Great Scientists - The Guessing Game
(with a bit of engineering history mixed in)
By James Barker

A gentleman, a certified eccentric, and a jerk: three seventeenth century scientists who made important contributions and developed concepts that are used today to serve the public and to make the world work a little better. Can you guess their identities from the clues below?

Mystery Scientist #1 developed the basic relationship that is used to analyze bridge trusses. The rule he devised also provides part of the solution to most other stress analysis problems. In developing his rule, he appropriated a law discovered by Mystery Scientist #3, and used it without crediting him. Thus a law of nature enunciated by MS #3 is now popularly attributed to MS #1. MS #1 also discovered the basic principles of additive color interaction (that any color can be made by combining red, blue and green light). Later in life, he was made chief financial officer for his entire country because its leaders figured he was clever with figures. At this task he floundered - which is an appropriate figure of speech, because payment for publishing his greatest work was seventy-five unsold copies of a book entitled The History of Fish. His name is well known today.

Mystery Scientist #2 developed a basic relationship that is used to predict the elastic response of structures. Every time a structure is designed, and every time the load limit is set on a highway bridge, this man's discovery is employed to do the job. His work is buried in the calculations, just as pistons are out of sight in an engine but are still at the heart of an automobile. But #2's greatest contribution was not this. It was to inspire MS #1 to develop a proof of a breakthrough law that advanced all branches of science and engineering. Oddly, the help did not flow from collegial cooperation, for the two men despised each other. MS #2's great gift was to tell #1 a mean-spirited lie intended to derail his work! Fortunately, #1's mind was running on tracks that #2 never guessed. The average citizen today has never heard of MS #2. But Peter Pan did.

In his spare time Mystery Scientist #3 measured the speed of light. He performed the first mathematical stress analysis in the history of mankind. He analyzed the internal stresses for a cantilever beam supporting a load at the end. He didn't get it right, but he was close, and in doing so he started an important field of study. He correctly determined how the depth of such a beam should vary to hold the load while using the least weight of material. Most people today are on a first name basis with this mystery scientist. But oddly, they don't know his last name.

Bonus Question (10 points): Government officials didn't like MS #3's religious opinions, and gave "heated arguments" for his revising them. Though he never renounced his views, he became more diplomatic. Why were the bureaucrats so persuasive with him?

As a teenager Mystery Scientist #1 managed to avoid the Black Death by fleeing to the country-side. As an adult, he was beguiled by mysticism, yet was tightly-strung and often tormented by great anger. He was so used to being right, exactly right, that he couldn't take criticism. He was borderline crazy. But he was a great scientist.

He invented calculus while in his early twenties. He was first to split white light into its component colors and study the spectrum. He invented the reflecting telescope. He posited and proved the theory of gravity. Indeed, he coined the word gravity by adapting the Latin term, gravitus, meaning "heavy." He is considered by many to be the greatest scientist ever. He is Isaac Newton.

He tried to discover fundamental and beautiful principles of nature, and he succeeded so well that he is sometimes criticized as advocating a "clockwork universe". But predictability has its uses, and it is hardly an exaggeration to say that Newton's contributions made engineering possible. His summary work was Principia Mathematica, the most influential book in the history of science. In it he stated his three laws of mechanics.

The First Law, "a body remains in its initial state (be that stationary or in motion) until acted on by an outside force," acknowledges the reality of inertia. This Law had been previously stated and published, exactly so, by MS #3. But Newton often slighted the contributions of others. In this case, he got away with it because the First Law isn't a basic principle at all, but is merely an application of the Second Law, which governs the operation of most of our human-scale environment, and which was all Newton's.

Newton's great Second Law, "the acceleration an object experiences, multiplied by its mass, equals the force pushing against the object" is often abbreviated F = M*A. To predict the motions of the planets, use the law. To predict the motions of artillery shells, or billiard balls, or jet airplanes, use the law. To calculate the force at a bend in piping due to flowing fluid, the same equation provides the answers. Do you want to check the forces in a highway truss? F=MA is where it's at.

Mystery Scientist #2 understood that all materials are elastic and behave like very stiff coil springs. He realized that the stretching of a bar of any material is proportional to the force of the pull. And this idea that strain is proportional to stress, combined with a bit of geometry, and added to Newton's Second Law (which requires an equilibrium of forces) yields the correct, modern analysis of beams and other structural constructs.

MS #2 was Robert Hooke, and his Law of Elasticity is known as Hooke's Law.

But the story is more complex; and juicy; and sad. Hooke was born in England in 1635, which made him eight years older than Newton. At age twenty, Hooke was Robert Boyle's chief assistant, and was partly responsible for Boyles Law, which started the scientific study of gases and meteorology.

In 1660 Hooke discovered his law, but it would take James Bernoulli forty-five years later, Leonhard Euler (the column-formula guy) twenty years after that, and finally the work of Thomas Young, a civil engineer and world-class archaeologist, to render his law usable and meaningful in the broadest applications.

In 1672 Hooke publicly criticized and belittled a paper on optics by young Isaac Newton. Bad move. Newton was even more combative than Hooke, and their differences turned personal. When Hooke said that he had proved the Inverse-Square Rule for gravity, hoping that Newton would abandon the field, Newton sensed the lie and redoubled his effort. The feud lasted the rest of Hooke's life -- in spite of an odd, begrudging assistance that Hooke gave Newton, but which Newton never returned.

Hooke also studied gravity, and both he and Newton independently concluded that gravitational force varied with the square of the separating distance. Hooke even wrote his opinion to Newton before Newton publicly asserted the same. But Hooke was unable to derive the law of gravity from observed planetary orbits, and Newton already had. So when Newton published, Hooke cried plagiarism. Newton was furious. Stung by Hooke's words, he refused to publish anything more until Hooke died. Astronomer Royal Edmund Halley (yes, that Halley) persuaded Newton to publish Principia Mathematica. But before releasing it to the printer, Newton went through the manuscript and expunged every reference to Hooke's assistance. Thus was Hooke cheated of his rightful place in science history. Newton also let it be known that he would not accept the presidency of the Royal Society, England's premier scientific body, until Hooke died, and made sure Hooke knew it. They both were brilliant, and they both fought dirty.

Later in life, Newton was appointed warden of the royal mint, a position equivalent to our Secretary of the Treasury. As such, he chased counterfeiters with special relish. Sentencing some of those he caught to capital punishment may have banked his internal fires but did not quench them. He railed against Hooke and Leibniz and certain other scientists until his death in 1727.

In his later years Hooke turned to biology. Microscopic studies led him to be the first person to use the word "cell" in describing living tissue. He became an early proponent of a theory of evolution, 140 years before Charles Darwin was born.

But Hooke had a reputation for arrogance and for claiming credit for accomplishments not his - unfortunate, because with his stellar achievements there was no need for him to exaggerate. It's a sad story: he evidently wanted to be the best, and thought he was the best, but by fate's caprice he had to share an era, and even a city, with men like Newton, Halley and Christopher Wren.

Mystery Scientist #3 was the first structural engineer. He performed the very first stress analysis. But he did much more. He blew away Aristotle's science of detached contemplation and debate, a tradition that had endured two thousand years, and replaced it with the scientific method that prevails today. He shaped our civilization by proclaiming that "The Book of Nature is written in mathematical characters," and then backing it up with overwhelming evidence. On the side, he discovered that the heavens didn't revolve around mankind, vexing church officials but moving them forward. Though Mr. Galilei tangled with the dreaded Inquisition, he emerged with his skin---an accomplishment in its own right.

Even four centuries after his birth, we call him by his first name, Galileo.

In 1610 Galileo learned of the first crude telescopes and quickly improved them tenfold, making the first research-quality scopes. What he saw was a system of moons revolving around an object (Jupiter) that was not the earth. And in our moon he saw a flawed, pockmarked surface, convoluted with mountains and valleys. Publication of his discovery that the heavens were neither perfect nor spherical nor earth-centered didn't play well in Rome. His first censure lasted seven years.

Ten years after the censure ended, Galileo published a work that virtually proved that the earth revolved around the Sun. Hauled before the Court of Inquisition, Galileo escaped death only because the Pope secretly believed him, and because Galileo publicly "cursed and detested" his own heresy. Just a few years earlier, the Inquisition had burned at the stake a prominent philosopher, Bruno (whose refusal to recant simple truths is still celebrated today). Galileo was sentenced to house arrest and seclusion of the last eight years of his life.

Most people associate Galileo with astronomy. Yet the Encyclopedia Britannica states that the "most substantial part of his work consisted of his contributions towards the establishment of mechanics as a science. Galileo was the first man who perceived that math and physics, previously kept separate, were going to join forces. His method was to combine experiment and calculation [using each to check and improve the other]. He created the modern idea of experiment... [His work] implied a knowledge of the laws of motion as later studied by Newton."

Indeed, decades before Newton enunciated his First Law, Galileo had already publicly proclaimed the same principle.

In 1634, about the time of his second censure, Galileo completed Dialogue Concerning Two New Sciences, which established engineering mechanics (the study of how things respond, deform or break under applied forces) as a field of study. In the book, Galileo used the equilibrium of forces to analyze the simplest beam, a cantilever beam supporting a weight at its end. He asked: for given dimensions and a known breaking stress of the material, what weight would break the beam? His analysis, though flawed, was basically correct, and his answer, by seventeenth century standards, was close. It was the first scientific stress analysis. The result of his later deductions may still be seen in the curve of the top chords of long truss bridges. His was the first instance of optimized structural design.

In the early 1600s Galileo wondered how fast light traveled. So he devised an ingenious experiment to measure it. At midnight he stood on a mountain near Florence and uncovered his lamp. His assistant, standing on another mountain several miles away, uncovered his lamp as soon as he saw Galileo's. Galileo timed the lag before he saw the second lamp. It was a good experiment for the times, though it supported the prevailing belief that light traveled instantaneously. Galileo admitted as much, but added a qualifier that redeemed his conclusion and illustrated his intellect. His exact words were "If not instantaneous, it is extraordinarily rapid." The qualifier means everything. It indicates that he was aware of the limitations of his measurements and that he considered possibilities that were masked by those limitations. No one had done that before. They didn't worry about tolerances. Galileo was first to be really self-aware, in a quantitative way. He was the first modern scientist, as well as the first structural engineer.

The above was published in The Ryder magazine, June 11, 1999