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Greatest Physicists in the World

Isaac Newton

The first and greatest physicist in my estimation is Isaac Newton, born in 1643. Lots of commenters absolutely correctly picked out Newton for the top spot, and had I picked anyone else (with the just barely plausible alternatives of Einstein or Galileo (and see his honorable mention for details)) I'd have been justifiably thought to be nuts.

Before Newton, there was no physics. There was science, but a systematic mathematicaldescription of the laws of nature did not exist. Indeed it could not exist, mathematics itself had not yet developed to the point where it could be used to formulate the necessary laws.

Newton singlehandedly changed that with the invention of calculus and the formulation of the laws of mechanics. The motions of the planets and the motion of things terrestrial ceased to be a mystery and suddenly became things that could be calculated. Newton didn't merely write the laws and leave their application and development for others - he went slashing through the unknown with a metaphorical machete. His three- volume brick of a work known as the Principia Mathematica derived everything from the resisting force due to fluid flow to to derivations of Kepler's laws, to the motion of the earth's moon and Jupiter's moons and numerous other major discoveries. Any one of those would have made the reputation of a lesser man. His mechanics reigned supreme until Einstein, and even then Newton's classical mechanics remain fine approximation for most everyday calculations. Certain other principles such as the conservation of energy, momentum, and angular momentum were either invented or heavily developed by Newton and they remain true even in relativity and quantum mechanics. In pure mathematics he didn't merely invent the basic ideas of differential and integral calculus. He developed the binomial theorem, worked in infinite series, and extended our understanding in various parts of geometry.

He invented the reflecting telescope. Galileo's refractor was a pretty snazzy piece of brilliance, but Newton's reflector has a large number of technical advantages as well as the ability to be made much, much larger at much smaller expense than the refractors. Today everything from the Hubble Space Telescope to the gargantuan land-based observatories is based on the use of mirrors to collect light.

This merely scratches the surface. Physics owes everything to Newton, who founded it and set it on a firm foundation of mathematical power and observational test.

Outside of science Newton was a bit of an odd bird. He as involved in alchemy, fringe theology, anti-counterfeiting detective work, a bizarre feud with the Leibniz (the independent co-inventor of calculus), and he may have been entirely asexual. Most of the greats had their idiosyncrasies, and given their skill I think we can overlook the excessively unusual.

He's worth learning more about. For the technically sophicistiated and hale of heart, there's Newton's own The Principia for your reading. As an exploration of Newton's life and work, there's James Gleick's Isaac Newton. Gleick, by the way, is one of my favorite science writers. As far as I can tell everything he's ever written is great.

And that completes the list. There's plenty of room for substitutions and switches, but I think what I've picked is probably close to an average opinion of who the greatest are. It was in many respects a close-run thing, there's at least ten more who have their own very good arguments for inclusion. I'd like to continue this series without any ranking conceit into some of the remaining greats who weren't specifically included on this list.

Avicenna Abū µAlī al-Ëusayn ibn µAbd Allāh ibn Sīnā, known as Abū Alī Sīnā[7][8] (Persian: ΍ϥ̵αέ̟ ˬ΍ϥ̵α ̵ϝωΏ΍) or, more commonly, Ibn Sīnā[9] or Pour Sina, but most commonly known in English by his Latinized name Avicenna (Greek: AȕȚIJȗȚĮȞȩȢ, Avitzianós),[10] (c. 980 - 1037) was a polymathof Persian (today's Tajiks)[11][12] origin and the foremost physician and philosopher of his time.[13] He was also an astronomer, chemist, geologist,Hafiz, Islamic psychologist, Islamic scholar, Islamic theologian, logician, paleontologist, mathematician, Maktab teac her, physicist, poet, andscientist.[14]

Ibn Sīnā studied medicine under a physician named Koushyar. He wrote almost 450 treatises on a wide range of subjects, of which around 240 have survived. In particular, 150 of his surviving treatises concentrate on philosophy and 40 of them concentrate on medicine.[7][15] His most famous works are The Book of Healing, a vast philosophical and scientific encyclopaedia, and The Canon of Medicine,[16] which was a standard medical text at many medieval universities.[17] The Canon of Medicine was used as a text-book in the universities of Montpellier and Louvain as late as 1650.[18]

Ibn Sīnā's Canon of Medicine provides a complete system of medicine according to the principles of Galen (and Hippocrates).[19][20]

George Sarton, an early author of the history of science, wrote in the Introduction to the History of Science:

One of the most famous exponents of Muslim universalism and an eminent figure in Islamic learning was Ibn Sina, known in the West as Avicenna (981-1037). For a thousand years he has retained his original renown as one of the greatest thinkers and medical scholars in history. His most important medical works are the Qanun (Canon) and a treatise on cardiac drugs. The 'Qanun fi-l-Tibb' is an immense encyclopedia of medicine. It contains some of the most illuminating thoughts pertaining to distinction of mediastinitis from pleurisy; contagious nature of phthisis; distribution of diseases by water and soil; careful description of skin troubles; of sexual diseases and perversions; of nervous ailments.[21]

The Canon of Medicine

Main article: The Canon of Medicine

A Latin copy of The Canon of Medicine, dated 1484, located at the P.I. Nixon Medical Historical Library of The University of Texas Health Science Center at San Antonio, USA.

An Arabic copy of The Canon of Medicine, dated 1593

Medical staff training college dedicated to Avicenna at his birthplace, Afshona

About 100 treatises were ascribed to Ibn Sina. Some of them are tracts of a few pages, others are works extending through several volumes. The best-known amongst them, and that to which Ibn Sina owed his European reputation, is his 14-volume The Canon of Medicine, which was a standard medical text in Europe and the Islamic world up until the 18th century.[28]

Medicine and pharmacology

The book is known for the discovery of contagious diseases and sexually transmitted diseases,[21] the introduction of quarantine to limit the spread ofinfectious diseases, the introduction of experimental medicine, clinical trials,[29] neuropsychiatry,[30] risk factor analysis, and the idea of a syndrome in the diagnosis of specific diseases,[31] and hypothesized the existence of microrganisms.[32] Ibn Sīnā adopted, from the Greeks, the theory that epidemics are caused by pollution in the air (miasma).[33] It classifies and describes diseases, and outlines their assumed causes. Hygiene, simple and complex medicines, and functions of parts of the body are also covered. In this, Ibn Sīnā is credited as being the first to correctly document the anatomy of the human eye, along with descriptions of eye afflictions such as cataracts. It asserts that tuberculosis was contagious, which was later disputed by Europeans, but turned out to be true. It also describes the symptoms and complications of diabetes. Both forms of facial paralysis were described in-depth. In addition, the workings of the heart as a valve are described.[citation needed]

The Canon of Medicine was the first book dealing with experimental medicine, evidence-based medicine, randomized controlled trials,[34][35] andefficacy tests,[36][37] and it laid out the following rules and principles for testing the effectiveness of new drugs and medications, which still form the basis of clinical pharmacology[37] and modern clinical trials:[29]

y The drug must be free from any extraneous accidental quality. y It must be used on a simple, not a composite, disease. y The drug must be tested with two contrary types of diseases, because sometimes a drug cures one disease by Its essential qualities and another by its accidental ones. y The quality of the drug must correspond to the strength of the disease. For example, there are some drugs whose heat is less than the coldness of certain diseases, so that they would have no effect on them. y The time of action must be observed, so that essence and accident are not confused. y The effect of the drug must be seen to occur constantly or in many cases, for if this did not happen, it was an accidental effect. y The experimentation must be done with the human body, for testing a drug on a lion or a horse might not prove anything about its effect on man.

An Arabic edition of the Canon appeared at Rome in 1593, and a Hebrew version at Naples in 1491. Of the Latin version there were about thirty editions, founded on the original translation by Gerard de Sabloneta. In the 15th century a commentary on the text of the Canon was composed. Other medical works translated into Latin are the Medicamenta Cordialia, Canticum de Medicina, and the Tractatus de Syrupo Acetoso.

It was mainly accident which determined that from the 12th to the 18th century, Ibn Sīnā should be the guide of medical study in European universities, and eclipse the names of Rhazes, Ali ibn al-Abbas and Averroes. His work is not essentially different from that of his predecessor Rhazes, because he presented the doctrine of Galen, and through Galen the doctrine of Hippocrates, modified by the system of Aristotle, as well as the Indian doctrines of Sushruta and Charaka.[38] But the Canon of Ibn Sīnā is distinguished from the Al-Hawi (Continens) or Summary of Rhazes by its greater method, due perhaps to the logical studies of the former.

The work has been variously appreciated in subsequent ages, some regarding it as a treasury of wisdom, and others, like Averroes, holding it useful only as waste paper. In modern times it has been mainly of historic interest as most of its tenets have been disproved or expanded upon by scientific medicine. The vice of the book is excessive classification of bodily faculties, and over-subtlety in the discrimination of diseases. It includes five books; of which the first and second discuss physiology, pathology and hygiene, the third and fourth deal with the methods of treating disease, and the fifth describes the composition and preparation of remedies. This last part contains some personal observations. He is ample in the enumeration of symptoms, and is said to be inferior in practical medicine and surgery. He introduced into medical theory the four causes of the Peripatetic system. Of natural history and botany he pretended to no special knowledge. Up to the year 1650, or thereabouts, theCanon was still used as a textbook in the universities of Leuven and Montpellier.

In the museum at Bukhara, there are displays showing many of his writings, surgical instruments from the period and paintings of patients undergoing treatment. Ibn Sīnā was interested in the effect of the mind on the body, and wrote a great deal on psychology, likely influencing Ibn Tufayl and Ibn Bajjah. He also introduced medical herbs.

Avicenna extended the theory of temperaments in The Canon of Medicine to encompass "emotional aspects, mental capacity, moral attitudes, self-awareness, movements and dreams." He summarized his version of the four humours and temperaments in a table as follows:[39] Avicenna's four humours and temperaments Evid Hot Cold Moist Dry ence Morb fevers related to id inflammations bec serious loss lassitude stat ome febrile humour, rheumatis of vigour es m Func tion deficient digesti difficult al deficient energy ve power digestion powe r Subj ecti bitter taste, mucoid sali ve Lack of desire insomnia, w excessive thirst, vation, sle sens for fluids akefulness burning at cardia epiness atio ns diarrhea, s Phys wollen rough skin, ical high pulse rate, eyelids, flaccid joints acquired sign lassitude rough skin, habit s acquired ha bit Food calefacients harm infrigidants harm moist artic dry regimen s & ful, infrigidants ful, calefacients les harmful harmful,hum medi beneficial beneficial ectants ben cine eficial s Rela tion bad in to worse in summer worse in winter autumn weat her

Aristotle (Greek: ËȡȚıIJȠIJȑȜȘȢ, Aristotélēs) (384 BC ± 322 BC)[1] was a Greek philosopher, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, politics, government, ethics, biology, and zoology. Together with Plato and Socrates (Plato's teacher), Aristotle is one of the most important founding figures in Western philosophy. Aristotle's writings were the first to create a comprehensive system of Western philosophy, encompassing morality and aesthetics, logic and science, politics and metaphysics.

Aristotle's views on the physical sciences profoundly shaped medieval scholarship, and their influence extended well into the Renaissance, although they were ultimately replaced by Newtonian physics. In the zoological sciences, some of his observations were confirmed to be accurate only in the 19th century. His works contain the earliest known formal study of logic, which was incorporated in the late 19th century into modern formal logic. In metaphysics, Aristotelianism had a profound influence on philosophical and theological thinking in the Islamic and Jewish traditions in the Middle Ages, and it continues to influence Christian theology, especially the scholastic tradition of the Catholic Church and some strains of Eastern Orthodoxthought[citation needed]. His ethics, though always influential, gained renewed interest with the modern advent of virtue ethics. All aspects of Aristotle's philosophy continue to be the object of active academic study today. Though Aristotle wrote many elegant treatises and dialogues (Cicero described his literary style as "a river of gold"),[2] it is thought that the majority of his writings are now lost and only about one-third of the original works have survived.

Analytics and the Organon

What we today call Aristotelian logic, Aristotle himself would have labeled "analytics". The term "logic" he reserved to mean dialectics. Most of Aristotle's work is probably not in its original form, since it was most likely edited by students and later lecturers. The logical works of Aristotle were compiled into six books in about the early 1st century AD:

1. Categories 2. On Interpretation 3. Prior Analytics 4. Posterior Analytics 5. Topics 6. On Sophistical Refutations

The order of the books (or the teachings from which they are composed) is not certain, but this list was derived from analysis of Aristotle's writings. It goes from the basics, the analysis of simple terms in the Categories, the analysis of propositions and their elementary relations in On Interpretation, to the study of more complex forms, namely, syllogisms (in the Analytics) and dialectics (in the Topics and Sophistical Refutations). The first three treatises form the core of the logical theory stricto sensu: the grammar of the language of logic and the correct rules of reasoning. There is one volume of Aristotle's concerning logic not found in the Organon, namely the fourth book of Metaphysics.[14]

Aristotle's scientific method

Plato (left) and Aristotle (right), a detail of The School of Athens, a fresco by Raphael. Aristotle gestures to the earth, representing his belief in knowledge through empirical observation and experience, while holding a copy of his Nicomachean Ethics in his hand, whilst Plato gestures to the heavens, representing his belief in The Forms.

For more details on this topic, see Aristotle's theory of universals.

Like his teacher Plato, Aristotle's philosophy aims at the universal. Aristotle, however, found the universal in particular things, which he called the essence of things, while Plato finds that the universal exists apart from particular things, and is related to them as their prototype or exemplar. For Aristotle, therefore, philosophic method implies the ascent from the study of particular phenomena to the knowledge of essences, while for Plato philosophic method means the descent from a knowledge of universal Forms (or ideas) to a contemplation of particular imitations of these. For Aristotle, "form" still refers to the unconditional basis of phenomena but is "instantiated" in a particular substance (see Universals and particulars, below). In a certain sense, Aristotle's method is both inductive and deductive, while Plato's is essentially deductive from a priori principles.[16]

In Aristotle's terminology, "natural philosophy" is a branch of philosophy examining the phenomena of the natural world, and includes fields that would be regarded today as physics, biology and other natural sciences. In modern times, the scope of philosophy has become limited to more generic or abstract inquiries, such as ethics and metaphysics, in which logic plays a major role. Today's philosophy tends to exclude empirical study of the natural world by means of the scientific method. In contrast, Aristotle's philosophical endeavors encompassed virtually all facets of intellectual inquiry.

In the larger sense of the word, Aristotle makes philosophy coextensive with reasoning, which he also would describe as "science". Note, however, that his use of the term science carries a different meaning than that covered by the term "scientific method". For Aristotle, "all science (dianoia) is either practical, poetical or theoretical" (Metaphysics 1025b25). By practical science, he means ethics and politics; by poetical science, he means the study of poetry and the other fine arts; by theoretical science, he means physics, mathematics and metaphysics.

If logic (or "analytics") is regarded as a study preliminary to philosophy, the divisions of Aristotelian philosophy would consist of: (1) Logic; (2) Theoretical Philosophy, including Metaphysics, Physics and Mathematics; (3) Practical Philosophy and (4) Poetical Philosophy.

In the period between his two stays in Athens, between his times at the Academy and the Lyceum, Aristotle conducted most of the scientific thinking and research for which he is renowned today. In fact, most of Aristotle's life was devoted to the study of the objects of natural science. Aristotle's metaphysics contains observations on the nature of numbers but he made no original contributions to mathematics. He did, however, perform original research in the natural sciences, e.g., botany, zoology, physics, astronomy, chemistry, meteorology, and several other sciences.

Aristotle's writings on science are largely qualitative, as opposed to quantitative. Beginning in the 16th century, scientists began applying mathematics to the physical sciences, and Aristotle's work in this area was deemed hopelessly inadequate. His failings were largely due to the absence of concepts like mass, velocity, force and temperature. He had a conception of speed and temperature, but no quantitative understanding of them, which was partly due to the absence of basic experimental devices, like clocks and thermometers.

His writings provide an account of many scientific observations, a mixture of precocious accuracy and curious errors. For example, in his History of Animals he claimed that human males have more teeth than females.[17] In a similar vein, John Philoponus, and later Galileo, showed by simple experiments that Aristotle's theory that a heavier object falls faster than a lighter object is incorrect.[18] On the other hand, Aristotle refutedDemocritus's claim that the Milky Way was made up of "those stars which are shaded by the earth from the sun's rays," pointing out (correctly, even if such reasoning was bound to be dismissed for a long time) that, given "current astronomical demonstrations" that "the size of the sun is greater than that of the earth and the distance of the stars from the earth many times greater than that of the sun, then...the sun shines on all the stars and the earth screens none of them."[19] In places, Aristotle goes too far in deriving 'laws of the universe' from simple observation and over-stretched reason. Today's scientific method assumes that such thinking without sufficient facts is ineffective, and that discerning the validity of one's hypothesis requires far more rigorous experimentation than that which Aristotle used to support his laws.

Aristotle also had some scientific blind spots. He posited a geocentric cosmology that we may discern in selections of the Metaphysics, which was widely accepted up until the 16th century. From the 3rd century to the 16th century, the dominant view held that the Earth was the center of the universe (geocentrism).

Since he was perhaps the philosopher most respected by European thinkers during and after the Renaissance, these thinkers often took Aristotle's erroneous positions as given, which held back science in this epoch.[20] However, Aristotle's scientific shortcomings should not mislead one into forgetting his great advances in the many scientific fields. For instance, he founded logic as a formal science and created foundations to biology that were not superseded for two millennia. Moreover, he introduced the fundamental notion that nature is composed of things that change and that studying such changes can provide useful knowledge of underlying constants.

Physics

Concerning the make up of matter, Aristotle followed prior Greek philosophy with an adapted theory of elements. He was not an "atomist" likeDemocritus. In particular he proposed a fifth element, aether, in addition to the more common four.

y Fire, which is hot and dry. y Earth, which is cold and dry. y Air, which is hot and wet. y Water, which is cold and wet. y Aether, which is the divine substance that makes up the heavenly spheres and heavenly bodies (stars and planets).

Each of the four earthly elements has its natural place; the earth at the centre of the universe, then water, then air, then fire. When they are out of their natural place they have natural motion, requiring no external cause, which is towards that place; so bodies sink in water, air bubbles rise up, rain falls, flame rises in air. The heavenly element has perpetual circular motion.

Motion

Main article: potentiality and actuality

Motion in Aristotle is defined in his Physics in a way which is quite different from modern science, and Aristotle's understanding of motion is closely connected to his actuality- potentiality distinction (see below concerning metaphysics). Taken literally, Aristotle defines motion as the actuality of a potentiality as such.[21] What Aristotle meant is the subject of several different interpretations, but because actuality and potentiality are normally opposites in Aristotle, interpreters either say that the wording which has come down to us is wrong, or that the addition of the "as such" to the definition is critical to understanding it.[22]

Causality, The Four Causes

y Material cause describes the material out of which something is composed. Thus the material cause of a table is wood, and the material cause of a car is rubber and steel. It is not about action. It does not mean one domino knocks over another domino. y The formal cause is its form, i.e. the arrangement of that matter. It tells us what a thing is, that any thing is determined by the definition, form, pattern, essence, whole, synthesis or archetype. It embraces the account of causes in terms of fundamental principles or general laws, as the whole (i.e., macrostructure) is the cause of its parts, a relationship known as the whole-part causation. Plainly put the formal cause is the idea existing in the first place as exemplar in the mind of the sculptor, and in the second place as intrinsic, determining cause, embodied in the matter. Formal cause could only refer to the essential quality of causation. A more simple example of the formal cause is the blueprint or plan that one has before making or causing a human made object to exist. y The efficient cause is "the primary source", or that from which the change or the ending of the change first starts. It identifies 'what makes of what is made and what causes change of what is changed' and so suggests all sorts of agents, nonliving or living, acting as the sources of change or movement or rest. Representing the current understanding of causality as the relation of cause and effect, this covers the modern definitions of "cause" as either the agent or agency or particular events or states of affairs. More simply again that which immediately sets the thing in motion. So take the two dominos this time of equal weighting, the first is knocked over causing the second also to fall over. This is effectively efficient cause. y The final cause is its purpose, or that for the sake of which a thing exists or is done, including both purposeful and instrumental actions and activities. The final cause or telos is the purpose or end that something is supposed to serve, or it is that from which and that to which the change is. This also covers modern ideas of mental causation involving such psychological causes as volition, need, motivation or motives, rational, irrational, ethical, and all that gives purpose to behavior.

Additionally, things can be causes of one another, causing each other reciprocally, as hard work causes fitness and vice versa, although not in the same way or function, the one is as the beginning of change, the other as the goal. (Thus Aristotle first suggested a reciprocal or circular causality as a relation of mutual dependence or influence of cause upon effect). Moreover, Aristotle indicated that the same thing can be the cause of contrary effects; its presence and absence may result in different outcomes. Simply it is the goal or purpose that brings about an event (not necessarily a mental goal). Taking our two dominos, it requires someone to intentionally knock the dominos over as they cannot fall themselves.

Aristotle marked two modes of causation: proper (prior) causation and accidental (chance) causation. All causes, proper and incidental, can be spoken as potential or as actual, particular or generic. The same language refers to the effects of causes, so that generic effects assigned to generic causes, particular effects to particular causes, operating causes to actual effects. Essentially, causality does not suggest a temporal relation between the cause and the effect.

Optics

Aristotle held more accurate theories on some optical concepts than other philosophers of his day. The earliest known written evidence of a camera obscura can be found in Aristotle's documentation of such a device in 350 BC in Problemata. Aristotle's apparatus contained a dark chamber that had a single small hole, or aperture, to allow for sunlight to enter. Aristotle used the device to make observations of the sun and noted that no matter what shape the hole was, the sun would still be correctly displayed as a round object. In modern cameras, this is analogous to the diaphragm. Aristotle also made the observation that when the distance between the aperture and the surface with the image increased, the image was magnified.[23]

Chance and spontaneity

According to Aristotle, spontaneity and chance are causes of some things, distinguishable from other types of cause. Chance as an incidental cause lies in the realm of accidental things. It is "from what is spontaneous" (but note that what is spontaneous does not come from chance). For a better understanding of Aristotle's conception of "chance" it might be better to think of "coincidence": Something takes place by chance if a person sets out with the intent of having one thing take place, but with the result of another thing (not intended) taking place. For example: A person seeks donations. That person may find another person willing to donate a substantial sum. However, if the person seeking the donations met the person donating, not for the purpose of collecting donations, but for some other purpose, Aristotle would call the collecting of the donation by that particular donator a result of chance. It must be unusual that something happens by chance. In other words, if something happens all or most of the time, we cannot say that it is by chance.

There is also more specific kind of chance, which Aristotle names "luck", that can only apply to human beings, since it is in the sphere of moral actions. According to Aristotle, luck must involve choice (and thus deliberation), and only humans are capable of deliberation and choice. "What is not capable of action cannot do anything by chance".[24]

Lorenzo Romano Amedeo Carlo Bernadette Avogadro di Quaregna e Cerreto[1], Count of Quaregna and Cerreto (9 August 1776, Turin,Piedmont ± 9 July 1856) was an Italian savant. He is most noted for his contributions to molecular theory, including what is known as Avogadro's law. In tribute to him, the number of elementary entities (atoms, molecules, ions or other particles) in 1 mole of a substance, 6.02214179(30)×1023, is known as the Avogadro constant.

Accomplishments Avogadro's Law states that the relationship between the masses of the same volume of different gases (at the same temperature and pressure) corresponds to the relationship between their respective molecular weights. Hence, the relative molecular mass of a gas can be calculated from the mass of sample of known volume.

Avogadro developed this hypothesis after Joseph Louis Gay- Lussac had published in 1809 his law on volumes (and combining gases). The greatest problem Avogadro had to resolve was the confusion at that time regarding atoms and molecules. One of his most important contributions was clearly distinguishing one from the other, stating that gases are composed of molecules, and these molecules are composed of atoms. For instance, John Dalton did not consider this possibility. Avogadro did not actually use the word "atom" as the words "atom" and "molecule" were used almost without difference. He believed that there were three kinds of "molecules," including an "elementary molecule" (our "atom"). Also, more attention was given to the definition of mass, as distinguished from weight.

In 1815, he published Mémoire sur les masses relatives des molécules des corps simples, ou densités présumées de leur gaz, et sur la constitution de quelques-uns de leur composés, pour servir de suite à l'Essai sur le même sujet, publié dans le Journal de Physique, juillet 1811 ("Note on the Relative Masses of Elementary Molecules, or Suggested Densities of Their Gases, and on the Constituents of Some of Their Compounds, As a Follow- up to the Essay on the Same Subject, Published in the Journal of Physics, July 1811") ([1]), about gas densities.

In 1821 he published another paper, Nouvelles considérations sur la théorie des proportions déterminées dans les combinaisons, et sur la détermination des masses des molécules des corps (New Considerations on the Theory of Proportions Determined in Combinations, and on Determination of the Masses of Atoms) and shortly afterwards, Mémoire sur la manière de ramener les composès organiques aux lois ordinaires des proportions déterminées (Note on the Manner of Finding the Organic Composition by the Ordinary Laws of Determined Proportions).

In 1841, he published his work in Fisica dei corpi ponderabili, ossia Trattato della costituzione materiale de' corpi, 4 volumes.

Response to the theory The scientific community did not give great attention to his theory, so Avogadro's hypothesis was not immediately accepted. André-Marie Ampèreachieved the same results three years later by another method (in his Sur la détermination des proportions dans lesquelles les corps se combinent d'après le nombre et la disposition respective des molécules dont leurs particules intégrantes sont composées -- On the Determination of Proportions in which Bodies Combine According to the Number and the Respective Disposition of the Molecules by Which Their Integral Particles Are Made), but the same indifference was shown to his theory as well.

Only through studies by Charles Frédéric Gerhardt and Auguste Laurent on organic chemistry was it possible to demonstrate that Avogadro's law explained why the same quantities of molecules in a gas have the same volume.

Unfortunately, related experiments with some inorganic substances showed seeming exceptions to the law. This was finally resolved by Stanislao Cannizzaro, as announced at Karlsruhe Congress in 1860, four years after Avogadro's death. He explained that these exceptions were due to molecular dissociations at certain temperatures, and that Avogadro's law determined not only molecular masses, but atomic masses as well.

In 1911, a meeting in Turin commemorated the hundredth anniversary of the publication of Avogadro's classic 1811 paper. King Victor Emmanuel IIIattended. Thus, Avogadro's great contribution to chemistry was recognized.

Rudolf Clausius, with his kinetic theory on gases, gave another confirmation of Avogadro's Law. Jacobus Henricus van 't Hoff showed that Avogadro's theory also held in dilute solutions.

Avogadro is hailed as a founder of the atomic-molecular theory.

Archimedes of Syracuse (Greek: ËȡȤȚȝȒįȘȢ; c. 287 BC ± c. 212 BC) was a Greek mathematician, physicist, engineer, inventor, and astronomer. Although few details of his life are known, he is regarded as one of the leading scientists in classical antiquity. Among his advances in physics are the foundations of hydrostatics, statics and an explanation of the principle of the lever. He is credited with designing innovative machines, including siege engines and the screw pump that bears his name. Modern experiments have tested claims that Archimedes designed machines capable of lifting attacking ships out of the water and setting ships on fire using an array of mirrors.[1]

Archimedes is generally considered to be the greatest mathematician of antiquity and one of the greatest of all time.[2][3] He used the method of exhaustion to calculate the area under the arc of a parabola with the summation of an infinite series, and gave a remarkably accurate approximation ofpi.[4] He also defined the spiral bearing his name, formulae for the volumes of surfaces of revolution and an ingenious system for expressing very large numbers.

Archimedes died during the Siege of Syracuse when he was killed by a Roman soldier despite orders that he should not be harmed. Cicero describes visiting the tomb of Archimedes, which was surmounted by a sphere inscribed within a cylinder. Archimedes had proven that the sphere has two thirds of the volume and surface area of the cylinder (including the bases of the latter), and regarded this as the greatest of his mathematical achievements.

Unlike his inventions, the mathematical writings of Archimedes were little known in antiquity. Mathematicians from Alexandria read and quoted him, but the first comprehensive compilation was not made until c. 530 AD by Isidore of Miletus, while commentaries on the works of Archimedes written by Eutocius in the sixth century AD opened them to wider readership for the first time. The relatively few copies of Archimedes' written work that survived through the Middle Ages were an influential source of ideas for scientists during the Renaissance,[5] while the discovery in 1906 of previously unknown works by Archimedes in the Archimedes Palimpsest has provided new insights into how he obtained mathematical results.[6]

Sir Joseph J. Thomson, headmaster of Trinity College, Cambridge, discoverer of the electron, and considered by many the greatest living physicist, is in the United States on an extended visit as the guest of Franklin Institute, Philadelphia. As guest of the Western Electric Company at luncheon in the Bell System laboratories, Sir Joseph saw in operation many applications of his fundamental theories and inventions. Among these was a water-cooled copper vacuum tube, devised by W. G. Housekeeper, with 40 times the capacity of the present glass-enclosed tube used in long-distance radio. This may shortly be installed on all American battleships. Professor Thomson's chief contribution to science is the proof (in 1897) that the rays given off from the cathode, or negative electrode, within a vacuum tube are streams of minute bodies of negative electricity, called by him "corpuscles," but later renamed "electrons." It is now believed that all matter is made up of "electrons," particles of negative electricity, and "protons," particles of positive electricity. The smallness of the electron is beyond human comprehension. Its diameter is about 30 trillionths of an inch. The most powerful microscope known would barely enable us to see an object 200 atoms wide, and if an atom were about the size of a large office building, an electron would be the size of a pinhead. Professor Thomson was Cavendish professor of experimental physics in Cambridge University from 1884 un- til 1918. During that time he developed a great research laboratory which attracted workers from all parts of the world. He received the Nobel prize for physics in 1906, and holds many other awards and honors from the great scientific societies of the world. In 1908 he was knighted, and during the World War he was an important figure in several Government research committees and technical departments.

A number of British scientific men, under the leadership of Sir Kenneth D. Mackenzie, formed the Scientific Expeditionary Research Association to facilitate and promote scientific expeditions to all parts of the world. The first voyage under its auspices will be to the South Pacific Ocean, starting this summer.

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 includeSpecial 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.

Max Karl Ernst Ludwig Planck was born in Kiel, Germany, on April 23, 1858, the son of Julius Wilhelm and Emma (néePatzig) Planck. His father was Professor of Constitutional Law in the University of Kiel, and later in Göttingen.

Planck studied at the Universities of Munich and Berlin, where his teachers included Kirchhoff and Helmholtz, and received his doctorate of philosophy at Munich in 1879. He was Privatdozent in Munich from 1880 to 1885, then Associate Professor of Theoretical Physics at Kiel until 1889, in which year he succeeded Kirchhoff as Professor at Berlin University, where he remained until his retirement in 1926. Afterwards he became President of the Kaiser Wilhelm Society for the Promotion of Science, a post he held until 1937. The Prussian Academy of Sciences appointed him a member in 1894 and Permanent Secretary in 1912.

Planck's earliest work was on the subject of thermodynamics, an interest he acquired from his studies under Kirchhoff, whom he greatly admired, and very considerably from reading R. Clausius' publications. He published papers on entropy, on thermoelectric ity and on the theory of dilute solutions.

At the same time also the problems of radiation processes engaged his attention and he showed that these were to be considered as electromagnetic in nature. From these studies he was led to the problem of the distribution of energy in the spectrum of full radiation. Experimental observations on the wavelength distribution of the energy emitted by a black body as a function of temperature were at variance with the predictions of classical physics. Planck was able to deduce the relationship between the ener gy and the frequency of radiation. In a paper published in 1900, he announced his derivation of the relationship: this was based on the revolutionary idea that the energy emitted by a resonator could only take on discrete values or quanta. The energy for a resonator of frequency v is hv where h is a universal constant, now called Planck's constant.

This was not only Planck's most important work but also marked a turning point in the history of physics. The importance of the discovery, with its far-reaching effect on classical physics, was not appreciated at first. However the evidence for its validi ty gradually became overwhelming as its application accounted for many discrepancies between observed phenomena and classical theory. Among these applications and developments may be mentioned Einstein's explanation of the photoelectric effect.

Planck's work on the quantum theory, as it came to be known, was published in the Annalen der Physik. His work is summarized in two books Thermodynamik (Thermodynamics) (1897) and Theorie der Wärmestrahlung (Theory of heat radiat ion) (1906).

He was elected to Foreign Membership of the Royal Society in 1926, being awarded the Society's Copley Medal in 1928.

Planck faced a troubled and tragic period in his life during the period of the Nazi government in Germany, when he felt it his duty to remain in his country but was openly opposed to some of the Government's policies, particularly as regards the persecuti on of the Jews. In the last weeks of the war he suffered great hardship after his home was destroyed by bombing.

He was revered by his colleagues not only for the importance of his discoveries but for his great personal qualities. He was also a gifted pianist and is said to have at one time considered music as a career.

Planck was twice married. Upon his appointment, in 1885, to Associate Professor in his native town Kiel he married a friend of his childhood, Marie Merck, who died in 1909. He remarried her cousin Marga von Hösslin. Three of his children died young, leaving him with two sons.

He suffered a personal tragedy when one of them was executed for his part in an unsuccessful attempt to assassinate Hitler in 1944.

He died at Göttingen on October 4, 1947.

alt="Marie Curie" u1:shapes="Picture_x0020_17" v:shapes="_x0000_s1028">Marie Curie, née Maria Sklodowska, was born in Warsaw on November 7, 1867, the daughter of a secondary-school teacher. She received a general education in local schools and some scientific training from her father. She became involved in a students' revolutionary organization and found it prudent to leave Warsaw, then in the part of Poland dominated by Russia, for Cracow, which at that time was under Austrian rule. In 1891, she went to Paris to continue her studies at the Sorbonne where she obtained Licenciateships in Physics and the Mathematical Sciences. She met Pierre Curie, Professor in the School of Physics in 1894 and in the following year they were married. She succeeded her husband as Head of the Physics Laboratory at the Sorbonne, gained her Doctor of Science degree in 1903, and following the tragic death of Pierre Curie in 1906, she took his place as Professor of General Physics in the Faculty of Sciences, the first time a woman had held this position. She was also appointed Director of the Curie Laboratory in the Radium Institute of the University of Paris, founded in 1914.

Her early researches, together with her husband, were often performed under difficult conditions, laboratory arrangements were poor and both had to undertake much teaching to earn a livelihood. The discovery of radioactivity by Henri Becquerel in 1896 inspired the Curies in their brilliant researches and analyses which led to the isolation of polonium, named after the country of Marie's birth, and radium. Mme. Curie developed methods for the separation of radium from radioactive residues in sufficient quantities to allow for its characterization and the careful study of its properties, therapeutic properties in particular.

Mme. Curie throughout her life actively promoted the use of radium to alleviate suffering and during World War I, assisted by her daughter, Irene, she personally devoted herself to this remedial work. She retained her enthusiasm for science throughout her life and did much to establish a radioactivity laboratory in her native city - in 1929 President Hoover of the United States presented her with a gift of $ 50,000, donated by American friends of science, to purchase radium for use in the laboratory in Warsaw.

Mme. Curie, quiet, dignified and unassuming, was held in high esteem and admiration by scientists throughout the world. She was a member of the Conseil du Physique Solvay from 1911 until her death and since 1922 she had been a member of the Committee of Intellectual Co-operation of the League of Nations. Her work is recorded in numerous papers in scientific journals and she is the author of Recherches sur les Substances Radioactives (1904),L'Isotopie et les Éléments Isotopes and the classic Traité' de Radioactivité (1910).

The importance of Mme. Curie's work is reflected in the numerous awards bestowed on her. She received many honorary science, medicine and law degrees and honorary memberships of learned societies throughout the world. Together with her husband, she was awarded half of the Nobel Prize for Physics in 1903, for their study into the spontaneous radiation discovered by Becquerel, who was awarded the other half of the Prize. In 1911 she received a secondNobel Prize, this time in Chemistry, in recognition of her work in radioactivity. She also received, jointly with her husband, the Davy Medal of the Royal Society in 1903 and, in 1921, President Harding of the United States, on behalf of the women of America, presented her with one gram of radium in recognition of her service to science.

For further details, cf. Biography of Pierre Curie. Mme. Curie died in Savoy, France, after a short illness, on July 4, 1934.

Niels Henrik David Bohr was born in Copenhagen on October 7, 1885, as the son of Christian Bohr, Professor of Physiology at Copenhagen University, and his wife Ellen, née Adler. Niels, together with his younger brother Harald (the future Professor in Mathematics), grew up in an atmosphere most favourable to the development of his genius - his father was an eminent physiologist and was largely responsible for awakening his interest in physics while still at school, his mother came from a family distinguished in the field of education.

After matriculation at the Gammelholm Grammar School in 1903, he entered Copenhagen University where he came under the guidance of Professor C. Christiansen, a profoundly original and highly endowed physicist, and took his Master's degree in Physics in 1909 and his Doctor's degree in 1911.

While still a student, the announcement by the Academy of Sciences in Copenhagen of a prize to be awarded for the solution of a certain scientific problem, caused him to take up an experimental and theoretical investigation of the surface tension by means of oscillating fluid jets. This work, which he carried out in his father's laboratory and for which he received the prize offered (a gold medal), was published in the Transactions of the Royal Society, 1908.

Bohr's subsequent studies, however, became more and more theoretical in character, his doctor's disputation being a purely theoretical piece of work on the explanation of the properties of the metals with the aid of the electron theory, which remains to this day a classic on the subject. It was in this work that Bohr was first confronted with the implications of Planck's quantum theory of radiation.

In the autumn of 1911 he made a stay at Cambridge, where he profited by following the experimental work going on in the Cavendish Laboratory under Sir J.J. Thomson's guidance, at the same time as he pursued own theoretical studies. In the spring of 1912 he was at work in Professor Rutherford's laboratory in Manchester, where just in those years such an intensive scientific life and activity prevailed as a consequence of that investigator's fundamental inquiries into the radioactive phenomena. Having there carried out a theoretical piece of work on the absorption of alpha rays which was published in the Philosophical Magazine, 1913, he passed on to a study of the structure of atoms on the basis of Rutherford's discovery of the atomic nucleus. By introducing conceptions borrowed from the Quantum Theory as established by Planck, which had gradually come to occupy a prominent position in the science of theoretical physics, he succeeded in working out and presenting a picture of atomic structure that, with later improvements (mainly as a result of Heisenberg's ideas in 1925), still fitly serves as an elucidation of the physical and chemical properties of the elements.

In 1913-1914 Bohr held a Lectureship in Physics at Copenhagen University and in 1914-1916 a similar appointment at the Victoria University in Manchester. In 1916 he was appointed Professor of Theoretical Physics at Copenhagen University, and since 1920 (until his death in 1962) he was at the head of the Institute for Theoretical Physics, established for him at that university.

Recognition of his work on the structure of atoms came with the award of the Nobel Prize for 1922.

Bohr's activities in his Institute were since 1930 more and more directed to research on the constitution of the atomic nuclei, and of their transmutations and disintegrations. In 1936 he pointed out that in nuclear processes the smallness of the region in which interactions take place, as well as the strength of these interactions, justify the transition processes to be described more in a classical way than in the case of atoms (Cf. »Neutron capture and nuclear constitution«, Nature, 137 (1936) 344).

A liquid drop would, according to this view, give a very good picture of the nucleus. This so-called liquid droplet theory permitted the understanding of the mechanism of nuclear fission, when the splitting of uranium was discovered by Hahn and Strassmann, in 1939, and formed the basis of important theoretical studies in this field (among others, by Frisch and Meitner).

Bohr also contributed to the clarification of the problems encountered in quantum physics, in particular by developing the concept of complementarity. Hereby he could show how deeply the changes in the field of physics have affected fundamental features of our scientific outlook and how the consequences of this change of attitude reach far beyond the scope of atomic physics and touch upon all domains of human knowledge. These views are discussed in a number of essays, written during the years 1933-1962. They are available in English, collected in two volumes with the title Atomic Physics and Human Knowledge and Essays 1958-1962 on Atomic Physics and Human Knowledge, edited by John Wiley and Sons, New York and London, in 1958 and 1963, respectively.

Among Professor Bohr's numerous writings (some 115 publications), three appearing as books in the English language may be mentioned here as embodying his principal thoughts:The Theory of Spectra and Atomic Constitution, University Press, Cambridge, 1922/2nd. ed., 1924; Atomic Theory and the Description of Nature, University Press, Cambridge, 1934/reprint 1961; The Unity of Knowledge, Doubleday & Co., New York, 1955.

During the Nazi occupation of Denmark in World War II, Bohr escaped to Sweden and spent the last two years of the war in England and America, where he became associated with the Atomic Energy Project. In his later years, he devoted his work to the peaceful application of atomic physics and to political problems arising from the development of atomic weapons. In particular, he advocated a development towards full openness between nations. His views are especially set forth in his Open Letter to the United Nations, June 9, 1950.

Until the end, Bohr's mind remained alert as ever; during the last few years of his life he had shown keen interest in the new developments of molecular biology. The latest formulation of his thoughts on the problem of Life appeared in his final (unfinished) article, published after his death: "Licht und Leben-noch einmal", Naturwiss., 50 (1963) 72: (in English: "Light and Life revisited", ICSU Rev., 5 ( 1963) 194).

Niels Bohr was President of the Royal Danish Academy of Sciences, of the Danish Cancer Committee, and Chairman of the Danish Atomic Energy Commission. He was a Foreign Member of the Royal Society (London), the Royal Institution, and Academies in Amsterdam, Berlin, Bologna, Boston, Göttingen, Helsingfors, Budapest, München, Oslo, Paris, Rome,Stockholm, Uppsala, Vienna, Washington, Harlem, Moscow, Trondhjem, Halle, Dublin, Liege, and Cracow. He was Doctor, honoris causa, of the following universities, colleges, and institutes: (1923-1939) - Cambridge, Liverpool, Manchester, Oxford, Copenhagen, Edinburgh, Kiel, Providence, California, Oslo, Birmingham, London; (1945-1962) - Sorbonne (Paris), Princeton, Mc. Gill (Montreal), Glasgow, Aberdeen, Athens, Lund, New York, Basel, Aarhus, Macalester (St. Paul), Minnesota, Roosevelt (Chicago, Ill.), Zagreb, Technion (Haifa), Bombay, Calcutta, Warsaw, Brussels, Harvard, Cambridge (Mass.), and Rockefeller (New York).

Professor Bohr was married, in 1912, to Margrethe Nørlund, who was for him an ideal companion. They had six sons, of whom they lost two; the other four have made distinguished careers in various professions - Hans Henrik (M.D.), Erik (chemical engineer), Aage (Ph.D., theoretical physicist, following his father as Director of the Institute for Theoretical Physics), Ernest (lawyer).

Enrico Fermi was born in Rome on 29th September, 1901, the son of Alberto Fermi, a Chief Inspector of the Ministry of Communications, and Ida de Gattis. He attended a local grammar school, and his early aptitude for mathematics and physics was recognized and encouraged by his father's colleagues, among them A. Amidei. In 1918, he won a fellowship of the Scuola Normale Superiore of Pisa. He spent four years at the University of Pisa, gaining his doctor's degree in physics in 1922, with Professor Puccianti.

Soon afterwards, in 1923, he was awarded a scholarship from the Italian Government and spent some months with Professor Max Born in Göttingen. With a Rockefeller Fellowship, in 1924, he moved to Leyden to work with P. Ehrenfest, and later that same year he returned to Italy to occupy for two years (1924-1926) the post of Lecturer in Mathematical Physics and Mechanics at the University of Florence.

In 1926, Fermi discovered the statistical laws, nowadays known as the «Fermi statistics», governing the particles subject to Pauli's exclusion principle (now referred to as «fermions», in contrast with «bosons» which obey the Bose-Einstein statistics).

In 1927, Fermi was elected Professor of Theoretical Physics at the University of Rome (a post which he retained until 1938, when he - immediately after the receipt of the Nobel Prize - emigrated to America, primarily to escape Mussolini's fascist dictatorship).

During the early years of his career in Rome he occupied himself with electrodynamic problems and with theoretical investigations on various spectroscopic phenomena. But a capital turning-point came when he directed his attention from the outer electrons towards the atomic nucleus itself. In 1934, he evolved the ß- decay theory, coalescing previous work on radiation theory with Pauli's idea of the neutrino. Following the discovery by Curie and Joliot of artificial radioactivity (1934), he demonstrated that nuclear transformation occurs in almost every element subjected to neutron bombardment. This work resulted in the discovery of slow neutrons that same year, leading to the discovery of nuclear fission and the production of elements lying beyond what was until then the Periodic Table.

In 1938, Fermi was without doubt the greatest expert on neutrons, and he continued his work on this topic on his arrival in the United States, where he was soon appointed Professor of Physics at Columbia University, N.Y. (1939-1942).

Upon the discovery of fission, by Hahn and Strassmann early in 1939, he immediately saw the possibility of emission of secondary neutrons and of a chain reaction. He proceeded to work with tremendous enthusiasm, and directed a classical series of experiments which ultimately led to the atomic pile and the first controlled nuclear chain reaction. This took place in Chicago on December 2, 1942 - on a squash court situated beneath Chicago's stadium. He subsequently played an important part in solving the problems connected with the development of the first atomic bomb (He was one of the leaders of the team of physicists on the Manhattan Project for the development of nuclear energy and the atomic bomb.)

In 1944, Fermi became American citizen, and at the end of the war (1946) he accepted a professorship at the Institute for Nuclear Studies of the University of Chicago, a position which he held until his untimely death in 1954. There he turned his attention to high-energy physics, and led investigations into the pion-nucleon interaction.

During the last years of his life Fermi occupied himself with the problem of the mysterious origin of cosmic rays, thereby developing a theory, according to which a universal magnetic field - acting as a giant accelerator - would account for the fantastic energies present in the cosmic ray particles.

Professor Fermi was the author of numerous papers both in theoretical and experimental physics. His most important contributions were:

"Sulla quantizzazione del gas perfetto monoatomico", Rend. Accad. Naz. Lincei, 1935 (also inZ. Phys., 1936), concerning the foundations of the statistics of the electronic gas and of the gases made of particles that obey the Pauli Principle.

Several papers published in Rend. Accad. Naz. Lincei, 1927-28, deal with the statistical model of the atom (Thomas-Fermi atom model) and give a semiquantitative method for the calculation of atomic properties. A resumé of this work was published by Fermi in the volume:Quantentheorie und Chemie, edited by H. Falkenhagen, Leipzig, 1928.

"Uber die magnetischen Momente der AtomKerne", Z. Phys., 1930, is a quantitative theory of the hyperfine structures of spectrum lines. The magnetic moments of some nuclei are deduced therefrom.

"Tentativo di una teoria dei raggi ß", Ricerca Scientifica, 1933 (also Z. Phys., 1934) proposes a theory of the emission of ß- rays, based on the hypothesis, first proposed by Pauli, of the existence of the neutrino.

The Nobel Prize for Physics was awarded to Fermi for his work on the artificial radioactivity produced by neutrons, and for nuclear reactions brought about by slow neutrons. The first paper on this subject "Radioattività indotta dal bombardamento di neutroni" was published by him in Ricerca Scientifica, 1934. All the work is collected in the following papers by himself and various collaborators: "Artificial radioactivity produced by neutron bombardment", Proc. Roy. Soc., 1934 and 1935; "On the absorption and diffusion of slow neutrons", Phys. Rev., 1936. The theoretical problems connected with the neutron are discussed by Fermi in the paper "Sul moto dei neutroni lenti", Ricerca Scientfica, 1936.

His Collected Papers are being published by a Committee under the Chairmanship of his friend and former pupil, Professor E. Segrè (Nobel Prize winner 1959, with O. Chamberlain, for the discovery of the antiproton).

Fermi was member of several academies and learned societies in Italy and abroad (he was early in his career, in 1929, chosen among the first 30 members of the Royal Academy of Italy).

As lecturer he was always in great demand (he has also given several courses at the University of Michigan, Ann Arbor; and Stanford University, Calif.). He was the first recipient of a special award of $50,000 - which now bears his name - for work on the atom.

Professor Fermi married Laura Capon in 1928. They had one son Giulio and one daughter Nella. His favourite pastimes were walking, mountaineering, and winter sports.

He died in Chicago on 28th November, 1954.

Guglielmo Marconi was born at Bologna, Italy, on April 25, 1874, the second son of Giuseppe Marconi, an Italian country gentleman, and Annie Jameson, daughter of Andrew Jameson of Daphne Castle in the County Wexford, Ireland. He was educated privately at Bologna, Florence and Leghorn. Even as a boy he took a keen interest in physical and electrical science and studied the works of Maxwell, Hertz, Righi, Lodge and others. In 1895 he began laboratory experiments at his father's country estate at Pontecchio where he succeeded in sending wireless signals over a distance of one and a half miles.

In 1896 Marconi took his apparatus to England where he was introduced to Mr. (later Sir) William Preece, Engineer-in-Chief of the Post Office, and later that year was granted the world's first patent for a system of wireless telegraphy. He demonstrated his system successfully in London, on Salisbury Plain and across the Bristol Channel, and in July 1897 formed The Wireless Telegraph & Signal Company Limited (in 1900 re- named Marconi's Wireless Telegraph Company Limited). In the same year he gave a demonstration to the Italian Government at Spezia where wireless signals were sent over a distance of twelve miles. In 1899 he established wireless communication between France and England across the English Channel. He erected permanent wireless stations at The Needles, Isle of Wight, at Bournemouth and later at the Haven Hotel, Poole, Dorset.

In 1900 he took out his famous patent No. 7777 for "tuned or syntonic telegraphy" and, on an historic day in December 1901, determined to prove that wireless waves were not affected by the curvature of the Earth, he used his system for transmitting the first wireless signals across the Atlantic between Poldhu, Cornwall, and St. John's, Newfoundland, a distance of 2100 miles.

Between 1902 and 1912 he patented several new inventions. In 1902, during a voyage in the American liner "Philadelphia", he first demonstrated "daylight effect" relative to wireless communication and in the same year patented his magnetic detector which then became the standard wireless receiver for many years. In December 1902 he transmitted the first complete messages to Poldhu from stations at Glace Bay, Nova Scotia, and later Cape Cod, Massachusetts, these early tests culminating in 1907 in the opening of the first transatlantic commercial service between Glace Bay and Clifden, Ireland, after the first shorter-distance public service of wireless telegraphy had been established between Bari in Italy and Avidari in Montenegro. In 1905 he patented his horizontal directional aerial and in 1912 a "timed spark" system for generating continuous waves.

In 1914 he was commissioned in the Italian Army as a Lieutenant being later promoted to Captain, and in 1916 transferred to the Navy in the rank of Commander. He was a member of the Italian Government mission to the United States in 1917 and in 1919 was appointed Italian plenipotentiary delegate to the Paris Peace Conference. He was awarded the Italian Military Medal in 1919 in recognition of his war service.

During his war service in Italy he returned to his investigation of short waves, which he had used in his first experiments. After further tests by his collaborators in England, an intensive series of trials was conducted in 1923 between experimental installations at the Poldhu Station and in Marconi's yacht "Elettra" cruising in the Atlantic and Mediterranean, and this led to the establishment of the beam system for long distance communication. Proposals to use this system as a means of Imperial communications were accepted by the British Government and the first beam station, linking England and Canada, was opened in 1926, other stations being added the following year.

In 1931 Marconi began research into the propagation characteristics of still shorter waves, resulting in the opening in 1932 of the world's first microwave radiotelephone link between the Vatican City and the Pope's summer residence at Castel Gandolfo. Two years later at Sestri Levante he demonstrated his microwave radio beacon for ship navigation and in 1935, again in Italy, gave a practical demonstration of the principles of radar, the coming of which he had first foretold in a lecture to the American Institute of Radio Engineers in New York in 1922.

He has been the recipient of honorary doctorates of several universities and many other international honours and awards, among them the Nobel Prize for Physics, which in 1909 he shared with Professor Karl Braun, the Albert Medal of the Royal Society of Arts, the John Fritz Medal and the Kelvin Medal. He was decorated by the Tsar of Russia with the Order of St. Anne, the King of Italy created him Commander of the Order of St. Maurice and St. Lazarus, and awarded him the Grand Cross of the Order of the Crown of Italy in 1902. Marconi also received the freedom of the City of Rome (1903), and was created Chevalier of the Civil Order of Savoy in 1905. Many other distinctions of this kind followed. In 1914 he was both created a Senatore in the Italian Senate and app ointed Honorary Knight Grand Cross of the Royal Victorian Order in England. He received the hereditary title of Marchese in 1929.

In 1905 he married the Hon. Beatrice O'Brien, daughter of the 14th Baron Inchiquin, the marriage being annulled in 1927, in which year he married the Countess Bezzi-Scali of Rome. He had one son and two daughters by his first and one daughter by his second wife. His recreations were hunting, cycling and motoring.

Marconi died in Rome on July 20, 1937.

alt="Werner Heisenberg" u1:shapes="Picture_x0020_21" v:shapes="_x0000_s1032">Werner Heisenberg was born on 5th December, 1901, at Würzburg. He was the son of Dr. August Heisenberg and his wife Annie Wecklein. His father later became Professor of the Middle and Modern Greek languages in the University of Munich. It was probably due to his influence that Heisenberg remarked, when the Japanese physicist Yukawa discovered the particle now known as the meson and the term "mesotron" was proposed for it, that the Greek word "mesos" has no "tr" in it, with the result that the name "mesotron" was changed to "meson".

Heisenberg went to the Maximilian school at Munich until 1920, when he went to the University of Munich to study physics under Sommerfeld, Wien, Pringsheim, and Rosenthal. During the winter of 1922-1923 he went to Göttingen to study physics under Max Born, Franck, and Hilbert. In 1923 he took his Ph.D. at the University of Munich and then became Assistant to Max Born at the University of Göttingen, and in 1924 he gained the venia legendi at that University.

From 1924 until 1925 he worked, with a Rockefeller Grant, with Niels Bohr, at the University of Copenhagen, returning for the summer of 1925 to Göttingen.

In 1926 he was appointed Lecturer in Theoretical Physics at the University of Copenhagen under Niels Bohr and in 1927, when he was only 26, he was appointed Professor of Theoretical Physics at the University of Leipzig.

In 1929 he went on a lecture tour to the United States, Japan, and India.

In 1941 he was appointed Professor of Physics at the University of Berlin and Director of the Kaiser Wilhelm Institute for Physics there.

At the end of the Second World War he, and other German physicists, were taken prisoner by American troops and sent to England, but in 1946 he returned to Germany and reorganized, with his colleagues, the Institute for Physics at Göttingen. This Institute was, in 1948, renamed the Max Planck Institute for Physics.

In 1948 Heisenberg stayed for some months in Cambridge, England, to give lectures, and in 1950 and 1954 he was invited to lecture in the United States. In the winter of 1955-1956 he gave the Gifford Lectures at the University of St. Andrews, Scotland, these lectures being subsequently published as a book.

During 1955 Heisenberg was occupied with preparations for the removal of the Max Planck Institute for Physics to Munich. Still Director of this Institute, he went with it to Munich and in 1958 he was appointed Professor of Physics in the University of Munich. His Institute was then being renamed the Max Planck Institute for Physics and Astrophysics.

Heisenberg's name will always be associated with his theory of quantum mechanics, published in 1925, when he was only 23 years old. For this theory and the applications of it which resulted especially in the discovery of allotropic forms of hydrogen, Heisenberg was awarded the Nobel Prize for Physics for 1932.

His new theory was based only on what can be observed, that is to say, on the radiation emitted by the atom. We cannot, he said, always assign to an electron a position in space at a given time, nor follow it in its orbit, so that we cannot assume that the planetary orbits postulated by Niels Bohr actually exist. Mechanical quantities, such as position, velocity, etc. should be represented, not by ordinary numbers, but by abstract mathematical structures called "matrices" and he formulated his new theory in terms of matrix equations.

Later Heisenberg stated his famous principle of uncertainty, which lays it down that the determination of the position and momentum of a mobile particle necessarily contains errors the product of which cannot be less than the quantum constant h and that, although these errors are negligible on the human scale, they cannot be ignored in studies of the atom.

From 1957 onwards Heisenberg was interested in work on problems of plasma physics and thermonuclear processes, and also much work in close collaboration with the International Institute of Atomic Physics at Geneva. He was for several years Chairman of the Scientific Policy Committee of this Institute and subsequently remained a member of this Committee.

When he became, in 1953, President of the Alexander von Humboldt Foundation, he did much to further the policy of this Foundation, which was to invite scientists from other countries to Germany and to help them to work there.

Since 1953 his own theoretical work was concentrated on the unified field theory of elementary particles which seems to him to be the key to an understanding of the physics of elementary particles.

Apart from many medals and prizes, Heisenberg received an honorary doctorate of the University of Bruxelles, of the Technological University Karlsruhe, and recently (1964) of the University of Budapest; he is also recipient of the Order of Merit of Bavaria, and the Grand Cross for Federal Services with Star (Germany). He is a Fellow of the Royal Society of London and a Knight of the Order of Merit (Peace Class). He is a member of the Academies of Sciences of Göttingen, Bavaria, Saxony, Prussia, Sweden, Rumania, Norway, Spain, The Netherlands, Rome (Pontificial), the German Akademie der Naturforscher Leopoldina (Halle), the Accademia dei Lincei (Rome), and the American Academy of Sciences. During 1949-1951 he was President of the Deutsche Forschungsrat (German Research Council) and in 1953 he became President of the Alexander von Humboldt Foundation.

One of his hobbies is classical music: he is a distinguished pianist. In 1937 Heisenberg married Elisabeth Schumacher. They have seven children, and live in Munich.

Erwin Schrödinger was born on August 12, 1887, in Vienna, the only child of Rudolf Schrödinger, who was married to a daughter of Alexander Bauer, his Professor of Chemistry at the Technical College of Vienna.

Erwin's father came from a Bavarian family which generations before had settled in Vienna. He was a highly gifted man with a broad education. After having finished his chemistry studies, he devoted himself for years to Italian painting. After this he took up botany, which resulted in a series of papers on plant phylogeny.

Schrödinger's wide interests dated from his school years at the Gymnasium, where he not only had a liking for the scientific disciplines, but also appreciated the severe logic of ancient grammar and the beauty of German poetry. (What he abhorred was memorizing of data and learning from books.)

From 1906 to 1910 he was a student at the University of Vienna, during which time he came under the strong influence of Fritz Hasenöhrl, who was Boltzmann's successor. It was in these years that Schrödinger acquired a mastery of eigenvalue problems in the physics of continuous media, thus laying the foundation for his future great work. Hereafter, as assistant to Franz Exner, he, together with his friend K. W. F. Kohlrausch, conducted practical work for students (without himself, as he said, learning what experimenting was). During the First World War he served as an artillery officer.

In 1920 he took up an academic position as assistant to Max Wien, followed by positions at Stuttgart (extraordinary professor), Breslau (ordinary professor), and at the University of Zurich (replacing von Laue) where he settled for six years. In later years Schrödinger looked back to his Zurich period with great pleasure - it was here that he enjoyed so much the contact and friendship of many of his colleagues, among whom were Hermann Weyl and Peter Debye. It was also his most fruitful period, being actively engaged in a variety of subjects of theoretical physics. His papers at that time dealt with specific heats of solids, with problems of thermodynamics (he was greatly interested in Boltzmann's probability theory) and of atomic spectra; in addition, he indulged in physiological studies of colour (as a result of his contacts with Kohlrausch and Exner, and of Helmholtz's lectures). His great discovery, Schrödinger's wave equation, was made at the end of this epoch-during the first half of 1926.

It came as a result of his dissatisfaction with the quantum condition in Bohr's orbit theory and his belief that atomic spectra should really be determined by some kind of eigenvalue problem. For this work he shared with Dirac the Nobel Prize for 1933.

In 1927 Schrödinger moved to Berlin as Planck's successor. Germany's capital was then a centre of great scientific activity and he enthusiastically took part in the weekly colloquies among colleagues, many of whom "exceeding him in age and reputation". With Hitler's coming to power (1933), however, Schrödinger decided he could not continue in Germany. He came to England and for a while held a fellowship at Oxford. In 1934 he was invited to lecture at Princeton University and was offered a permanent position there, but did not accept. In 1936 he was offered a position at University of Graz, which he accepted only after much deliberation and because his longing for his native country outweighed his caution. With the annexation of Austria in 1938, he was immediately in difficulty because his leaving Germany in 1933 was taken to be an unfriendly act. Soon afterwards he managed to escape to Italy, from where he proceeded to Oxford and then to University of Ghent. After a short stay he moved to the newly created Institute for Advanced Studies in Dublin, where he became Director of the School for Theoretical Physics. He remained in Dublin until his retirement in 1955.

All this time Schrödinger continued his research and published many papers on a variety of topics, including the problem of unifying gravitation and electromagnetism, which also absorbed Einstein and which is still unsolved; (he was also the author of the well-known little book "What is Life?", 1944). He remained greatly interested in the foundations of atomic physics. Schrödinger disliked the generally accepted dual description in terms of waves and particles, with a statistical interpretation for the waves, and tried to set up a theory in terms of waves only. This led him into controversy with other leading physicists.

After his retirement he returned to an honoured position in Vienna. He died on the 4th of January, 1961, after a long illness, survived by his faithful companion, Annemarie Bertel, whom he married in 1920.

Pierre Curie was born in Paris, where his father was a general medical practitioner, on May 15, 1859. He received his early education at home before entering the Faculty of Sciences at the Sorbonne. He gained his Licenciateship in Physics in 1878 and continued as a demonstrator in the physics laboratory until 1882 when he was placed in charge of all practical work in the Physics and Industrial Chemistry Schools. In 1895 he obtained his Doctor of Science degree and was appointed Professor of Physics. He was promoted to Professor in the Faculty of Sciences in 1900, and in 1904 he became Titular Professor.

In his early studies on crystallography, together with his brother Jacques, Curie discovered piezoelectric effects. Later, he advanced theories of symmetry with regard to certain physical phenomena and turned his attention to magnetism. He showed that the magnetic properties of a given substance change at a certain temperature - this temperature is now known as the Curie point. To assist in his experiments he constructed several delicate pieces of apparatus - balances, electrometers, piezoelectric crystals, etc.

Curie's studies of radioactive substances were made together with his wife, whom he married in 1895. They were achieved under conditions of much hardship - barely adequate laboratory facilities and under the stress of having to do much teaching in order to earn their livelihood. They announced the discovery of radium and polonium by fractionation of pitchblende in 1898 and later they did much to elucidate the properties of radium and its transformation products. Their work in this era formed the basis for much of the subsequent research in nuclear physics and chemistry. Together they were awarded half of the Nobel Prize for Physics in 1903 on account of their study into the spontaneous radiation discovered by Becquerel, who was awarded the other half of the Prize.

Pierre Curie's work is recorded in numerous publications in the Comptes Rendus de l'Académie des Sciences, the Journal de Physique and the Annales de Physique et Chimie.

Curie was awarded the Davy Medal of the Royal Society of London in 1903 (jointly with his wife) and in 1905 he was elected to the Academy of Sciences.

His wife was formerly Marie Sklodowska, daughter of a secondary- school teacher at Warsaw, Poland. One daughter, Irene, married Frederic Joliot and they were joint recipients of the Nobel Prize for Chemistry in 1935. The younger daughter, Eve, married the American diplomat H. R. Labouisse. They have both taken lively interest in social problems, and as Director of the United Nations' Children's Fund he received on its behalf the Nobel Peace Prize in Oslo in 1965. She is the author of a famous biography of her mother, Madame Curie (Gallimard, Paris, 1938), translated into several languages.

Pierre was killed in a street accident in Paris on April 19, 1906.

alt="Wilhelm Conrad Röntgen" u1:shapes="Picture_x0020_24" v:shapes="_x0000_s1035">Wilhelm Conrad Röntgen was born on March 27, 1845, at Lennep in the Lower Rhine Province of Germany, as the only child of a merchant in, and manufacturer of, cloth. His mother was Charlotte Constanze Frowein of Amsterdam, a member of an old Lennep family which had settled in Amsterdam.

When he was three years old, his family moved to Apeldoorn in The Netherlands, where he went to the Institute of Martinus Herman van Doorn, a boarding school. He did not show any special aptitude, but showed a love of nature and was fond of roaming in the open country and forests. He was especially apt at making mechanical contrivances, a characteristic which remained with him also in later life. In 1862 he entered a technical school at Utrecht, where he was however unfairly expelled, accused of having produced a caricature of one of the teachers, which was in fact done by someone else.

He then entered the University of Utrecht in 1865 to study physics. Not having attained the credentials required for a regular student, and hearing that he could enter the Polytechnic at Zurich by passing its examination, he passed this and began studies there as a student of mechanical engineering. He attended the lectures given by Clausius and also worked in the laboratory of Kundt. Both Kundt and Clausius exerted great influence on his development. In 1869 he graduated Ph.D. at the University of Zurich, was appointed assistant to Kundt and went with him to Würzburg in the same year, and three years later to Strasbourg.

In 1874 he qualified as Lecturer at Strasbourg University and in 1875 he was appointed Professor in the Academy of Agriculture at Hohenheim in Württemberg. In 1876 he returned to Strasbourg as Professor of Physics, but three years later he accepted the invitation to the Chair of Physics in the University of Giessen.

After having declined invitations to similar positions in the Universities of Jena (1886) and Utrecht (1888), he accepted it from the University of Würzburg (1888), where he succeeded Kohlrausch and found among his colleagues Helmholtz and Lorenz. In 1899 he declined an offer to the Chair of Physics in the University of Leipzig, but in 1900 he accepted it in the University of Munich, by special request of the Bavarian government, as successor of E. Lommel. Here he remained for the rest of his life, although he was offered, but declined, the Presidency of the Physikalisch-Technische Reichsanstalt at Berlin and the Chair of Physics of the Berlin Academy.

Röntgen's first work was published in 1870, dealing with the specific heats of gases, followed a few years later by a paper on the thermal conductivity of crystals. Among other problems he studied were the electrical and other characteristics of quartz; the influence of pressure on the refractive indices of various fluids; the modification of the planes of polarised light by electromagnetic influences; the variations in the functions of the temperature and the compressibility of water and other fluids; the phenomena accompanying the spreading of oil drops on water.

Röntgen's name, however, is chiefly associated with his discovery of the rays that he called X-rays. In 1895 he was studying the phenomena accompanying the passage of an electric current through a gas of extremely low pressure. Previous work in this field had already been carried out by J. Plucker (1801- 1868), J. W. Hittorf (1824-1914), C. F. Varley (1828-1883), E. Goldstein (1850-1931), Sir William Crookes (1832-1919), H. Hertz (1857-1894) and Ph. von Lenard (1862-1947), and by the work of these scientists the properties of cathode rays - the name given by Goldstein to the electric current established in highly rarefied gases by the very high tension electricity generated by Ruhmkorff's induction coil - had become well known. Röntgen's work on cathode rays led him, however, to the discovery of a new and different kind of rays.

On the evening of November 8, 1895, he found that, if the discharge tube is enclosed in a sealed, thick black carton to exclude all light, and if he worked in a dark room, a paper plate covered on one side with barium platinocyanide placed in the path of the rays became fluorescent even when it was as far as two metres from the discharge tube. During subsequent experiments he found that objects of different thicknesses interposed in the path of the rays showed variable transparency to them when recorded on a photographic plate. When he immobilised for some moments the hand of his wife in the path of the rays over a photographic plate, he observed after development of the plate an image of his wife's hand which showed the shadows thrown by the bones of her hand and that of a ring she was wearing, surrounded by the penumbra of the flesh, which was more permeable to the rays and therefore threw a fainter shadow. This was the first "röntgenogram" ever taken. In further experiments, Röntgen showed that the new rays are produced by the impact of cathode rays on a material object. Because their nature was then unknown, he gave them the name X- rays. Later, Max von Laue and his pupils showed that they are of the same electromagnetic nature as light, but differ from it only in the higher frequency of their vibration.

Numerous honours were showered upon him. In several cities, streets were named after him, and a complete list of Prizes, Medals, honorary doctorates, honorary and corresponding memberships of learned societies in Germany as well as abroad, and other honours would fill a whole page of this book. In spite of all this, Röntgen retained the characteristic of a strikingly modest and reticent man. Throughout his life he retained his love of nature and outdoor occupations. Many vacations were spent at his summer home at Weilheim, at the foot of the Bavarian Alps, where he entertained his friends and went on many expeditions into the mountains. He was a great mountaineer and more than once got into dangerous situations. Amiable and courteous by nature, he was always understanding the views and difficulties of others. He was always shy of having an assistant, and preferred to work alone. Much of the apparatus he used was built by himself with great ingenuity and experimental skill.

Röntgen married Anna Bertha Ludwig of Zürich, whom he had met in the café run by her father. She was a niece of the poet Otto Ludwig. They married in 1872 in Apeldoorn, The Netherlands. They had no children, but in 1887 adopted Josephine Bertha Ludwig, then aged 6, daughter of Mrs. Röntgen's only brother. Four years after his wife, Röntgen died at Munich on February 10, 1923, from carcinoma of the intestine.

Blaise Pascal, the French scientist was one of the most reputed mathematician and physicist of his time. He is credited with inventing an early calculator, amazingly advanced for its time. A genuis from a young age, Blaise Pascal composed a treatise on the communication of sounds at the age of twelve, and at the age of sixteen he composed a treatise on conic sections.

The Pascaline The idea of using machines to solve mathematical problems can be traced at least as far as the early 17th century. Mathematicians who designed and implemented calculators that were capable of addition, subtraction, multiplication, and division included Wilhelm Schickhard, Blaise Pascal, and Gottfried Leibnitz. In 1642, at the age of eighteen Blaise Pascal invented his numerical wheel calculator called the Pascaline to help his father a French tax collector count taxes. The Pascaline had eight movable dials that added up to eight figured long sums and used base ten. When the first dial (one's column) moved ten notches - the second dial moved one notch to represent the ten's column reading of 10 - and when the ten dial moved ten notches the third dial (hundred's column) moved one notch to represent one hundred and so on.

Christiaan Huygens (April 14, 1629 - June 8, 1695)

Born in The Hague in 1629, Christiaan Huygens was a famous Dutchman for his development of advanced pendulum clocks (1659). He also invented an improved type of 2-lense eyepieces (1703), now named after him, and constructed very long air telescopes of up to 250 feet focal length. With these, he made important discoveries such as a dark surface feature on Mars, later named Syrtis Major and shown in the first map of Mars created in 1659, the polar caps of Mars first depicted in 1772, and Jupiter's equatorial bulge. He discovered Saturn's satellite Titan (March 25, 1655) and was the first to clearly see its rings and to explain their appearance over time (1655-59). In 1656 he independently discovered the Orion Nebula M42 and made detailed studies and sketches of this object, including the discovery of three stars of the Trapezium cluster.

He visited London in 1665 and was made a member of the Royal Society. On invitation of the French King Louis XIV, he came to Paris in 1666 and became a founding member of the Academie Royale des Sciences (Royal Academy of Sciences) where he worked with G.D. Cassini. In 1684, he undertook new studies of the Orion Nebula and independently discovered the fourth Trapezium star which had been originally discovered in the meantime by Picardin 1673.

Huygens also contributed significantly to physics: In 1656, he derived the conservation of momentum law, in 1659, he established the idea of centrifugal forces, and in 1678 in Paris, he developed his famous wave theory of light.

Huygens left France in about 1686 for religious reasons, fearing persecution as he was a protestant, visited England in 1689 and then retired to The Hague, where he died in 1695 at age 66.

He was honored by naming a Lunar mountain range, Mons Huygens (20.0N, 2.9W, 40 km diameter, in 1961) and a Mars Crater after him (14.3S, 304.6W, 470.0 km diameter, named 1973), as well as the Huygens Probe spacecraft which is to land on Saturn's moon Titan. Asteroid (2801) Huygens has been discovered on September 28, 1935 by H. van Gent at Johannesburg, provisionally named 1935 SU1 as well as 1968 UG, 1976 JP5, 1977 TT1, 1980 FF11, and 1982 UZ on the occasion of later independent findings.

Robert Hooke (1635-1708)

Robert Hooke was perhaps one of the most important scientists from the 17th century. While his research and findings were often overshadowed by those of his rival Sir Isaac Newton, one cannot argue their importance in the development of fields such as physics, astronomy, biology, and medicine, to name a few.

One could say he was England's equivalent of 14th century genius Leonardo da Vinci, that he was a true renaissance man who was constantly seeking answers to questions, and inventing new and ingenious scientific instruments. Hooke's inventions include the spring control of the balance wheel in watches, and the first reflecting telescope. Hooke also worked as an architect, although his dreams of redesigning London following the Great Fire of 1666 were brought down to smaller proportions.

One must realize that Robert Hooke's advances in the field of Microscopy and Astronomy opened doors which would one day lead to discoveries from scientists such as Dr. Edwin Hubble, and that some of his other inventions such as the universal joint, which is being used in the automobile industry, and his balanced springs, which are still part of some of the watches we wear. Hooke's Law and his combustion theory are still used by today's scientists.

Alas, for all the genius and for all his triumphs, Hooke was a sickly, bitter man who's work had oft been at the source of others' successes, a man who spent his entire life alone, orphaned at the age of 13 following his father's suicide. To make matters worse, Hooke's one true love (Grace Hooke), also happened to be his niece, and the short while the two actually lived together at Hooke's home, there is no indication his love was reciprocated. Hooke died alone, his estate being sold at auction to an illiterate woman by the name of Elizabeth Stevens.

Robert Hooke's remains were exhumed and reburied somewhere in North London in the 18th century, nut no one seems to know exactly where. If the remains are found,Professor Michael Cooper of City University, London plans to utilize the forensic anthropology technique of facial reconstruction to give Robert Hooke a face, and perhaps more of the recognition he deserves. The only likeness of Robert Hooke's that was available until now was the Hooke memorial window, St Helen's Bishopsgate, but it was destroyed during the IRA Bishopsgate bombing.

Benjamin Franklin was born on January 17, 1706 in Boston, Massachusetts. His accomplishments as a scientist, publisher and statesman are particularly remarkable when considered in the context of colonial North America, which lacked the cultural and commercial institutions to nourish original ideas. He dedicated himself to the improvement of everyday life for the widest number of people and, in so doing, made an indelible mark on the emerging nation.

Benjamin Franklin initially gained acclaim through his organization of the Junto (or the Leather Apron Club), a small group of young men who engaged in business and debated morality, politics, and philosophy. Through his work with the club, Ben Franklin is credited with initiating a paid city watch, volunteer fire department, subscription library (Library Company of Philadelphia), and the American Philosophical Society, which promoted scientific and intellectual dialogue and, to this day, is one of the nation's premiere scholarly associations.

Scientist Benjamin Franklin's inventions include bifocal glasses and the iron furnace stove, a small contraption with a sliding door which burns wood on a grate, thus allowing people to cook food and heat their homes at the same time.

Mid-eighteenth century scientists and inventors considered electricity to be Franklin's most remarkable area of investigation and discovery. In his famous experiment using a key and a kite during a thunderstorm, Franklin (working with his son) tested his hypothesis that lightning bolts are actually powerful electrical currents. This work led to the invention of the lightning rod which had the dramatic effect of preventing structures from igniting and burning as the result of being struck by lightning.

Charles Augustin Coulomb's father was Henry Coulomb and his mother was Catherine Bajet. Both his parents came from families which were well known in their fields. His father's family were important in the legal profession and in the administration of the Languedoc region of France, and his mother's family were also quite wealthy. After being brought up in Angoulême, the capital of Angoumois in southwestern France, Coulomb's family moved to Paris. In Paris he entered the Collège Mazarin, where he received a good classical grounding in language, literature, and philosophy, and he received the best available teaching in mathematics, astronomy, chemistry and botany.

At this stage in his education there was a crisis for Coulomb. Despite his father's good standing, he had made unsuccessful financial speculations, had lost all his money and moved from Paris to Montpellier. Coulomb's mother remained in Paris but Coulomb had a disagreement with her over the direction his career should take so he left Paris and went to Montpellier to live with his father. At this stage Coulomb's interests were mainly in mathematics and astronomy and while in Montpellier he joined the Society of Sciences there in March 1757 and read several papers on these topics to the Society.

Coulomb wanted to enter the École du Génie at Mézières but realised that to succeed in passing the entrance examinations he needed to be tutored. In October 1758 he went to Paris to receive the tutoring necessary to take the examinations. Camus had been appointed as examiner for artillery schools in 1755 and it was his Cours de mathématiques that Coulomb studied for several months. In 1758 Coulomb took the examinations set by Camus which he passed and he entered the École du Génie at Mézières in February 1760. He formed a number of important friendships around this time which were important in his later scientific work, one with Bossut who was his teacher at Mézières and the other with Borda.

Coulomb graduated in November 1761. He was now a trained engineer with the rank of lieutenant in the Corps du Génie. Over the next twenty years he was posted to a variety of different places where he was involved in engineering, in structural design, fortifications, soil mechanics, and many other areas. His first posting was to Brest but in February 1764 he was set to Martinique in the West Indies. Martinique fell under the sovereignty of France under Louis XIV in 1658. However Martinique was attacked by a number of foreign fleets over the following years. The Dutch attacked it in 1674 but were driven off, as were the English in 1693 and the English again in 1759. Martinique was finally captured by the English in 1762 but were returned to France under the terms of the Treaty of Paris in 1763. The French then made attempts to make the island more secure by building a new fort.

Coulomb was put in charge of the building of the new Fort Bourbon and this task occupied him until June 1772. It was a period during which he showed the practical side of his engineering skills which were needed to organise the construction, but his experiences would play a major role in the later theoretical memoirs he wrote on mechanics. As far as Coulomb's health was concerned these were difficult years and the illnesses which he suffered while on Martinique left him in poor health for the rest of his life.

On his return to France, Coulomb was sent to Bouchain. However, he now began to write important works on applied mechanics and he presented his first work to the Académie des Sciences in Paris in 1773. This work, Sur une application des règles, de maximis et minimis à quelque problèmes de statique, relatifs à l'architecture was written (in Coulomb's words, see for example [1]):-

... to determine, as far as a combination of mathematics and physics will permit, the influence of friction and cohesion in some problems of statics.

Perhaps the most significant fact about this memoir from a mathematical point of view is Coulomb's use of the calculus of variations to solve engineering problems. As Gillmor writes in [1]:- In this one memoir of 1773 there is almost an embarrassment of riches, for Coulomb proceeded to discuss the theory of comprehensive rupture of masonry piers, the design of vaulted arches, and the theory of earth pressure. In the latter he developed a generalised sliding wedge theory of soil mechanics that remains in use today in basic engineering practice. A reason, perhaps, for the relative neglect of this portion of Coulomb's work was that he sought to demonstrate the use of variational calculus in formulating methods of approach to fundamental problems in structural mechanics rather than to give numerical solutions to specific problems.

It is often the case that a sophisticated use of mathematics in an application to an area where most have less mathematical sophistication, gives the work a long term values which is not often seen at the time. The memoir was certainly highly valued by the Académie des Sciences for it led to him being named as Bossut's correspondent on 6 July 1774. From Bouchain, Coulomb was next posted to Cherbourg. While he was there he wrote a famous memoir on the magnetic compass which he submitted for the Grand Prix of the Académie des Sciences in 1777.

This 1777 paper won Coulomb a share of the prize and it contained his first work on the torsion balance [1]:-

... his simple, elegant solution to the problem of torsion in cylinders and his use of the torsion balance in physical applications were important to numerous physicists in succeeding years. ... Coulomb developed a theory of torsion in thin silk and hair threads. Here he was the first to show how the torsion suspension could provide physicists with a method of accurately measuring extremely small forces.

Another interesting episode occurred during the time which Coulomb spent at Cherbourg. Robert-Jacques Turgot was appointed comptroller general by Louis XVI on 24 August 1774. He began to feel threatened by his political opponents in 1775 and began a series of reforms. Among these was the reform of the Corps du Génie and Turgot called for memoirs on its possible reorganisation. Coulomb submitted a memoir giving his ideas and it is a fascinating opportunity to understand his political views. Coulomb wanted the state and the individual to play equal roles. He proposed that the Corps du Génie in particular, and all public service in general, should recognise the talents of its individual members in promotion within the organisation. In 1779 Coulomb was sent to Rochefort to collaborate with the Marquis de Montalembert in constructing a fort made entirely from wood near Ile d'Aix. Like Coulomb, the Marquis de Montalembert had a reputation as a military engineer designing fortifications, but his innovative work had been criticised by many French engineers [2]:-

Viewing fortresses as nothing more than immense permanent batteries designed to pour overwhelming fire on attacking armies, Montalembert simplified the intricate geometric designs of Vauban and relied on simple polygonal structures, often with detached peripheral forts instead of projecting bastions.

During his time at Rochefort, Coulomb carried on his research into mechanics, in particular using the shipyards in Rochefort as laboratories for his experiments. His studies into friction in Rochefort led to Coulomb's major work on friction Théorie des machines simples which won him the Grand Prix from the Académie des Sciences in 1781. In this memoir Coulomb [1]:-

... investigated both static and dynamic friction of sliding surfaces and friction in bending of cords and in rolling. From examination of many physical parameters, he developed a series of two-term equations, the first term a constant and the second term varying with time, normal force, velocity, or other parameters.

Because of this prize winning work, the authors of [5] write:-

Coulomb's contributions to the science of friction were exceptionally great. Without exaggeration, one can say that he created this science.

In fact this 1781 memoir changed Coulomb's life. He was elected to the mechanics section of the Académie des Sciences as a result of this work, and he moved to Paris where he now held a permanent post. He never again took on any engineering projects, although he did remain as a consultant on engineering matters, and he devoted his life from this point on to physics rather than engineering. He wrote seven important treatises on electricity and magnetism which he submitted to the Académie des Sciences between 1785 and 1791. These seven papers are discussed in [6] where the author shows that Coulomb:-

... had obtained some remarkable results by using the torsion balance method: law of attraction and repulsion, the electric point charges, magnetic poles, distribution of electricity on the surface of charged bodies and others. The importance of Coulomb's law for the development of electromagnetism is examined and discussed.

In these he developed a theory of attraction and repulsion between bodies of the same and opposite electrical charge. He demonstrated an inverse square law for such forces and went on to examine perfect conductors and dielectrics. He suggested that there was no perfect dielectric, proposing that every substance has a limit above which it will conduct electricity. These fundamental papers put forward the case for action at a distance between electrical charges in a similar way as Newton's theory of gravitation was based on action at a distance between masses.

These papers on electricity and magnetism, although the most important of Coulomb's work over this period, were only a small part of the work he undertook. He presented twenty-five memoirs to theAcadémie des Sciences between 1781 and 1806. Coulomb worked closely with Bossut, Borda, de Prony, and Laplace over this period. Remarkably he participated in the work of 310 committees of the Academy. He still was involved with engineering projects as a consultant, the most dramatic of which was his report on canal and harbour improvements in Brittany in 1783-84. He had been pressed into this task against his better judgement and he ended up taking the blame when criticisms were made and he spent a week in prison in November 1783.

He also undertook services for the respective French governments in such varied fields as education and reform of hospitals. In 1787 he made a trip to England to report on the conditions in the hospitals of London. In July 1784 he was appointed to look after the royal fountains and took charge of a large part of the water supply of Paris. On 26 February 1790 Coulomb's first son was born, although he was not married to Louise Françoise LeProust Desormeaux who was the mother of his son.

When the French Revolution began in 1789 Coulomb had been deeply involved with his scientific work. Many institutions were reorganised, not all to Coulomb's liking, and he retired from the Corps du Génie in 1791. At about the same time that the Académie des Sciences was abolished in August 1783, he was removed from his role in charge of the water supply and, in December 1793, the weights and measures committee on which he was serving was also disbanded. Coulomb and Borda retired to the country to do scientific research in a house he owned near Blois. The Académie des Sciences was replaced by the Institut de France and Coulomb returned to Paris when he was elected to the Institute in December 1795. On 30 July 1797 his second son was born and, in 1802, he married Louise Françoise LeProust Desormeaux, the mother of his two sons. We mentioned above that Coulomb was involved with services to education. These were largely between 1802 and 1806 when he was inspector general of public instruction and, in that role, he was mainly responsible for setting up the lycées across France.

Let us end with quoting the tribute paid to him by Biot who wrote:-

Daniel Bernoulli Basel The Swiss doctor, mathematician and physician Daniel Bernoulli (1700-82), son of the mathematician Johann Bernoulli, studied medicine and mathematics in his home town of Basel, in Heidelberg and Strasbourg. After he had made a name for himself with various works (including the pharaoh game and the principle of water flowing out of a container), he was called to the St. Petersburg academy of science in 1725, where he spent a total of eight fruitful years. During this time he wrote important texts on the theory of mechanics, including a first version of his famous treatise on hydrodynamics. In 1733 he became a professor of anatomy and botany in Basel. He had to wait until 1750 for his desired chair for physic, which he had wanted for a long time. His pioneering success was the combination of Newton's physics with methods of Leibniz's infinitesimal calculus, whereby he examined the hypotheses he reached with careful experiments. He was the first among the mathematicians in the Bernoulli family, to fully accept Newton's theory of physics, after he had given up trying to find a mechanical explanation for gravitation. In his famous main work "Hydrodynamica" (Basel 1738), which was a milestone in the theory of the flowing behavior of liquids, Daniel Bernoulli developed the theory of watermills, windmills, water pumps and water propellers. He was the first to differentiate between hydrostatic and hydrodynamic pressure. His "Bernoulli Principle on stationary flow" has remained the general principle of hydrodynamics and aerodynamics up to date and forms the basis of modern aviation. The solution he presented to the wave equation for a vibrating string with a sum of an infinite number of trigonometrical functions was further developed by Fourier and Dirichlet and now forms a mathematical tool for today's quantum mechanics.

Leonhard Euler - a greatest mathematician of all times

Material prepared by Simon Patterson

Leonhard Euler was one of the greatest mathematicians of all time. His numerous works (over 900 publications) in many areas had a decisive influence on the development of mathematics, an influence that is felt to this day.

Euler was born in Switzerland, in the town of Basel, on the 15th of April 1707, in the family of a pastor. At that time, Basel was one of the main centres of mathematics in Europe. At the age of 7, Euler started school while his father hired a private mathematics tutor for him. At 13, Euler was already attending lectures at the local university, and in 1723 gained his masters degree, with a dissertation comparing the natural philosophy systems of Newton and Descartes. On his father's wishes, Euler furthered his education by enrolling in the theological faculty, but devoted all his spare time to studying mathematics. He wrote two articles on reverse trajectory which were highly valued by his teacher Bernoulli. In 1727 Euler applied for a position as physics professor at Basel university, but was turned down.

At this time a new centre of science had appeared in Europe - the Petersburg Academy of Sciences. As Russia had few scientists of its own, many foreigners were invited to work at this centre - among them Euler. On the 24th of May 1727 Euler arrived in Petersburg. His great talents were soon recognised. Among the areas he worked in include his theory of the production of the human voice, the theory of sound and music, the mechanics of

vision, and his work on telescopic and microscopic perception. On the basis of this last work, not published until 1779, the construction of telescopes and microscopes was made possible.

In his study of colour effects, Euler hoped to make use of the observation of the conjunction of Venus and the moon, due to take place on the 8th of September 1729. However, no such effects were observed during this conjunction, and Euler was forced to wait for the eclipse of the sun which would take place in 1748. He observed this eclipse in Berlin, where he moved in 1741. Here he worked in the Berlin Academy of Sciences and was appointed as head of the Berlin Observatory, and was also tutor to the nieces of King Frederich II of Prussia.

Observations of the eclipse of the sun made by scientists of the day led them to believe that the moon did not contain sufficient atmosphere to provide the effects of diffraction or refraction. Only Euler was able to detect the moon's atmosphere. And in 1761, when Venus passed over the face of the sun, he detected the atmosphere of Venus.

Euler's works were not devoted solely to the natural sciences. A true renaissance man, he also involved himself in the philosophical debates of the day, and triumphantly declared himself a firm believer in the freedom of the will. Such views won him few friends in Germany, and the book in which he thus expressed himself was published for the first time in Russia, where Euler returned in 1766. Here he found many who agreed with his views, among them enemies of the views of Leibnitz and Voltaire.

In 1763 Catherine II came to the throne. She carried out reforms in the Academy of Sciences and aimed to make it a more prestigious institution. When Euler returned to Petersburg with his two elder sons they were given a two-storey house on the banks of the Neva and Euler given a position at the head of the Academy of Sciences.

At the time of his return to Petersburg Euler had already reconsidered his views on the atmosphere of planets. The work of Lomonosov and Bernoulli in this field led him to conclude that the atmosphere on the Earth and on other planets must be considerably more transparent than he had thought. Euler took a very active role in the observation of the movement of Venus across the face of the sun, despite the fact that at this time he was nearly blind. He had already lost one eye in the course of an experiment on light diffraction in 1738, and an eye disease and botched operation in 1771 led to an almost total loss of vision.

This did not, however, stop Euler's creative output. Until his death in 1783, the Academy was presented with over 500 of his works. The Academy continued to publish them for another half century after the death of the great scientist. To this day, his theories are studied and taught, and his incredibly diverse works make him one of the founding fathers of modern science.

Josef Stefan's parents, although living near Klagenfurt in Austria-Hungary (now Austria), were of Slovenian origin and spoke Slovenian. His father, Ales Stefan (1805-1872), worked as a miller of flour and as a baker. Josef's mother, Marija Startinik (1815-1863), was employed as a maidservant. They were both illiterate and were not married. Josef showed his brilliance when at elementary school in Klagenfurt and he showed himself to have both the desire and ability to do well at the Gymnasium which was recommended by his teachers. However, as an illegitimate child he would not be allowed to attend a Gymnasium so, when he was eleven years old, his parents married to give Josef to opportunity of a good education. Stefan entered the Gymnasium in Klagenfurt in 1846.

On 13 March 1848, eleven days before Stefan's thirteenth birthday, a Revolution began in Austria. It was prompted by the Paris Revolution in February of the same year. People sought basic freedoms but the country was divided and revolutionary and counter-revolutionary groups fought for power. Stefan was at an impressionable age and the Revolution made him much more aware of the various ethnic groupings and his own Slovenian origins. He reacted by writing Slovenian poetry which he published. His poetry touched on scientific topics as well as sometime being fiercely patriotic while at other times it was romantic. In 1853 he completed his studies at the Gymnasium as the top student in his class and, although having a range of interests which he could have chosen to study at university, nevertheless was quite certain that mathematics and physics were for him. He did consider joining the Benedictine Order for a while but soon gave up the idea.

Stefan entered the University of Vienna in 1853. He graduated four years later with a degree in mathematics and physics. He continued to write Slovenian poetry and prose throughout his student years but after criticisms by the Slovenian literary experts, he gave this up around the time he graduated from the University of Vienna. For the next year he taught physics for pharmacy students, then accepted a position with Karl Ludwig at the Physiology Institute of Vienna University. Here he carried out experimental work on the flow of water through tubes. During this period he was preparing to habilitate which he did in 1858. Appointed a lecturer in mathematical physics at the University of Vienna in 1858, he was elected to the Austrian Academy of Sciences in 1860, then he became a professor at the University of Vienna in 1863. In 1866 he became director of the Physical Institute at Vienna. This Institute had been founded by Doppler in 1850.

His career at the University of Vienna included a spell as dean of the Philosophy Faculty in 1869-70, and rector in 1876-77. We noted his election to the Austrian Academy of Sciences in 1860. He became a full member in 1865, was secretary of the Mathematical Sciences Class of the Academy from 1875, and was vice-president of the Academy from 1885 until his death.

The programme of research that Stefan embarked on was wide ranging across a number of different areas. He was a great admirer of Maxwell's contributions and was a major player in making his work known on the Continent. It was in Maxwell's papers that he came across the following:-

It would be almost impossible to establish the value of the conductivity of a gas by direct experiment, as the heat radiated from the sides of the vessel would be far greater than the heat conducted through the air, even if current could be entirely prevented.

Of course Maxwell was right about the difficulties but Stefan was one to rise to a challenge, especially when it came to devising experiments thought to be almost impossible. A new instrument would be needed to determine the thermal conductivity of air, reasoned Stefan, and he set about devising one which he called a diathermometer described in his paper Untersuchung über die Wärmeleitung in Gasen, Erste Abhandlung (1872). With this he was able to find a value of the thermal conductivity or air which only has an error of about 10%. Maxwell, and also Clausius who had also worked on the problem, had deduced that thermal conductivity should be independent of the pressure of the gas, and Stefan was able to verify this experimentally. He went on the find the thermal conductivity of hydrogen, nitrous oxide, methane, carbon monoxide, and carbon dioxide, presenting the results in Untersuchung über die Wärmeleitung in Gasen, Zweite Abhandlung (1875).

Stefan showed empirically, in 1879, that total radiation from a blackbody is proportional to the fourth power of its absolute temperature. This is the result for which he is best known and it was the work which we have described above which set him up to undertake this next piece of research. In fact he was led to the result by data produced by Tyndall in an 1865 book. Tyndall measured the radiation from a platinum wire heated by an electric current. Stefan, using Tyndall's data, wrote in Über die Beziehung zwischen der Wärmestrahlung und der Temperatur (1879):-

From weak red heat (about 525° C) to complete white heat (about 1200° C) the intensity of radiation increases from 10.4 to 122, thus nearly twelvefold (more precisely 11.7). This observation caused me to take the heat radiation as proportional to the fourth power of the absolute temperature. The ratio of the absolute temperature 273 + 1200 and 273 + 525raised to the fourth power gives 11.6.

Stefan then applied it to determine the approximate temperature of the surface of the Sun. Boltzmann, who was one of Stefan's students, showed in 1884 that this Stefan-Boltzmann law could be demonstrated mathematically.

After this work, Stefan looked at the problem of the polar ice caps. Several ships had been trying to find the Northwest Passage and in so doing had become stuck in the polar ice over the winter. The scientists on board had taken recordings of the air temperature and ice growth. Stefan realised that this was a variant of the problem he had been studying. Instead of considering the transfer of heat across a fixed boundary, this problem involved the transfer of heat across a moving boundary. He presented his results in Über die Theorie der Eisbildung, insbesondere über die Eisbildung im Polarmeere (1889).

Other work by Stefan includes studies of surface tension and evaporation, during which he proposed what today is called 'Stefan's number' and 'Stefan's law'. He also undertook research on alternating electric currents, studying the induction coefficients of wire coils. His wide range of topics can be illustrated by noting that he also made important contributions to optics, discovering secondary rings in Newton's experiments. The life which Stefan led was totally dedicated to science. He frequently slept in his laboratory and on occasions would spend several days in the laboratory without ever leaving. Of course with such total dedication to his work, Stefan had little time for friends and had hardly any social life. However he was liked by his students who found him an excellent teacher who could enthuse them for physics. Although his great strength as a researcher was on the experimental side, nevertheless he was an excellent mathematician who could show insight on the theoretical side too. His most famous student, Boltzmann said this of him (see for example [5]):-

He used the tools of advanced mathematics and understood how to present the most difficult developments in the clearest and most lucid form without ever having to resort to mathematical formalism. ... [He] never tried to flaunt [his] mental superiority. [His] uplifting humour, which turned the most difficult discussion into an entertaining game for the student, made such a deep impression on me.

Boltzmann painted a picture of a wonderful research environment:-

Nothing diminishes the excellence of [Stefan's] character, the magic [he] worked on the young academics. That magic could only be experienced personally. [The experience] stayed with me my whole life as a symbol of serious, inspired experimental activity.

For most of his life Stefan was unmarried, too dedicated to his profession to have space for wife or family. However, in 1891 when he was 56 years old, he married Marija Neumann who was a widow. He lived only a little over a year after his marriage, suffering a stroke. He was buried in the Zentralfriedhof in Vienna.

10 OUTSTANDING PHYSICISTS IN PH.D.

Eduardo San Juan - Filipino Inventor: Mechanical engineer, Eduardo San Juan (aka The Space Junkman) worked on the team that invented the Lunar Rover or Moon Buggy. Eduardo San Juan is considered the primary designer of the Lunar Rover. San Juan was also the designer for the Articulated Wheel System. Prior, to the Apollo Program, Eduardo San Juan worked on the Intercontinental Ballistic Missile (ICBM).

Moon Buggy:

In 1971, the Moon Buggy was first used by during the Apollo 12 landing to explore the Moon.

Eduardo San Juan - Education & Awards:

Eduardo San Juan graduated from Mapua Institute of Technology. He then studied Nuclear Engineering at the University of Washington. In 1978, San Juan received one of the Ten Outstanding Men (TOM) awards in science and technology.

Eduardo San Juan - On a Personal Note:

Elisabeth San Juan, the proud daughter of Eduardo San Juan, had the following to say about her father.

When my Father submitted the conceptual design for the Lunar Rover he submitted it via Brown Engineering, a company owned by Lady Bird Johnson.

During the final test demonstration to select one design from various submissions, his was the only one that worked. Thus, his design won the NASA Contract.

His overall concept and design of the Articulated Wheel System was considered brilliant. Each wheel appendage was mounted not underneath the vehicle, but were placed outside the body of the vehicle and each was motorized. Wheels could work independently of the others. It was designed to negotiate crater ingress and egress. The other vehicles did not make it into or out of the test crater.

Our Father, Eduardo San Juan, was a very positively charged creative who enjoyed a healthy sense of humor.

Isaac Newton The first and greatest physicist in my estimation is Isaac Newton, born in 1643. Lots of commenters absolutely correctly picked out Newton for the top spot, and had I picked anyone else (with the just barely plausible alternatives of Einstein or Galileo (and see his honorable mention for details)) I'd have been justifiably thought to be nuts.

Before Newton, there was no physics. There was science, but a systematic mathematicaldescription of the laws of nature did not exist. Indeed it could not exist, mathematics itself had not yet developed to the point where it could be used to formulate the necessary laws.

Newton singlehandedly changed that with the invention of calculus and the formulation of the laws of mechanics. The motions of the planets and the motion of things terrestrial ceased to be a mystery and suddenly became things that could be calculated. Newton didn't merely write the laws and leave their application and development for others - he went slashing through the unknown with a metaphorical machete. His three- volume brick of a work known as the Principia Mathematica derived everything from the resisting force due to fluid flow to to derivations of Kepler's laws, to the motion of the earth's moon and Jupiter's moons and numerous other major discoveries. Any one of those would have made the reputation of a lesser man. His mechanics reigned supreme until Einstein, and even then Newton's classical mechanics remain fine approximation for most everyday calculations. Certain other principles such as the conservation of energy, momentum, and angular momentum were either invented or heavily developed by Newton and they remain true even in relativity and quantum mechanics.

In pure mathematics he didn't merely invent the basic ideas of differential and integral calculus. He developed the binomial theorem, worked in infinite series, and extended our understanding in various parts of geometry.

He invented the reflecting telescope. Galileo's refractor was a pretty snazzy piece of brilliance, but Newton's reflector has a large number of technical advantages as well as the ability to be made much, much larger at much smaller expense than the refractors. Today everything from the Hubble Space Telescope to the gargantuan land-based observatories is based on the use of mirrors to collect light. This merely scratches the surface. Physics owes everything to Newton, who founded it and set it on a firm foundation of mathematical power and observational test.

Outside of science Newton was a bit of an odd bird. He as involved in alchemy, fringe theology, anti-counterfeiting detective work, a bizarre feud with the Leibniz (the independent co-inventor of calculus), and he may have been entirely asexual. Most of the greats had their idiosyncrasies, and given their skill I think we can overlook the excessively unusual.

He's worth learning more about. For the technically sophicistiated and hale of heart, there's Newton's own The Principia for your reading. As an exploration of Newton's life and work, there's James Gleick's Isaac Newton. Gleick, by the way, is one of my favorite science writers. As far as I can tell everything he's ever written is great.

And that completes the list. There's plenty of room for substitutions and switches, but I think what I've picked is probably close to an average opinion of who the greatest are. It was in many respects a close-run thing, there's at least ten more who have their own very good arguments for inclusion. I'd like to continue this series without any ranking conceit into some of the remaining greats who weren't specifically included on this list.

Pierre Curie was born in Paris, where his father was a general medical practitioner, on May 15, 1859. He received his early education at home before entering the Faculty of Sciences at the Sorbonne. He gained his Licenciateship in Physics in 1878 and continued as a demonstrator in the physics laboratory until 1882 when he was placed in charge of all practical work in the Physics and Industrial Chemistry Schools. In 1895 he obtained his Doctor of Science degree and was appointed Professor of Physics. He was promoted to Professor in the Faculty of Sciences in 1900, and in 1904 he became Titular Professor.

In his early studies on crystallography, together with his brother Jacques, Curie discovered piezoelectric effects. Later, he advanced theories of symmetry with regard to certain physical phenomena and turned his attention to magnetism. He showed that the magnetic properties of a given substance change at a certain temperature - this temperature is now known as the Curie point. To assist in his experiments he constructed several delicate pieces of apparatus - balances, electrometers, piezoelectric crystals, etc.

Curie's studies of radioactive substances were made together with his wife, whom he married in 1895. They were achieved under conditions of much hardship - barely adequate laboratory facilities and under the stress of having to do much teaching in order to earn their livelihood. They announced the discovery of radium and polonium by fractionation of pitchblende in 1898 and later they did much to elucidate the properties of radium and its transformation products. Their work in this era formed the basis for much of the subsequent research in nuclear physics and chemistry. Together they were awarded half of the Nobel Prize for Physics in 1903 on account of their study into the spontaneous radiation discovered by Becquerel, who was awarded the other half of the Prize.

Pierre Curie's work is recorded in numerous publications in the Comptes Rendus de l'Académie des Sciences, the Journal de Physique and the Annales de Physique et Chimie.

Curie was awarded the Davy Medal of the Royal Society of London in 1903 (jointly with his wife) and in 1905 he was elected to the Academy of Sciences.

His wife was formerly Marie Sklodowska, daughter of a secondary- school teacher at Warsaw, Poland. One daughter, Irene, married Frederic Joliot and they were joint recipients of the Nobel Prize for Chemistry in 1935. The younger daughter, Eve, married the American diplomat H. R. Labouisse. They have both taken lively interest in social problems, and as Director of the United Nations' Children's Fund he received on its behalf the Nobel Peace Prize in Oslo in 1965. She is the author of a famous biography of her mother, Madame Curie (Gallimard, Paris, 1938), translated into several languages.

Pierre was killed in a street accident in Paris on April 19, 1906.

Marie Curie, née Maria Sklodowska, was born in Warsaw on November 7, 1867, the daughter of a secondary-school teacher. She received a general education in local schools and some scientific training from her father. She became involved in a students' revolutionary organization and found it prudent to leave Warsaw, then in the part of Poland dominated by Russia, for Cracow, which at that time was under Austrian rule. In 1891, she went to Paris to continue her studies at the Sorbonne where she obtained Licenciateships in Physics and the Mathematical Sciences. She met Pierre Curie, Professor in the School of Physics in 1894 and in the following year they were married. She succeeded her husband as Head of the Physics Laboratory at the Sorbonne, gained her Doctor of Science degree in 1903, and following the tragic death of Pierre Curie in 1906, she took his place as Professor of General Physics in the Faculty of Sciences, the first time a woman had held this position. She was also appointed Director of the Curie Laboratory in the Radium Institute of the University of Paris, founded in 1914.

Her early researches, together with her husband, were often performed under difficult conditions, laboratory arrangements were poor and both had to undertake much teaching to earn a livelihood. The discovery of radioactivity by Henri Becquerel in 1896 inspired the Curies in their brilliant researches and analyses which led to the isolation of polonium, named after the country of Marie's birth, and radium. Mme. Curie developed methods for the separation of radium from radioactive residues in sufficient quantities to allow for its characterization and the careful study of its properties, therapeutic properties in particular.

Mme. Curie throughout her life actively promoted the use of radium to alleviate suffering and during World War I, assisted by her daughter, Irene, she personally devoted herself to this remedial work. She retained her enthusiasm for science throughout her life and did much to establish a radioactivity laboratory in her native city - in 1929 President Hoover of the United States presented her with a gift of $ 50,000, donated by American friends of science, to purchase radium for use in the laboratory in Warsaw.

Mme. Curie, quiet, dignified and unassuming, was held in high esteem and admiration by scientists throughout the world. She was a member of the Conseil du Physique Solvay from 1911 until her death and since 1922 she had been a member of the Committee of Intellectual Co-operation of the League of Nations. Her work is recorded in numerous papers in scientific journals and she is the author of Recherches sur les Substances Radioactives (1904),L'Isotopie et les Éléments Isotopes and the classic Traité' de Radioactivité (1910).

The importance of Mme. Curie's work is reflected in the numerous awards bestowed on her. She received many honorary science, medicine and law degrees and honorary memberships of learned societies throughout the world. Together with her husband, she was awarded half of the Nobel Prize for Physics in 1903, for their study into the spontaneous radiation discovered by Becquerel, who was awarded the other half of the Prize. In 1911 she received a secondNobel Prize, this time in Chemistry, in recognition of her work in radioactivity. She also received, jointly with her husband, the Davy Medal of the Royal Society in 1903 and, in 1921, President Harding of the United States, on behalf of the women of America, presented her with one gram of radium in recognition of her service to science.

Ernest Rutherford was born on August 30, 1871, in Nelson, New Zealand, the fourth child and second son in a family of seven sons and five daughters. His father James Rutherford, a Scottish wheelwright, emigrated to New Zealand with Ernest's grandfather and the whole family in 1842. His mother, néeMartha Thompson, was an English schoolteacher, who, with her widowed mother, also went to live there in 1855.

Ernest received his early education in Government schools and at the age of 16 entered Nelson Collegiate School. In 1889 he was awarded a University scholarship and he proceeded to the University of New Zealand, Wellington, where he entered Canterbury College*. He graduated M.A. in 1893 with a double first in Mathematics and Physical Science and he continued with research work at the College for a short time, receiving the B.Sc. degree the following year. That same year, 1894, he was awarded an 1851 Exhibition Science Scholarship, enabling him to go to Trinity College, Cambridge, as a research student at the Cavendish Laboratory under J.J. Thomson. In 1897 he was awarded the B.A. Research Degree and the Coutts-Trotter Studentship of Trinity College. An opportunity came when the Macdonald Chair of Physics at McGill University, Montreal, became vacant, and in 1898 he left for Canada to take up the post.

Rutherford returned to England in 1907 to become Langworthy Professor of Physics in the University of Manchester, succeeding Sir Arthur Schuster, and in 1919 he accepted an invitation to succeed Sir Joseph Thomson as Cavendish Professor of Physics at Cambridge. He also became Chairman of the Advisory Council, H.M. Government, Department of Scientific and Industrial Research; Professor of Natural Philosophy, Royal Institution, London; and Director of the Royal Society Mond Laboratory, Cambridge.

Rutherford's first researches, in New Zealand, were concerned with the magnetic properties of iron exposed to high-frequency oscillations, and his thesis was entitled Magnetization of Iron by High-Frequency Discharges. He was one of the first to design highly original experiments with high-frequency, alternating currents. His second paper, Magnetic Viscosity, was published in the Transactions of the New Zealand Institute (1896) and contains a description of a time-apparatus capable of measuring time intervals of a hundred-thousandth of a second.

On his arrival at Cambridge his talents were quickly recognized by Professor Thomson. During his first spell at the Cavendish Laboratory, he invented a detector for electromagnetic waves, an essential feature being an ingenious magnetizing coil containing tiny bundles of magnetized iron wire. He worked jointly with Thomson on the behaviour of the ions observed in gases which had been treated with X-rays, and also, in 1897, on the mobility of ions in relation to the strength of the electric field, and on related topics such as the photoelectric effect. In 1898 he reported the existence of alpha and beta rays in uranium radiation and indicated some of their properties.

In Montreal, there were ample opportunities for research at McGill, and his work on radioactive bodies, particularly on the emission of alpha rays, was continued in the Macdonald Laboratory. With R.B. Owens he studied the "emanation" of thorium and discovered a new noble gas, an isotope of radon, which was later to be known as thoron. Frederick Soddy arrived at McGill in 1900 from Oxford, and he collaborated with Rutherford in creating the "disintegration theory" of radioactivity which regards radioactive phenomena as atomic - not molecular - processes. The theory was supported by a large amount of experimental evidence, a number of new radioactive substances were discovered and their position in the series of transformations was fixed. Otto Hahn, who later discovered atomic fission, worked under Rutherford at the Montreal Laboratory in 1905-06.

At Manchester, Rutherford continued his research on the properties of the radium emanation and of the alpha rays and, in conjunction with H. Geiger, a method of detecting a single alpha particle and counting the number emitted from radium was devised. In 1910, his investigations into the scattering of alpha rays and the nature of the inner structure of the atom which caused such scattering led to the postulation of his concept of the "nucleus", his greatest contribution to physics. According to him practically the whole mass of the atom and at the same time all positive charge of the atom is concentrated in a minute space at the centre. In 1912 Niels Bohrjoined him at Manchester and he adapted Rutherford's nuclear structure to Max Planck's quantum theory and so obtained a theory of atomic structure which, with later improvements, mainly as a result of Heisenberg's concepts, remains valid to this day. In 1913, together with H. G. Moseley, he used cathode rays to bombard atoms of various elements and showed that the inner structures correspond with a group of lines which characterize the elements. Each element could then be assigned an atomic number and, more important, the properties of each element could be defined by this number. In 1919, during his last year at Manchester, he discovered that the nuclei of certain light elements, such as nitrogen, could be "disintegrated" by the impact of energetic alpha particles coming from some radioactive source, and that during this process fast protons were emitted. Blackett later proved, with the cloud chamber, that the nitrogen in this process was actually transformed into an oxygen isotope, so that Rutherford was the first to deliberately transmute one element into another. G. de Hevesy was also one of Rutherford's collaborators at Manchester.

An inspiring leader of the Cavendish Laboratory, he steered numerous future Nobel Prize winners towards their great achievements: Chadwick, Blackett, Cockcroft and Walton; while other laureates worked with him at the Cavendish for shorter or longer periods: G.P. Thomson,Appleton, Powell, and Aston. C.D. Ellis, his co-author in 1919 and 1930, pointed out "that the majority of the experiments at the Cavendish were really started by Rutherford's direct or indirect suggestion". He remained active and working to the very end of his life.

Rutherford published several books: Radioactivity (1904); Radioactive Transformations(1906), being his Silliman Lectures at Yale University; Radiation from Radioactive Substances, with James Chadwick and C.D. Ellis (1919, 1930) - a thoroughly documented book which serves as a chronological list of his many papers to learned societies, etc.; The Electrical Structure of Matter (1926); The Artificial Transmutation of the Elements (1933); The Newer Alchemy (1937).

Rutherford was knighted in 1914; he was appointed to the Order of Merit in 1925, and in 1931 he was created First Baron Rutherford of Nelson, New Zealand, and Cambridge. He was elected Fellow of the Royal Society in 1903 and was its President from 1925 to 1930. Amongst his many honours, he was awarded the Rumford Medal (1905) and the Copley Medal (1922) of the Royal Society, the Bressa Prize (1910) of the Turin Academy of Science, the Albert Medal (1928) of the Royal Society of Arts, the Faraday Medal (1930) of the Institution of Electrical Engineers, the D.Sc. degree of the University of New Zealand, and honorary doctorates from the Universities of Pennsylvania, Wisconsin, McGill, Birmingham, Edinburgh, Melbourne, Yale, Glasgow, Giessen, Copenhagen, Cambridge, Dublin, Durham, Oxford, Liverpool, Toronto, Bristol, Cape Town, London and Leeds.

Rutherford married Mary Newton, only daughter of Arthur and Mary de Renzy Newton, in 1900. Their only child, Eileen, married the physicist R.H. Fowler. Rutherford's chief recreations were golf and motoring.

He died in Cambridge on October 19, 1937. His ashes were buried in the nave of Westminster Abbey, just west of Sir Isaac Newton's tomb and by that of Lord Kelvin.

Caesar A. Saloma is a professor of physics at the National Institute of Physics, University of the Philippines, Diliman, Quezon City, Philippines. He has been the Dean of the College of Science, University of the Philippines in Diliman, Quezon City since June 2006. He also served as Director of the National Institute of Physics from June 2000 to May 2006 (two terms). Saloma obtained his BS, MS, and PhD degrees from the University of the Philippines in 1981, 1984, and 1989, respectively. The College of Science is the primary producer of new scientific knowledge as well as PhD and MS graduates in the basic and applied sciences and mathematics in the Philippines today. It operates the National Science Complex of the Philippines that was established by Philippine President Gloria Macapagal-Arroyo through Executive Order No. 583 issued on 8 December 2006. Saloma spent his childhood in Baclayon, Bohol and attended high school at the Immaculate Heart of Mary Seminary in nearby Tagbilaran City. He is included in the Marquis Who's Whoin Science and Engineering 2011-2012 (11th Edition). Marko Arciaga, Ph.D.¶s Summary

A graduate of Ph.D. in Physics from University of the Philippines with magna cum laude honors in B.S. Applied Physics from the same university.

Currently working as a Product Development Engineer in Littelfuse Inc., responsible for the design and development of company's new fuse products for electronics applications, starting from design conceptualization until release to mass production.

With 6 years experience as College Physics Instructor and more than 10 years experience in research (from academic to industrial).

Co-author of 5 technical papers published in international scientific journals and 1 high school physics textbook. Marko Arciaga, Ph.D.¶s Specialties: -Physics, plasma, gas discharges, semiconductors, optoelectronics, optics, materials processing, granular matter -Project management -Research and development -Teaching college physics

Nicolaus Copernicus was born in Thorn, Poland on February 19, 1473. He was the son of a wealthy merchant. After his father's death, he was raised by his mother's brother, a bishop in the Catholic Church. Copernicus studied mathematics and astronomy at the University of Krakow. Through his uncle's influence Copernicus was appointed a canon (church official) of the Catholic Church. He used the income from the position to help pay for additional studies. Copernicus studied law and medicine at the universities of Bologna, Padua, and Ferrara in Italy. While he was studying at the University of Bologna, his interest in astronomy was stimulated. He lived in the home of a mathematics professor who influenced him to question the astronomy beliefs of the day. After his return to Poland, Copernicus lived in his uncle's bishopric palace. While there he performed church duties, practiced medicine and studied astronomy. In Copernicus' time most astronomers believed the theory the Greek astronomer Ptolomy had developed more than 1,000 years earlier. Ptolomy said the Earth was the center of the universe and was motionless. He believed all other heavenly bodies moved in complicated patterns around the Earth. Copernicus felt that Ptolomy's theory was incorrect. Sometime between 1507 and 1515, he first circulated the principles of his heliocentric or Sun- centered astronomy. Copernicus' observations of the heavens were made with the naked eye. He died more than fifty years before Galileo became the first person to study the skies with a telescope. From his observations, Copernicus concluded that every planet, including Earth, revolved around the Sun. He also determined that the Earth rotates daily on its axis and that the Earth's motion affected what people saw in the heavens. Copernicus did not have the tools to prove his theories. By the 1600s, astronomers such as Galileo would develop the physics that would prove he was correct. Copernicus died on May 24, 1543.

Max Karl Ernst Ludwig Planck was born in Kiel, Germany, on April 23, 1858, the son of Julius Wilhelm and Emma (néePatzig) Planck. His father was Professor of Constitutional Law in the University of Kiel, and later in Göttingen.

Planck studied at the Universities of Munich and Berlin, where his teachers included Kirchhoff and Helmholtz, and received his doctorate of philosophy at Munich in 1879. He was Privatdozent in Munich from 1880 to 1885, then Associate Professor of Theoretical Physics at Kiel until 1889, in which year he succeeded Kirchhoff as Professor at Berlin University, where he remained until his retirement in 1926. Afterwards he became President of the Kaiser Wilhelm Society for the Promotion of Science, a post he held until 1937. The Prussian Academy of Sciences appointed him a member in 1894 and Permanent Secretary in 1912.

Planck's earliest work was on the subject of thermodynamics, an interest he acquired from his studies under Kirchhoff, whom he greatly admired, and very considerably from reading R. Clausius' publications. He published papers on entropy, on thermoelectric ity and on the theory of dilute solutions. At the same time also the problems of radiation processes engaged his attention and he showed that these were to be considered as electromagnetic in nature. From these studies he was led to the problem of the distribution of energy in the spectrum of full radiation. Experimental observations on the wavelength distribution of the energy emitted by a black body as a function of temperature were at variance with the predictions of classical physics. Planck was able to deduce the relationship between the ener gy and the frequency of radiation. In a paper published in 1900, he announced his derivation of the relationship: this was based on the revolutionary idea that the energy emitted by a resonator could only take on discrete values or quanta. The energy for a resonator of frequency v is hv where h is a universal constant, now called Planck's constant.

This was not only Planck's most important work but also marked a turning point in the history of physics. The importance of the discovery, with its far-reaching effect on classical physics, was not appreciated at first. However the evidence for its validi ty gradually became overwhelming as its application accounted for many discrepancies between observed phenomena and classical theory. Among these applications and developments may be mentioned Einstein's explanation of the photoelectric effect.

Planck's work on the quantum theory, as it came to be known, was published in the Annalen der Physik. His work is summarized in two books Thermodynamik (Thermodynamics) (1897) and Theorie der Wärmestrahlung (Theory of heat radiat ion) (1906).

He was elected to Foreign Membership of the Royal Society in 1926, being awarded the Society's Copley Medal in 1928.

Planck faced a troubled and tragic period in his life during the period of the Nazi government in Germany, when he felt it his duty to remain in his country but was openly opposed to some of the Government's policies, particularly as regards the persecuti on of the Jews. In the last weeks of the war he suffered great hardship after his home was destroyed by bombing.

He was revered by his colleagues not only for the importance of his discoveries but for his great personal qualities. He was also a gifted pianist and is said to have at one time considered music as a career. Planck was twice married. Upon his appointment, in 1885, to Associate Professor in his native town Kiel he married a friend of his childhood, Marie Merck, who died in 1909. He remarried her cousin Marga von Hösslin. Three of his children died young, leaving him with two sons.

He suffered a personal tragedy when one of them was executed for his part in an unsuccessful attempt to assassinate Hitler in 1944.

He died at Göttingen on October 4, 1947.

SUBMITTED BY:

CEDRIC m. RAYLA

TO

Mr. JEROME ZAMORA