Many things are known about optics: the rectilinearity of light rays; the law of reflection; transparency of materials; that rays passing obliquely from less dense to more dense medium is refracted toward the perpendicular of the interface; general laws for the relationship between the apparent location of an object in reflections and refractions; the existence of metal mirrors (glass mirrors being a 19th century invention).
A major contribution to Western thought was the publication in 1543 of De revolutionibus orbium coelestium, libri VI (Eng. trans., On the Revolutions of the Celestial Spheres, 1952; Latin reprint, 1965) by Copernicus, Polish astronomer, who is noted for the Copernican theory of the heavens. By attributing to the Earth a daily motion around its own axis and a yearly motion around the stationary Sun, Copernicus developed an idea that had far-reaching implications for the rise of modern science. Henceforth, the Earth could no longer be considered the centre of the cosmos; rather, as one celestial body among many, it became subject to mathematical description.
Medicine has made tremendous progress in the 20th century. Information provided in this museum are on medicines, drugs & substances
which were in use during late 19th & early 20th century; the most important period for basic advancement of modern medicine, manufactured by nearly 148 manufacturers around the globe, in collection with a pharmacy established in 1912.
Ever wonder how people figured out there used to be such things as dinosaurs? Curious about how scientists learned to reconstruct fossil skeletons? The knowledge we take for granted today was slow in coming, and along the way, scientists and scholars had some weird ideas. This Web site shows some of their mistakes, provides a timeline of events, gives biographies of a few of the people who have gotten us where we are today, and lists resources you can use to learn more.
The 1930s saw the flowering of a unique mathematical community at Princeton University with the construction of a luxurious new building Fine Hall (now Jones Hall) dedicated to the mathematician and Dean Harry Fine and designed to facilitate a real community of mathematicians engaged in research and closely linked with mathematical physicists in the attached Palmer physics laboratory to which it was connected and shared a joint math-physics library. This community was unlike any other in America before that time and perhaps afterwards, and had important consequences for American mathematics. With the planning and founding of the Institute for Advanced Study at the beginning of the decade, originally having only a mathematics department, which then shared Fine Hall with the university mathematics department as a single institute during the period 1933 to 1939, starting with three of the university's leading mathematicians joined by Einstein and Gödel and attracting many visitors, a very exciting environment developed which many students and faculty were loath to leave.
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Brahmagupta (598-670) writes Khandakhadyaka which solves quadratic equations and allows for the possibility of negative solutions.
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1136 Abraham bar Hiyya Ha-Nasi writes the work Hibbur ha-Meshihah ve-ha-Tishboret, translated in 1145 into Latin as Liber embadorum, which presents the first complete solution to the quadratic equation.
1484 Nicolas Chuquet (1445-1500) writes Triparty en la sciences des nombres. The fourth part of which contains the "Regle des premiers," or the rule of the unknown, what we would today call an algebra. He introduced an exponential notation, allowing positive, negative, and zero powers. In solving general equations he showed that some equations lead to imaginary solutions, but dismisses them ("Tel nombre est ineperible").
Perseus is an evolving digital library, engineering interactions through time, space, and language. Our primary goal is to bring a wide range of source materials to as large an audience as possible. We anticipate that greater accessibility to the sources for the study of the humanities will strengthen the quality of questions, lead to new avenues of research, and connect more people through the connection of ideas.
Ancient Greeks struggled to understand the nature of matter
Empedocles (around 490 to 444 BC) thought there were four original elements: Earth, Air, Fire, Water. He thought everything else came about through their combination and/or separation by the two opposite principles of Love and Strife.
Leucippus (around 460 to 420 BC) and Democritus (around 460 to 370 BC), supposedly a pupil of Leucippus, are considered the founders of atomism. Leucippus regarded atoms as imperceptible, individual particles that differ only in shape and position.
Plato (about 427 to 347 BC) in his work, the Timaeus, proposes a mathematical construction of the elements - earth, air, fire, water. Each of these elements is said to consist of particles or primary bodies. Each particle is a regular geometrical solid- the cube, tetrahedron, octahedron and icosahedron. Each of these particles is composed of simple right triangles. The particles are like the molecules of the theory; the triangles are its atoms.
Plato's beliefs as regards the universe were that the stars, planets, Sun and Moon move round the Earth in crystalline spheres. The sphere of the Moon was closest to the Earth, then the sphere of the Sun, then Mercury, Venus, Mars, Jupiter, Saturn and furthest away was the sphere of the stars. He believed that the Moon shines by reflected sunlight.
Marin Mersenne attended school at the College of Mans, then, from 1604 spent five years in the Jesuit College at La Fleche. From 1609 to 1611 he studied theology at the Sorbonne.
Mersenne joined the religious order of the Minims in 1611. The name of the order comes since the Minims regard themselves as the least (minimi) of all the religious; they devote themselves to prayer, study and scholarship. Mersenne continued his education within the order at Nigeon and then at Meaux. He returned to Paris where in 1612 he became a priest at the Place Royale.
