Tuesday, September 30, 2014

Étienne de Condillac and the Importance of Language in Logical Reasoning

Étienne Bonnot de Condillac (1714-1780)
On September 30, 1714, French philosopher and epistemologist Étienne Bonnot de Condillac was born. A leading advocate in France of the ideas of John Locke de Condillac further emphasized the importance of language in logical reasoning, stressing the need for a scientifically designed language and for mathematical calculation as its basis.

Étienne de Condillac was born at Grenoble as the youngest of three brothers to Gabriel Bonnot, Vicomte de Mably, and Catherine de La Coste. “Condillac” was the name of an estate purchased by his father in 1720. He is said to have had very poor eyesight and a weak physical constitution, factors that so retarded his intellectual development that as late as his twelfth year he was still unable to read. His education began only in his teens, first under the direction of a local priest, then at Lyons, later as seminarian in Paris, at Saint-Suplice and at the Sorbonne. He took holy orders in 1740 at Saint-Sulpice church in Paris and was appointed as Abbot of Mureauand, but did no pastoral work. [1]

Condillac published two main philosophical works: the Essay on the Origin of Human Knowledge of 1746, and the Treatise on Sensations of 1754, both of which were devoted to expositing his views on the role of experience in the development of our cognitive capacities. In his works La Logique (1780) and La Langue des calculs (1798), Condillac emphasized the importance of language in logical reasoning, stressing the need for a scientifically designed language and for mathematical calculation as its basis.[2] As a philosopher, Condillac gave systematic expression to the views of John Locke, previously made fashionable in France by Voltaire.

In retrospect, Condillac’s importance is both in virtue of his work as a psychologist, and his systematic establishment of Locke’s ideas in France. Like Locke, Condillac maintained an empirical sensationalism based on the principle that observations made by sense perception are the foundation for human knowledge. In the Traité des sensations, Condillac questioned Locke’s doctrine that the senses provide intuitive knowledge. He doubted, for example, that the human eye makes naturally correct judgments about the shapes, sizes, positions, and distances of objects. Examining the knowledge gained by each sense separately, he concluded that all human knowledge is transformed sensation, to the exclusion of any other principle, such as Locke’s additional principle of reflection.[2]

According to Condillac, all sensation is affective, that is, causes pain or pleasure. Sensations, consequently, are the source of all active faculties. Need, for example, is the result of the privation of some object whose presence is demanded either by nature of habit. Need, subsequently, directs all energy towards this missing object. This directionality, Condillac claimed, is what we call desire. Will is absolute desire, made vigilant by hope.

In Paris Condillac spent some years spent living the life of a man of letters in Paris and was involved with the circle of Denis Diderot, the philosopher who was co-contributor to the Encyclopédie. He developed a friendship with Jean Jacques Rousseau, which lasted in some measure to the end of his life. Together with his brother Gabriel, who became the well-known political writer known as Abbé de Mably, Condillac introduced Rousseau to an intellectual circle. Condillac's relations with unorthodox philosophers did not injure his career. He had already published several works when the French court sent him to Parma to educate the orphan duke Prince Ferdinand of Parma, then a child of seven years.

In 1768, on his return from Italy, Condillac was elected to the Académie française. Contrary to the popular idea that he attended only one meeting, he was a frequent attendee until two years before his death. Near the end of his life, Condillac turned his attention to politics and economics. His economic views, which were presented in Le Commerce et le gouvernement, were based on the notion that value depends not on labour but rather on utility. The need for something useful, he argued, gives rise to value, while prices result from the exchange of valued items.[2] Finding the irreligious climate of Parisian intellectual society offensive, he retired to spend his last years at Flux, near Beaugency on the Loire River. He died there on 3 August 1780.

At yovisto, you can learn more about Condillac's age of enlightenment in the talk of Gresham College Prof. Justin Champion on 'Why the Enlightenment still matters today'.


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Monday, September 29, 2014

Fritz Kahn and the Mensch Maschine

The Original Poster of the Industrial Palace
From: Fritz Kahn. Das Leben des Menschen
Franckh'sche Verlagshandlung, Stuttgart
On September 29, 1888, German Jewish physician Fritz Kahn was born. He is best known for his publication of popular science books and especially for his illustrations, which pioneered infographics.

Fritz Kahn was born in Halle, Germany and grew up with Jewish orthodox traditions and a decent education. In his early years, the Kahn family relocated several times and even lived in the United States for quite a while before settling in Berlin. The young Fritz enrolled at the University of Berlin in order to study medicine and also heard numerous lectures in various sciences. He specialized in gynecology and began published several scientific works for national newspapers and magazines.

However, World War I started and Fritz Kahn became a combat medic. During his free time, he also worked on his then very popular book 'The Milky Way'. Back in Berlin, Kahn was appointed surgeon and obstretician in a private hospital and created his successful books 'The Cell' as well as 'The Jews as a Race and Cultural People'. Also, Kahn released the highly illustrated five-volume series 'The Life of Man'. Quickly, Kahn became a very well known bestseller author. [1]

In 'The Life of Man', an oversize poster version of one of his suggestive illustrations as an aside was published. It showed the interior workings of the upper part of a human body with the help of machine parts. While the figure is identified as human by its silhouette and its profile of a human face looking to the right, the installations in the body’s interior appear as an industrial complex. When looking at the image, it becomes clear that the illustration assembles specific machinery to represent a particular organ and its function within its natural place. For instance, the ventilation system stands for the lungs and the mechanical break-up of substances along the chain of conveyer belts represents the digestive tract. [2]

In the meantime, Germany faced an increasing antisemitic atmosphere and the author founded a Jewish humanistic lodge and became chairman of the Jewish Senior Aid. Unfortunately, Kahn was expelled from Germany in early 1933. The Nazis also did not hesitate to burn his books, confiscate them and ban them with their “list of harmful and unwanted writing“.

In the following years, Kahn resettled several times. He first emigrated to Palestine in order to continue his career and release his internationally best selling book 'Our Sex Life'. In this period, he also published to remakes of 'The Life of Man', but unfortunately, his illustrations were abused in Germany for a short version including a new chapter with racist and antisemitic content. After living in Bordeaux for a short time, the restless man then had to escape via Portugal to the U.S. in 1941, which he accomplished with the help of his friend Albert Einstein. There, Kahn's restart was a bit easier due to the English translation of his various works, especially his masterpiece Man in 'Structure and Function'. Two further books were then published in Switzerland. [1]

At yovisto, you may be interested in a video on The Anatomy of Movement of a Violin Player at the University of Stanford.



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Sunday, September 28, 2014

Seymour R. Cray - the Father of Supercomputing

CRAY 1 with exposed interiors
On September 28, 1925, American electrical engineer and supercomputer architect Seymour Roger Cray was born. He designed a series of computers that were the fastest in the world for decades, and founded Cray Research which built many of these machines. Called "the father of supercomputing," Cray has been credited with creating the supercomputer industry.

Seymour Cray was born in 1925 in Chippewa Falls, Wisconsin, a small town situated in the heart of Wisconsin's dairy farm country, to Seymour R. and Lillian Cray. His father was a civil engineer who fostered Cray's interest in science and engineering. As early as the age of ten he was able to build a device out of Erector Set components that converted punched paper tape into Morse code signals. The basement of the family home was given over to the young Cray as a "laboratory". Cray graduated from Chippewa Falls High School in 1943 before being drafted for World War II as a radio operator. He saw action in Europe, and then moved to the Pacific theatre where he worked on breaking Japanese naval codes. On his return to the U.S. he received a B.Sc. in Electrical Engineering at the University of Minnesota, graduating in 1949. He also was awarded a M.Sc. in applied mathematics in 1951.

In 1950, Cray joined Engineering Research Associates (ERA) in Saint Paul, Minnesota. ERA had formed out of a former United States Navy lab that had built code breaking machines, a tradition ERA carried on when such work was available. ERA was introduced to computer technology during one such effort, but in other times had worked on a wide variety of basic engineering as well. There, Cray quickly came to be regarded as an expert on digital computer technology, especially following his design work on the ERA 1103, one of the first commercially successful scientific computer. He remained at ERA when it was bought by Remington Rand and then Sperry Corporation in the early 1950s. At the newly formed Sperry-Rand, ERA became the "scientific computing" arm of their UNIVAC division.[1]

In 1957, a number of employees of the scientific computer division left to form Control Data Corporation (CDC). Cray joined the new company later and by 1960 he had completed the design of the CDC 1604, an improved low-cost ERA 1103 that had impressive performance for its price range. Cray did not enjoy working on traditional business computers constrained to design for low-cost construction, so CDC could sell lots of them. His desire was to produce the fastest computer in the world. Although in terms of hardware his design of the CDC 6600 was not on the leading edge, Cray invested considerable effort in an attempt to enable it to run as fast as possible. Unlike most high-end projects, Cray realized that there was considerably more to performance than simple processor speed, that I/O bandwidth had to be maximized as well in order to avoid "starving" the processor of data to crunch. As he later noted, Anyone can build a fast CPU. The trick is to build a fast system.[2]

The CDC 6600 was the first commercial supercomputer, the first to employ freon to cool its 350,000 transistors, outperforming everything then available by a wide margin. While expensive, for those that needed the absolutely fastest computer available there was nothing else on the market that could compete. Cray continued to design further supercomputers for CDC, such as the CDC 7600 and CDC 8600, but the supercomputer projects had almost bankrupted the company while they were being designed and Cray decided to start his own company Cray Research in 1972. The first Cray-1 system was installed at Los Alamos National Laboratory in 1976 for $8.8 million. It boasted a world-record speed of 160 million floating-point operations per second (160 megaflops) and an 8 megabyte main memory. The Cray-1's architecture reflected its designer's penchant for bridging technical hurdles with revolutionary ideas. In order to increase the speed of this system, the Cray-1 had a unique "C" shape which enabled integrated circuits to be closer together. No wire in the system was more than four feet long. To handle the intense heat generated by the computer, Cray developed an innovative refrigeration system using Freon [2].

In order to concentrate his efforts on design, Cray left the CEO position in 1980 and became an independent contractor. The Cray-2 system appeared in 1985, providing a tenfold increase in performance over the Cray-1. In 1988, Cray Research introduced the Cray Y-MP, the world's first supercomputer to sustain over 1 gigaflop on many applications. Multiple 333 MFLOPS processors powered the system to a record sustained speed of 2.3 gigaflops. Always a visionary, Seymour Cray had been exploring the use of gallium arsenide in creating a semiconductor faster than silicon. However, the costs and complexities of this material made it difficult for the company to support both the Cray-3 and the Cray C90 development efforts. In 1989, Cray Research spun off the Cray-3 project into a separate company, Cray Computer Corporation, headed by Seymour Cray and based in Colorado Springs, Colorado. Tragically, Seymour Cray died of injuries suffered in an auto accident in September 1996 at the age of 71.[2]

Cray had always resisted the massively parallel solution to high-speed computing, offering a variety of reasons that it would never work as well as one very fast processor. He famously quipped "If you were plowing a field, which would you rather use: Two strong oxen or 1024 chickens?" By the mid-1990s this argument was becoming increasingly difficult to justify, and modern compiler technology made developing programs on such machines not much more difficult than their simpler counterparts

At yovisto, you can listen to a panel discussion about the 30th anniversary of the first CRAY supercomputer.


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Saturday, September 27, 2014

Pavlov and the Conditional Reflex

Ivan Petrovich Pavlov (1849-1936)
On September 27, 1849, Russian physiologist and Nobel Laureate Ivan Petrovich Pavlov was born. He is primarily known primarily for his work in classical conditioning. And what is the first thing you will think about when you hear Pavlov's name? Well, probably his experiments with dogs, where he conditioned dogs to salivate when hearing a bell ringing because they expected to get food. But, let's take a closer look at Pavlov and his work.

"Science demands from a man all his life. If you had two lives that would not be enough for you. Be passionate in your work and in your searching." - Ivan Pavlov

Ivan Pavlov, the eldest of eleven children, was born in Ryazan of the Russian Empire, to Peter Dmitrievich Pavlov, a village priest, and Varvara Ivanovna Uspenskaya, a devoted homemaker. Although able to read by the age of 7, Pavlov was seriously injured when he fell from a high wall onto stone pavement, and he did not undergo formal schooling until he was 11 years old as a result of his injuries. Pavlov attended and graduated from the Ryazan Church School before entering the local theological seminary. But, without graduating he went to attend the university at St. Petersburg where he enrolled in the physics and math department. In his fourth year, his first research project on the physiology of the nerves of the pancreas won him a prestigious university award. He proceeded to the Academy of Medical Surgery, where he obtained a position as a laboratory assistant to Professor Ustimovich at the physiological department of the Veterinary Institute. In 1879, Pavlov graduated from the Medical Military Academy with a gold medal award for his research work. In 1883, he presented his doctor's thesis on the subject of The centrifugal nerves of the heart and posited the idea of nervism and the basic principles on the trophic function of the nervous system.

In 1890 Pavlov was invited to organize and direct the Department of Physiology at the Institute of Experimental Medicine. Under his direction, which continued over a period of 45 years to the end of his life, this Institute became one of the most important centers of physiological research. Also in 1890 Pavlov was appointed Professor of Pharmacology at the Military Medical Academy and five years later he was appointed to the then vacant Chair of Physiology, which he held till 1925. There, Pavlov developed the surgical method of the «chronic» experiment with extensive use of fistulas, which enabled the functions of various organs to be observed continuously under relatively normal conditions. This discovery opened a new era in the development of physiology, for until then the principal method used had been that of acute vivisection, and the function of an organism had only been arrived at by a process of analysis. With his method of research, Pavlov opened the way for new advances in theoretical and practical medicine.[1]

Pavlov's observations led him to formulate his concept of the conditioned reflex. While researching the digestive function of dogs, he noted his subjects would salivate before the delivery of food. In his most famous experiment, he sounded a tone just before presenting dogs with food, conditioning them to begin salivating every time he sounded the tone. Pavlov published his results in 1903, and delivered a presentation on "The Experimental Psychology and Psychopathology of Animals" at the 14th International Medical Congress in Madrid, Spain, later that year.[2] Pavlov also discovered that these reflexes originate in the cerebral cortex of the brain.[3]

Pavlov received considerable acclaim for his work, including a 1901 appointment to the Russian Academy of Sciences and the 1904 Nobel Prize in Physiology. The Soviet government also offered substantial support for Pavlov's work, and the Soviet Union soon became a well-known center of physiology research.[3] Conscious until his very last moment, Pavlov asked one of his students to sit beside his bed and to record the circumstances of his dying. He wanted to create unique evidence of subjective experiences of this terminal phase of life. Pavlov died of double pneumonia at the age of 86.

At yovisto you can learn more about the human mind in the TED talk of MIT Prof. Marvin Minsky on Health, Society, and the human mind.

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Friday, September 26, 2014

Joseph Proust and the Law of Constant Composition

Joseph Proust (1754-1826)
On September 26, 1754, French chemist Joseph Louis Proust was born. He was best known for his discovery of the law of constant composition in 1799, stating that in chemical reactions matter is neither created nor destroyed.

Joseph L. Proust was born on September 26, 1754 in Angers, France as the second son of Joseph Proust, an apothecary, and Rosalie Sartre. Joseph studied chemistry in his father’s shop and later came to Paris, where he studied chemistry with Hilaire-Martin Rouelle. In 1776 Proust was appointed a pharmacist at the Salpêtrière Hospital in Paris. He published his first papers while at this hospital. However, his position was short-lived, for in 1778 Proust abandoned pharmacy to take a professorship of chemistry at the recently established Seminario Patriótico Vascongado in Vergara, Spain. This school was the creation of the Real Sociedad Económica Vascongada de Amigos del País, the first and most important of the “enlightened” provincial societies in Spain.[1]

In 1780 Proust returned to Paris, where he taught chemistry at the Musée, a private teaching institution founded by scientific impresario and aeronaut Jean-François Pilâtre de Rozier. Part of this association involved Proust with aerostatic experiments, which culminated in a balloon ascent with Pilâtre on June 23, 1784, at Versailles, in the presence of the king and queen of France, the king of Sweden, and the French court. In 1786 Proust returned to Spain to teach chemistry, first at Madrid and then in 1788 at the Royal Artillery School in Segovia. Founded in 1764, this school was part of the program of the government of Charles III to bring Spain abreast of the northern European countries regarding military training. Because of Spain’s scientific backwardness, expert instructors had to be sought abroad and Proust had been recommended by no less than the great French chemist Antoine-Laurent de Lavoisier.

But when Napoleon invaded Spain, they burned Proust's laboratory and forced him back to France. Proust is best known for two major advances in analytical chemistry. First, he developed the use of hydrogen sulfide as a reagent (a substance used to detect the presence of other substances by the chemical reactions it causes). Hydrogen sulfide is a colorless, extremely poisonous gas with a sweetish taste and a strong odor of rotten eggs. Chemical compounds containing sulfur produce hydrogen sulfide when they react with certain other chemical compounds. This is why the odor of hydrogen sulfide can be detected around decaying organic matter. Hydrogen sulfide is flammable and burns with a pale blue flame. Chemists make hydrogen sulfide in the laboratory by combining such strong acids as hydrochloric acid with such metal sulfides as iron sulfide. They use the gas to analyze the composition of mixtures and to produce other compounds.[2]

His second achievement derived from a controversy with C.L. Berthollet on the law of definite proportions, which is sometimes also known as Proust's Law. Proust studied copper carbonate, the two tin oxides, and the two iron sulfides to prove this law. He did this by making artificial copper carbonate and comparing it to natural copper carbonate. With this he showed that each had the same proportion of weights between the three elements involved . Between the two types of the other compounds, Proust showed that no intermediate compounds exist between them. Proust published this paper in 1794, and his famous opponent Berthollet did not believe that substances always combine in constant and definite proportions. Moreover, Bethollet claimed that that the products of a reaction depend on the ratio of reactants. Proust's law was not accepted until 1812, when the Swedish chemist Jöns Jacob Berzelius gave him credit for it.

Although Proust was correct in his observations, the reason why reagents behave in the way he described did not become clear until English chemist John Dalton formulated his atomic theory in 1803. According to Dalton, a fixed number of atoms of one substance always combined with a fixed number of atoms of another substance in forming a compound. Dalton realized that substances must combine in the same proportions by weight as the weight proportions of their atoms. Other chemists had already observed that pure substances do combine in fixed proportions. They called that finding the law of definite (or constant) proportions. Dalton's theory explained the law.

Proust also performed a series of researches to characterize different types of sugars, present in vegetable products. After the death of his wife in 1817, Proust moved to Angers, where in 1820 he took over the pharmacy of his brother Joachim. In 1819 he became a chevalier of the Legion of Honor, and in 1820 he was granted a pension by Louis XVIII. [3] On July 5, 1826 he died in Angers, France.

At yovisto, you can earn a better understanding basic chemistry in the organic chemistry lecture series of Yale Prof. J. Michael McBride on Rise of the Atomic Theory (1790-1850).


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Thursday, September 25, 2014

Abraham Werner and the School of Neptunism

Abraham Gottlob Werner (1749-1817)
On September 25, 1749, German geologist Abraham Gottlob Werner was born. He is best known for his early theory about the stratification of the Earth's crust. Moreover, he propounded an earth history that others labeled Neptunism that states that holding that all rocks have aqueous origins. While most tenets of Neptunism were eventually set aside, science is indebted to Werner for clearly demonstrating the chronological succession of rocks, for the zeal which he infused into his pupils, and for the impulse which he thereby gave to the study of geology. Thus, he has been called the “father of German geology.”

Abraham Gottlob Werner was born in Wehrau (now Osiecznica, Lower Silesian Voivodeship), a village in Prussian Silesia, as second child, and only son. His family had been involved in the mining industry for many years, where his father, Abraham David Werner, was an inspector at the Duke of Solm's ironworks. Werner was educated at Freiberg and Leipzig, where he studied law and mining after working with his father for five years in the ironworks at Wehrau and Lorzendorf. While in Leipzig, Werner became interested in the systematic identification and classification of minerals. Within a year he published the first modern textbook on descriptive mineralogy, Von den äusserlichen Kennzeichen der Fossilien (On the External Characters of Fossils, or of Minerals; 1774). During his career, he discovered eight minerals and named 26. In 1775 he was then appointed as Inspector and Teacher of Mining and Mineralogy at the small, but influential, Freiberg Mining Academy. During his 40-year tenure, the school grew from a local academy into a world-renowned centre of scientific learning. Werner was a brilliant lecturer and a man of great charm, and his genius attracted students who, inspired by him, became the foremost geologists of Europe.[1]

A distinguishing feature of Werner’s teaching was the care with which he taught the study of rocks and minerals and the orderly succession of geological formations, a subject that he called geognosy. Influenced by the works of Johann Gottlob Lehmann and Georg Christian Füchsel, Werner demonstrated that the rocks of the Earth are deposited in a definite order. Although he had never travelled, he assumed that the sequence of the rocks he observed in Saxony was the same for the rest of the world.[1]

 In the 18th century, rocks were explained in terms of the biblical flood, and were classified into three categories that most people associated with the biblical flood: "primary" for ancient rocks without fossils (believed to precede the flood), "secondary" for rocks containing fossils (often attributed to the flood itself) and "tertiary" for sediments believed to have been deposited after the flood. Werner didn't overturn the commonly held belief in the biblical flood, but he did recognize a different group of rocks that didn't fit this classification: rocks with a few fossils that were younger than primary rocks but older than secondary rocks. He called these "transition" rocks.[4] During his career, Werner published very little, but his fame as a teacher spread throughout Europe, attracting students, who became virtual disciples, and spread his interpretations throughout their homelands. Socratic in his lecturing style, Werner developed an appreciation for the broader implications and interrelations of geology within his students, who provided an enthusiastic and attentive audience.

Werner theorized that at one time the earth had been completely covered with oceans and that as sediments and chemicals in the water fell to the ocean floor, they formed layers of rock, which eventually became the land. Over time, water from the ocean evaporated, exposing the land and leaving pockets of water in low-lying areas. Werner's ideas had many followers and they came to be known as Neptunists, after Neptune, the Roman god of the water. But Werner's theory was not without opposition. Scottish geologist James Hutton had a much different theory. Hutton led a group known as the Plutonists, named for Pluto, the Roman god of the underworld. The Plutonists held that rock formed with the aid of heat instead of water. During the late 1700's, there was a great deal of debate in the scientific community as to which group was correct. Although some of Hutton's ideas were later modified, scientists in the early 1800's were able to prove that his theory was more accurate, and Werner's Neptunism was discredited.[2] One criticism of this hypothesis was that Werner hadn't traveled enough to verify it.

However, Neptunism certainly had its attractions, with Werner's disciples distributed all over Europe. The advantages of the theory were that it was theologically acceptable, it was simple, and it showed how the Earth could be formed in the short time available.[3] Werner was also a mineralogist and he constructed a new classification of minerals. There was a major split among 18th-century mineralogists as to whether minerals should be classified according to their external form (the natural method) or by their chemical composition (the chemical method). Werner finally adopted, in 1817, a mixed set of criteria by which he divided minerals into four main classes – earthy, saline, combustible, and metallic.[3] He was elected a foreign member of the Royal Swedish Academy of Sciences in 1810.

Werner was plagued by frail health his entire life, and passed a quiet existence in the immediate environs of Freiberg. He died at Dresden as a bachelor in 1817, from internal complications said to have been caused by his consternation over the misfortunes that had befallen Saxony during the Napoleonic Wars.

At yovisto you can learn more about basic geology in the lecture of Aida Awan 'Introduction to Geology 01'.



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Wednesday, September 24, 2014

William F. Friedman and the Art of Cryptology

William F. Friedman (1894-1969)
On September 1894, US cryptologist William F. Friedman was born. He is considered one of the world's greatest cryptologists, who helped decipher enemy codes from World War I to World War II.

Friedman was born as Wolfe Frederick Friedman, then part of imperial Russia, now Chisinau, capital of Moldova, as the son of Frederick Friedman, a Jew from Bucharest who worked as a translator and linguist for the Russian Postal Service, and the daughter of a well-to-do wine merchant. Friedman's family fled Russia in 1892 to escape the virulent anti-semitism there, ending up in Pittsburgh, Pennsylvania. Like many other too, Friedman was introduced to cryptography already as a child while reading Edgar Allan Poe's famous short story "The Gold-Bug". Actually, I also heart of ciphers and secret writings for the first time as a child with the very same story of an adventure where the protagonists after deciphering a secret message were lead to a buried treasure.

Friedman studied at the Michigan Agricultural College and received a scholarship to work on genetics at Cornell University. In September 1915, Friedman joined Fabyan's Riverbank Laboratories outside Chicago, a private research laboratory. As head of the Department of Genetics. Besides other industrial and agricultural topics, there was a cipher department at Riverbank studying the "Baconian Cipher," i.e. secret messages which Sir Francis Bacon had allegedly hidden in various texts during the reigns of Elizabeth I and James I and Friedman became interested in the study of codes and ciphers. When Riverbank was asked to train the military in the use of codes, Friedman was assigned as the principal instructor. Friedman served as a lieutenant in G6A2, the crypt unit of the American Expeditionary Forces during World War I, as the personal cryptographer for General John J. Pershing.

He returned to the US in 1920 and published an eighth monograph, "The Index of Coincidence and its Applications in Cryptography", considered by some to be the most important publication in modern cryptography to that time. His texts for Army cryptographic training were well thought of and remained classified for several decades. In 1921 he became chief cryptanalyst for the War Department and later led the Signals Intelligence Service(SIS)—a position he kept for a quarter century. In 1929 he was selected to be the head of the newly organized Signal Intelligence Service (SIS). There, he created the organizational foundations of a cryptologic structure which evolved into the Army Security Agency (ASA) in World War II. In the process, he led the transition from paper and pencil cryptology into the modern era characterized by the application of machines to both cryptography and cryptanalysis.[1]

On the outbreak of World War II Friedman became involved in Magic, the codename given for the American operation to break the Japanese diplomatic and military codes. The Communication Special Unit (US Navy) and the Signals Intelligence Section (US Army) worked together in monitoring the traffic of coded messages sent by the Japanese Government and the Imperial Headquarters to their commanders at sea and in the field. In 1939 Japan began using a new cipher machine invented by Jinsaburo Ito. Nicknamed the Purple Machine, the code was not broken until September 1940 by Friedman and his team. However, because of the large volume of intelligence being received by the staff of Magic, they were unable to give adequate warnings about the proposed attack at Pearl Harbor. With increases in the number of people working at Magic they were able to discover the attack plan at the Battle of Midway. This enabled Admiral Chester Nimitz to use this information to fight off a much larger force and halt the Japanese offensive in the Pacific.[2]

Following World War II, Friedman remained in government signals intelligence. In 1949 he became head of the cryptographic division of the newly formed Armed Forces Security Agency (AFSA) and in 1952 became chief cryptologist for the National Security Agency (NSA). Friedman produced a classic series of textbooks, "Military Cryptanalysis", which was used to train NSA students. During his early years at NSA, he encouraged it to develop what were probably the first super-computers, although he was never convinced a machine could have the "insight" of a human mind. Friedman also spent much of his free time trying to decipher the famous Voynich Manuscript, written sometime between 1403–1437. However, after four decades of study he finally had to admit defeat, contributing no more than an educated guess as to its origins and meaning.

At yovisto you can learn more about cryptology in the lecture of Gresham College Prof. Raymond Flood on 'Public Key Cryptography: Secrecy in Public'.

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Tuesday, September 23, 2014

Hippolyte Fizeau and the Speed of Light

Hippolyte Fizeau (1819-1896)
photo: Charles Reutlinger, Académie des Sciences,
Smithsonian Institution Libraries
On September 23, 1819, French physicist Armand Hippolyte Louis Fizeau was born. He is well known for his calculation of the speed of light and his suggestion to use length of a light wave be used as a length standard.

Hippolyte Fizeau was born in Paris as the eldest son of Béatrice and Louis Fizeau, who was professor of Pathology at the Paris Medical School. He attended the prestigious Collège Stanislas in Paris where he became a friend with one of his fellow students, Léon Foucault. In September 1839. Famous Louis Daguerre put on a free course on his new photographic techniques in Paris and the two friends Fizeau and Foucault attended. They watched Daguerre expose a plate in a camera pointing out the window, then after talking about his process for about 30 minutes, he developed the plate using a variety of chemicals to reveal the picture. Although Fizeau and Foucault were impressed they also realised the limitations of the process - it would be wonderful to be able to take portraits, they thought, but the subject could not be expected to remain motionless for 30 minutes. After the course ended they began to experiment to try to speed up the process. [1]

Fizeau entered the Paris Medical School in 1840, but he soon gave up on medicine because of severe migraines and spent some time travelling during which time he regained his health. His new focus of attention should be physics. He attended Arago's lectures at the Observatory, and enrolled in a course on optics at the Collège de France. Furthermore, he began to deeply study notebooks containing the lecture notes taken by his brother who attended courses at the École Polytechnique. It was Arago, who encouraged Fizeau and Foucault in 1845 and suggested that they might attempt to make photographs of an image of the sun produced by a telescope. Thus, Fizeau and Foucault produced what is considered the first astronomical photography.

It was in the field of optics that Fizeau earned a lasting reputation. The original inspiration came from François Arago, who looked for a decisive test between the corpuscular and wave theories of light. If the wave theory was true, the velocity of light had to be greater in moving media, such as water flowing in a tube. The project implied the working out of a terrestrial method of measuring the speed of light, and Arago suggested that this could be done by using a rotating mirror.[2] In 1849, Fizeau calculated a value for the speed of light more precise than the previous value determined by Ole Rømer in 1676. He used a beam of light reflected from a mirror eight kilometers away. The beam passed through the gaps between teeth of a rapidly rotating wheel. The speed of the wheel was increased until the returning light passed through the next gap and could be seen.

Fizeau calculated the speed of light to be 313,300 kilometres per second, which was within about five percent of the correct value (299,792.458 kilometers per second). Fizeau published the first results obtained by his method for determining the speed of light in 1849. In 1851 he carried out a series of experiments in an attempt to detect the luminiferous ether—a hypothetical material that was thought to occupy all of space and to be necessary for carrying the vibrations of light waves. The experimental results failed to demonstrate the existence of the ether, but his work helped lead to the discarding of the ether theory in the early years of the 20th century.[3] Fizeau was elected a member of the Academy of Sciences in 1860, an a member of the Bureau des Longitudes in 1878. He received the decoration of the Legion of Honour in 1849 and became officer in 1875. In 1866 the Royal Society of London awarded him the Rumford Medal.

At yovisto you can learn more about the physics behind the speed of light in the NASA documentary 'Einsteins Cosmic Speed Limit'.



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Monday, September 22, 2014

William Playfair and the Beginnings of Infographics

Playfair's trade-balance time-series chart, from The Commercial and Political Atlas and Statistical Breviary, 1786
On September 22, 1759, Scottish engineer and political economist William Playfair was born. He is generally considered the founder of graphical methods of statistics. William Playfair invented four types of diagrams: line graph, bar chart, pie chart, and circle graph.

Playfair was born in 1759 in Scotland during the Enlightenment, a Golden Age in the arts, sciences, industry and commerce. He was the fourth son of the reverend James Playfair of the parish of Liff & Benvie near the city of Dundee in Scotland. His notable brothers were architect James Playfair and John Playfair, Professor of Mathematics and later Professor of Natural Philosophy at the University of Edinburgh. His father died in 1772 when William was 13, leaving the eldest brother John to care for the family and his education. His early taste for mechanics prompted his friends to place him as apprentice to a mill-wright Andrew Meikle, the inventor of the threshing machine. But, this is were William Playfair's multifaceted career should only start. He was in turn a millwright, engineer, draftsman, accountant, inventor, silversmith, merchant, investment broker, economist, statistician, pamphleteer, translator, publicist, land speculator, convict, banker, ardent royalist, editor, blackmailer and journalist.

In 1780, he went to England, was engaged as draftsman and personal assistant of the inventor James Watt at the steam engine manufacturing works of Boulton & Watt in Birmingham in 1777, where he received a scientific and engineering training. Among the most useful of his mechanical efforts, was the unrequited discovery of the French telegraph, gathered from a few partial hints, and afterwards adapted by an alphabet of his own invention to British use. [1] On leaving Watt's company in 1782, he set up a silversmithing business and shop in London, which failed. In 1787 he moved to Paris, taking part in the storming of the Bastille two years later. He returned to London in 1793, where he opened a "security bank", which also failed. From 1775 he worked as a writer and pamphleteer and did some engineering work.

Playfair's main achievement lies primarily in his innovations in the presentation of quantitative information by means of graphs and charts. But, he was not the first to come up with the idea. Already in 1765, Joseph Priestley had created the innovation of the first timeline charts, in which individual bars were used to visualize the life span of a person to compare the life spans of multiple persons. These timelines directly inspired Wiliam Playfair's invention of the bar chart, which first appeared in his Commercial and Political Atlas, published in 1786. Actually, Playfair was driven to this invention by a lack of data. He had collected data about the import and export from different countries over the years, which he presented as line graphs. Because he lacked the necessary series data for Scotland, he graphed its trade data for a single year (1781) as a series of bars, one for each of Scotland's trading partners.[4]

Playfair's Pie Charts from The Commercial and Political Atlas and Statistical Breviary, 1786
Playfair, who argued that charts communicated better than tables of data, has been credited with inventing the line, bar, and pie charts. His time-series plots are still presented as models of clarity. Playfair first published The Commercial and Political Atlas in London in 1786. It contained 43 time-series plots and one bar chart, a form apparently introduced in this work. It has been described as the first major work to contain statistical graphs. Playfair's Statistical Breviary, published in London in 1801, contains what is generally credited as the first pie chart. He was the first to use hachure, shading, and color, thus incorporating elements of classification into the quantitative depiction. The quality and detail of his work was such that in the two centuries since there has been no appreciable improvement of his basic designs. [5]

After the Bourbon restoration in France, William Playfair returned to Paris, where he edited a journal called Galignani’s Messenger. He had to flee the country a second time when prosecuted for libel, and thereafter spent his time writing in London, where he died at the age of 64.[3] Playfair has invented a universal language useful to science and commerce alike and though his contemporaries failed to grasp the significance, he had no doubt that he had forever changed the way we would look at data. However, it took almost a century after his death before his invention was fully accepted. [5]

At yovisto you can learn more about the visualization of statistical data in the famous TED-talk of Prof. Hans Rosling on 'Let my dataset change your mindset'.

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Sunday, September 21, 2014

Juan de la Cierva and the Autogiro

Demonstration of Cierva C.6 autogiro at Farnborough, Oct. 1925
On September 21, 1895, Spanish civil engineer and aviation pioneer Juan de la Cierva y Codorníu was born. His most famous accomplishment was the invention in 1920 of the Autogiro, a single-rotor type of aircraft, a predecessor of today's helicopter.

Juan de la Cierva was born in Murcia, Spain to a wealthy family. Although trained as a civil engineer, Cierva became interested in aviation early in his youth. After several successful experiments with aviation as a boy, he eventually earned a civil engineering degree. For six years he attended the Escuela Especial de Ingenieros de Caminos, Canales y Puertos in Madrid, Spain, where he studied theoretical aerodynamics. Following this, he entered a competition to design military aircraft for the government and built a biplane bomber with an airfoil (the part of a plane that provides lift) that he designed mathematically. The plane was tested in May 1919, but it crashed when the pilot stalled it.[1]

Cierva believed that fixed-wing aircraft were unsafe, so he experimented with a rotary-wing design. In 1919 he started to consider the use of a rotor to generate lift at low airspeed, and eliminate the risk of stall. In order to achieve this, he utilized the ability of a lifting rotor to autorotate, whereby at a suitable pitch setting, a rotor will continue to rotate without mechanical drive, sustained by the torque equilibrium of the lift and drag forces acting on the blades. This phenomenon was already known, and was available as a safety feature to allow controlled descent of a helicopter in the event of engine failure. With De la Cierva's autogiro, the rotor was drawn through the air by means of conventional propeller, with the result that the rotor generated sufficient lift to sustain level flight, climb and descent.

Before this could be satisfactorily achieved, De la Cierva experienced several failures primarily associated with the unbalanced rolling movement generated when attempting take-off, due to dissymmetry of lift between the advancing and retreating blades. This major difficulty was resolved by the introduction of the flapping hinge. In 1923, De la Cierva's first successful Autogiro was flown in Spain. In a fixed-wing aircraft, lift is provided by the wing, thrust by the propeller. Cierva, though, believed that the autogiro controlled these forces better than fixed-wing aircraft, which had a tendency in those days to stall, or lose lift suddenly. He also wanted to develop an aircraft that needed only a short takeoff run and could slowly land in small areas. The autogiro was a major step toward those goals.[1]

In 1925, he demonstrated his autogiro to the British Air Ministry at Farnborough, Hampshire, which was a great success, and resulted in an invitation to continue the work in the UK. The same year, de la Cierva moved to England where, with the support of Scottish industrialist James G. Weir, he established the Cierva Autogiro Company. On September 18, 1928, he flew one of his autogiros (C.8) across the English Channel, and in 1930, he flew one from England to Spain. As De la Cierva's autogiros achieved success and acceptance, others began to follow and with them came further innovation. Most important was the development of direct rotor control through cyclic pitch variation, achieved initially by tilting the rotor hub and subsequently by Raoul Hafner by the application of a spider mechanism that acted directly on each rotor blade. The introduction of jump take-off was another major improvement in capability. The rotor was accelerated in no-lift pitch until the rotor speed required for flight was achieved, and then declutched.

At the outbreak of the Spanish Civil War in 1936, de la Cierva supported the forces of Francisco Franco, while his brother was executed by the Republican army in Paracuellos del Jarama. In a very ironic twist of fate the man who spent the better part of his life to develop a safe aircraft would loose his own life in an aircraft accident. On the morning of 9 December 1936, de la Cierva boarded a Dutch DC-2 of KLM at Croydon Airfield, bound for Amsterdam, which during take off should stall and crash on the roof of a building at the end of the runway.[2] Autogiros were used during the 1930s for military liaison, mail delivery, and agricultural purposes. De la Cierva’s work on rotor dynamics and control made possible the modern helicopter, whose development as a practical means of flight had been prevented by these problems.

At yovisto you can learn more about the history of early helicopters in a short documentary produced for Encyclopedia Britannica, now part of the Prellinger archive on Helicopters from 1953.



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Saturday, September 20, 2014

James Dewar and the Liquefaction of Gases

Sir James Dewar (1842-1923)
On September 1842, Scottish chemist and physicist Sir James Dewar was born. He is probably best-known today for his invention of the Dewar flask, which he used in conjunction with extensive research into the liquefaction of gases.

James Dewar was born in Kincardine, Fife, Scotland, in 1842, the youngest of six boys. He lost his parents at the age of 15. He was educated at Dollar Academy and the University of Edinburgh, where he studied under Lord Playfair, a famous Scottish scientist and Liberal politician, whose assistant he later became. Dewar would also study under August Kekulé at Ghent. In 1875, Dewar was elected Jacksonian professor of natural experimental philosophy at the University of Cambridge and became a member of the Royal Institution. In 1877, he replaced Dr. John Hall Gladstone in the role of Fullerian Professor of Chemistry in 1877. Dewar was also the President of the Chemical Society in 1897 and the British Association for the Advancement of Science in 1902, as well as serving on the Royal Commission established to examine London's water supply from 1893 to 1894 and the Committee on Explosives. It was whilst he was serving on the Committee on Explosives that he and Frederick Augustus Abel developed cordite, a smokeless gunpowder alternative.

Dewar's scientific work covers a wide field and his earlier papers cover a wide range of topics; organic chemistry, Hydrogen and its physical constants, high temperature research, the temperature of the sun and of the electric spark, electro-photometry and the chemistry of the electric arc. In 1867 he described several chemical formulas for benzene. Ironically, one of the formulae, which does not represent benzene correctly and was not advocated by Dewar, is sometimes still called Dewar benzene. Dewar investigated the physiological action of light, and examined the changes which take place in the electrical condition of the retina under its influence. In 1878 a long series of spectroscopic observations, the later of which were devoted to the spectroscopic examination of various gaseous elements separated from atmospheric air by the aid of low temperatures.

Dewar is most widely known in connection with his work on the liquefaction of the so-called permanent gases and his researches at temperatures approaching absolute zero. In 1877, Louis Cailletet and Raoul Pictet independently were able to create small amounts of oxygen and nitrogen in liquid form at temperatures less than 80° above absolute zero, a feat even Michael Faraday, who had liquified most of the known gases by 1845, had been unable to carry out.[1]

In 1878 he devoted a Friday evening lecture at the Royal Institution to the then recent work of Cailletet and Pictet, and exhibited for the first time in Great Britain the working of the Cailletet apparatus. Six years later, again at the Royal Institution, he described the researches of Zygmunt Florenty Wróblewski and Karol Olszewski, and illustrated for the first time in public the liquefaction of oxygen and air. Soon afterwards he built a machine from which the liquefied gas could be drawn off through a valve for use as a cooling agent, before using the liquid oxygen in research work related to meteorites; about the same time he also obtained oxygen in the solid state.

The greatest stumbling block he encountered in his work with liquification was keeping the gases cold long enough to study them. Liquid oxygen kept in a flask absorbed heat from the surrounding air and returned to its gaseous phase. To eliminate the effect of the warm air, Dewar put the flask of liquid gas inside a larger flask and created a vacuum between them. A vacuum would prevent the transfer of energy that occurred through conduction or convection; heat would not penetrate and cold would not escape. To eliminate the transfer of radiant energy, Dewar silvered the walls of the flasks so they would reflect, rather than absorb, energy. He also invented a technique to create a more efficient vacuum.[1] Dewar found that charcoal eats gas at low temperatures. So he placed a bit of charcoal in the gap; then evacuated it as best he could. When cold liquid gas filled the tank, the charcoal removed the remaining air from the wall space, and made the insulation nearly perfect.[2]

James Dewar died in London in 1923, still holding the office of Fullerian Professor of Chemistry at the Royal Institution, having refused to retire.

At yovisto, you can earn a better understanding of temperature in the laws of physics and chemistry in the lecture of Prof. Gerbrand Ceder from Massachussetts Institute of Technology on Atomistic Computer Modeling of Materials.



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