The Newtonian Era 1660-1734
If the science of this era were to be categorized, most would say that science became organized during this time. Various scientific academies started during this era, the strongest being the Royal Society in England in 1660. This would be followed by the Royal Academy being formed in Paris in 1666. Communication between these academies allowed for the sharing of new discoveries. Once again, we return to “trade” as being the impetus for science to flourish. The use of the same scientific method by all of these scientists made sure that the discoveries could be tested and were genuine. Observation and experimentation became the pillars of all scientific activity, while relying on the writings of the ancients became less and less accepted. Isaac Newton called this new method a system of “analysis and synthesis”; a process that he felt should be both inductive and deductive. It should be based on observation to formulate theories followed by experimentation, which would then be used to predict other phenomena. Newton also tried to link natural phenomena to mathematical laws. In Newton’s opinion, the presence of a direction to natural laws implied the presence of a “Perfect Being” that created the universe.
In fact, the joining of science and religion remained strong during this era. Newton, himself, was very religious. Many books were written that tried to explain astronomy and creation through scientific and spiritual paths. However, some separation still remained as various books continued to be banned due to disagreeing with the church. In 1664, Rene Descartes had books about animals and the Copernican model banned. In his book about animals, Descartes explained that animals were mechanical beings in that there was no “life force” that made them different from other material objects. It is simple to see why this may bring about a ban from the Church.
Measurement of the experiments also became very important during this era. Values for weight, volume, temperature and time were necessary for scientific accuracy. The instruments for these measurements became more and more reliable as well as more available to the general public. However, scientists also struggled with new measurements such as heat, electricity and chemical energy.
A by-product of all this experimentation was some confusion. Many of the observations discovered during experiments could not be explained or understood. Still, experimentation would serve as the foundation of all science for the next 300 years.
In keeping with a previously mentioned theme, Newton would become a great scientist by “having time to sit around and think”. Newton was at Cambridge in 1665 when the great plague struck England, killing 75,000 people and closing Cambridge for two years. This allowed Newton to retire to his parent’s home in the country where he would develop a form of calculus, discover that white light can be separated into all colors, and develop the law of universal gravitation. He observed that an apple and the moon must be attracted toward the Earth. The story about getting hit by an apple while sitting under a tree was largely believed to be made up by Newton in his old age. However, this “free time” allowed Newton to “sit around and think”.
Isaac Newton was definitely the lead scientist of this era, if not of all time. Newton was recently chosen by A&E Biographies as the most influential person of all time. Newton achieved many accomplishments during his lifetime. He was the president of the Royal Society, a member of the House of Commons and a professor at Cambridge University. His Law of Gravitation and 3 Generalizations of Motion completely revolutionized the scientific community. He invented the first reflecting telescope. Finally, his book Principia became one of the most important scientific texts of all time. In this book, Newton sets out to settle a score with Robert Hooke. Hooke had previously given Newton a poor review on a paper Newton wrote to the Royal Society. So, when Newton heard that Hooke was going to release a paper on the orbits of the planets and the laws that govern them, Newton set out to prove how this worked. By writing Principia, Newton unified the mechanics of Galileo with the mathematics of Kepler. He demonstrated the attractive force of gravity and how the planets orbits must be elliptical. Amazingly, Newton might have never published this work if it wasn’t for the coaxing by friend Edmund Halley to do so. Newton was very fearful of exposing his work in print and was believed to be very sensitive to criticism. It is frightful to think of our lives without his discoveries.
Much advancement took place in astronomy during this era. Newton’s Law of Universal Gravitation strengthened most of these. Newton’s ideas also gave creditability to Copernican and Kepler’s previous theories. Newton’s invention of a reflecting telescope in 1668 (first described by James Gregory in 1663) would open up the skies and lead to more discoveries. A reflecting telescope used mirrors to focus light through a lens instead of just lenses. Giovanni Cassini made many of the new discoveries with the reflecting telescope and could be considered to be the lead astronomer of this era. Cassini was the first to describe the rotation of Jupiter and discovered the polar ice caps on Mars. The rotation of Jupiter was aided by the discovery of the Great Red Spot on Jupiter by Robert Hooke the previous year in 1664. Cassini went on to calculate the orbits of the four satellites of Jupiter in 1668 and then discovered Iapetus, a fifth moon of Jupiter in 1671. Also in 1671, Cassini used Kepler’s third law of planetary motion and his own observations to calculate the distances of the planets from the Earth, just as Kepler had determined the distances from the planets to the Sun. Cassini’s study of the solar system was not limited to Jupiter. In 1672, he discovered Rhea, a new moon of Saturn, followed by the discovery of Dione and Theyts in 1684. In 1675, Cassini noted that the rings of Saturn were not one solid ring. Instead, there was a separation within the rings. This division is still known as the Cassini’s Division today. Cassini’s final observation would be in 1712, when he passed away. The other leading astronomer of this time would have to be Edmund Halley. Halley is most famous for his prediction of the return of the Great Comet. In 1682, he observed the Great Comet. In 1705, he compared other documentations of the Great Comet in 1607 and 1682, he predicted that the Great Comet would return in 1758, which it did. Sadly, Halley died in 1742, so he never saw his prediction come true. This did prove that Newton’s Law of Gravity applied at least as far as the distant borders of our solar system. Halley was also one of the first to catalogue 341 stars of the Southern Hemisphere in 1679. Before this, majorities of the people were living in the Northern Hemisphere, but navigation to other parts led to a need to catalogue the stars. Some other discoveries of this era include the rotation of Venus in 1728 and an observation of the Aurora Borealis by Anders Celsius.
Giovanni Cassini Edmund Halley
Finally, with the expansion of the solar system and many discoveries within, everyday thought began to change. One of these thoughts was of the Sun being just one of a myriad of stars which, in turn, led to the idea that humans are no longer at the center of the universe.
What is the Great Red Spot on Jupiter? How does its size compare to that of Earth?
What is the common name for the Aurora Borealis?
What would Anders Celsius become famous for besides observing the Aurora Borealis?
As the astronomy of this time would be aided by the invention of the reflecting telescope, biology was aided by its own “scope”. Zacharias Janssen invented the microscope during the previous era in 1609, the same year Hans Lippershey invented the telescope. It should be of little surprise to see that the telescope and microscope were both invented by the Dutch. Being navigators of the oceans, they would have a definite need for the telescope. That same technology could be employed to look at small objects and make them appear larger. Robert Hooke would use this microscope to describe “tiny rooms” that he saw in cork. He called these tiny rooms “cells”. However, it is Anton van Leeuwenhoek and his simple microscope that would make a majority of the discoveries of this time and thus the microscope is placed within this unit. Anton was talented in the grinding of lenses of which he made 400 during his lifetime and he invented his own microscope in 1673. He would use this microscope to discover protozoa in 1677. This is the first time humans would see single-celled organisms. This would lead Leeuwenhoek to write a book entitled The Mysteries of Nature, in which he made very detailed drawings of his discoveries that would be leading reference for many years to come. The same year, Leeuwenhoek would confirm the discovery of sperm described by Louis Hamm. However, Leeuwenhoek disagreed with Hamm about what sperm were. Hamm claimed that sperm were evidence of disease in males. Leeuwenhoek thought sperm were the source for reproduction. Sadly, he thought that sperm were actually tiny human larvae that would simply grow inside of the female. In 1683, Leeuwenhoek would be the first to describe bacteria. It would be 50 years until someone else would see and describe bacteria. Otto Muller did this work as he classified bacteria in 1730.
Now that new organisms had been discovered, they needed to be classified. John Ray would lead this charge, first with plants and later with animals. Ray began his classification of plants in 1667. By 1686, Ray had classified 18,600 plants. He based his classification on monocots and dicots. Seven years later, Ray would start his work with the classification of animals. He based his classification of animals as Aristotle did, by starting with blooded and bloodless. Ray also followed Aristotle by classifying whales as mammals. Carolus Linnaeus would use this groundwork in his classification system that we still use today. Other scientists were also working hard at classifying organisms, often through the use of dissection to help with anatomies. In 1669, Marcello Malpighi described the anatomy of a silkworm, which was the first invertebrate to be dissected for comparative anatomy. Francesco Redi dissected a torpedo fish in an attempt to discover how the torpedo fish was able to generate an electric charge. With all this dissection going on, Nathaniel Grew decided it was time for a new “branch of science” called comparative anatomy, which he coined in 1676. Another scientist named Luigi Marsigli began his work on sea corals. He discovered that the coral was actually an animal rather than the plant it was believed to be. In 1694, Rudolph Jakob Camerarius provided experimental evidence about plants that had been first hypothesized by Theophrastus. Camerarius proved that plants have two distinct sexes and reproduce sexually. He performed experiments where he would remove the stamen of one plant or the stigmas of another plant. These plants then lost their ability to seed. These experiments would set the groundwork for Gregor Mendel and his experiments on the laws of heredity. Finally, in 1734, Rene de Reaumur would write a book entitled The History of Insects, which would be the leading work in entomology for many years.
During this era, there were two questions that remained on scientists’ mind. The first was “Where did we come from?” the second was “What are we?” The first question was more of a touchy subject due to religious implications. One of the first experiments to try and solve the question of “Where we came from?” was done by Francesco Redi. At this time there was a belief in a theory called “Spontaneous Generation”. According to this theory, “Life could spring from non-life”. Again, this idea had its roots go all the way back to Aristotle. Aristotle believed that turtles come from mud and decaying wood. He also believed that rats came from straw. Later ideas included that flies come from rotting meat. It is this final idea that Redi wanted to disprove and hopefully disprove Spontaneous Generation as well. This experiment will be discussed more at a later date. In 1673, Marcello Malpighi described the development of a chicken within the egg. Two years later, Nicholas Steno would use this information to claim that mammals had eggs, a view that was widely disputed.
The second question, “What are we?” was attempted to be answered though the study of human anatomy. In 1660, Marcello Malpighi was the first to describe the important function of the lungs in the circulatory system as he discovered that they are connected. In 1665, Malpighi would also describe the nervous system. Not all scientists were willing to work with human subjects. Richard Lower performed one of the first blood transfusions during his work with two dogs. Three years later, Lower would use this experiment to aid him in describing the structure of the heart and the color change in blood as it enters and leaves the lungs. Jean-Baptiste Denis would take this to the next step when he tried to cure a sick boy by transfusing 350 ml (12oz) of lamb’s blood into the boy. The boy ended up being cured. Denis was not always so successful. Two other boys died after receiving blood transfusions from lambs and Denis was tried for murder. He was acquitted, but transfusions were banned in France.
Why would very intelligent people believe in the theory of Spontaneous Generation? Is this idea supported in any way?
Now that we were classifying many new types of organisms, how do you think we gave them names? Think historically.
Earlier, we discussed some of the contributions made by Isaac Newton during this era. If there were one area of science, in which Newton would excel, it would be in physics. Newton would create two theories that would explain many of the discoveries of the past and set the foundation for future discoveries. In 1679, Newton received a letter from Robert Hooke. Hooke was asking Newton about the motion of the planets as described by Kepler. Hooke believed he had figured out a mathematical explanation of why the planets moved the way they did. Kepler had explained how the planets moved, but couldn’t explain why. Newton thought about this idea but failed to write Hooke back. Hooke began to boast that he had solved the problem of planetary motion in 1680. Newton knew that Hooke’s calculations were wrong but did not want to embarrass Hooke. Edmund Halley then visited Newton and asked him about the problem of planetary motion. Newton told Halley that he had already calculated the answer and the effects of gravity on planetary motion. This is known as the inverse-square law. In 1686, Newton would write the book for which he is probably the most famous. Principia included the inverse-square law, the 3 laws of motion, and the Law of Gravitation.
The inverse-square law states that the gravitational attraction of an object varies inversely with the distance between the objects squared. Again, this can be used with the planets and the Sun. Newton is probably most famous for his Three Laws of Motion. These are often called the Three Generalizations of Motion since they do not always hold true. Here are the Three Generalizations:
1. An object at rest will remain at rest or an object in motion will remain in
motion, until acted upon by an unbalanced force. INERTIA
2. If an object is acted upon by an unbalanced force, the object will move in the direction of the force and with the magnitude of that force. F= ma
3. For every action, there is an equal and opposite action.
Newton’s Law of Gravitation had many implications. First, it helped explain the motions of the planets. Second, it helped explain the curvature of the Earth. There was a wide debate on where the Earth was flattened and where it was curved. Many believed that the Earth was flattened at the equator and rounded at the poles. Many believed just the opposite. Newton’s Law of Gravitation implied that the Earth would be flattened at the poles and rounded at the equator. Rene Descartes believed the opposite. Jacques Cassini, the son of Giovanni, made measurements that seemed to agree with Descartes. Later, two other explorers would make journeys towards the equator, which lasted 10 years. Their measurements backed Newton and proved that the Earth is flattened at the poles. A second challenge to the Law of Gravitation was that it didn’t seem to explain the motion of the moon. A modification was needed because the Moon is affected by the gravity of the Earth and the gravity of the Sun. This is known as three bodies problems. Again, the Law of Gravitation was proven to be correct. The Law of Gravitation received one more vote of validation when a mathematician would use it to calculate the exact date for the return of the Great Comet. The comet returned at the predicted time.
The same time that Newton was working on his ideas, a scientist named John Wallis was working on his own theory. In 1668, Wallis wrote the Law of Conservation of Momentum. Basically, the law states this: When objects strike each other, the momentum distributed to the objects is equal to their momentum prior to the collision. This law will have many future applications, especially in racing cars.
One of the instruments, the pendulum, which began a lot of the studies in forces and motion, would still be tested during this era. In 1664, Christiaan Huygens proposed that a pendulum that had a period of 1 second, also be used as a standard of length. It is believed that this length is equal to 1 meter. In 1672, Jean Richer did some experiments and found that the pendulum had a longer period the closer that you got to the equator. He continued this study and in 1679, he wrote a book showing the period of a pendulum at various locations on the Earth.
Please rewrite Newton’s Three Generalizations of Motion.
How would Richer’s experiments impact everyday actions around the world?
How do Richer’s experiments support Newton’s ideas about the shape of the Earth?
With the discovery of the New World, scientists were now finding new fossils that they had not seen before. There also became a greater interest on how these fossils were formed. Nicholas Steno played a major role when he wrote his book A Dissertation about a Solid Body Enclosed by a Process of Nature Within a Solid. Steno was correct in his explanation of how a fossil formed and how to interpret different rock strata. According to Steno, fossils and strata could be used to reconstruct a sequence of events in the history of life on Earth. This book was written in 1669. John Ray would also play a part in the description of fossils with his own book entitled, The wisdom of God manifested in the works of creation. In this book, Ray suggested that fossils are the remains of animals from a very distant past. This book also established Ray as the leader of the natural history movement in England.
With the Great Earthquake in China, scientist became more and more interested in the workings of an earthquake and just as important, how to predict them. In 1703, De la Hautefeuille designed the first Western seismograph. Two years later, Richard Waller published Robert Hooke’s lectures on how earthquakes might have substantially changed the surface of the Earth since its creation. At this time, scientists still had no idea about plate tectonics and the movement of the Earth’s crust.
1667—Throughout history, science has been categorized as “masculine philosophy”.
However, it is during this era when we find mention of Margaret Cavendish,
the Duchess of Newcastle. Margaret often tried to become a member of the
Royal Society, but was not admitted as a member until 1667 and was known as
“Mad Madge” among the male members. No other woman was admitted until
1945.
1673—Christiaan Huygens built a motor driven by the explosion of gunpowder.
1709—Fahrenheit constructed an alcohol thermometer which would be followed by the
construction of his mercury thermometer, which we still use today.