Man Of Sience

Nikolaus August Otto

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(June 14, 1832 Holzhausen an der Haide, Nassau - January 26, 1891 Cologne) was the German inventor of the first internal-combustion engine to efficiently burn fuel directly in a piston chamber. Although other internal combustion engines had been invented (e.g. by Étienne Lenoir) these were not based on four separate strokes. The concept of four strokes is likely to have been around at the time of Otto's invention but he was the first to make it practical. [1]

Otto's Life

Nikolaus August Otto was born June, 14 1832. He was born in the small city of Holzhausen, Germany. It was here that he obtained his primary education; but in 1848, when Otto was only sixteen, he left school. He started earning a living by working at a grocery store, and later moved to Cologne. After first seeing Etienne Lenoir’s gas-coal engine design, in 1859, Otto began experimenting with internal combustion engines.

In 1861 Otto had built his first engine based on Lenoir’s design. In 1864, Otto co-founded an engine manufacturing business in Cologne. Along with his business partner Eugen Langen he established “N.A. Otto & Cie.”. This company exists today as “Deutz AG”, who boasts the fact that they are the world's oldest engine manufacturers, with over 140 years of experience. Otto’s company first produced a two stroke engine in 1867. The first major breakthrough at Otto's company was during its founding year, with the development of the "atmospheric gas power machine". This atmospheric engine was later awarded a Gold Medal at the World Exhibition in Paris as an economical drive engine for small businesses. Manufacturing of these engines began in 1868. In 1872 Gottlieb Daimler and Wilhelm Maybach joined his company for a while and together they produced the idea of the four-stroke cycle or, Otto cycle engine, which was first described in 1876. In 1877 Otto received a patent for the “Otto Cycle”, and In 1882, the Philosophical Faculty of the University of Wurzburg awarded Otto with an honorary doctorate[2].

In 1884, Otto once again revolutionized engine design. At this point in time internal combustion engines were stationary due to the fact that they could not run on liquid fuel. They were run with gas, and required a pilot light in order to operate. This changed with the introduction of a low-voltage magneto ignition. This electrical ignition system allows engines to use liquid fuel, making mobile use possible.

Otto’s competitors discredited his Otto Cycle patent in 1886, with a discovery of a pamphlet in which a French engineer named, Alphonse-Eugène Beau de Rochas, had earlier suggested the four stroke engine. This annulled Otto’s patent, but by this time Otto’s engines were the only internal combustion engines widely used. The Otto Cycle engine is the engine that is most widely used today in automobiles, motorcycles and motorboats. Nikolaus August Otto died on January, 26 1891[3].

Engine development

Daimler and Maybach left Deutz-AG-Gasmotorenfabrik in 1890 and established Daimler Motoren Gesellschaft (Daimler Engines Company) or DMG. Its purpose was the construction of small, high speed engines based on the same technology they helped discover at Otto's firm. In 1885 Daimler and Maybach designed and built a motorcycle with an engine of the Otto Cycle type that they patented. In 1886 they placed a stationary engine into a stagecoach as an experiment and, in 1889, designed and built their first automobile. In 1892 they first sold an automobile to a customer.

In 1900 Daimler died and in 1909 Maybach left Daimler Motoren Gesellschaft. In 1926, their successors at DMG merged with the Karl Benz company, forming Daimler-Benz which is now known as Mercedes-Benz.

Otto Cycle

This engine was designed as a stationary engine and in the action of the engine, the stroke is an upward or downward movement of a piston in a cylinder. Used later in an adapted form as an automobile engine, four up-down strokes are involved: (1) downward intake stroke—coal-gas and air enter the piston chamber, (2) upward compression stroke—the piston compresses the mixture, (3) downward power stroke—ignites the fuel mixture by electric spark, and (4) upward exhaust stroke—releases exhaust gas from the piston chamber. Otto only sold his engine as a stationary motor.

Earlier patents

According to recent historical studies, the Italian inventors Eugenio Barsanti and Felice Matteucci patented a first working efficient version of an internal combustion engine in 1854 in London (pt. Num. 1072). It is claimed that the Otto engine is in many parts at least inspired from this precedent invention [4], but, as yet there is no documentation of knowledge about the Italian engine by Otto.

Thomas Alva Edison

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In his lifetime, Thomas Alva Edison profoundly affected the technology of modern society. The American inventor was born February 11, 1847 in Milan, Ohio. He was the seventh and last child of Samuel Edison, Jr. and Nancy Elliot Edison. When Edison was 7 years old, his family moved to Port Huron, Michigan, after his father hired on as a carpenter at the Fort Gratiot military post.

Edison entered school in Port Huron, but his teachers considered him to be a dull student. Because of hearing problems, Edison had difficulty following the lessons and his school attendance became sporadic. Nevertheless, Edison became a voracious reader and at age 10, he set up a laboratory in his basement.

When his mother could not longer stand the smell of his chemistry lab, Edison took a job as a trainboy on the Grand Trunk Railway and established a new lab in an empty freight car. He was 12 at the time. Edison also began printing a weekly newspaper, which he called the Grand Trunk Herald.

While Edison was working for the railroad, something happened that changed the course of his career. Edison saved the life of a station official's child, who had fallen onto the tracks of an oncoming train. For his bravery, the boy's father taught Edison how to use the telegraph.

From 1862 to 1868, Edison worked as a roving telegrapher in the Midwest, the South, Canada, and New England. During this time, he began developing a telegraphic repeating instrument that made it possible to transmit messages automatically. By 1869, Edison's inventions, including the duplex telegraph and message printer, were progressing so well, he left telegraphy and began a career of full-time inventing and entrepreneurship.

Edison moved to New York City and within a year, he was able to open a workshop in Newark, New Jersey. He produced the Edison Universal Stock Printer, the automatic telegraph, the quadruplex, as well as other printing telegraphs, while working out of Newark. During this same period, Edison married Mary Stilwell.

Edison was a poor financial manager and by 1875, he began to experience financial difficulties. To reduce costs, Edison asked his widowed father to help him build a new laboratory and machine shop in Menlo Park, New Jersey. He moved into the new building in March, 1876 along with two associates, Charles Batchelor and John Kruesi. Edison achieved his greatest successes in this laboratory and he was dubbed the "Wizard of Menlo Park."

In 1877, Edison invented the carbon-button transmitter that is still used in telephone speakers and microphones. In December of the same year, he unveiled the tinfoil phonograph. (It was 10 years before the phonograph was available as a commercial product). In the late 1870s, backed by leading financiers including J.P. Morgan and the Vanderbilts, Edison established the Edison Electric Light Company. In 1879, he publicly demonstrated his incandescent electric light bulb. In 1882, he supervised the installation of the first commercial, central power system in lower Manhattan. In 1883, one of Edison's engineers William J. Hammer, made a discovery which later led to the electron tube. The discovery was patented the "Edison effect."

In 1884, Edison's wife Mary died, leaving him with three young children. He married Mina Miller in 1886, and began construction on a new laboratory and research facility in West Orange, New Jersey. The new lab employed approximately 60 workers and Edison attempted to personally manage this large staff. The story goes that when a new employee once asked about rules, Edison answered, "There ain't no rules around here. We're trying to accomplish something." However, the operation in West Orange lacked the intimacy of Menlo Park, and Edison's time was often consumed by administrative chores.

During his time in West Orange, Edison produced the commercial phonograph, the Kinetoscope, the Edison storage battery, the electric pen, the mimeograph, and the microtasimeter. In 1913, Edison introduced the first talking moving pictures. In 1915, he was appointed president of the U.S. Navy Consulting Board. In all, Edison patented more than 1,000 discoveries. Edison's inventions were often in response to demand for new or improved products. However, others also came about accidentally or serendipitously.

Thomas Alva Edison died in West Orange, New Jersey on October 18,1931. At the time of this death, he was experimenting on rubber from goldenrod. After his death, Edison became a folk hero of legendary status. His inventions had truly and profoundly affected the shaping of modern society.

Newton, Sir Isaac

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Newton, Sir Isaac (1642-1727), English natural philosopher, generally regarded as the most original and influential theorist in the history of science. In addition to his invention of the infinitesimal calculus and a new theory of light and color, Newton transformed the structure of physical science with his three laws of motion and the law of universal gravitation. As the keystone of the scientific revolution of the 17th century, Newton's work combined the contributions of Copernicus, Kepler, Galileo, Descartes, and others into a new and powerful synthesis. Three centuries later the resulting structure - classical mechanics - continues to be a useful but no less elegant monument to his genius.

Life & Character - Isaac Newton was born prematurely on Christmas day 1642 (4 January 1643, New Style) in Woolsthorpe, a hamlet near Grantham in Lincolnshire. The posthumous son of an illiterate yeoman (also named Isaac), the fatherless infant was small enough at birth to fit 'into a quartpot.' When he was barely three years old Newton's mother, Hanna (Ayscough), placed her first born with his grandmother in order to remarry and raise a second family with Barnabas Smith, a wealthy rector from nearby North Witham. Much has been made of Newton's posthumous birth, his prolonged separation from his mother, and his unrivaled hatred of his stepfather. Until Hanna returned to Woolsthorpe in 1653 after the death of her second husband, Newton was denied his mother's attention, a possible clue to his complex character. Newton's childhood was anything but happy, and throughout his life he verged on emotional collapse, occasionally falling into violent and vindictive attacks against friend and foe alike.

With his mother's return to Woolsthorpe in 1653, Newton was taken from school to fulfill his birthright as a farmer. Happily, he failed in this calling, and returned to King's School at Grantham to prepare for entrance to Trinity College, Cambridge. Numerous anecdotes survive from this period about Newton's absent-mindedness as a fledging farmer and his lackluster performance as a student. But the turning point in Newton's life came in June 1661 when he left Woolsthorpe for Cambridge University. Here Newton entered a new world, one he could eventually call his own.

Although Cambridge was an outstanding center of learning, the spirit of the scientific revolution had yet to penetrate its ancient and somewhat ossified curriculum. Little is known of Newton's formal studies as an undergraduate, but he likely received large doses of Aristotle as well as other classical authors. And by all appearances his academic performance was undistinguished. In 1664 Isaac Barrow, Lucasian Professor of Mathematics at Cambridge, examined Newton's understanding of Euclid and found it sorely lacking. We now know that during his undergraduate years Newton was deeply engrossed in private study, that he privately mastered the works of René Descartes, Pierre Gassendi, Thomas Hobbes, and other major figures of the scientific revolution. A series of extant notebooks shows that by 1664 Newton had begun to master Descartes' Géométrie and other forms of mathematics far in advance of Euclid's Elements. Barrow, himself a gifted mathematician, had yet to appreciate Newton's genius.

In 1665 Newton took his bachelor's degree at Cambridge without honors or distinction. Since the university was closed for the next two years because of plague, Newton returned to Woolsthorpe in midyear. There, in the following 18 months, he made a series of original contributions to science. As he later recalled, 'All this was in the two plague years of 1665 and 1666, for in those days I was in my prime of age for invention, and minded mathematics and philosophy more than at any time since.' In mathematics Newton conceived his 'method of fluxions' (infinitesimal calculus), laid the foundations for his theory of light and color, and achieved significant insight into the problem of planetary motion, insights that eventually led to the publication of his Principia (1687).

In April 1667, Newton returned to Cambridge and, against stiff odds, was elected a minor fellow at Trinity. Success followed good fortune. In the next year he became a senior fellow upon taking his master of arts degree, and in 1669, before he had reached his 27th birthday, he succeeded Isaac Barrow as Lucasian Professor of Mathematics. The duties of this appointment offered Newton the opportunity to organize the results of his earlier optical researches, and in 1672, shortly after his election to the Royal Society, he communicated his first public paper, a brilliant but no less controversial study on the nature of color.

In the first of a series of bitter disputes, Newton locked horns with the society's celebrated curator of experiments, the bright but brittle Robert Hooke. The ensuing controversy, which continued until 1678, established a pattern in Newton's behavior. After an initial skirmish, he quietly retreated. Nonetheless, in 1675 Newton ventured another yet another paper, which again drew lightning, this time charged with claims that he had plagiarized from Hooke. The charges were entirely ungrounded. Twice burned, Newton withdrew.

In 1678, Newton suffered a serious emotional breakdown, and in the following year his mother died. Newton's response was to cut off contact with others and engross himself in alchemical research. These studies, once an embarrassment to Newton scholars, were not misguided musings but rigorous investigations into the hidden forces of nature. Newton's alchemical studies opened theoretical avenues not found in the mechanical philosophy, the world view that sustained his early work. While the mechanical philosophy reduced all phenomena to the impact of matter in motion, the alchemical tradition upheld the possibility of attraction and repulsion at the particulate level. Newton's later insights in celestial mechanics can be traced in part to his alchemical interests. By combining action-at-a-distance and mathematics, Newton transformed the mechanical philosophy by adding a mysterious but no less measurable quantity, gravitational force.

In 1666, as tradition has it, Newton observed the fall of an apple in his garden at Woolsthorpe, later recalling, 'In the same year I began to think of gravity extending to the orb of the Moon.' Newton's memory was not accurate. In fact, all evidence suggests that the concept of universal gravitation did not spring full-blown from Newton's head in 1666 but was nearly 20 years in gestation. Ironically, Robert Hooke helped give it life. In November 1679, Hooke initiated an exchange of letters that bore on the question of planetary motion. Although Newton hastily broke off the correspondence, Hooke's letters provided a conceptual link between central attraction and a force falling off with the square of distance. Sometime in early 1680, Newton appears to have quietly drawn his own conclusions.

Meanwhile, in the coffeehouses of London, Hooke, Edmund Halley, and Christopher Wren struggled unsuccessfully with the problem of planetary motion. Finally, in August 1684, Halley paid a legendary visit to Newton in Cambridge, hoping for an answer to his riddle: What type of curve does a planet describe in its orbit around the sun, assuming an inverse square law of attraction? When Halley posed the question, Newton's ready response was 'an ellipse.' When asked how he knew it was an ellipse Newton replied that he had already calculated it. Although Newton had privately answered one of the riddles of the universe--and he alone possessed the mathematical ability to do so--he had characteristically misplaced the calculation. After further discussion he promised to send Halley a fresh calculation forthwith. In partial fulfillment of his promise Newton produced his De Motu of 1684. From that seed, after nearly two years of intense labor, the Philosophiae Naturalis Principia Mathematica appeared. Arguably, it is the most important book published in the history of science. But if the Principia was Newton's brainchild, Hooke and Halley were nothing less than midwives.

Although the Principia was well received, its future was cast in doubt before it appeared. Here again Hooke was center stage, this time claiming (not without justification) that his letters of 1679-1680 earned him a role in Newton's discovery. But to no effect. Newton was so furious with Hooke that he threatened to suppress Book III of the Principia altogether, finally denouncing science as 'an impertinently litigious lady.' Newton calmed down and finally consented to publication. But instead of acknowledging Hooke's contribution Newton systematically deleted every possible mention of Hooke's name. Newton's hatred for Hooke was consumptive. Indeed, Newton later withheld publication of his Opticks (1704) and virtually withdrew from the Royal Society until Hooke's death in 1703.

After publishing the Principia, Newton became more involved in public affairs. In 1689 he was elected to represent Cambridge in Parliament, and during his stay in London he became acquainted with John Locke, the famous philosopher, and Nicolas Fatio de Duillier, a brilliant young mathematician who became an intimate friend. In 1693, however, Newton suffered a severe nervous disorder, not unlike his breakdown of 1677-1678. The cause is open to interpretation: overwork; the stress of controversy; the unexplained loss of friendship with Fatio; or perhaps chronic mercury poisoning, the result of nearly three decades of alchemical research. Each factor may have played a role. We only know Locke and Samuel Pepys received strange and seemingly deranged letters that prompted concern for Newton's 'discomposure in head, or mind, or both.' Whatever the cause, shortly after his recovery Newton sought a new position in London. In 1696, with the help of Charles Montague, a fellow of Trinity and later earl of Halifax, Newton was appointed Warden and then Master of the Mint. His new position proved 'most proper,' and he left Cambridge for London without regret.

During his London years Newton enjoyed power and worldly success. His position at the Mint assured a comfortable social and economic status, and he was an active and able administrator. After the death of Hooke in 1703, Newton was elected president of the Royal Society and was annually reelected until his death. In 1704 he published his second major work, the Opticks, based largely on work completed decades before. He was knighted in 1705.

Although his creative years had passed, Newton continued to exercise a profound influence on the development of science. In effect, the Royal Society was Newton's instrument, and he played it to his personal advantage. His tenure as president has been described as tyrannical and autocratic, and his control over the lives and careers of younger disciples was all but absolute. Newton could not abide contradiction or controversy - his quarrels with Hooke provide singular examples. But in later disputes, as president of the Royal Society, Newton marshaled all the forces at his command. For example, he published Flamsteed's astronomical observations - the labor of a lifetime - without the author's permission; and in his priority dispute with Leibniz concerning the calculus, Newton enlisted younger men to fight his war of words, while behind the lines he secretly directed charge and countercharge. In the end, the actions of the Society were little more than extensions of Newton's will, and until his death he dominated the landscape of science without rival. He died in London on March 20, 1727 (March 31, New Style).

Scientific Achievements

Mathematics - The origin of Newton's interest in mathematics can be traced to his undergraduate days at Cambridge. Here Newton became acquainted with a number of contemporary works, including an edition of Descartes Géométrie, John Wallis' Arithmetica infinitorum, and other works by prominent mathematicians. But between 1664 and his return to Cambridge after the plague, Newton made fundamental contributions to analytic geometry, algebra, and calculus. Specifically, he discovered the binomial theorem, new methods for expansion of infinite series, and his 'direct and inverse method of fluxions.' As the term implies, fluxional calculus is a method for treating changing or flowing quantities. Hence, a 'fluxion' represents the rate of change of a 'fluent'--a continuously changing or flowing quantity, such as distance, area, or length. In essence, fluxions were the first words in a new language of physics.

Newton's creative years in mathematics extended from 1664 to roughly the spring of 1696. Although his predecessors had anticipated various elements of the calculus, Newton generalized and integrated these insights while developing new and more rigorous methods. The essential elements of his thought were presented in three tracts, the first appearing in a privately circulated treatise, De analysi (On Analysis),which went unpublished until 1711. In 1671, Newton developed a more complete account of his method of infinitesimals, which appeared nine years after his death as Methodus fluxionum et serierum infinitarum (The Method of Fluxions and Infinite Series, 1736). In addition to these works, Newton wrote four smaller tracts, two of which were appended to his Opticks of 1704.

Newton and Leibniz. Next to its brilliance, the most characteristic feature of Newton's mathematical career was delayed publication. Newton's priority dispute with Leibniz is a celebrated but unhappy example. Gottfried Wilhelm Leibniz, Newton's most capable adversary, began publishing papers on calculus in 1684, almost 20 years after Newton's discoveries commenced. The result of this temporal discrepancy was a bitter dispute that raged for nearly two decades. The ordeal began with rumors that Leibniz had borrowed ideas from Newton and rushed them into print. It ended with charges of dishonesty and outright plagiarism. The Newton-Leibniz priority dispute--which eventually extended into philosophical areas concerning the nature of God and the universe--ultimately turned on the ambiguity of priority. It is now generally agreed that Newton and Leibniz each developed the calculus independently, and hence they are considered co-discoverers. But while Newton was the first to conceive and develop his method of fluxions, Leibniz was the first to publish his independent results.

Optics. Newton's optical research, like his mathematical investigations, began during his undergraduate years at Cambridge. But unlike his mathematical work, Newton's studies in optics quickly became public. Shortly after his election to the Royal Society in 1671, Newton published his first paper in the Philosophical Transactions of the Royal Society. This paper, and others that followed, drew on his undergraduate researches as well as his Lucasian lectures at Cambridge.

In 1665-1666, Newton performed a number of experiments on the composition of light. Guided initially by the writings of Kepler and Descartes, Newton's main discovery was that visible (white) light is heterogeneous--that is, white light is composed of colors that can be considered primary. Through a brilliant series of experiments, Newton demonstrated that prisms separate rather than modify white light. Contrary to the theories of Aristotle and other ancients, Newton held that white light is secondary and heterogeneous, while the separate colors are primary and homogeneous. Of perhaps equal importance, Newton also demonstrated that the colors of the spectrum, once thought to be qualities, correspond to an observed and quantifiable 'degree of Refrangibility.'

The Crucial Experiment. Newton's most famous experiment, the experimentum crucis, demonstrated his theory of the composition of light. Briefly, in a dark room Newton allowed a narrow beam of sunlight to pass from a small hole in a window shutter through a prism, thus breaking the white light into an oblong spectrum on a board. Then, through a small aperture in the board, Newton selected a given color (for example, red) to pass through yet another aperture to a second prism, through which it was refracted onto a second board. What began as ordinary white light was thus dispersed through two prisms.

Newton's 'crucial experiment' demonstrated that a selected color leaving the first prism could not be separated further by the second prism. The selected beam remained the same color, and its angle of refraction was constant throughout. Newton concluded that white light is a 'Heterogeneous mixture of differently refrangible Rays' and that colors of the spectrum cannot themselves be individually modified, but are 'Original and connate properties.'

Newton probably conducted a number of his prism experiments at Cambridge before the plague forced him to return to Woolsthorpe. His Lucasian lectures, later published in part as Optical Lectures (1728), supplement other researches published in the Society's Transactions dating from February 1672.

The Opticks. The Opticks of 1704, which first appeared in English, is Newton's most comprehensive and readily accessible work on light and color. In Newton's words, the purpose of the Opticks was 'not to explain the Properties of Light by Hypotheses, but to propose and prove them by Reason and Experiments.' Divided into three books, the Opticks moves from definitions, axioms, propositions, and theorems to proof by experiment. A subtle blend of mathematical reasoning and careful observation, the Opticks became the model for experimental physics in the 18th century.

The Corpuscular Theory. But the Opticks contained more than experimental results. During the 17th century it was widely held that light, like sound, consisted of a wave or undulatory motion, and Newton's major critics in the field of optics--Robert Hooke and Christiaan Huygens--were articulate spokesmen for this theory. But Newton disagreed. Although his views evolved over time, Newton's theory of light was essentially corpuscular, or particulate. In effect, since light (unlike sound) travels in straight lines and casts a sharp shadow, Newton suggested that light was composed of discrete particles moving in straight lines in the manner of inertial bodies. Further, since experiment had shown that the properties of the separate colors of light were constant and unchanging, so too, Newton reasoned, was the stuff of light itself-- particles.

At various points in his career Newton in effect combined the particle and wave theories of light. In his earliest dispute with Hooke and again in his Opticks of 1717, Newton considered the possibility of an ethereal substance--an all-pervasive elastic material more subtle than air--that would provide a medium for the propagation of waves or vibrations. From the outset Newton rejected the basic wave models of Hooke and Huygens, perhaps because they overlooked the subtlety of periodicity.

The question of periodicity arose with the phenomenon known as 'Newton's rings.' In book II of the Opticks, Newton describes a series of experiments concerning the colors of thin films. His most remarkable observation was that light passing through a convex lens pressed against a flat glass plate produces concentric colored rings (Newton's rings) with alternating dark rings. Newton attempted to explain this phenomenon by employing the particle theory in conjunction with his hypothesis of 'fits of easy transmission [refraction] and reflection.' After making careful measurements, Newton found that the thickness of the film of air between the lens (of a given curvature) and the glass corresponded to the spacing of the rings. If dark rings occurred at thicknesses of 0, 2, 4, 6... , then the colored rings corresponded to an odd number progression, 1, 3, 5, 7, .... Although Newton did not speculate on the cause of this periodicity, his initial association of 'Newton's rings' with vibrations in a medium suggests his willingness to modify but not abandon the particle theory.

The Opticks was Newton's most widely read work. Following the first edition, Latin versions appeared in 1706 and 1719, and second and third English editions in 1717 and 1721. Perhaps the most provocative part of the Opticks is the section known as the 'Queries,' which Newton placed at the end of the book. Here he posed questions and ventured opinions on the nature of light, matter, and the forces of nature.

Mechanics. Newton's research in dynamics falls into three major periods: the plague years 1664-1666, the investigations of 1679-1680, following Hooke's correspondence, and the period 1684-1687, following Halley's visit to Cambridge. The gradual evolution of Newton's thought over these two decades illustrates the complexity of his achievement as well as the prolonged character of scientific 'discovery.'

While the myth of Newton and the apple maybe true, the traditional account of Newton and gravity is not. To be sure, Newton's early thoughts on gravity began in Woolsthorpe, but at the time of his famous 'moon test' Newton had yet to arrive at the concept of gravitational attraction. Early manuscripts suggest that in the mid-1660's, Newton did not think in terms of the moon's central attraction toward the earth but rather of the moon's centrifugal tendency to recede. Under the influence of the mechanical philosophy, Newton had yet to consider the possibility of action- at-a-distance; nor was he aware of Kepler's first two planetary hypotheses. For historical, philosophical, and mathematical reasons, Newton assumed the moon's centrifugal 'endeavour' to be equal and opposite to some unknown mechanical constraint. For the same reasons, he also assumed a circular orbit and an inverse square relation. The latter was derived from Kepler's third hypothesis (the square of a planet's orbital period is proportional to the cube of its mean distance from the sun), the formula for centrifugal force (the centrifugal force on a revolving body is proportional to the square of its velocity and inversely proportional to the radius of its orbit), and the assumption of circular orbits.

The next step was to test the inverse square relation against empirical data. To do this Newton, in effect, compared the restraint on the moon's 'endeavour' to recede with the observed rate of acceleration of falling objects on earth. The problem was to obtain accurate data. Assuming Galileo's estimate that the moon is 60 earth radii from the earth, the restraint on the moon should have been 1/3600 (1/60²) of the gravitational acceleration on earth. But Newton's estimate of the size of the earth was too low, and his calculation showed the effect on the moon to be about 1/4000 of that on earth. As Newton later described it, the moon test answered 'pretty nearly.' But the figures for the moon were not exact, and Newton abandoned the problem.

In late 1679 and early 1680 an exchange of letters with Hooke renewed Newton's interest. In November 1679, nearly 15 years after the moon test, Hooke wrote Newton concerning a hypothesis presented in his Attempt to Prove the Motion of the Earth (1674). Here Hooke proposed that planetary orbits result from a tangential motion and 'an attractive motion towards the centrall body.' In later letters Hooke further specified a central attracting force that fell off with the square of distance. As a result of this exchange Newton rejected his earlier notion of centrifugal tendencies in favor of central attraction. Hooke's letters provided crucial insight. But in retrospect, if Hooke's intuitive power seems unparalleled, it never approached Newton's mathematical power in principle or in practice.

When Halley visited Cambridge in 1684, Newton had already demonstrated the relation between an inverse square attraction and elliptical orbits. To Halley's 'joy and amazement,' Newton apparently succeeded where he and others failed. With this, Halley's role shifted, and he proceeded to guide Newton toward publication. Halley personally financed the Principia and saw it through the press to publication in July 1687.

The Principia. Newton's masterpiece is divided into three books. Book I of the Principia begins with eight definitions and three axioms, the latter now known as Newton's laws of motion. No discussion of Newton would be complete without them: (1) Every body continues in its state of rest, or uniform motion in a straight line, unless it is compelled to change that state by forces impressed on it (inertia). (2) The change in motion is proportional to the motive force impressed and is made in the direction of the straight line in which that force is impressed (F = ma). (3) To every action there is always an opposed and equal reaction. Following these axioms, Newton proceeds step by step with propositions, theorems, and problems.

In Book II of the Principia, Newton treats the Motion of bodies through resisting mediums as well as the motion of fluids themselves. Since Book II was not part of Newton's initial outline, it has traditionally seemed somewhat out of place. Nonetheless, it is noteworthy that near the end of Book II (Section IX) Newton demonstrates that the vortices invoked by Descartes to explain planetary motion could not be self-sustaining; nor was the vortex theory consistent with Kepler's three planetary rules. The purpose of Book II then becomes clear. After discrediting Descartes' system, Newton concludes: 'How these motions are performed in free space without vortices, may be understood by the first book; and I shall now more fully treat of it in the following book.'

In Book III, subtitled the System of the World, Newton extended his three laws of motion to the frame of the world, finally demonstrating 'that there is a power of gravity tending to all bodies, proportional to the several quantities of matter which they contain.' Newton's law of universal gravitation states that F = G Mm/R²; that is, that all matter is mutually attracted with a force (F) proportional to the product of their masses (Mm) and inversely proportional to the square of distance (R2) between them. G is a constant whose value depends on the units used for mass and distance. To demonstrate the power of his theory, Newton used gravitational attraction to explain the motion of the planets and their moons, the precession of equinoxes, the action of the tides, and the motion of comets. In sum, Newton's universe united heaven and earth with a single set of laws. It became the physical and intellectual foundation of the modern world view.

Perhaps the most powerful and influential scientific treatise ever published, the Principia appeared in two further editions during Newton's lifetime, in 1713 and 1726.

Other Researches. Throughout his career Newton conducted research in theology and history with the same passion that he pursued alchemy and science. Although some historians have neglected Newton's nonscientific writings, there is little doubt of his devotion to these subjects, as his manuscripts amply attest. Newton's writings on theological and biblical subjects alone amount to about 1.3 million words, the equivalent of 20 of today's standard length books. Although these writings say little about Newtonian science, they tell us a good deal about Isaac Newton.

Newton's final gesture before death was to refuse the sacrament, a decision of some consequence in the 18th century. Although Newton was dutifully raised in the Protestant tradition his mature views on theology were neither Protestant, traditional, nor orthodox. In the privacy of his thoughts and writings, Newton rejected a host of doctrines he considered mystical, irrational, or superstitious. In a word, he was a Unitarian.

Newton's research outside of science--in theology, prophecy, and history--was a quest for coherence and unity. His passion was to unite knowledge and belief, to reconcile the Book of Nature with the Book of Scripture. But for all the elegance of his thought and the boldness of his quest, the riddle of Isaac Newton remained. In the end, Newton is as much an enigma to us as he was, no doubt, to himself.

Robert A. Hatch
University of Florida

Albert Einstein

2008-03-27T18:24:00.000-07:00

Albert Einstein was born at Ulm, in Württemberg, Germany, on March 14, 1879. Six weeks later the family moved to Munich, where he later on began his schooling at the Luitpold Gymnasium. Later, they moved to Italy and Albert continued his education at Aarau, Switzerland and in 1896 he entered the Swiss Federal Polytechnic School in Zurich to be trained as a teacher in physics and mathematics. In 1901, the year he gained his diploma, he acquired Swiss citizenship and, as he was unable to find a teaching post, he accepted a position as technical assistant in the Swiss Patent Office. In 1905 he obtained his doctor's degree.

During his stay at the Patent Office, and in his spare time, he produced much of his remarkable work and in 1908 he was appointed Privatdozent in Berne. In 1909 he became Professor Extraordinary at Zurich, in 1911 Professor of Theoretical Physics at Prague, returning to Zurich in the following year to fill a similar post. In 1914 he was appointed Director of the Kaiser Wilhelm Physical Institute and Professor in the University of Berlin. He became a German citizen in 1914 and remained in Berlin until 1933 when he renounced his citizenship for political reasons and emigrated to America to take the position of Professor of Theoretical Physics at Princeton*. He became a United States citizen in 1940 and retired from his post in 1945.

After World War II, Einstein was a leading figure in the World Government Movement, he was offered the Presidency of the State of Israel, which he declined, and he collaborated with Dr. Chaim Weizmann in establishing the Hebrew University of Jerusalem.

Einstein always appeared to have a clear view of the problems of physics and the determination to solve them. He had a strategy of his own and was able to visualize the main stages on the way to his goal. He regarded his major achievements as mere stepping-stones for the next advance.

At the start of his scientific work, Einstein realized the inadequacies of Newtonian mechanics and his special theory of relativity stemmed from an attempt to reconcile the laws of mechanics with the laws of the electromagnetic field. He dealt with classical problems of statistical mechanics and problems in which they were merged with quantum theory: this led to an explanation of the Brownian movement of molecules. He investigated the thermal properties of light with a low radiation density and his observations laid the foundation of the photon theory of light.

In his early days in Berlin, Einstein postulated that the correct interpretation of the special theory of relativity must also furnish a theory of gravitation and in 1916 he published his paper on the general theory of relativity. During this time he also contributed to the problems of the theory of radiation and statistical mechanics.

In the 1920's, Einstein embarked on the construction of unified field theories, although he continued to work on the probabilistic interpretation of quantum theory, and he persevered with this work in America. He contributed to statistical mechanics by his development of the quantum theory of a monatomic gas and he has also accomplished valuable work in connection with atomic transition probabilities and relativistic cosmology.

After his retirement he continued to work towards the unification of the basic concepts of physics, taking the opposite approach, geometrisation, to the majority of physicists.

Einstein's researches are, of course, well chronicled and his more important works include Special Theory of Relativity (1905), Relativity (English translations, 1920 and 1950), General Theory of Relativity (1916), Investigations on Theory of Brownian Movement (1926), and The Evolution of Physics (1938). Among his non-scientific works, About Zionism (1930), Why War? (1933), My Philosophy (1934), and Out of My Later Years (1950) are perhaps the most important.

Albert Einstein received honorary doctorate degrees in science, medicine and philosophy from many European and American universities. During the 1920's he lectured in Europe, America and the Far East and he was awarded Fellowships or Memberships of all the leading scientific academies throughout the world. He gained numerous awards in recognition of his work, including the Copley Medal of the Royal Society of London in 1925, and the Franklin Medal of the Franklin Institute in 1935.

Einstein's gifts inevitably resulted in his dwelling much in intellectual solitude and, for relaxation, music played an important part in his life. He married Mileva Maric in 1903 and they had a daughter and two sons; their marriage was dissolved in 1919 and in the same year he married his cousin, Elsa Löwenthal, who died in 1936. He died on April 18, 1955 at Princeton, New Jersey.