In existographies, Leonardo da Vinci (1452-1519) (IQ:200|#6) (Cattell 1000:86) [RGM:1|1,500+] (Murray 4000:3|T / 4|WA) (Gottlieb 1000:9) [GEE] [LPKE] [uberman] (RE:67) (RMS:13) (EP:4) [CR:194] was an Italian artist, technologist, general polymath, universal genius, physicist, lay astronomer, and general philosopher, noted for his 1487 Vitruvian man, a geometrical model of the ideal human; for his 1494 classification of perpetual motion as impossible, based on the principle that “for every action there is an equal and opposite reaction”, otherwise known as Newton’s third law of motion; for his discarding of Galen’s innate heat (or animal heat) model of the heart; for his rejection of Biblical flood myth (see: Noah’s flood); for his view that an animal was a machine functioning according to the laws of mathematics; for his views on liberty and freedom vs tyranny; among other subjects of interest.

Vacuum
Da Vinci read all of Hero's work, who believed in vacuums, or at least "partial vacuums"; the following evidences this:

“Leonardo’s comparison of the elements is made explicit in the text where he mentions Heron of Alexandria’s steam-driven rotating ball, the Eolipile, as a demonstration of applied pressure created by the heat.”
— Michael Desmond (2000), Leonardo da Vinci: the Codex Leicester: Notebook of a Genius (pg. 116)

The following are statements by da Vinci on vacuums:

“When air [steam] is condensed into rain it will produce a vacuum, if the rest of the air does not prevent this by filling its place, as it does with a violent rush; and this is the wind which rises in the summer time, accompanied by heavy rain.”
— Leonardo da Vinci (1505), “Of Rainbows and Rain” (#480); MS E (back cover); Reti (1969) translation [21]

“The motion of the air is seen by the motion of the dust thrown up by the horse’s running and this motion is as swift in again filling up the ‘vacuum’ left in the air which enclosed the horse, as he is rapid in passing away the air.”
— Leonardo da Vinci (c.1505), The Literary Works (pg. 304)

“And if you want to convince yourself that water is not drawn up by fire, make a hole in the vessel m at point p, and you will see that the water will not leave its place.”
— Leonardo da Vinci (c.1505), Codex Leicester (Ѻ)

On this last quote, some have commented:

“Despite this deviation, he accurately describes that a ‘vacuum’ effect, not heat, draws the water up. He applies the specific result of the experiment to the real world, arguing that in an open system, with the necessary hole on the side of the mountain as an outlet for water, the application of heat from above would not draw water up but air in.”
— Author (1996), Codex Leicester: a Masterpiece of Science (pg. 56); cited by Michael Desmond (2000) in: Leonardo da Vinci: the Codex Leicester: Notebook of a Genius (pg. 44)

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Life
The following are quotes on da Vinci’s views about life:

“Motion is the cause of all life.”
— Leonardo da Vinci (c.1500), “Philosophical Maxim” (#1139) [20]

“Where there is life there is heat, and where vital heat is, there is movement of vapor.”
— Leonardo da Vinci (c.1500), “On the Nature of Water” (#941) [20]

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Steam | Volume change experiments
In c.1505, da Vinci conducted an experiment to determine the amount of volume increase when water turns to vapor; the following, supposedly, is a sketch of the device he used to solve this problem: [19]

While difficult to say just what this device is; the following seem to pointing to what this is:

“In 1504, da Vinci sketched a machine using steam, and this survives in his Codex Leicester (later renamed the Codex Hammer and now owned by Bill Gates). His design involved steam from a metal receptacle to power a pulley, but there is no indication whether or not he put this idea into practice, or even manufactured the machines that he drew.”
— Kenneth Henderson (2014), Encyclopedia of the Industrial Revolution in World History, Volume Three (pg. 903)

“To our greatest surprise, all the famous ‘theorems’ of Salomon de Caus, which made him one of the founding fathers of the conquest of steam power, had been clearly enunciated by Leonardo, as shown in my cited publication. Leonardo da Vinci attempted to determine the volume of steam obtainable by evaporating a given amount of water, long before Della Porta (1606), as can be seen in the familiar folio 10r of the Codex Leicester. Less known in the same Codex (fol. 15r) is Leonardo's description of other analogous experiments, revealing an amazing knowledge of the relation existing between volume, temperature, and pressure of vapors and gases. His approximate estimation of the quantity of steam evolved by the evaporation of an ounce of water points to the ratio 1:1,500. J.B. Besson, in his 1569 L’ Art et la Science de Trouver les Eaux, still believed that the proportion was 1:10, a ratio raised to 1:255 in the famous experiments of Jean Rey. It was not until 1683 that a better estimate 1:2,000 was made by Samuel Moreland, the correct figure being around 1:1,700.”
— Ladislao Reti (1969), “Leonardo da Vinci the Technologist: the Problem of Prime Movers” (pg. #)

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Automatons
In c.1500, da Vinci, in his notebooks, according to Graham Short (2004), was aware of the metal tree with singing birds automaton, made by Guillaume Boucher (1346), for one of the gardens of Genghis Khan or his grandson (Ѻ); and in his 1502 to 1503 draft notes for his plans for a garden, likely while in service of Cesare Borgia, he wrote that he know how to make all manner of mills for making music and how to create the means for producing the songs of birds. [18] This indicates that da Vinci had read Hero’s Pneumatics (50AD).

Love
In c.1490, da Vinci made the following pictograph (Ѻ), drawn in the margins of a draft architectural plan (Ѻ), on a question of love (top quote), below which he supplies the answer (bottom quote); read right to left:

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Heat engine

See main: Da Vinci engine

In 1508, da Vinci, in his folio 16v of MS F, sketched a heat engine, shown below:

described as follows:

“A mechanism to lift heavy weights. To lift a heavy weight with fire, like a cupping glass. And the vessel should be one braccio [about 2 feet] wide and ten long, and should be strong. It should be lit from below like a bombard (Ѻ) and the touchhole rapidly and immediately closed on top. The bottom, that has a very strong leather, like a bellow, will rise and this is the way to lift any heavy weight.”
— Leonardo da Vinci (1508), “note on device to lift heavy weight with fire”, Folio 16v of MS F [17]

This, supposedly, anticipated the later gunpowder engines of Christiaan Huygens, Jean Hautefeuille, and Denis Papin; one comment on this is as follows:

“The only detail that differentiates Leonardo’s machine from those of Huygens and Papin is the system adopted for raising the weight sustained by the piston. Huygens and Papin use a pulley and rope transmission (the same that Leonardo adopted in his experiments with steam), while Leonardo preferred to attach a rod to the bottom of the piston.”
— Ladislao Reti (1969), “Leonardo da Vinci the Technologist: the Problem of Prime Movers” [17]

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Soul
In c.1500, Da Vinci, in his anatomical notes on child birth, specifically “Quaderni d’ Anatomia III, 3 and 8 verso”, stated the following: [14]

“I reveal to me the origin of their second – first or perhaps second – cause of existence. Though these figures will be shown the cause of many dangers of ulcers and diseases. Division of the spiritual from the material parts. And how the child breathes and how it is nourished through the umbilical cord; and why one soul governs two bodies, as when one sees that the mother desires a certain food and the child bears the mark of it. And why the child [born] at eight months does not live. Here Avicenna contends that the soul gives birth to the body and every member, but he is in error. In the case of this child the heart does not beat and it does not breath because it lies continually in water. And if it were to breathe it would be drowned, and breathing is not necessary to it because it receives life and is nourished from the life and food of the mother. And this food nourished such creature in just the same way as it does the other parts of the mother, namely the hands, feet and other members. And a single soul governs these two bodies, and the desires and fears and pains are common to this creature as to all the other animated members. And from this it proceeds that a thing desired by the mother is often found engraved upon those parts of the child which the mother keeps in herself at the time of such desire; and a sudden fear kills both mother and child. We conclude therefore that a single soul governs the bodies and nourishes the two [bodies].”

At another time, in his physiology notes, he says the following:

“The soul seems to reside in the judgment, and the judgment would seem to be seated in that part where all the senses meet; and this is called the ‘common sense’ and is not all-pervading throughout the body as many have thought. Rather it is entirely in one part. Because, if it were all-pervading and the same in every part, there would have been no need to make the instruments of the senses meet in one center and in one single spot; on the contrary it would have sufficed that the eye should fulfil the function of its sensation on its surface only and not transmit the image of the things seen, to the sense, by means of the optic nerves, so that the soul—for the reason given above—may perceive it in the surface of the eye. In the same way as to the sense of hearing , it would have sufficed if the voice had merely sounded in the porous cavity of the indurated portion of the temporal bone which lies within the ear, without making any farther transit from this bone to the common sense, where the voice confers with and discourses to the common judgment. The sense of smell, again, is compelled by necessity to refer itself to that same judgment. Feeling passes through the perforated cords and is conveyed to this common sense. These cords diverge with infinite ramifications into the skin which encloses the members of the body and the viscera. The perforated cords convey volition and sensation to the subordinate limbs. These cords and the nerves direct the motions of the muscles and sinews, between which they are placed; these obey, and this obedience takes effect by reducing their thickness; for in swelling, their length is reduced, and the nerves shrink which are interwoven among the particles of the limbs; being extended to the tips of the fingers, hey transmit to the sense the object which they touch. The nerves with their muscles obey the tendons as soldiers obey the officers, and the tendons obey the common [central] sense as the officers obey the general. Thus, the joint of the bones obeys the never, and the never the muscle, and the muscle the tendon and the tendon the common sense. And the common sense is the seat of the soul, and memory is its ammunition, and the impressiblity is its referendary since the sense waits on the soul and not the soul on the sense. And where the sense that ministers to the soul is not at the service of the soul, all the functions of that sense are also wanting in that man’s life, as it is seen in those born mute and blind.”
— Leonardo da Vinci (c.1500), “How the Five Senses are the Ministers of the Soul” (#838) [20]

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Other
Da Vinci, among other things, as summarized by Leonard Shlain, was not only opinionated on the blue sky problem, but had experimentally deduced a wave theory of light; the phenomenon of wave intersection; along with a semi-conception of a heliocentric cosmology, as evidenced by statements such as: [11]

“The sun does not move.”

“The earth is but a speck in the universe.”

He also had the invention of the telescope in mind, in his mental note jotting “make glasses to see the moon enlarged”. He also invented the first contact lens, specifically by putting a man's head in a round fish bowl, filled with water, and therein noting that the man was able to see better.


A 2013 art piece (Ѻ) shown Goethe’s Elective Affinities in upside down mirror writing, as used by Da Vinci; possibly symbolic of multiple layers of secret coding, messages, and meaning Goethe claimed to have hidden in his novel.

Elective Affinities (upside down mirror writing) (2013)

A 2013 art piece (Ѻ) shown Goethe’s Elective Affinities in upside down mirror writing, as used by Da Vinci; possibly symbolic of multiple layers of secret coding, messages, and meaning Goethe claimed to have hidden in his novel.

Physics | Laws of motion
In 1490, Da Vinci, in his notebooks, moved from simply describing inventions to a more intense search for underlying principles, the laws of motion, in particular. In respect to what Newton would later categorized, in 1687, as the first law of motion, Da Vinci wrote: [11]

“Nothing whatever can be moved by itself, but its motion is effected through another. There is no other force.”

“All movement tends to maintenance, or rather that all moved bodies continue to move along as the impression of the force of their motors (original impulse) remains in them.”

In 1494, Da Vinci, in his notebooks (e.g. Codex Arundel, f. 44v), penned next to his designs (shown below), penned something about how he arrived at conclusion of the impossibility of perpetual motion, supposedly, foreshadowing Newton's third law in some way. [12] The following statement, by Da Vinci, according to Leonard Shlain, is said to express the idea or essential principle behind the third law: [11]

“See how the wings, striking the air, sustain the heavy eagle in the thin air on high. As much force is exerted by the object against the air as the air against the object.”

The following is another quote on the topic of force:

“Forces arise from the dearth or abundance; it is the child of physical motion, and the grand-child of spiritual motion, and the mother and origin of gravity. Gravity is limited to the elements of water and earth; but this force is unlimited, and by it infinite worlds might be moved if instruments could be made by which the force could be generated. Force, with physical motion, and gravity, with resistance are the four external powers on which all actions of mortals depend. Force has its origin in spiritual motion; and this motion, flowing through the limbs of sentient animals, enlarges their muscles. Being enlarged by this current the muscles are shrunk I length and contract the tendons which are connected with them, and this is the cause of the force of the limbs in man. The quality and quantity of the force of a man are able to give birth to other forces, which will be proportionally greater as the motions produced by them last longer.”
— Leonardo da Vinci (c.1500), “Earth as a Planet” (#859) [20]

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Associations
In 1500, Da Vinci, then forty-eight, engaged in competition with Michelangelo, then twenty-five, who four years early had just finished his statue of David, and also began to find competition with Raphael, then aged 17. Michelangelo, supposedly, intensely disliked Da Vinci, being that Da Vinci derided sculpting as a lesser art.

In 1502, Da Vinci met and formed a lasting relationship with Niccolo Machiavelli. [11]

Collected works
In 1519, at the reaction end of Leonardo da Vinci, his manuscripts passed to Francisco Melzi, from which the first two main synopsis publications of which were done by Gerolamo Cardano. [16]

Conservative estimates indicate that da Vinci archives, housed around the world, hold in excess of 4,000 pieces of papers, many loosely collected into "notebooks" or "manuscripts". [14]

Da Vinci, according to Leonard Shlain (2009), penned over 5,000-pages of writing in the form of unpublished manuscripts, mostly written in Italian (though he did attempt to learn Latin in his 40s); never once actually publishing anything; the only cohesive "book" he attempted to assemble was his Treatise on Painting. [11] More robust estimate, according to the British Library, indicates that Da Vinci's surviving manuscripts consist of some 7,000 pages of notes and drawings, bound and unbound: about half of what is believed to have existed at the time of his death (reaction end); they are the most important sources for understanding Leonardo's work as a natural philosopher, engineer, and (in addition to his finished paintings), an artist. [13]

Steam engines
Da Vinci drew out a design for a steam driven cannon. [6] Specifically, in the late 15th century, he designed a steam-powered cannon called the Architonnere which works by the sudden influx of hot water into a sealed red hot cannon. [7] A description of the design is found in the papers of da Vinci, although he attributes its invention to Archimedes in the 3rd century BC. [8]

Perpetual motion
At some point da Vinci investigated perpetual motion devices; the following are some of his sketches and notes, text written in his characteristic personal note coded mirror writing (Ѻ) format, shown adjacent, next to which he, supposedly, wrote “for every action there is an opposite and equal reaction”, implying something to the effect of the conclusion that the machines will not work, which of course is the famous third law of motion, of the laws of motion, formulated by Isaac Newton two centuries later. (Ѻ)


Some of Da Vinci's drawings and notes on perpetual motion, in which he wrote “for every action there is an opposite and equal reaction”, implying something to the effect of the conclusion that the machines will not work, which of course is the famous third law of motion, of the laws of motion, formulated by Isaac Newton two centuries later. [12]

Leonardo-da-vinci-perpetual-motion-machines

Some of Da Vinci's drawings and notes on perpetual motion, in which he wrote “for every action there is an opposite and equal reaction”, implying something to the effect of the conclusion that the machines will not work, which of course is the famous third law of motion, of the laws of motion, formulated by Isaac Newton two centuries later. [12]

“In whatever system where the weight attached to the wheel should be the cause of motion of the wheel, without any doubt the center of the gravity of the weight will stop beneath the center of its axle. No instrument devised by human ingenuity, which turns with its wheel, can remedy this effect. Oh, speculators about perpetual motion, how many vain chimeras have you created in the like quest. Go and take you place with the seekers after gold.”
— Leonardo da Vinci (1494) [10]

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Animal machine
The following are da Vinci's views on what a bird is:

“A bird is a machine functioning in accordance with the laws of mathematics, an instrument that man can reproduce with all its motions.”
— Leonardo da Vinci (c.1500), Machine for Flying [9]

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Animal heat
Da Vinci seems to have been the first of note to discard the innate heat or animal heat model of the heart as had been espoused previously for centuries by Galen back to pre-Hippocratic times along lines that heat was a kind of spiritual energy originating in the left ventricle. Unsatisfied with this view, Da Vinci viewed heat as existing but asserted that it is due to the friction of the blood swirling through the organ’s valves and chambers, in what might be one of the first precursors to what would later become the mechanical theory of heat. In support of his view, Da Vinci pointed out that the heart beats faster when a patient has a fever. [4]

Da Vinci is said to have recognized, firstly, that fire consumed air (although this may be contentious mis-attribution) and, secondly, that animals could not live in the variety of air that could not support the flame. [5]

Religion
Da Vinci, supposedly, rejected the notion that the Biblical flood was responsible for depositing fossils many miles from their origin and deduced the existence of very long spans of geological time. (Ѻ)


Left: Original circa 1487 drawing of the Vitruvian man by Da Vinci, with theoretical description of man as being a tiny geometrical universe. Right: 2008 depiction of Da Vinci's Vitruvian man defined as a 26-element molecule as shown on the cover of the book The Human Molecule by American chemical engineer Libb Thims. [2] A similar 2010 cover design for the book retitled as Molecules Humans, inspired by Thims' design, was done by John Hodgson. [3]

Left: Original circa 1487 drawing of the Vitruvian man by Da Vinci, with theoretical description of man as being a tiny geometrical universe. Right: 2008 depiction of Da Vinci's Vitruvian man defined as a 26-element molecule as shown on the cover of the book The Human Molecule by American chemical engineer Libb Thims. [2] A similar 2010 cover design for the book retitled as Molecules Humans, inspired by Thims' design, was done by John Hodgson. [3]

Vitruvian man Other

See main: Human molecule

In 1487, da Vinci penned his now-iconic so-called Vitruvian man, shown adjacent, an ideal human conceived modeled on a geometrical theory of universal structure. [1]

The artwork and theory behind the concept of a Vitruvian man was discussed in the opening chapter to American chemical engineer Libb Thims' 2008 book The Human Molecule, shown adjacent; a cover-design which inspired the second edition cover-redesigned printing of American writer John Hodgson’s 2010 book Molecules Humans.

Contact lens
In 1508, Da Vinci invented the first conceptual model for the contact lens, firstly by doing an experiment in which he filled a bowl with water, then placed a man’s face into it. It is said that for the first time the individual was able to see clearly. Secondly, he made a contact lens with a funnel on one side so that water could be poured into it. Ideas for which he made diagrams of. (Ѻ)

Family
Leonardo was born on 15 Apr 1452 at the ‘third hour of the night’ in the Tuscan hill town of Vinci, in the lower valley of the Arno River in the territory of Florence. He was the illegitimate son of Messer Piero Fruosino di Antonio da Vinci, a Florentine notary, and Caterina, a peasant who may have been a slave from the Middle East. Leonardo had no surname in the modern sense, ‘da Vinci’ simply meaning ‘of Vinci’: his full birth name was "Leonardo di ser Piero da Vinci", meaning ‘Leonardo, son of (Mes)ser Piero from Vinci’. Little is known about Leonardo's early life. He spent his first five years in the hamlet of Anchiano, then lived in the household of his father, grandparents and uncle, Francesco, in the small town of Vinci. His father had married a sixteen-year-old girl named Albiera, who loved Leonardo but died young. (Ѻ) When his father died (de-existed), Leonardo wrote the following:

“On Wednesday at the 7th hour Se Piero da Vinci died, on the 9th day of July 1504.”
— Leonardo da Vinci (1504), note on the passing of his father

His mother Caterina had died (de-existed) several years previous; her passing going unremarked by Leonardo. Da Vinci, at some point, had learned that his father, in 1492, had made a will that left nothing for him, but instead left all his money and possessions to his eleven legitimate children. When Leonardo visited Francesco, his uncle, in Aug 1504, he found that Francesco had changed his will, leaving all his money to Leonardo, and none to the eleven legitimate children. (Ѻ)

Education

The following is a quote on the early education of da Vinci:

“His father, a well-to-do notary of Florence, gave him his name and his initial education in art under Andrea Verrochio. The youth was soon better than his teacher. His left-handedness, so complete that he wrote backwards, produced the mirror writing which is deplored today as an obstacle to the intellectual progress of children. It interfered not at all with the effectiveness of Leonardo; in fact. it may have helped. Sketches along the margins of his writing indicate that his hand was free to do as he wished while his mind worked on something else.”
— Richard Kirby (1956), History of Engineering (pg. 124)

Quotes | On
The following are quotes on da Vinci:

“Leonardo deserves fame in the profession rather less as practicing engineer than as prophet of engineering's future. Besides his machine guns, breech-loading cannon, tanks, a submarine, and a flying machine, Leonardo's sketches included lathes, pumps, cranes, jacks, water wheels, a canal lock, drawbridges, wheelbarrows, a diver's helmet with air hose, roller bearings, a self-propelled carriage, a double-decked city street, sprocket chains, an automatic printing press, a universal joint, a helicopter, and a wooden truss bridge. There were a great many more devices as varied and ingenious. His ideas are recorded on more than five thousand sheets of drawings and notes. But these were scattered over Europe in private collections and libraries beyond the reach of practicing engineers and were not published for centuries after his death. In recent years efforts have been made to gather and publish them.”
— Richard Kirby (1956), History of Engineering (pgs. 124-25)

“Da Vinci wrote 5,000 pages on mechanics, flight, and machines.”
— William Leith (1966), Resources for Man (pg. 140)

“I'm really surprised! From what I know of the three personalities. I do not understand how you can compare Leonardo da Vinci with Goethe or Einstein. Da Vinci had an IQ of 260, he is far from the other two.”
— Cecilia Araugo (2017), “Email to Libb Thims”, Apr 19.

Quotes | By
The following are noted da Vinci quotes:

“The desire to know is natural to good men.”
— Leonardo da Vinci (c.1490) [11]

“It is a good plan every now and then to go away and have a little relaxation; for then when you come back to the work your judgment will be surer, since to remain constantly at work will cause you to lose the power of judgment.”
— Leonardo da Vinci (c.1490), “On Judging Your Own Picture”, Codex Ashburnham, Manuscript 2038 [14]

“It seems to me that those sciences which are not born of experience, the mother of all certainty, and which do not end in known experience—that is to say, those sciences whose origin or process or end does not pass through any one of the five senses—are vain and full of error.”
— Leonardo da Vinci (c.1500), A Treatise on Painting (Trattato della Pittura) (pg. 33); cited by Lawrence Henderson (1938) in “Sociology 23” (pg. 78)

“Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory.”

— Leonardo da Vinci (c.1500)

“No human investigation can be called real science if it cannot be demonstrated mathematically.”
— Leonardo da Vinci (c.1500)

“The noblest pleasure is the joy of understanding.”

— Leonardo da Vinci (c.1500) [14]

“When besieged by ambitious tyrants I find a means of offense and defense in order to preserve the chief gift of nature, which is liberty. Death rather than loss of liberty. The goldfish bring spurge [a poisonous plant] to its young when they are imprisoned in a cage. It is better to die than to lose one’s freedom.”
— Leonardo da Vinci (c.1500) [11]

“Astrology is that deceptive opinion by means of which a living is made from fools.”
— Leonardo da Vinci (1490) [11]

“Nothing strengthens authority so much as silence.”
— Leonardo da Vinci (c.1500) (Ѻ)

“The man who blames the supreme certainty of mathematics, feeds on confusion, and can never silence the contradictions of sophisticated sciences, which lead to an eternal quackery.”
— Leonardo da Vinci (c.1500), Literary Works, Volume Two [15]

References
1. Vitruvian man – Wikipedia.
2. Thims, Libb. (2008). The Human Molecule (issuu) (preview) (Google Books) (docstoc). LuLu.
3. (a) Hodgson, John. (2002). Little Fun Book of Molecules/Humans. 1st Books.
(b) Hodgson, John. (2010). molecules humans. Lulu.com.
4. Nuland, Sherwin B. (2005). Leonardo Da Vinci (pg. #). Penguin.
5. Hemmeter, John C. (1918). “Lavoisier and the History of the Physiology of Respiration and Metabolism: Contemporary Views of the Life Processes”, Bulletin of the Johns Hopkins Hospital (pg. 262), 29: 254-64, Nov.
6. Murrell, John. (date). “A Very Brief History of Thermodynamics”, Sussex University.
7. Thurston, Robert Henry (1996). A History of the Growth of the Steam-Engine (pg. 12). Elibron.
8. Architonnerre – Wikipedia.
9. Savoiu, Gheorghe. (2012). Econophysics: Background and Applications in Economics, Finance, and Sociophysics (pg. 19). Academic Press.
10. Astarita, Gianni. (1989). Thermodynamics: and Advanced Textbook for Chemical Engineers (pg. 19). Springer.
11. Shlain, Leonard. (2009). Leonardo’s Brain: Understanding da Vinci’s Creative Genius (manuscripts, pg. 6; spurge, pg. 9; Machiavelli, pg. 27; desire to know, pg. 75; laws of motion, pgs. 111-14; astrology, pg. 120; light waves, pgs. 118-19; sun does not move, pg. 120). Lyons Press, 2014.
12. (a) Perpetual motion machines – LeonardoDaVinciInventions.com.
(b) Blackadder, Warren. (2013). Produce Basic Engineering Detail Drawings (pg. 12). LuLu.
(c) Leonardo da Vinci’s Notebooks (overview) – British Library.
(d) Insights (Leonardo’s Notebooks) – British Library.
13. Leonardo da Vinci’s Notebooks (overview) – British Library.
14. Da Vinci, Leonardo. (c.1518). The Notebooks of Leonardo Da Vinci (understanding, pg. 7; works, pg. 7; relaxation, pg. 15, soul, pgs. 68-71). Arcturus, 2017.
15. (a) Da Vinci, Leonardo. (c.1500). Literary Works, Volume Two (pg. 241). Oxford University Press, 1939.
(b) Kirby, Richard; Withington, Sidney; Darling, Arthur; and Kilgour, Frederick. (1956). Engineering in History (pg. 126). Courier, 1990.
16. Usher, Abbott P. (1929). A History of Mechanical Inventions (pgs. 109-10). Courier, 2013.
17. Reti, Ladislao. (1969). “Leonardo da Vinci the Technologist: the Problem of Prime Movers”, in: Leonardo’s Legacy: and International Symposium (editor: C.D. O’Malley) §4:67-100; quotes, pgs. 95-98). University of California Press.
18. Hollister-Short, Graham. (2004). “The Formation of Knowledge Concerning Atmospheric Pressure and Steam Power in Europe from Aleotti [1589] to Papin [1690]” (pg. 146), History of Technology, Volume 25 (editor: Ian Inkster) (§10, pgs. 137-50; da Vinci, pg. 138). Bloomsbury, 2016.
19. (a) Da Vinci, Leonardo. (c.1507). “Steam Expansion Vacuum Experiment”, Codex Leicester: A Master of Science, 1510, 111, folio 10r.
(b) Cort, Johns. (2019). The Lost Industrial Revolution: Lost in Antiquity (steam expansion, pg. #). Publisher.
20. Da Vinci, Leonardo. (1519). The Literary Works of Leonardo da Vinci: Compiled and Edited from the Original Manuscripts, Volume Two (editor: Jean Paul) (soul, #838, pgs. 127-28). Publisher, 1883.
21. (a) Da Vinci, Leonardo. (1519). The Literary Works of Leonardo da Vinci: Compiled and Edited from the Original Manuscripts, Volume One (editor: Jean Paul) (pg. 239-40). Publisher, 1883.
(b) Reti, Ladislao. (1969). “Leonardo da Vinci the Technologist: the Problem of Prime Movers”, in: Leonardo’s Legacy: and International Symposium (editor: C.D. O’Malley) §4:67-100; quotes, pgs. 95-98). University of California Press.

Further reading
● Da Vinci, Leonardo. (1519). The Literary Works of Leonardo da Vinci: Compiled and Edited from the Original Manuscripts, Volume One (editor: Jean Paul) (vacuum, pg. 239-40). Publisher, 1883.
● Da Vinci, Leonardo. (1519). The Literary Works of Leonardo da Vinci: Compiled and Edited from the Original Manuscripts, Volume Two (editor: Jean Paul) (soul, #838, pgs. 127-28). Publisher, 1883.

External links
● Leonardo da Vinci – Wikipedia.