Science Year by Year. A Visual History, From Stone Tools to Space Travel

NEW IDEAS Astronomical observer The things of this world cannot An avid astronomer, Bacon argued that the Universe must be spherical. “be made without a knowledge He calculated the distance from Earth ”of mathematics. to the stars as 130 million miles (209 million km). We now know Roger Bacon, Opus Maius, the distance is many millions of 1267–1268 times greater. 49

1245 ▶1345 In 1267, English monk Roger Bacon described the eye’s structure, the The earliest use of magnifying lenses, and also manuscript of an early type of telescope. Song Ci’s The Washing Away 1286 of Wrongs is Eyeglasses from 1408. This example is from In the 13th century, scientists the 19th century. began experiments with magnifying objects using 1247 glass lenses. In 1286, Italian friar Giordano da Pisa gave Work on forensic medicine the first description of lenses used as spectacles. Early Song Ci, a Chinese lawyer, wrote The Washing eyeglasses corrected Away of Wrongs—the world’s first work on forensic farsightedness, a particular medicine (the use of scientific knowledge in crime problem for monks and investigation). His aim was to improve the evidence friars who often had to presented in legal cases, particularly of murder. He read and write manuscripts collected information about past cases and was in dim light. critical about the unreliable tests traditionally conducted by court officers. French clergyman wears eyeglasses for close work. 1245 1275 Seeds from 1260 1269 poppy head Using anesthetics Magnetic force In his groundbreaking medical writings, Italian French scholar Pierre de Marincourt surgeon Teodorico Borgognoni discussed described the lines of magnetic many aspects of surgery and the care of force surrounding a magnet. He wounds. Using an early form of anesthesia, showed that a compass has two he sedated his patients before operations poles, and that oppositely charged with sponges soaked in opium or other magnetic poles attract each other, sleep-inducing herbs. while similarly charged poles repel (push apart) each other. Mandrake root SHepe7eea6opl–pia7nlg7eges Dial marked in degrees Magnetized needle A solution made with ingredients Then the stone that you Diagram of a needle compass, such as opium poppy seeds or from de Marincourt’s Epistola de mandrake root was soaked on “hold in your hand will appear Magnete (Letter on the Magnet) a sponge and given to patients ”to flee the floating stone. to make them sleep. Pierre de Marincourt on magnetic 50 repulsion, Epistola de Magnete, 1269

LENSES AND THE EYE The Ancient Greeks believed that vision was the result of the eye emitting a wave that bounced back from an object in the line of sight. By the 13th century, scholars such as Roger Bacon (see pp.48–49) understood it was the other way around: that light emitted from an object hit the lens of the eye to create an image. 3. Cells on retina turn light rays into signals that are sent to the brain and interpreted as images. 2. Lens focuses light onto retina (light-sensitive layer at back of eye). 1300 Light Rainbow theory 1. Cornea diffracts Cross-section of the human eye (bends) light as German monk Theodoric of Freiburg used it strikes eye. small, water-filled glass bottles to show that light passing through them was both reflected and refracted (sent in different directions). He concluded that beams of sunlight hitting water drops in a cloud bend in the same way, causing a rainbow. 1305 1345 1315 1323 First public dissection Ockham’s razor Italian physician Mondino da Luzzi In his book Summa Logicae (The Sum of Logic), performed the first public dissection English friar William of Ockham reasoned that of a body at Bologna, Italy. This gave seeking an explanation for something should be simplified by cutting out any unnecessary medical students and doctors a information or arguments. The principle became greatly improved understanding known as Ockham’s razor. of human anatomy. c 1200–1280 ALBERTUS MAGNUS German Dominican friar Albertus Magnus was inspired Page from Magnus’s treatise by the work of the Ancient Greek philosopher Aristotle on natural history (see pp.30–31) to compile an encyclopedia of philosophical and scientific knowledge. Albertus believed in discovering the causes of things through science, and he is regarded as the founder of natural science as a field of study. His work ranged across many subjects, including theology (study of religion), logic, zoology, and alchemy (medieval chemistry). He was an excellent teacher and among his pupils was the famous Christian theologian Thomas Aquinas.

1390, MAHDIA, TUNISIA French crusaders use cannons in an attempt to breach the walls of the North African city of Mahdia in 1390. 52

NEW IDEAS History of gunpowder The Chinese understood the explosive properties of gunpowder—a mixture of saltpeter, sulfur, and charcoal—as early as the 9th century ce. They adapted its use to military purposes, producing “fire-arrows,” rockets, and flamethrowers. Around 1250, they made the first cannons. Knowledge of gunpowder weaponry spread westward, reaching Europe about 1300. Cannons soon appeared in battles there. Within a hundred years, handheld guns were developed, but it was early artillery — the big guns—that proved most effective in sieges, where they could demolish fortifications once thought indestructible. There was no such success for the French at the so-called Mahdia Crusade pictured here, as their firepower was not sufficient to breach city walls. It made such a noise in the “going, as though all the devils ”of hell had been on the way. Jean Froissart, Chronicles, giving an account of the use of cannons at the siege of Oudenaarde, in Flanders, 1382 53

1345▶1445 In 1357, French philosopher Jean SAeneaptaogmeys 1368 Buridan developed the 36–37 theory of impetus, Guild of Surgeons the force that makes an object move. The foundation of a Guild of Surgeons in England, in 1368, was the first attempt 1380 to provide rules and regulations for the profession. Before this, anyone—commonly Rocket warfare barbers—had been able to practice surgery. reaches Europe 1349 The first recorded use in Europe of rockets in warfare came at the Motion and forces battle of Chioggia, a naval conflict between the Italian cities of Venice French mathematician and Genoa. Rockets are difficult Nicolas d’Oresme worked to make and their military out a new way of drawing use showed how a greater graphs to represent the understanding of gunpowder motion of moving objects. weaponry was developing. The graphs helped to explain the relationship An array of surgical instruments illustrated in the between the speed, time, manuscript De Chirurgia (On Surgery) by the great and distance traveled. Arab physician Albucasis. 1345 1385 1364 1377 Astronomical clock A rotating Earth Italian clockmaker Giovanni de In his Livre du ciel et du monde (Book of Dondi completed his astrarium—a Heaven and Earth), Nicolas d’Oresme complex clock with dials showing disproved all the popular ideas that the movements of the Sun, Moon, Earth was stationary at the center of the and planets. It had more than 100 solar system. He also suggested that gear wheels. As well as allowing Earth rotated on its axis. However, astronomers to calculate the position he could not go as far as believing of heavenly bodies, it provided that Earth moved around the Sun. a calendar of Church holy days. The astrarium had seven dials and its central weight swung around 30 times a minute. “One could by this Nicolas d’Oresme seated by an armillary sphere, a model of the solar system believe that the earth and not the heavens is so moved, and there ”is no evidence to the contrary. Nicolas d’Oresme on the rotation of Earth, Livre du ciel et du monde, 1377

c 1400 –1600 RENAISSANCE ARCHITECTURE NEW IDEAS Inner dome During the Renaissance, a cultural movement that Ring and herringbone of lighter began in Italy in the mid-14th century, artists and pattern on outer dome material architects rediscovered the classical past. Architects based their buildings on Greek and Roman models, using columns, arches, and domes. Architect Filippo Brunelleschi of Florence spent 16 years building the remarkable dome of Florence Cathedral. This dome, at 147 ft (45 m) wide and 374 ft (114 m) high, was the largest unsupported dome yet built. The dome of Florence Cathedral The campanile, or bell tower, is 278 ft (85 m) high. Building such a huge dome was believed to be impossible. Brunelleschi designed an inner dome of lightweight material and an outer one of heavier stone. Oak timbers set in rings connected the two domes and supported them. Constructing the outer dome was made easier because the builder could balance on the already finished inner dome. 1405 1445 1421 1436 First recorded patent Perspective in painting The first patent—a license Roman artists knew how to use perspective giving an inventor sole (a mathematical system for creating the rights to an invention—was appearance of distance on a flat surface). granted by the city of Florence Knowledge of the technique was later to the Italian architect Filippo lost, but rediscovered during the Italian Brunelleschi. It was for Renaissance. In 1436, Leon Battista Alberti, a barge and hoist used to an architect and scholar, gave a full account transport heavy marble slabs of it in his work On Painting. up the Arno River. The patent forbade anyone else from Vanishing copying the idea for three years. point Nicholas of Cusa Eye German theologian level Nicholas of Cusa (1401– 1464) believed that all Vanishing lines 55 things in the Universe are in motion. From this he Perspective gives the illusion of depth. concluded that Earth is not The artist draws objects smaller and closer fixed and must move together until eventually they form a single point known as the vanishing point. around the Sun. Nicholas of Cusa, portrayed here in a woodcut, had theories on the Universe that would influence scientists in later centuries.

1445 ▶1545 In 1490, Leonardo da Vinci described capillary action: when water moves Wooden plate 1450 up inside a thin tube, in a direction for holding opposed to the force of gravity. paper 1489 Lever tightens plates together, Solid wooden Gutenberg’s press First use of pressing inked frame holds + and – signs type onto paper. plates steady to Johannes Gutenberg set up the first prevent slippage. European printing press in Mainz, Johannes Widman, a German Germany. This used movable type mathematician, was the first to that could be rearranged and reused to make up different pages of text. use the modern signs for plus Producing books was made much (+) and minus (–). Previously, easier and the technique spread rapidly throughout Europe. mathematicians had used a variety of signs, including “p” and “m.” The sign “=” to mean “equals” came into use later, in 1557. Replica of Gutenberg’s original press 1464 Page from Regiomontanus’s Trigonometry text On Triangles German mathematician Johannes Müller (known by his Latin name, Regiomontanus) wrote On Triangles, the first textbook on trigonometry (the study of the relationship between angles and lengths in triangles). 1445 1465 1485 Tent canvas on 1472 1492 a wooden frame A comet observed Christopher Columbus discovers America An interest in astronomy led Regiomontanus (Johannes When Genoese mariner Christopher Müller) to make the first detailed Columbus sailed westward from observations and descriptions of Spain, he was hoping to reach a comet. Using trigonometrical techniques, he worked out methods China. Instead he discovered the for calculating the size of a comet Americas, landing somewhere in and its distance from Earth. the Bahamas. His voyage led to Model of European colonization and an the parachute exchange of food crops—and Leonardo designed diseases—between Europe in his sketchbooks and the Americas. Da Vinci’s Woodcut of a comet, from the Model of Santa Maria, parachute Nuremberg Chronicle, 1493 Columbus’s flagship on In his notebooks, Leonardo da Vinci (see pp.58–59) his first expedition sketched out many ideas for machines centuries before their final invention. In 1481, he drew and described a parachute made of tent canvas. 56

NEW IDEAS 1473–1543 NICOLAUS COPERNICUS Born in Poland, Copernicus studied astronomy, mathematics, law, and medicine in Italy. When asked to take part in a reform of the calendar, Copernicus began to study Greek astronomer Ptolemy’s 1,500-year-old system of celestial spheres, in which he found flaws. First The Copernican cosmos surviving Copernicus did not disagree with globe Ptolemy’s idea that the planets The first surviving globe of the world was produced rotated in concentric spheres, but in 1492 by cartographer he made corrections to some of Martin Behaim, who made it Ptolemy’s other notions. In his for his home city of Nuremberg amended version, he placed the in Germany. It shows a world Sun at the center of the Universe, map and has many not Earth, as Ptolemy had done. decorative illustrations. Painting by Andreas Cellarius depicting 1505 Copernicus’s Sun-centered Universe, 1660 1525 1545 1527 Classifying chemicals German chemist Theophrastus von Hohenheim (better known as Paracelsus) worked out a new classification for chemical substances. This was based on a division of substances into salts, sulfurs, and mercuries, according to their properties. 1543 Illustrated anatomy Flemish physician Andreas Vesalius published De Humani Corporis Fabrica (On the Structure of the Human Body), which remained a standard textbook for centuries. New printing techniques produced full-color plates illustrating human anatomy in the clearest detail seen so far. By 1500, printing presses Diagram of muscles from had been set up in 282 cities De Humani Corporis Fabrica and had printed around 28,000 editions of books. 57

The artist Out of Leonardo’s artistic output only 15 of his paintings are known to have survived, and several are unfinished. But among these are masterpieces such as the Mona Lisa and The Adoration of the Magi. He also left thousands of sketches, including this self-portrait. 58

GREAT SCIENTISTS NEW IDEAS The anatomist Leonardo da Vinci From the 1490s, Leonardo studied anatomy. He dissected animals and attended The Italian artist Leonardo da Vinci (1452–1519) was also an post-mortems of human corpses so that he extremely clever scientist. As well as painting the Mona Lisa, could see the internal structure of the body. one of the most famous works of art of all time, he studied As a result, he was able to produce a series anatomy, geology, geography, and optics. He was a brilliant of highly detailed anatomical sketches. engineer and drew designs for submarines, parachutes, and airships centuries before the technology existed to build them. Renaissance Florence In 14th-century Italy, people began to take a fresh interest in Greek and Roman learning that had been lost for centuries. By the late 15th century, the city of Florence, Leonardo’s birthplace, was at the heart of what is called the Renaissance (rebirth), a time of cultural renewal. From art to medicine and from architecture to engineering, scholars relearned old techniques and discovered new ones. The engineer Leonardo’s desire to understand how things worked, combined with his skill at technical drawing, sparked in him an interest in machines and engineering. He designed complex levers, pulleys, and springs for use in construction. Leonardo was also a talented military engineer, and in 1500, he advised the Venetians on how to defend themselves from attacks by the Turks. One of his suggestions was to use a form of submarine to sink enemy ships. In his lifetime, Leonardo’s inventions attracted little public interest. Today, we recognize his importance to science. Ropes and pulleys control flight. Leonardo Netting wings and flight were intended to Leonardo was intrigued support a covering by flight. He made many of feathers. studies of the bodies of birds and their wings, and believed these Pilot uses Pilot pedals to worked according to mathematical hand lever to move wings laws that he could use to design move wings downward. flying machines. Leonardo drew up plans for mechanical wings upward. operated by levers and pulleys, but he never built such a machine. “No human investigation Leonardo’s inventions This wooden tanklike vehicle for storming fortifications was just can be called real science if one among many ingenious machines that Leonardo devised. ”it cannot be demonstrated Others included a parachute, a dredging machine, and a robotic mathematically. knight that could grasp objects and open and close its jaw. Leonardo da Vinci, Trattato della Pittura (Treatise on Painting) 59



1545–1790 The age of discovery In the 16th century, new scientific knowledge replaced old ways of thinking. The invention of the microscope and the telescope stimulated the study of anatomy and astronomy. Long-distance travel at sea led to more accurate ways of measuring distance and time. These advances created a need for complex calculations, which brought about advances in mathematics. Instead of relying on traditional teaching, scientists (then known as natural philosophers) began to test ideas and theories through observation, investigation, and experimentation. Their discoveries laid the foundations of modern science.

1545 ▶1570 All the platinum ever mined would fit in an average-sized 1551 living room. Measuring distances Platinum nugget English surveyor Leonard Digges invented Eye piece an early theodolite, an instrument used in surveying to measure distances accurately. His device could measure vertical and horizontal angles to work out distances, but did not have a telescope, unlike modern examples. Telescope 1551 1557 Knob to adjust Prolific inventor Rare metal horizontal position Islamic scientist Taqi Italian scholar Julius Modern example al-Din wrote a book Caesar Scaliger wrote of a theodolite describing how a steam that Spanish explorers turbine worked. He also in Mexico had found a invented the first weight- substance that did not driven astronomical clock, melt at high temperatures clocks that measured and did not rust. It is the minutes and seconds, first known reference in and an early telescope. European writings to platinum, one of Earth’s rarest metals. 1545 1550 1555 Gesner’s 1551 1557 illustration of a two-humped Animal magic Math symbols (Bactrian) camel and driver Swiss naturalist Konrad von Gesner set out to catalog all the Welsh mathematician Robert world’s animals in his five-volume Historiae Animalium Recorde wrote The Whetstone of (History of Animals), one of the first works of zoology. Witte, the first book on algebra in English. He popularized the use Although his colorful drawings are noted for their accuracy, he included some fictional beasts such as unicorns. of + (plus) and – (minus) signs, and is credited with inventing the = (equals) sign. TtShreae9ev2wpe–alo9ignr3elgds

1560 First scientific society Giambattista della Porta was an Italian playwright and polymath (someone who knows a lot about many subjects). He founded what is believed to be the world’s first scientific society in Naples, Italy. Membership of the society, called the Academia Secretorum Naturae (Academy of the Mysteries of Nature) was open to anyone who had made a new scientific discovery. 1561 Ambroise Paré operates on a patient in this 19th-century print Anatomical discovery 1564 Gabriello Falloppio, an Italian Compassionate surgery anatomist and professor of surgery at Padua University, in Italy, published a French surgeon Ambroise Paré wrote a manual of modern surgery description of the human reproductive based on his experience of carrying out amputations on the battlefield. Ahead of his time, Paré stated that pain relief, healing, and good organs. He gave his name to the patient care were essential to successful surgery. Fallopian tubes, the pair of channels 1565 1570 in female mammals through which eggs pass from the ovaries to the uterus. 1560 1550–1570 MAPMAKING SKILLS Advances in navigation and exploration in the 1500s led to improvements in mapmaking. The center of mapmaking was Antwerp (in modern-day Belgium), then a busy center of international trade. Printed collections of maps familiarized Europeans with the new lands discovered in America and Asia. Gerard Mercator The first atlas In 1569, Flemish Abraham Ortelius, a Flemish cartographer, published the first modern mapmaker Gerard world atlas in 1570. It contained 70 separate maps on 53 sheets, Mercator published showing all the countries and continents known at that time. a new world map. His represention, or 63 projection, of the globe on a flat surface used a grid of straight lines to show direction. This proved an aid to sailors.

Measuring things Measuring small distances In ancient times, parts of the human body were used Engineers and others who need to to measure length (some systems today still use measure small distances use a “feet”). The first weights were often based on fixed two-armed instrument called quantities of grain. These traditional units served well for thousands of years, until the rise of scientific a caliper. The simplest form of experimentation brought the need for far more caliper is a pair of compasses accurate methods of measuring things. or dividers. This much more elaborate gunner’s caliper was used to measure the bore (internal dimension) of a cannon as well as the external width of a cannonball. Early weights Arc marked and measures with a scale Today, we measure length, weight, gives diameter. Compass for and volume using international standard navigation also has a sundial. units. In the past, these units were local— each city or country set their own. For example, in medieval England, an inch was equivalent to three grains of barley laid length to length. Balance Rod is one scale used for cubit (the weighing goods length of a forearm) Divided into 28 Thermometer Curved arm segments called with Fahrenheit with scale fingers (width of scale, 1720s a human finger) Points are used to and seven palms Degrees of temperature measure internal and (width of a external distances. human hand) Two scales for accurately measuring temperature were invented in the 1700s— Egyptian royal cubit the Fahrenheit scale in 1724 and the measuring rod Celsius (or centigrade) scale in 1742. Today, the Celsius scale is used in nearly every country in the world. The US still uses the Fahrenheit scale. Key events Egyptian c 3000 bce 1631 1724 royal cubit The royal cubit was a standard French mathematician Paul Vernier Dutch physicist Gabriel measurement of length in Ancient invented a sliding scale for taking Fahrenheit devised the Egypt. It was based on the length of accurate measurements that are temperature scale named the forearm, from the middle smaller than the smallest on an after him. It has 32° as the fingertip to the elbow. instrument’s main scale. The freezing point of water, and vernier scale is still used today. 212° as its boiling point. Cubit Caliper using vernier scale Palm 64

THE AGE OF DISCOVERY Another ranging pole is set in Metric and ground to establish a right angle imperial systems Surveyor’s assistant Wooden cross The metric system, first introduced holds a ranging pole with arms of in France, is the official system of (used to establish equal length measurement in most countries today. a straight line) The imperial system was once used throughout the British Empire. The US Swivel arm is the only major country that still uses it officially—it is known there as the customary measurement system. While both systems are still in use, the values are not directly equivalent. Marker stake Metric Imperial Centimeter (cm) Inch (in) Plumb line Meter (m) Foot (ft) Kilometer (km) Mile (m) Surveyor’s tool Kilometer per Mile per hour (km/h) hour (mph) The Romans, who were skilled builders and surveyors, Gram (g) Ounce (oz) used a device called a groma to measure right angles. It consisted of a horizontal wooden cross and a weighted Kilogram (kg) Pound (lb) Liter (l) Gallon (gal) cord (plumb line), which hung from each of the four Celsius (°C) Fahrenheit (°F) arms. The surveyor would look down each pair of plumb lines in turn to establish a right angle. Scale marked in degrees Gunner’s caliper Dual-purpose device Sailor’s tobacco box from Venice, Italy, Perpetual calendar 16th century The lid of this small tobacco box, which possibly belonged engraved on lid to an 18th-century seaman, was engraved with a perpetual calendar (meaning it is valid for numerous years) so he always knew what day of the week it was. Mathematical tables on the bottom, used with the ship’s log float (see p.93), also enabled him to calculate the ship’s speed. 1875 1960 Leica DISTO D3 1993 is an LDM The Treaty of the Meter, signed in The International System of The handheld Laser Distance Paris by representatives of 17 nations, Units (SI), the modern form of Meter (LDM) came into use. It agreed to international standard units the metric system, was officially shoots a laser pulse at a distant of measurement based on the meter adopted. It is the most widely object and measures the time and the kilogram. used system of measurement. taken for the pulse to be reflected back. 65

1570 ▶1590 StTehe8eel0plt–iian8mgg1ees 19th-century replica of the Strasbourg The light passes through Darkened room a lens (or small opening). astronomical clock The image of the Moving building appears figures upside down on the opposite wall. Building 1574 1570 Complex timepiece Camera obscura An astronomical clock, nearly 59 ft (18 m) high, was built in Italian scholar Giambattista della Porta refined the Cathedral of Notre-Dame the camera obscura—an optical device that in Strasbourg (now in France). projects an image of an object through a It included a celestial globe, pinhole (small opening) onto a flat surface. an astrolabe, a calendar dial, Instead of using a pinhole to focus the image, and automata (moving della Porta used a convex lens (see p.137). figures), representing the This innovation imitated the shape of the latest ideas in mathematics, lens in the human eye. astronomy, and clockmaking. 1570 1575 1577 Taqi al-Din’s observatory Islamic scientist Taqi al-Din built an observatory in Istanbul (in modern-day Turkey) equipped with the latest instruments for measuring the positions of the planets and other heavenly bodies. Unfortunately, he also incorrectly predicted that the Sultan would win a war against the Persians. When he lost, the Sultan ordered the observatory to be pulled down. Typhoid fever In 1576, Italian physician Gerolamo Cardano wrote the first clinical description of the symptoms of typhoid fever. This highly infectious disease killed many people. Astronomers at work in Taqi al-Din’s observatory in Istanbul

THE AGE OF DISCOVERY Seed 1546–1601 TYCHO BRAHE Roots Botanical Danish nobleman Tycho Brahe was one of the leading illustration astronomers of his day. Under the patronage of King of a dandelion Frederick II of Denmark, he built a huge observatory on the island of Ven (in Sweden), where he studied the stars and planets. He made all his observations with the naked eye, before the invention of the telescope. As a student, he lost part of his nose in a duel and wore a false metal one for the rest of his life. 1583 Brahe’s new star Modern-day image of SN 1572, In 1572, Brahe observed believed to be Brahe’s supernova Plant studies a bright new star in Italian botanist the constellation of Andrea Cesalpino Cassiopeia (at the top, developed a method labeled “I” on his map). of grouping flowering Modern telescopes have plants by their fruits, revealed that this was seeds, and roots in his book De Plantis Libris an exploding star, XVI (The Book of or supernova. Plants XVI). Brahe’s map of Cassiopeia showing his new star 1585 1590 1582 1589 Spring maintains New calendar First knitting machine tension Great Britain did not switch to the Pope Gregory XIII introduced a new English inventor William Lee designed Gregorian calendar until 1752. calendar to modify the Julian calendar, a machine called a stocking frame for which had been used in Europe since knitting woollen and silk stockings. He Roman times. Known as the Gregorian demonstrated it to Queen Elizabeth I, who calendar, this calendar calculated the date feared his invention might put hand- of the holy festival of Easter more accurately. knitters out of work. He was unable to At first recognized only by Catholic patent his invention in England, countries, the Gregorian calendar is now used by many countries around the world. so he moved to France. Knitted stocking Pope Gregory XIII presides over the discussion Foot Wool or to reform the calendar in Rome treadle for silk yarn operating 67 machine Replica of William Lee’s knitting machine

Surface of the Moon GREAT SCIENTISTS Galileo was one of the first people to point a telescope at the sky and he made many important observations. Galileo Galilei He wrote about his discoveries in a book called The Starry Messenger. Until then, people had thought the Italian scientist Galileo Galilei, who is always known by his Moon was a flat, silvery disc. Galileo’s drawings, based first name, was born in 1564 near the town of Pisa, Italy. on his observations, revealed that it is a sphere with an He originally studied to become a doctor, but was much more uneven surface ridged with mountains and craters. The interested in mathematics. While still a medical student, he book brought him instant fame. noticed a lamp in Pisa Cathedral swaying back and forth. Using his pulse to time the intervals, he worked out that the It is a beautiful and lamp took the same time to complete each swing, regardless of the length of the arc followed during the swings. “delightful sight to behold ”the body of the Moon. Professor of mathematics Galileo never became a doctor. He was made Professor of Mathematics Galileo Galilei, at Pisa University at the age of 25 and began to study the physics of The Starry Messenger, 1610 motion, as well as engineering. He moved to Padua University and turned his attention to astronomy after building his first telescope in 1609. Lever (pawl) attached to pendulum stops and releases Support for Copernicus pinwheel with each swing In 1614, Galileo publicly stated his support for the Copernican theory back and forth. that the planets, including Earth, orbit the Sun. This went against the Church’s teaching that Earth was at the center of the Universe and Galileo was told to stop spreading such ideas. He was a devout Catholic and agreed to remain silent, though he was convinced that Copernicus was right. Final years Galileo continued with his scientific experiments, but was arrested and put on trial in 1633 for denying the Church’s teachings. He spent the rest of his life under house arrest in the village of Arcetri, near Florence. Here he wrote Dialogues Concerning Two New Sciences, his last great work on physics, which included his law of falling bodies. He died in 1642. Pendulum clock The trial of Galileo Galileo studied pendulums Galileo’s trial took place before a crowded Church court in Rome. throughout his life. Just before Charged with heresy and facing a punishment of torture or death, his death, he designed a clock Galileo publicly denied that Earth moves around the Sun. He is said to have muttered defiantly under his breath “And yet, it moves.” that used the regular sweeps of a pendulum to keep time. By now he was totally blind, but he described the mechanism to his son Vincenzio, who made a drawing of it. Vincenzio began building the clock but it was never completed. This model is based on Vincenzio’s drawing. Weighted pendulum swings to other extreme. 68

THE AGE OF DISCOVERY Galileo in old age This portrait of Galileo was painted in 1636, when he was living at Arcetri. He holds a telescope in his right hand, though by this time he was going blind. “Mathematics is the language with which ”God has written the Universe. Galileo Galilei 69

1590 ▶1610 Compass needle held 1600 at different positions always points north Giant magnet English scientist William North Pole Gilbert believed that Earth must have a huge magnet inside because navigators’ SLceoleookpsaeinglyges Model of Earth compasses always pointed 84–85 made from north. He made models of Earth from magnetic rock magnetic rock and found that compass needles held close to the 1590 rock pointed toward the model’s North Pole, Inventing the microscope behaving just like real compass needles on Earth. Dutch spectacles-maker Zacharias Janssen is credited with inventing the Illustration of Earth South Pole compound microscope. He inserted two as a magnetic rock lenses into a tube and looked through 1600 one end. Small objects at the other end appeared nine times larger. Burned at the stake Giordano Bruno, an Italian friar and mathematician, was burned at the stake as a heretic by the Catholic Church. Influenced by Copernicus’s ideas of Earth revolving around the Sun, Bruno had argued that the Sun was not the center of the Universe because the Universe was infinite, and that Earth was Replica of Janssen’s original microscope unlikely to be the only inhabited world. 1590 1595 Water cistern 1596 1596 Flush toilet Puzzle of continents Sir John Harington, a member of After noting that their coastlines Queen Elizabeth’s court, invented a seemed to fit together like pieces of flush toilet, called the Ajax. It worked a jigsaw puzzle, Flemish mapmaker much like a modern toilet except that Abraham Ortelius suggested that the the water swept the contents of the continents of Africa and the Americas pan straight into a pit below. Sadly, his were once joined together. This idea invention did not catch on. Hygienic, would be confirmed by the theory of flushing toilets did not come into use continental drift developed by German for another three centuries. geophysicist Alfred Wegener in 1915 (see p.170). Handle releases water into toilet Toilet seat Illustration Exit pipe “It would make of Harington’s water closet, 1596 unsavory Places World maps, such as this one from 1590, could have 70 ”sweet… and filthy inspired Ortelius’s theory. Places cleanly. Sir John Harington, describing his flush toilet

THE AGE OF DISCOVERY 1608 THE TELESCOPE Hans Lippershey was a German lensmaker working in the Netherlands, then the center of the optical industry. He is believed to have invented the refracting telescope in 1608, though Zacharias Janssen may also have had a hand in its development. A refracting telescope uses two lenses to gather and focus light, making distant objects appear closer than they are. Lippershey’s invention could make objects seem three times larger. It is likely that he intended his telescope for use at sea or on the battlefield. Gold patterning Galileo’s telescope The tube is made of strips of wood Based on reports of Lippershey’s telescope, covered with leather. Galileo built his own telescope in 1609. It could make distant objects appear eight times larger. He later built a telescope that could magnify objects 30 times. Lippershey experiments with lenses 1605 1610 1604 1609 Falling objects Planetary motion Galileo worked out a law that describes how objects German astronomer Johannes fall under the influence of gravity. At the time, most Kepler published a work confirming scientists believed Greek philosopher Aristotle’s idea, Copernicus’s belief in a Sun-centered that the heavier an object is, the faster it falls. Galileo cosmos. He also used mathematics to had already realized that all objects should fall at the prove that the planets travel in elliptical same rate and land together, but that air resistance orbits around the Sun, and that their affects the falls of some objects more than others. He speed is not constant, they speed up supposedly tested his idea by dropping cannonballs of when they come closest to the Sun. various weights from the Leaning Tower of Pisa, Italy, although historians dispute the story. Elliptical orbit Faster firing Sun is not Planet travels The flintlock was first at the center more slowly used in France in 1608. of the orbit. when it’s The spring-operated farther from Metal balls mechanism increased the the Sun. of different firing rate and safety of weights handheld muskets and pistols. It remained in use for more than 200 years. Galileo dropping balls English flintlock from the Leaning pistol, c 1650 Tower of Pisa The falling flint strikes a spark to ignite the gunpowder. 71

Circular orbits Paths in the sky Nicolaus Copernicus Astronomers had no idea what keeps planets in their was the first European orbits, until English scientist Isaac Newton realized that astronomer to argue it is a force called gravity. This force, which makes objects that the Sun was at the fall down on Earth, is the same force that keeps the center of the Universe. He planets from flying off in straight lines. The planets are believed that Earth and actually falling toward the Sun—but they are also moving the other planets traveled sideways in their orbits. If they stopped moving, they around it in circular would crash into the Sun. orbits. He published his revolutionary ideas just before his death in 1543. Copernicus’s drawing of the Jupiter with Sun Mercury Sun (at the center) and planets its moons Saturn with its moons Venus Mars Moon Earth Sun in the middle This clockwork model of the solar system is called an orrery, a mechanical instrument usually used as a teaching aid. When it is set in motion, the arms rotate to demonstrate the relative positions of the planets and their moons as they orbit the Sun. This orrery must have been made before 1781 as it does not include the planets Uranus and Neptune. Key events 140 ce 1543 1609 1610 Greek mathematician Ptolemy Nicolaus Copernicus published a In his three laws of planetary Using a telescope, Italian stated that Earth is the fixed book in which he proposed that motion, Johannes Kepler scientist Galileo observed center of the Universe. His Earth and the other planets travel proved mathematically views were not challenged around the Sun in circular orbits. that the planets travel four moons in orbit around for the next 1,500 years. in elliptical paths. Jupiter, proving that not everything in space orbits Earth. Europa, a moon of Jupiter 72

THE AGE OF DISCOVERY Sun Earth is 93 million miles (149.6 million km) from Newton’s law of gravity the Sun and takes a year to complete an orbit. Astronomers could not explain why the planets follow elliptical orbits until Isaac Newton, the great English physicist, supplied the answer (see p.88). Gravity, which makes an apple fall to the ground on Earth, also keeps the planets in orbit around the Sun. All matter exerts gravity, pulling other matter toward it. The strength of gravity depends on the mass of the object, and weakens with distance. Elliptical orbits Planet’s elliptical orbit Newton’s law of gravitation predicts mathematically what the gravitational force on an object will be—the force between any two objects depends Orbital times Jupiter is 5.2 times farther away upon their masses and how from the Sun than Earth. It takes 11.9 Earth years to complete an orbit. far apart they are. Newton Gravity pulls the worked out the Sun toward forces on planets— the planet. and his equation Kepler’s discoveries predicted that Johannes Kepler, a German astronomer, set out to prove that Copernicus’s theory of a Sun-centered Universe was orbits would Sun correct. Rather than orbit the Sun in circles, Kepler be elliptical, found that the planets travel around it in ellipses (oval paths). He also discovered that the farther a planet is just as Gravity pulls the planet from the Sun, the longer it takes to complete its orbit. Johannes Kepler toward the Sun. had observed. Planet The planet revolves Mercury’s orbit around the Sun in changes over time. this direction due to gravity. The planet would move in a straight line in the absence of gravity. Artist’s impression of Kepler-444 star system Mercury’s wobbly orbit Planets beyond our solar system Over time, the planet Mercury’s orbit shifts slightly. Newton’s law of gravity could not We now know of thousands of planets orbiting explain this puzzling fact. In 1915, physicist parent stars beyond our solar system. They are Albert Einstein solved the mystery in outlining his theory of relativity (see p.173). known as exoplanets. NASA’s Kepler space The wobbly orbit is due to Mercury having telescope, launched in 2009, is able to detect to travel through an area of space that is orbits of exoplanets by measuring how far a Sun curved due to the Sun’s mass. star’s light dims when a planet passes “ ”We revolve around the Sun in front of it. The Kepler-444 star system, like any other planet. discovered by this telescope, contains five Nicolaus Copernicus planets that orbit their star in less than 10 days. 1687 1781 1846 2009 Isaac Newton formulated the William Herschel, a British Mathematical calculations correctly NASA launched Kepler, a universal law of gravitation and astronomer, discovered the predicted the existence of a new space observatory, to discover explained that it is the force of planet Uranus in orbit beyond planet, later given the name of habitable, Earth-sized gravity that holds the planets Saturn. It was the first planet Neptune, before it was observed planets orbiting other in elliptical orbits around the Sun. to be discovered since by telescope. stars. By 2016, it ancient times. had discovered 21 Earth-like planets. 73

1610 ▶1630 CmaS1elac2ecu4phl–aai1ntg2ieen5ssg Fixed column divided Set of movable rods into numbers from 1 to 9 inscribed with digits for multiplying and dividing 1610 Io 1614 Europa Moons of Jupiter Multiplying Ganymede numbers Observing the night skies Callisto through the telescope he had Scottish mathematician built himself, Galileo Galilei John Napier introduced (see pp.68–69) noticed three logarithms, which are used small stars near the planet to multiply and divide very Jupiter that changed position large numbers—especially over a period of time. He useful in astronomy. In realized they were moons, 1617, he introduced another or satellites (objects that orbit aid to calculation—a set a planet or star), circulating of rods divided into sections the planet, and later identified and marked with digits, a fourth. These four were the which became known brightest of Jupiter’s moons, as Napier’s bones. often called the Galilean moons. Galileo’s observation contradicted the Church’s teaching that everything in the Universe rotated around Earth. Napier’s bones 1610 1615 1620 1620 Slide rule Another handy aid to First submarine calculation was the slide rule, invented by English Cornelis Drebbel, a Dutch inventor living in mathematician William England, built a submarine made of a wooden Oughtred in 1622. Slide frame covered with leather. It was powered by oars. rules remained in use until The submarine stayed underwater for three hours when the late 20th century, when given a trial run in the Thames River, but it is unclear they were replaced by how the oarsmen sitting inside were able to breathe. pocket calculators. Replica of Drebbel’s submarine 74

THE AGE OF DISCOVERY 1578–1657 WILLIAM HARVEY English physician William Harvey proved that the heart pumps blood around the body. He found that the body has a fixed amount of blood that is always circulating. Before this discovery, doctors believed that blood was continuously being made in the liver. Illustration of Santorio’s Royal physician clinical thermometer Harvey studied at the universities 1626 of Cambridge, England, and Padua, Italy. On returning to Body temperature England, he became physician Italian physiologist Santorio Santorio to King James I, and tended was the first person to use a thermometer to victims of the English to measure the temperature of the human Civil War (1642–1651). body. Santorio was an early pioneer of the study of metabolism—the chemical processes in the body essential for life. 1625 1630 1629 One-way flow Fanciful Arteries carry blood away from the heart and veins return it steam engine to the heart. This key discovery of the circulatory system was Italian inventor Giovanni outlined in Harvey’s book De Motu Cordis (The Motion of the Branca published a design for a steam engine known Heart), where he shows how a one-way valve in a forearm as an aeolipile. He suggested it could be used to power vein prevents the blood from flowing back to the hand. pestles and mortars to grind medicinal drugs. 4. Weighted arms It was never built and it rise and fall. is doubtful it would have been of any practical use. 3. Rotating Branca’s aeolipile, turbine shifts a an early type of 2. Steam is series of gears. steam engine blown through 1626 a pipe onto a Death by freezing horizontal turbine. Sir Francis Bacon, a major 5. Pestle English figure in the history moves up and down. of science, is said to have died of pneumonia after trying to see if he could preserve meat by stuffing a chicken carcass with snow. Bacon famously maintained that scientists should prove the truth of their ideas through experimentation. 1. Fire heats water in boiler shaped like a man.

Healing people In the past, the practice of healing the sick was based on traditional knowledge of herb-based remedies. The Ancient Greeks were the first to study the causes of sickness, and passed their knowledge on to Roman and Islamic physicians. The scientific study of medicine emerged again in western Europe in the 1600s, leading to ever more effective ways of diagnosing, preventing, and treating disease. Islamic medicine The physician Alternative medicine In the Middle Ages, translations of The “is only nature’s Canon of Medicine, a book by Persian scholar ”assistant. Alternative medicine refers to any form Ibn-Sina (Avicenna), brought Greek and of healing that falls outside the “western” Arabic knowledge of medicine to the West. Galen, Roman scientific tradition of medicine. Some This illustrated page from an edition dated physician forms are very old and are followed by 1440 shows a pharmacist’s shop alongside millions of people around the world. various medical practices of the time. and surgeon + Ayurveda Leeches Bloodletting were kept Originating in ancient India, ayurveda in water. The process of removing blood aims for balance between mind, body, from a patient, or bloodletting, was and spirit. It uses dietary adjustments, practiced in medicine for thousands herbal remedies, and massage treatments. of years. It was thought to balance + Acupuncture the body’s fluids and was believed to be a cure for In this Chinese form of healing, fine most ailments. One way needles are inserted into certain sites in of taking blood was to the skin to treat a variety of conditions. attach leeches (blood- sucking parasitic worms) + Homeopathy to the skin. Leeches are sometimes used today Based on the idea of “like cures like,” to clean wounds. homeopathy treats ailments with tiny doses of natural drugs. The gauge displays Sphygmomanometer the pressure. for measuring blood A woman attaches pressure, c 1883 leeches to her arm in a woodcut from 1638. Key events 460 bce 1543 1628 1816 Hippocrates, the Ancient Greek Flemish physician Andreas Vesalius English physician William Harvey René Laennec, a French physician, was born. The first published De humani corporis fabrica described the circulation of blood hospital doctor, invented the person to study the causes of (On the Fabric of the Human Body), in animals, showing that the heart stethoscope—an instrument to disease, he is called the father a work that revolutionized the pumps blood in one direction listen to the chest of patients of modern medicine. understanding of human anatomy. around the body. as an aid to their diagnosis. Laennec’s stethoscope 76

THE AGE OF DISCOVERY An antiseptic spray is used during an operation, c 1870 Hospital care Deadly diseases In the past, hospitals were In most parts of the world, people live dirty, overcrowded places. far longer than they did 500 years ago, Two of the people who when average life expectancy was about helped to change all that 40 years. With vaccines and antibiotics, were British surgeon medical workers can now prevent or Joseph Lister (see p.144), cure many infectious diseases that would who introduced previously have killed thousands. antiseptics, making surgery safer, and British + Smallpox nursing pioneer Florence Nightingale, who Once a feared killer, smallpox has demonstrated that clean now been wiped out thanks to a hospitals prevented global immunization campaign. infection and helped sick people get better faster. + Polio The very first requirement in a hospital This highly infectious viral disease targets children. Vaccines are helping “ ”is that it should do the sick no harm. to end it worldwide. Florence Nightingale, Notes on Nursing, 1860 + Plague Bubonic plague (the Black Death) killed millions of people in Europe in the 1300s. Outbreaks still occur today, but the disease is treatable with antibiotics. Medical aids Wood and pewter syringe, late 1700s Tools such as tweezers and scalpels (sharp-bladed knives), Candle similar to those doctors use today, date back to ancient times. Over the centuries, Nozzle as medical knowledge advanced, the need arose for more complicated instruments, such as endoscopes and blood pressure monitors to identify and treat patients’ symptoms. The tube ends in a rubber bulb, which is placed on the skin and inflated. The funnel directs light from the candle. Viewing lens Engraving of a doctor wearing a beak-shaped mask for protection against plague, 1656 Otoscope for looking inside the ear, 1890s 1865 1895 1928 1977 Joseph Lister introduced life- German physicist Wilhelm C. Sir Alexander Fleming, a Scottish The first MRI (magnetic saving standards of cleanliness Röntgen produced the first X-ray biologist, discovered penicillin, resonance imaging) and hygiene into operating photograph. X-rays, which can heralding the era of antibiotics. scan was carried out. rooms and hospitals. penetrate skin and tissue to Penicillin was first used as an MRI creates multiple reveal bone, have become effective drug in the 1940s. images of the body a key tool in medicine. without exposing it to damaging radiation. First MRI machine 77

1630 ▶1650 1637 1637 It is not enough to have Descartes’s discourse Mathematical puzzle “a good mind. The main French philosopher René Descartes ”thing is to use it well. published Discourse on the Method, French mathematician Pierre de Fermat scribbled René Descartes, one of the most important books a theorem (a mathematical Discourse on the Method written in the history of philosophy statement) in the margin of an old textbook. He and science. In it, he said that claimed he had proof in order to arrive at the truth, you that his theorem was should start by doubting everything. true, but had no room to write out the answer. Fermat’s theorem was not solved until 1995. Cinchona leaves 1631 Descartes’s Discourse Pierre de Fermat and bark on the Method Wonder drug Agostino Salumbrino, an Italian missionary living in Peru, noticed that the Quechua people used the powdered bark of the local cinchona tree to treat fever. A small sample was sent to Rome, where it was used successfully to treat malaria, then a common disease in marshy parts of Europe. We now know that cinchona bark contains a drug called quinine. 1630 1634 1638 1633 1639 The trial of Galileo Transit of Venus Italian astronomer Galileo Galilei was put on trial English astronomer Jeremiah Horrocks in Rome on charges of heresy. He had published a correctly predicted that the shadow of the planet Venus would pass in front of the Sun, a rare book attacking the Church’s view that the Earth was event known as the transit of Venus. To observe the occurrence, Horrocks projected the Sun’s image at the center of the Universe and supported Polish through a telescope onto a sheet of paper. astronomer Nicolaus Copernicus’s theory of a Sun-centered Universe. Fearing torture or death, Galileo SeGGeaaplliaillgeeeoi s denied his beliefs in court. 68–69 Title page of Somnium 1634 Roundel from a stained glass window celebrates Horrocks’s observation of the transit of Venus 78 First sci-fi novel Johannes Kepler, a German astronomer, wrote a story about a young Icelandic boy who was taken by demons to the Moon. The novel was published a year after Kepler’s death in 1633. Written in Latin, it was titled Somnium (The Dream), and has been described as the first work of science fiction.

1643 Replica of THE AGE OF DISCOVERY Torricelli’s The first barometer barometer One of Hevelius’s maps of the Moon When Italian physicist Evangelista Torricelli placed 1647 a glass tube filled with mercury in a bowl of mercury, the mercury in the tube fell, leaving a vacuum at the Atlas of the Moon top. He realized this was due to atmospheric pressure (weight of air). Torricelli’s discovery led to the Polish astronomer Johannes Hevelius invention of the barometer, an instrument that published the first atlas of the Moon’s surface. measures air pressure to forecast the weather. Hevelius, who was a brewer by trade, built his own observatory. His detailed maps showing How a barometer works Higher atmospheric the Moon’s mountains and craters were the pressure exerts stronger result of four years of observation. Thin-walled, inverted glass tube force on the mercury. Vacuum Mercury At low pressure, Mercury reservoir mercury rises a rises higher short way up up the tube. the tube. Low atmospheric pressure exerts less force on the mercury. Low atmospheric High atmospheric pressure pressure 1642 1646 1650 1642 CmaS1elac2ecu4phl–aai1ntg2ieen5ssg French scientist Blaise Pascal built Calculating machine about 20 calculators in his lifetime. At the age of 19, Blaise Pascal invented a mechanical calculating machine to help his father, a French Display windows government tax collector. The machine could add, show answers subtract, divide, and multiply. Pascal went on to become a leading mathematician and philosopher of the age. Pascal’s first calculator Dials for inputting numbers 79

Telling the time Hour hand indicates the hour of the day The earliest people who tried to keep track of time used simple devices such as sundials to track the movement of the Sun through the sky. It was many centuries later, about 700 years ago, that mechanical clocks were introduced in Europe. Faster communications in the 19th century led to timekeeping becoming standardized across the world. Gilded sun marks the position of the Sun in the Zodiac Early timekeeping Sundials Sundials measure time by using a shadow cast by an upright rod (gnomon) to track the position of the Sun in the sky. Water clocks Originally, the phases of In water clocks, a jar is filled with water, which drains away the Moon were at an even rate to indicate how indicated. much time has passed. Sundial (9th century) in Northern Ireland Hourglasses When the sand has run Astronomical clocks through to the bottom, A specific quantity of sand flows Early mechanical clocks in from one glass bulb into another the hourglass can be Europe used a falling weight through a narrow opening. The turned upside down. sand flows through at a fixed on a chain and a pendulum rate, usually taking an hour. to turn a series of gears (see box opposite). They Incense clocks often combined 24-hour In China and Japan, incense clock faces with information about the Sun, Moon, and sticks that burn at an even rate stars. Their elaborate designs often included were used to measure time. moving figures (automata) Candle clocks Hourglasses from The clock tower and detail of clock that danced or rang bells at the 17th century face (above) in St. Mark’s Square, Venice. certain times of the day. Slow-burning wax candles had evenly spaced lines marked on them, which were numbered to mark the hours. Key events 1500 bce 1088 1656 1759 Sundials were first used in In China, Su Song Dutch inventor Christiaan English clockmaker John Egypt and Mesopotamia (now built a water-driven Huygens built the first Harrison built the marine Iraq) thousands of years ago. mechanical clock to pendulum clock. Driven chronometer—a spring-driven They are only able to tell the track the cycles of by the regular sweeps of timepiece that was accurate time when the Sun is shining. the stars and planets. a weighted pendulum, it over a long time, allowing was accurate to within sailors at sea to calculate a few seconds a day. longitude (see p.93). Su Song’s water clock 80

THE AGE OF DISCOVERY Inner dial How pendulum This catch Escape wheel Gears connect shows the clocks work swings back the escape wheel signs of and forth with to the second hand, the Zodiac. A pendulum clock can keep the pendulum, moving it forward excellent time because the every second. rate at which the pendulum alternately swings can be precisely catching and Hour hand controlled. Inside the clock, the pendulum regulates the releasing Drum Another set of rate at which a drum turns, the cogs on the gears from the via a catch on the escape main wheel wheel. A weight unwinds the escape wheel. moves the minute cord from around the drum The drum rotates and hour hands and turns the gears, which the main wheel that forward at the are connected to the minute connects through correct intervals. and hour hands. The weight gears to the minute takes eight days to unwind The falling weight Workings inside a the cord and then the cord and hour hands. unwinds a cord to pendulum clock must be rewound with a key. Each swing of the turn the drum. pendulum takes Minute hand one second. Atomic clocks Atomic clocks are the most accurate way of keeping time yet known. They keep time by counting the high-frequency waves emitted by energized atoms in elements such as caesium. A caesium clock will not gain a second in 1 million years. Outer dial shows the World’s first caesium 24 hours of the day atomic clock, 1955 in Roman numerals. Time zones run along Greenwich Mean Time International Time zones lines of longitude date line Since 1884, to standardize Modern watches the time around the Wristwatches have been world, the globe has been popular since the early divided into 24 time zones. 1900s. Today’s watches use quartz crystals to keep Times are measured from time and are powered by Greenwich Mean Time, or a battery, or even by solar GMT, with each zone either power. They display the hours ahead or behind GMT. time in analog (the way it For example, New York City appears on a traditional is five hours behind GMT and clock face) or in digital Tokyo is nine hours ahead. form, according to the New York City Areas that have Tokyo wearer’s preference. adopted a time between two zones Early digital watch, 1970s 1884 1927 1949 1970s Greenwich Mean Time The first quartz clock, driven The first atomic clock was built in Watches and clocks began to became the global by the natural electricity Washington D.C. In 1967, a show the time in digital form time standard after an generated by a rapidly second was redefined as the time using light-emitting diode international conference vibrating quartz crystal, that elapses during 9,192,631,770 (LED) or liquid-crystal display adopted the Greenwich was built at the Bell Telephone cycles of radiation from a (LCD) instead of a traditional meridian in the UK as the Prime Laboratories, New York City. caesium-133 atom. (analog) clock face. Meridian (line of 0° longitude). Marker for the Prime Meridian 81 Line at Greenwich, UK

1650 ▶1670 1654 Von Guericke made an Display of power early friction machine for producing static electricity. To demonstrate his understanding of vacuums, German inventor Otto von Guericke made two Von Guericke carries copper hemispheres, sealed them together, and out his experiment at emptied them of air using a vacuum pump he Magdeburg, Germany had invented earlier. Then he got two teams of eight horses to try and pull the hemispheres apart. They failed to do so because the external air pressure that kept the hemispheres pressed together so tightly was too strong. 1650 1655 1629 –1695 CHRISTIAAN HUYGENS Christiaan Huygens was a Dutch physicist, astronomer, KEY DATES mathematician, and instrument-maker. Best known for proposing that light is made of waves, he made 1654 Huygens began making improvements important discoveries in many areas of science. to telescopes with his He also traveled widely in Europe and met with brother Constantijn. many of the leading scientists of the day. 1656 He produced Astronomical discoveries his design for a pendulum clock. Huygens taught himself to grind the lenses for the telescopes he built. It was with his 1678 He proposed that light is made up of waves. 12-ft- (3.7-m-) long telescope, which could magnify objects 50 times, that he first 1689 He met Isaac Newton observed the rings around Saturn (see on a visit to England. p.87), and discovered its largest moon, later named Titan. Pendulum clock Swinging pendulum Huygens designed a clock keeps regular time. with a weighted pendulum that kept time accurately to within a few seconds a day—a vast improvement on existing clocks. 82

1662 THE AGE OF DISCOVERY Boyle’s law Lower transfuses blood from a lamb Anglo-Irish scientist Robert Boyle published to a man a law to show that the volume of a gas decreases with increasing pressure, and vice Artist’s impression versa. Boyle carried out many experiments of a dodo using an air pump he had made. Often called the father of modern chemistry, he introduced the idea of an element as a substance that cannot be broken down. Diffusion Pressure One weight creates Two weights pressure within double the the container. pressure within the container. Dead as a dodo 1666 The dodo, a large flightless bird, had become extinct Blood transfusion by 1662. It lived only on Richard Lower, an English doctor, carried the island of Mauritius in the out a successful blood transfusion Indian Ocean, where it was between two dogs. A year later, he injected a small quantity of lamb’s hunted for food by visiting blood into the vein of a human patient, European sailors. who appears to have survived despite the risk of a massive allergic reaction. Evenly spread Higher pressure packs molecules the molecules into half of the original space. 1665 1670 Network of Malpighi’s 1669 1669 capillaries drawing of a covering frog’s lungs Fossils in rock A new element exterior of lung Danish geologist Nicolas In his search for the “philosopher’s Steno explained that sediment stone,” to turn base metal into gold, formed horizontal layers of rock (called strata) over time. German alchemist Hennig Brand As new strata formed on top, boiled up concentrated human animal remains within each layer turned gradually into urine and accidentally discovered fossils. So the oldest fossils the element phosphorus, which are always at the bottom, with gives off a greenish glow. the newer ones above them. Cross-section Hennig Brand 83 shows tiny sacs is said to have used 1,250 gallons called alveoli (5,670 liters) of human urine in 1661 his experiments. Microscopic discoveries Hennig Brand in his laboratory Italian biologist Marcello Malpighi used a microscope to study the structure of the lung. He discovered capillaries, the minute blood vessels that connect the veins and arteries. William Harvey had suggested 30 years earlier that these blood vessels existed (see p.75).

Looking Eyepiece lens Scientific bestseller closely Micrographia, published by Robert Hooke in The invention of the microscope 1665, introduced the public to the world of the revealed a whole new world. microscope. It included wonderfully detailed For the first time, scientists could drawings of the objects observed through his observe objects too small to be seen microscope, including fleas, hairs, and even a with the naked eye. Researchers began fly’s eye. The book became an instant bestseller. to understand the building blocks of life as they studied the structure of Hooke’s cells and discovered the existence of illustration microorganisms. Today, microscopes of a flea can even identify individual atoms. Water-filled sphere focuses light from oil lamp. Wooden barrel Discovering cells Lens concentrates light onto specimen. Robert Hooke, a noted English 19th-century poster celebrates Janssen scientist, was the curator of and his invention of the microscope experiments at the Royal Society in London, England. He designed a compound microscope that used a water-filled sphere to focus light from an oil lamp onto the specimen. Hooke noticed the spaces between long empty cell walls in a piece of cork he was examining and first coined the word “cell” to describe them. The first microscope Specimen mounted on pin By the 1590s, Dutch spectacle-makers were making microscopes by fixing two lenses in a tube. They found that Hooke’s light, refracted by the two lenses, made objects larger than compound a single lens did on its own. One of these spectacle-makers, microscope Zacharias Janssen, may have made the first microscope. Key events 1590 1661 1665 1674 1860 Zacharias Janssen is Italian biologist Marcello Robert Hooke published Antoni van Leeuwenhoek French chemist usually credited with Malpighi saw red blood Micrographia. It contained designed a single-lens Louis Pasteur used the invention of the first cells, which he called illustrations of the tiny microscope that was a microscope to compound microscope. particles, through objects he had observed able to magnify objects carry out research a microscope. through a microscope. up to 270 times. into disease- carrying microbes. 84

Leeuwenhoek’s drawings of microscopic life How a compound Eye looking microscope works through Single-lens microscope eyepiece lens Compound light microscopes use at Eyepiece lens Dutch scientist Antoni van Leeuwenhoek was least two lenses. Light from below is Path of light able to achieve greater magnifications with his reflected up through the object single-lens microscopes than Robert Hooke did being viewed—the specimen— Objective with his compound microscope. Leeuwenhoek into the objective lens, which lens used ground all his lenses himself, some of them no produces the first magnification. to magnify bigger than a pinhead. The eyepiece lens then magnifies specimen the image again. Oil lamp Specimen Mirror reflects light through specimen. The world 2,000 times 10 million times 1 billion times magnified This 19th-century light Electron microscopes fire The scanning tunneling microscope can magnify a beam of electrons at a microscope (STM) uses Today, there are three objects up to 2,000 times. specimen contained in a sharp metal probe to kinds of microscope. Its achromatic lenses a vacuum. This example, scan the surface of an Researchers use light, create a sharper image by dating from around 1946, object at an atomic level, or optical, microscopes focusing different color was one of the first to be allowing scientists to to view biological wavelengths together. mass-produced. Modern “see” individual atoms. The specimens such as versions can magnify up atomic force microscope cells and tissue. Electron to 10 million times. works in a similar way. microscopes, including the scanning tunneling microscope, which use a beam of electrons to reveal an image, can look at much smaller things in very great detail. 1880s 1882 1903 1931 1981 Working for German German microbiologist German chemist Richard German physicist Ernst The scanning tunneling instrument-maker Carl Robert Koch developed Zsigmondy built the Ruska invented the microscope was the first Zeiss, German optical ways of staining bacteria ultramicroscope, which let first scanning electron that allowed scientists to scientist Ernst Abbe made with violet dye to make him view objects that could microscope (SEM) that see at an extremely small radical improvements to them more visible under not be seen with a used electron beams scale, down to a nanometer microscope design. a microscope. light microscope. to create images. (a billionth of a meter). Zsigmondy’s ultramicroscope 85

1670 ▶1690 1678 1672 CmaS1elac2ecu4phl–aai1ntg2ieen5ssg Hooke’s law Rainbow colors 1672 English scientist Robert Hooke observed that the force needed to stretch a spring is proportional English physicist Isaac Newton Calculating questions (see pp.88–89) published a to the distance it stretches. If the force is doubled, Gottfried Leibniz, a German the distance is doubled. There is a point beyond paper on light. He described an mathematician, created a experiment he had carried out calculating machine called which the spring does not stretch, but snaps. using two prisms to show that the step reckoner. In 1674, white light is made up of the he invented calculus, the Length of seven colors of the rainbow. mathematics of infinitesimal unstretched (very small) changes. Isaac spring Newton’s sketch of his Newton (see pp.88–89) also experiment with prisms devised a version of calculus, The spring When the Weight is and the two men fell out over is stretched force applied doubled who had done so first. when a force is doubled, is applied. the spring Object applies stretches twice as far. downward force on spring. 1670 1675 1675 1679 Astronomer to the king Steam digester England’s King Charles II appointed John Flamsteed the first French inventor Denis Papin Astronomer Royal to head a new observatory in Greenwich, demonstrated a cooking device London. This observatory marked what would later become that used high-pressure steam to extract fat from bones. A forerunner the Prime Meridian (0° longitude) between east and west. of the modern pressure cooker, Papin’s digester was fitted with a steam release valve and a piston, leading in time to the development of the steam engine. Lens for viewing Screw adjusts microscopic position of samples specimen. 1676 Leeuwenhoek’s microscope Life in miniature Antoni van Leeuwenhoek, a Dutch merchant, made his own microscopes. He used them to observe tiny living creatures swimming in a drop of water, which he called “animalcules.” These were, in fact, single- celled protozoans called amoeba. Royal Observatory, Greenwich, UK

1625–1712 GIOVANNI CASSINI THE AGE OF DISCOVERY Born in Italy, astronomer Giovanni Cassini moved to France in 1669, Isaac Newton where he was put in charge of the Paris Observatory. Among his was born in 1642, the year contributions to astronomy, Cassini calculated the that Galileo died. distance from Earth to Mars, and from Mars to the Sun. His figures were close to current estimates. He Dental discovered four of Saturn’s moons—Iapetus, Rhea, hygiene Tethys, and Dione—and also shares credit with One of the first books on English scientist Robert Hooke for the discovery of dentistry was published a storm on Jupiter known as the Great Red Spot. in 1685. It recommended brushing teeth only once The large Rings around Saturn a week. Not surprisingly, gap between most people had rotten Saturn’s rings is In 1675, Cassini identified teeth, which had to be known as the a gap that appeared to divide extracted by force. “Cassini Division.” Saturn’s rings into two. He also correctly suggested that the rings were made up of thousands of tiny particles. 1685 1690 1686 Newton’s universal law of gravitation New term Gravitation exerts an identical force on two objects, pulling them together. In Historia Plantarum, a three-volume history of plants, English naturalist Doubling the mass of both objects increases the forces to four times John Ray used the word “species” to describe a group of plants or animals their original strength. sharing the same characteristics and Doubling the distance between them able to breed with one another. It reduces the forces by a quarter. was the first biological use of the term, and established “species” as 1687 the basic unit of taxonomy (the Breakthrough science classification of living things). His Isaac Newton published a book called Principia book described 18,600 species. Mathematica in which he described his three laws of motion and the universal law of gravitation. According Title page of John Ray’s Isaac to the latter, the force of gravity between two objects Historia Plantarum SNee8ew8p–at8og9nes is stronger as their masses increase, and weaker when the distance between them is bigger. These four laws One species never springs together form the basis of mechanics—the science of forces and how things move. “from the seed of another ”nor vice versa. 87 John Ray, Historia Plantarum, 1686

3. Observer sees reflected image GREAT SCIENTISTS from small mirror through eyepiece. Isaac Newton 2. Concave mirror reflects image back British scientist Isaac Newton was born in the village up tube onto angled of Woolsthorpe, England, in 1642. One of the leading small mirror. minds of the 17th-century scientific revolution, he is best known for outlining the law of universal gravitation 1. Light to explain what holds the Universe together. enters telescope tube. Replica of Reflecting telescope Schoolboy and student Newton’s While he was studying Newton’s interest in science and mechanics became apparent at reflecting optics, Newton built the an early age. An uncle recognized his ability and encouraged him telescope, first reflecting telescope, to continue his studies at a university. In 1661, he became a c 1672 using two mirrors to reflect student at Trinity College, Cambridge, England. and focus the image. It gave Escape from the plague a better result than the When the plague broke out in Cambridge in 1665, Newton traditional refracting withdrew to Woolsthorpe. He is said to have developed his theory telescope (see p.71). of gravity after seeing an apple fall from a tree in the orchard there. This is probably just a story, but it was during his time at If I have seen further it is Woolsthorpe that he developed his ideas on gravitation and made his first experiments with light. “by standing on the shoulders ”of giants. Cambridge professor Returning to Cambridge, Newton was appointed Lucasian Professor Isaac Newton, in a letter to Robert Hooke, 1675, of Mathematics at the age of 26. In 1687, he published Philosophiae supposedly acknowledging earlier Naturalis Principia Mathematica (usually called the Principia work by other scientists Mathematica), one of the most important works in the history of science, and where he described his three laws of motion. Principia Mathematica Later years Newton’s most famous book was published with the In 1689, Newton became a Member of Parliament and moved to help of fellow scientist Edmond Halley. In this book, London. Appointed Master of the Royal Mint in 1699, he reformed Newton described the universal law of gravitation the coinage and took severe measures against forgers. He was (see p.87) and the three laws of motion (below). elected President of the Royal Society in 1703 and made a knight in 1705. He died in 1727 and was buried in Westminster Abbey. The laws of motion 1. Without speed to 2. With added speed, 4. With even greater speed 1. An object remains carry it forward, the ball follows a curve the ball travels so fast it at rest or continues gravity pulls the for some distance before escapes Earth’s gravity moving in a straight gravity pulls it back to Earth. and goes off into space. line unless a force ball straight down. acts upon it. 2. The greater the 3. If the speed is Newton’s cannonball mass of an object, the greater, the ball To explain why one more force it will take object orbits another, to accelerate it. goes into orbit Newton imagined around Earth firing a cannonball 3. For every action, horizontally from the there is an equal and because Earth top of a very high opposite reaction. is rotating away mountain on Earth. In each experiment Title page of from the ball he would increase Principia Mathematica as fast as the the velocity (speed) at ball is falling which the ball travels. toward Earth. 88

THE AGE OF DISCOVERY Studying light Newton made many studies of light. In his book Opticks, published in 1704, he described light as a stream of tiny particles traveling at speed and showed that white light contains all the colors of the rainbow. “To myself I seem to have been only like a boy playing on the seashore... while the great ocean of ”truth lay all undiscovered before me. Isaac Newton 89

1690 ▶1710 In 1699, Welsh naturalist and museum keeper Edward Lhyud Fruit 1694 published the first illustrated catalogue of British fossils. Secrets of flowers Comparing brain sizes German botanist Rudolf Camerarius provided Macaque monkey Chimpanzee Human brain scientific proof that brain brain flowering plants 1699 reproduce sexually. He showed that pollen, a Chimpanzee study powdery dust produced Edward Tyson was an English physician on the male stamens, is and anatomist. He dissected the body of a necessary for fertilization chimpanzee, which he called an orang-outang, of the female germ cells or “man of the woods.” The creature had been brought to London on a ship from Africa and (called ovules). When died shortly afterward. Tyson concluded that its he removed the anatomy, particularly its brain, was closer stamens, the flowers to that of a man than a monkey. failed to seed. Flower Castor oil plant, studied by Camerarius 1690 1695 1697 1698 3. Tank showers Mistaken theory Steam pump water on vessel to Georg Stahl, a German chemist, argued that a English inventor Thomas Savery condense substance or “essence” called phlogiston is designed a steam pump to extract steam. released into the air whenever something floodwater from mines. It worked by is burned, leaving the calx (or ash). His condensing steam to create a vacuum. theory was widely believed until disproved As air rushed in to fill it, atmospheric by Antoine Lavoisier (see p.107). pressure forced up water from the World mine. The entire process was traveler controlled by a system of taps. William Dampier, an English adventurer, sailed 2. Steam enters three times around the world, vessel beneath making one of the earliest cold water tank. scientific expeditions to the coast of New Holland (now 1. Water in boiler Australia). He wrote a is heated to best-selling account of his voyages. produce steam. Model of Savery’s steam pump Dampier drew this 90 bird on his voyage to 4. Water New Holland in 1699. from below is forced up pipe.

Crowds turn out to admire Halley’s Comet 1705 THE AGE OF DISCOVERY on its appearance in 1835. Mercury thermometer Halley’s prediction by Fahrenheit, c 1718 English astronomer Edmond Halley predicted that “... I dare venture a comet he had observed in 1682 would be seen again from Earth in 1758. His prediction proved to foretell, That it [the comet] will correct. The comet, which is visible roughly every 75 years, is now known as Halley’s Comet. ”return again in the Year 1758. Edmond Halley, A Synopsis of the Astronomy of Comets, 1705 1709 Handy thermometer Gabriel Fahrenheit, a Polish physicist working in the Netherlands, made the first compact, modern-style thermometer. It had a series of scaled markings and was filled with colored alcohol, which expanded as the temperature rose. Later versions used mercury. Fahrenheit devised the temperature scale named after him in 1724. 1701 1705 1710 Agricultural pioneer Sheep and cattle were 1708 improved by selective Jethro Tull, an English farmer, breeding in order to Porcelain discovery invented the mechanical seed produce more meat. drill—a device that planted Porcelain, a bluish-white seeds in neat, evenly spaced Hopper ceramic imported from China, rows. His drill wasted much contains seed was extremely popular in less seed than the traditional Europe, but no one knew method of scattering it by how to make it. After 20 hand. Although Tull’s invention years of experimentation, did not catch on at first, it Ehrenfried von Tschirnhaus, would have a key role in a German scientist, found modernizing farming. the secret: a paste made of kaolin (a fine white clay) mixed with alabaster. Plow digs Tube drops The farmer’s yield is furrow for seeds seed into increased because furrow the seeds have more Jethro Tull’s space to grow. seed drill Handles guide drill 91

Traveling Celestial navigation the world The sextant was a highly accurate instrument The word “navigation” originally meant finding used to determine latitude (position north or your way at sea. For centuries, sailors would keep south of the equator) by measuring the angle close to the coast, using landmarks and local between the horizon and the Sun during the knowledge of currents and weather conditions day, or the Moon, planets, and stars at night. to navigate by. Later, they used compasses to Invented in the 18th century, it remained the indicate the direction in which to sail and they ultimate navigational tool until the arrival developed navigational aids to calculate their of satellite navigation (sat nav). position at sea. Now we use the term navigation to mean finding your way anywhere. Top mirror 2. Lower mirror reflects light to the telescope and is fixed on the horizon. Early mariners’ compass, c 1500–1700s Portolan chart of the Gulf of Mexico, 1547 Arc measures one-sixth (sextant) Early navigational chart of circle. This portolan is drawn “upside-down” with south at the 1. Movable arm adjusts top top. Places along the coast are carefully named and located, mirror to reflect light from while inland areas contain fanciful scenes. Compass “roses” Sun onto lower mirror. give direction. The captain plotted a course by following the lines that crisscross the chart from the roses. Key events 1000 1300 1400 1569 The Vikings used a Knowledge of the magnetic European sailors began using Mercator’s map projection, device called a sun compass reached Europe coastal charts called portolans on which lines of latitude and compass (a wooden disc from China, where it had in combination with a compass longitude intersect at right with directional markings) been in use for at least to plot a course from port to port. angles, made it easier to to help them navigate by 1,000 years. navigate at sea. the Sun. Viking sun compass 92

THE AGE OF DISCOVERY Log float with gauge, c 1861 The marine chronometer Measuring speed In the 1700s, ships were frequently lost at Speed at sea is measured in knots because sea because captains had no way of keeping sailors used to throw a rope (also called a log) track of longitude (how far the ship has tied with knots behind their ship. They allowed traveled east or west). To do this required it to roll out for a specific amount of time, then an accurate clock that would always show counted the number of knots to calculate how the right time back at home port. Sailors fast the ship was moving. Later, a log float with worked out their longitude by comparing a mechanical gauge was thrown from the ship. that time with “local” time. This was difficult to achieve on board a rolling ship. After working on the problem for many years, John Harrison built the first accurate marine chronometer (timepiece) in 1759. The original designs for Harrison’s chronometer. It was about the size of a large pocket watch. 3. Telescope Lighthouses focuses light from mirrors so you The Romans built the first see the Sun on lighthouses at the entrance to the horizon. harbors. Modern lighthouses date from the early 1800s. They were 4. Angle between designed to prevent shipwrecks by horizon and the Sun shining a powerful beam of light is read off the scale. to warn approaching ships of Sextant, 18th century dangerous hazards such as rocky reefs. Early lighthouses were often built on rocky outcrops. Satellite navigation Sat nav systems such as GPS (Global Positioning System) use a series of global satellites to work out where a receiver is located. The receiver, which could be a smartphone, picks up signals from at least four satellites to instantly calculate its position and speed (see p.232). 1750 1759 1935 1990 Sextants, navigational instruments John Harrison built an Radar, which locates unseen objects GPS, the first sat nav system, used to measure the altitude of the accurate marine chronometer by bouncing radio waves off came into use. It quickly planets and stars, had come into use. to calculate longitude at sea. them, was invented. It is replaced most other Sailors used them to determine used on ships to reveal latitude at night as well as day. coastlines and navigation aids. other ships. Radar screen 93

1710 ▶1730 “The whole cavity of the bell was kept entirely free from water, so that I sat ”on a bench… with all my clothes on. Edmond Halley, on going underwater in the diving bell, 1715 Illustration of Halley’s diving bell, from a 19th-century encyclopedia 1715 Halley’s diving bell English scientist Edmond Halley designed a practical diving bell. An air-filled, weighted barrel was suspended next to the bell and kept it constantly fed with air through a hose. Halley dived to a depth of 60 ft (18 m) inside his bell and remained submerged for 90 minutes. Diving bells were used to recover goods from sunken ships. 1710 1715 1712 1716 MALARIA Practical steam engine Italian physician Giovanni Lancisi argued that mosquitoes, which Thomas Newcomen, an English engineer, breed in swamps, are responsible built the world’s first practical steam for spreading malaria. Few people believed him at the time, but he was engine, designed to pump water out of proved right in 1894. mines. A growing demand for coal meant Female 6. It bites another 1. An infected that mines were being dug deeper, and Anopheles person, who also mosquito lands flooding was a serious problem. mosquito becomes ill with malaria. on a human host. 4. The up-and-down action of the Malaria lifecycle 2. Its bite infects the pump expels water from the mine. host with parasites Malaria is transmitted carrying malaria. 2. The rocking beam to humans in the bite 3. The parasites falls, pushing the of infected female pump down. Anopheles mosquitoes. multiply in the liver. Tiny parasites from the 3. Cold water sprays mosquito’s saliva enter into the cylinder to the victim’s bloodstream condense the steam. and multiply in the liver, This creates a vacuum causing fever. that forces the piston down and the pump up. 5. A second mosquito is 4. More red blood infected after feeding cells are infected. 1. Steam from the on the host’s blood. boiler enters the cylinder, pushing the piston up. Fire 94 Diagram of Newcomen’s steam engine

THE AGE OF DISCOVERY Sweet tooth Illustration from 1729 Pierre Fauchard, The Surgeon Dentist, a French doctor, published in 1728 was the first person to link the eating of sugar Electrifying experiments to tooth decay. In his book Stephen Gray, a self-taught English scientist, was an early The Surgeon Dentist, he urged people to give pioneer of electricity, which he produced by friction. He up eating sugar. was able to conduct an electric charge hundreds of yards along a thread, which was draped through the house and out into the garden. He later put on public displays of electricity, including a spectacle called the Flying Boy. 1721 2. The charged 3. Silk 4. The static charge rod is passed over cords from the boy’s face Smallpox protection act as and hands attracts the boy’s body insulators. pieces of paper. Variolation was a way of protecting to give him an healthy people from getting smallpox electrostatic charge. by scratching them with infected material from a smallpox scab. It became fashionable after members of the British royal family underwent the procedure. Instrument used 1. A glass rod to puncture the is rubbed to skin in variolation generate static electricity. 5. A small ivory ball is also attracted. Gray’s Flying Boy 1725 1730 1725 StehT8ee0epl–tla8iinmg1gees 1727 Speedy weaving Indian observatory Basile Bouchon, a French silk maker, Jai Singh II, Maharaja of the kingdom invented the first semiautomated of Jaipur, India, began constructing the Jantar Mantar astronomical observatory weaving machine. He came up with a at Jaipur. It contained a collection of way to speed up weaving by using a massive astronomical instruments built perforated paper tape to control of brick and stone—including the world’s the raising of the warp threads on largest sundial, Samrat Yantra. the loom. His invention was the forerunner of other programmable This triangular wall is This wall is a scale that machines, such as the computer. the gnomon (the part of registers the position a sundial that casts a of the shadow cast by Samrat Yantra shadow from the Sun). the gnomon. sundial The shadow travels at a rate of about 0.04 in (1 mm) per second. Samrat Yantra, the sundial at Jantar Mantar, has a height of 88 ft (27 m).

1729, ENGLAND Celestial atlas This atlas of the heavens (Atlas Coelestis) was published in 1729—ten years after the death of its author John Flamsteed, Astronomer Royal of Great Britain. It is based on his detailed observations of 2,935 stars visible with a telescope from the Royal Observatory at Greenwich. Atlas Coelestis was one of the first major atlases to be based on observations through a telescope, and was considered much more accurate than previous star atlases. 96

THE AGE OF DISCOVERY The constellations of the northern and southern hemispheres from the Atlas Coelestis You are to apply the most exact care and diligence “ ”to rectifying… the places of the fixed stars. King Charles II’s instructions to John Flamsteed on making him Astronomer Royal, 1675 97

1730 ▶1750 Stretchy stuff While in the Amazon Seismic 1731 waves rainforest, French See page Earthshaking discovery explorer Charles de la Condamine came across 164 Inventor Nicholas Cirillo used a the substance rubber, Laura Bassi pendulum to measure earthquakes which is obtained from in Naples, Italy. The amplitude of a rainforest tree called the pendulum’s sways (the extent Hevea brasiliensis. He of their back-and-forth movement) indicated where the earth tremors sent samples back were most intense. His device to Europe. was the first seismograph. Incision made in 1731 the tree’s bark Female pioneer Page from Linnaeus’s Rubber latex fluid Systema Naturae collected from tree Italian academic Laura Bassi was the first woman to hold a 1735 university post in science when she was appointed Professor Classifying life of Anatomy at the University of Bologna, Italy. A year later, she Swedish botanist Carl Linnaeus divided was also made Professor the natural world into three kingdoms— of Philosophy. animal, plant, and mineral. In his book Systema Naturae, he introduced the binomial (two-name) system that classified plants and animals by genus and species. This system is still used today. 1730 1734 1738 1733 1738 The flying shuttle Bernoulli’s principle Invented by Englishman John Kay, Swiss mathematician Daniel the flying shuttle was a simple Bernoulli stated that as the device that revolutionized the textile speed of a moving fluid industry. On a loom, the shuttle (liquid or gas) increases, the drew the weft (yarn) through the pressure within it decreases. warp (lengthwise threads). The His principle explains how an weaver then passed Kay’s aircraft gains lift because air flying shuttle, which was in flows faster over the top of its a box attached to a cord, wings and slower underneath. at high speed back and forth across the warp. Bernoulli published his principle in a book, Bornite, an ore 1735 Hydrodynamica containing cobalt Bobbin Shuttle Goblin ore (spindle) Georg Brandt, a Swedish of yarn mineralogist, identified the element Rollers reduced friction cobalt, which is present in Earth’s for greater speed. crust in combination with other minerals. The name cobalt comes from the German word kobold, meaning “goblin ore.” Pitot tubes, invented in 1732 to measure how fast rivers flow, are still 98 used to measure airspeed on aircraft.