made him sign a letter in which Leonardo
promised to return to Florence within three months and to leave a
deposit of one hundred and fifty florins which would be held against his
return. It was signed, notarized and dated May 30, 1506. Nevertheless,
Leonardo had decided to accept the French envoy’s offer; moreover, he
looked forward to the prospect of returning to his vineyard at Porta
Vercellina and the understanding of a sympathetic patron.
Indeed, Charles d’Amboise turned out to be more than sympathetic. He
recognized Leonardo as a great artist; but even more, he was one of the
few patrons who could appreciate the magnitude of Leonardo’s scientific
and mechanical genius. In the court of Charles, Leonardo once more
enjoyed a time of peace and an assured income. The French
Vice-Chancellor of Milan, Geffroy Carles, who was second in command, was
also a distinguished scholar and a patron of the arts and natural
sciences. With the admiration and support of these two men and
especially with the distant backing of King Louis XII of France,
Leonardo’s dismal memories of Florence began to fade.
Leonardo’s three months’ allotted absence from Florence, however, were
soon past and a letter arrived from Soderini demanding either Leonardo’s
return or a forfeiture of the one hundred and fifty florins deposit. Now
a tug-of-war developed between the Viceroy of Milan and the governor of
Florence over Leonardo. The Signoria reminded Charles that Leonardo had
his work to complete, while Charles d’Amboise and Geffroy Carles
demanded an extension of time. One month more was granted. More letters
were exchanged until the affair became so heated that the King of France
himself intervened. In January of 1507 the French King informed Soderini
and the Signoria that Leonardo was “not to move from Milan until our
arrival.” Since Florence at this time was under the protection of the
French, such final authority silenced the Signoria. Shortly afterwards
Leonardo discharged his obligation to the Signoria by relinquishing the
one hundred and fifty florins, and he at last became free from the
demands of his native city.
On May 24, 1507 King Louis XII re-entered Milan with all the splendor
and color that France and the Dukedom of Milan could confer upon their
ruler. Knights in armor and the ladies of the courts followed the king
who rode in flowing white and gold under a canopy of blue decorated with
the lilies of France.
With such pomp and display in Milan, Leonardo was soon back at his old
occupation of designing pageants and tournaments. While some of the
people from the days of the Sforzas returned, not many remembered Duke
Ludovico, who was slowly dying in a French dungeon. Among the people
that Leonardo now met, there appeared Francesco de’ Melzi, a noble from
an old Milanese family, who entered Leonardo’s life at this time as a
pupil. Soon the young man became like a son to Leonardo. Of handsome
appearance, he had the sensitivity to appreciate the essential
loneliness of Leonardo and so, almost without realizing it, he filled a
gap in Leonardo’s life that was to last until the end of his days.
Yet, as Franceso de’ Melzi opened one door of Leonardo’s life another
door closed. He received word that his beloved uncle Francesco had died
at Vinci and that he had become the heir to his uncle’s property. No
sooner had this news been delivered when Leonardo was notified that
Giuliano, a son of Piero, and now a lawyer in his own right, was
contesting the will. All the frustrations of his life in Florence now
rose to an angry pitch and he set out once again for Florence to fight
for his own rights.
Wisely, Leonardo had armed himself with letters from his new,
influential patrons and even one from King Louis himself recommending,
“... we request that you will cause this dispute to be settled in the
best and briefest delivery of justice....” In August of that same
year—1507—Charles d’Amboise added his personal letter suggesting that
the king could not spare Leonardo too long from the court at Milan.
It was with the title of Painter and Engineer to the King of France that
Leonardo rode back to Florence to await the outcome of the judges in his
case. He went to stay with a sculptor friend, Giovanni Rustici, a man of
thirty-five and also an ex-student of Verrochio. They lived in a house
lent to Rustici by a wealthy scholar and patron named Piero Martelli.
Leonardo soon found that he and Rustici had much in common. Rustici,
too, collected the odds and ends of his journeys into the country.
Flying about the house were a tame eagle and a raven, while, at dinner,
a pet porcupine begged for food. Rustici, however, was a believer in
alchemy and magic. To practice these arts the young man devoted one room
to the strange mixtures which bubbled over flames as he attempted to
change base metals into gold, or to call upon the spirits to predict the
future.
Leonardo settled into the life of the house very quickly and even helped
his friend on an important sculpture commission. This was a group
composition of St. John between the Pharisee and the Levite for over the
doors of the baptistry. He also started to gather together his scattered
notes on all the subjects that he had written about, going through them
making corrections and erasing the repetitions. Possibly Leonardo was
considering the publication of all his material for he wrote, “Begun at
Florence in the house of Piero di Braccio Martelli, on the 22nd day of
March, 1508. This will be a collection without order, made up of many
sheets which I have copied here, hoping afterwards to arrange them in
order in their proper places according to the subjects of which they
treat....” This “collection without order” of almost forty years
extended into practically all branches of human knowledge, founded on
years of observation and experiment. Indeed, it was the magnificent
effort of one extraordinary mind to push back the curtains of ignorance
in order to let the light of natural truth shine through to mankind.
In addition, Leonardo returned to his studies of anatomy and comparative
anatomy. For this latter he made many beautiful drawings of the legs of
animals as compared to those of man. With them, Leonardo tried to
indicate man’s place in the natural order of the world. He pointed out
that our physical bodies are basically the same as those of animals, and
that the muscular and organic differences are those of function only.
For example, bird and man have the same chest muscles, called the
pectoralis. But the bird, in order to fly, has developed these into
powerful instruments of motion. Man, on the other hand, has learned to
stand and move in an upright position. He has developed the muscles of
the back, called the erectores spinae, and those of the buttocks to hold
him erect. Leonardo intended to enlarge upon his studies of comparative
anatomy to include all living creatures, even the insects.
Meanwhile, the Viceroy of Milan was becoming impatient for Leonardo’s
return. The judgment against his half-brothers had been settled in
Leonardo’s favor, and he hastened back to Milan. By the summer of 1508
he was once more in the routine of the court’s activities. King Louis
had granted Leonardo a regular allowance and it was the first time he
had enjoyed such a long freedom from the concerns of earning a living.
With these steady payments Leonardo now had the leisure and support to
pursue his own multitude of interests.
As his notes began to take shape and he thought of printing them, it was
natural for the inventive Leonardo to design his own printing press. It
is one of the earliest such designs on record. Because the carrying bed
which held the type and the paper was automatically adjusted to the
handlebar, the press could be operated by one man. Besides his notes
Leonardo also considered printing a work by Roger Bacon, the thirteenth
century English scientist.
This project for printing his own books, however, was never realized by
Leonardo. Lately, he had received a commission which took him back in
memory to the days of Ludovico. The subject was Marshal Gian Giacomo
Trivulzio, a soldier-of-fortune. Originally this man was a loyal
commander of Galeazzo Sforza’s but when Ludovico came to power he had
had Trivulzio banished from Milan. Embittered, Trivulzio had become a
stubborn enemy of Ludovico from that time on, serving under any banner
that marched against the house of Sforza. A stocky, square-faced man,
his body was covered with the scars of many battles. He had been
fighting with the French ever since the time Ludovico had betrayed
Charles VIII. Trivulzio had seen the great monument that Leonardo had
modeled and, although it was riddled by French arrows and damaged by
wind and rain, the Marshal was impressed and wished for a similar
memorial to himself.
Leonardo set to work immediately. His past experience with the Sforza
monument was now to his advantage. This time there was no need for
experimenting. He knew how much material he needed and the approximate
cost of everything including the casting. He submitted an estimate of
three thousand and forty—six ducats for the completed work, one hundred
of which would go to Leonardo. The sum was acceptable to Trivulzio and
Leonardo began his preliminary studies.
As he gathered the material for this new equestrian statue, Leonardo and
the French Viceroy Charles d’Amboise became interested in the further
canalization of the plains of Lombardy. The use of canals and locks had
been in practice for roughly a hundred years and around Milan there were
already some fifty miles of canals and about twenty-five locks. Leonardo
started another survey of the area. In his imagination, he envisioned a
vast hydraulic engineering project.
On September 12, 1508 Leonardo announced in his notes the beginning of a
book on the nature of water. He had decided to separate this book from
the one on hydraulics because it was necessary to separate theory and
practice. His pages treating the science of hydraulics, or the practical
applications of water power, had reached to “forty books of benefits.”
By the spring of 1509 he had expanded his notes on the nature of water
to include the greatest wave to the smallest raindrop.
Concerning the practical applications of water power, Leonardo put forth
many designs for new locks. He introduced new methods of raising the
gates by windlasses and chains which could easily be set in motion by
one man. But most important is Leonardo’s discovery of the use of
centrifugal force for draining marshes—the ancestor of the centrifugal
pump. When you rapidly rotate a stick in a pail of water, the water
spins in a spiral rising on the sides, and, if you rotate the stick fast
enough it bares the bottom of the pail. When you remove the stick
suddenly, the water continues to whirl as it slowly subsides.
This is basically the same principle Leonardo used to raise the water
from a marsh to a level above the sea so that it could be drained away.
The centrifugal pump was also used with a hydraulic screw which
converted water power to mechanical power. The force of a stream of
water was injected into the base of a vertical cylinder. In the base of
this cylinder was a six-bladed propeller mounted on a vertical shaft.
The force of the water turned the screw and at the same time the water
was forced to rise in the cylinder to an outlet above. The turning
propeller revolved the vertical shaft. This shaft, emerging from the top
of the cylinder, turned a cogged wheel. This wheel was joined to another
cogged wheel mounted on a horizontal shaft, thus providing the
mechanical power. Not only is this the forerunner of the turbine, but
the use of the propeller, itself, for propulsion in water, was a new
idea not to be thought of again until the eighteenth century. For
certain types of hydraulic pumps he conceived of the cone-headed mitre
valve still in use today.
Leonardo, besides studying the practical applications of water power,
explored the very nature of water itself. In his proposed books on this
subject he intended to examine why clouds and fog form, why rain falls
and the raindrop itself—even how the raindrop is held together. He
understood the nature of capillary attraction, which holds the raindrop
together, and his notes show us that he was exploring the science of
hydrostatics which relates to the pressure and equilibrium of liquids in
general.