101 Things You Didn't Know About Da Vinci (14 page)

Architecture, for Leonardo and most Renaissance architects, was a matter of harmonious modularity. As Leonardo proved with this drawing, it was possible to view the human body the same way: a composition of anatomical building blocks comparable to those of the built world. Interestingly, it's been said that in a not-so-rare moment of artistic hubris, Leonardo may have borrowed his own self-portrait to use for the head of Vitruvius in this influential work! Doesn't it seem appropriate, though, that Leonardo himself might be both model and artist for this symbol of the Renaissance?

52
Getting physical with science

Leonardo did more than draw circles and squares! Sure, he studied anatomy, but his interest in science didn't end there. He was also a student of the physical and natural sciences. In particular, he used his methods of observation and inquiry to look at a number of problems in physics, geology, astronomy, and other fields.

In geology, Leonardo's contribution is particularly striking. While working as part of Duke Sforza's court, Leonardo devoted time to surveying various mountains and valleys, and this work served as background for military engineering projects, such as making roads and tunnels. During this period, Leonardo most likely had ample time to study the area's various rocks, and he also observed the fossils (mostly mollusk shells) present within the rocks. From his writings, we know that Leonardo understood the process of sedimentary rock formation, which occurs through sequential deposition of small layers in a watery environment. He also understood erosion, the idea that wind, rain, and rivers progressively wear away rocks. In fact, he realized that, as a result of erosion, sand and rock particles are eventually carried to the ocean to repeat the cycle.

How is it that shells could be found in rocks that currently lay atop mountains? Scientists pondered this central geological question in Leonardo's day, and Leonardo rejected the two main suggestions prevalent at that time, which held that the shells had either been carried there by the great flood mentioned in the Bible, or that they had formed there in the rocks. From his observations of nature, Leonardo knew that shells had to come from living creatures and that these living creatures would have had to move around to eat and grow—they couldn't have formed inside a rock. He also noted that the world probably wasn't ever covered by a single great flood, since the water wouldn't have had anywhere to drain. Even if a flood had taken place locally in biblical times, any shells carried up to the mountaintops would have formed a jumbled mess, not the orderly layers that Leonardo saw.

Remarkably, Leonardo's solution to this puzzle came very close to the modern understanding. He suggested that when the fossils had been living sea creatures, they had been in an ocean environment. At some later time, mountains formed, and their gradual formation lifted the ocean sediments up to the mountain peaks. In fact, we know today that this model is a pretty good approximation of what actually happened!

But Leonardo didn't have the same good luck with all of his scientific theories; some of his beliefs were just wrong. In the field of astronomy, for example, Leonardo seemed to think that the sun and moon both orbited around the earth, and that the moon reflected the light of the sun because it was covered with water. Although he tried his best and did conduct some experiments with optics and lenses, telescopes were not invented until 100 years after Leonardo's time.

According to a sketch from 1510, Leonardo did manage to calculate a way to determine the distance from the earth to the moon, and the earth to the sun. He was also apparently one of the first to realize that even when only part of the moon was lit, the dark part of the crescent moon could still be seen faintly. (This illumination comes from sunlight that bounces off the earth and is then reflected off the moon.)

Clearly, while some of Leonardo's achievements in science were noteworthy, others weren't. Looking back, you could say that Leonardo's theoretical studies were generally less important than his practical innovations. However, you can also see that his inventions allowed Leonardo to discover and pursue new theoretical lines of research. Even modern scientists often need both theories and experiments to make breakthroughs!

53
It's all in the circle game

Leonardo first became interested in geometry while he was working for Duke Sforza in the 1480s and 1490s. He first encountered mathematical constructs—geometry in particular—through his study of architecture and perspective painting. In 1496, the well-known mathematician Luca Pacioli was invited to Sforza's court, nominally to teach mathematics there, and Leonardo and Pacioli became friends in Milan, apparently spending much time together discussing the overlap between art and mathematics. During his time in Milan, Pacioli was writing a book, later published as the first of a three-volume set in 1509, called
Divina Proportione
. Leonardo was so interested in this project that he actually drew the figures for this text.

Leonardo's drawings of three-dimensional shapes called polyhedra (one example is a soccer ball) were the highlight of Pacioli's book. Leonardo came up with a new way of drawing these complicated shapes—he showed them with solid edges and hollow faces that let you see right through them to the structure on the other side. For the book, Leonardo drew about sixty pairs of illustrations. Each pair showed a different three-dimensional shape, in both a solid view and a hollow view. Some of the shapes were new—no one had figured out how to draw them before!

The method of drawing shapes was a breakthrough for the day, and it took a visual artist of Leonardo's talents to come up with it. Leonardo's obsession with geometry continued even after he finished working on Pacioli's book. If you look through his notebooks, you'll find sketches of different geometric shapes in unlikely places, for example, among studies for military fortifications and designs for a fountain.

In addition to his direct work with Pacioli, Leonardo spent some time in Milan conducting his own research into geometry based on that of Euclid and Pacioli. In particular, he was interested in trying to “square a circle,” meaning he wanted to find a way of creating a square with the same area as a particular circle, using only drawing tools such as a ruler and compass.

Beyond his theoretical work in mathematics, Leonardo was also interested in the mechanical methods of automating mathematical work, and he designed a machine that could have been one of the first calculators. A working replica was built in 1968, but whether or not this replica actually represented Leonardo's intention is another story. The sketches on which the calculating machine replica was based are unclear, and it's possible that the machine was not, in fact, a calculating machine, but a ratio machine instead.

54
Before planes, trains, and automobiles

Renaissance inventors were at a crossroads, whether they knew it or not. Europe was slowly emerging from the Dark Ages, and there had already been several significant inventions. At the same time, some of history's greatest achievements were yet to come. Leonardo, living fairly early in the Renaissance period, was on the leading edge of the era's innovation. Against what backdrop can we view his inventions?

One of the most significant inventions of the Renaissance was the mechanical timepiece. Though Casio calculator wristwatches wouldn't come along for a while yet, society was beginning to place more importance on an easy way to tell the time. Clocks were first created in the 1300s, but it was not until the 1580s that Galileo (a scientist and researcher from Florence) developed the idea for a pendulum. It wasn't until the 1600s, long after Leonardo's death, that the concept of the clock was further mechanized with the introduction of gears and screws.

Certainly, Leonardo and his contemporaries didn't have access to most of the modern conveniences we take for granted today. One of the things most noticeably lacking was electricity, which was not discovered until the seventeenth century and not widely used until the late 1800s. The first standardized fuel type was probably fish oil used by ancient Romans and those who came after them, so in the absence of electric lighting, fuel-driven lanterns would have been a possibility for Leonardo. Candles, torches, and lamps were other popular light sources during the Renaissance years.

In terms of weaponry, Leonardo had the advantage of
not
starting from scratch. Military technology, even in ancient Rome, was years ahead of the general technology available to the rest of the population. Hand-powered weapons such as spears and arrows had been around for generations, and gunpowder was in use by the middle of the eleventh century, though it probably wasn't used in Europe until the 1350s. This invention changed the course of warfare because it became nearly impossible to defend against guns with only hand-powered weapons. Leonardo's designs for cannons, for example, were a response to the new way of waging war.

Eyeglasses were another significant Medieval and Renaissance invention. By the 1300s, guilds in Venice were regulating eyeglass production, which, at the time, were probably considered a luxury item. When Johannes Gutenberg's invention of the printing press (see number 61) made reading into more of a hobby than a luxury, though, eyeglasses came into much higher demand. Everyone wanted to read, and their eyes needed to keep up with them! Readily available books were a major factor for Leonardo because he was able to read the writings of ancient masters and, in the process, create his own interpretations and additions. Plus, if books could be published easily, he could also publish his own writings. In addition to all of these other inventions, Leonardo used the growing worldwide interest in mechanics to utilize and explore water. Naturally, his concepts relied on existing research with water pumps, which were developed in the Middle Ages.

55
War games

When several Florentine forts were attacked in 1479, Leonardo became interested in ladders for scaling walls during an attack as well as methods for defending against those same efforts. Military engineering was just one of Leonardo's many interests, but as with everything else, he dove into it wholeheartedly and came up with several important designs.

Leonardo designed a number of different ladders for wall climbing. Some were stiff, solid ladders, while others were flexible and made from rope. To attach securely to the top of the wall, some of Leonardo's ladders had hooks; others had spikes on the base to keep them immobile on the ground. He also thought about flexible ladders that could hang from a wall as well as the type of chain ladder that's often used for fire escapes today. Ladders were, in a way, a symptom of the problem: war. Leonardo got to the root of the issue and also designed entire defense systems. One of his most clever ideas involved ladders lining a wall, where the tops of the ladders were all attached to a bar. Leonardo's assumption was that attackers would rush to climb the ladders in a sneak attempt to overtake the castle inside. Not so fast! Leonardo's defensive soldiers would push the bar out, and any poor, unsuspecting attackers would fall to the ground along with the row of ladders. It sounds complicated, and it was; perhaps this overdesign was one of the reasons it was never tested.

During his time with Duke Sforza, Leonardo also designed bridges for military applications. Some of these were portable; troops could carry the bridges with them and set them up quickly when needed. Others were designed to be particularly strong and resistant to fire or other means of destruction. Leonardo also considered methods to burn and destroy enemy bridges.

Leonardo's military bridges had a number of different designs. One was arched in such a way as to be particularly strong when assembled. Others used traditional pilings, or were flexible so they could swing without breaking. Leonardo also designed adjustable jacks for opposite sides of a river, to be used if the banks were different heights on each side.

Leonardo designed one particularly massive bridge during his time with Cesare Borgia. In order to connect the Golden Horn and the Bosporus, Leonardo suggested building a huge bridge across the Gulf of Istanbul. This route would have had immense strategic importance, but other engineers vetoed the plan when they saw how large the bridge would have to be. Nevertheless, modern studies show that the structure would have been possible to build with the resources of that era, and the bridge itself would have been solid and well designed.

Vehicles that could serve offensive or defensive purposes also piqued Leonardo's design curiosity. Take, for instance, his design for a horse-drawn chariot, which had four large scythe-like blades mounted to the axles. As the horse pulled the chariot, the blades would rotate, slicing off the limbs of enemy soldiers. A similar design placed the four large blades at the front of the machine, in front of the horses even, where a screw-type device turned them, and included a series of smaller scythe blades placed at the back of the chariot. This chariot was designed as a brutal weapon, indeed. Even the initial sketches included images of dead and dying soldiers left in its wake. For the peace-loving Leonardo, this was an incredibly gruesome design!

56
Building a better …cannon?

Leonardo's peaceful, harmonious landscape paintings do not tell the entire story of his career. In addition to his work to support troops with better ladders and bridges, Leonardo also designed or improved weapons. Guns, cannons, and other artillery weapons were on the rise during the Renaissance. Newer was better, especially when it came to national defense. Leonardo appeared to have had a nostalgic side, though, because he still spent time working to perfect or improve older weapons such as catapults, slingshots, and crossbows.

One of his innovations was the rapid-firing crossbow. This was no ordinary crossbow—it actually included four crossbows and got its power from a large treadmill. A number of men walked on steps that were located around the outside of a large wheel, and as they made the machine rotate, an archer would fire each crossbow, reloading them in sequence.