Ptolemy

Claudius Ptolemy (/ˈtɒləmi/; Greek: Κλαύδιος Πτολεμαῖος, Klaúdios Ptolemaîos, [kláwdios ptolɛmɛ́ːos]; Latin: Claudius Ptolemaeus; c. AD 100 – c. 170) was a Greco-Egyptian writer, known as a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in the city of Alexandria in the Roman province of Egypt, wrote in Koine Greek, and held Roman citizenship. Beyond that, few reliable details of his life are known. His birthplace has been given as Ptolemais Hermiou in the Thebaid in an uncorroborated statement by the 14th-century astronomer Theodore Meliteniotes. This is a very late attestation, however, and there is no other reason to suppose that he ever lived anywhere else than Alexandria, where he died around AD 168.

Ptolemy was the author of several scientific treatises, three of which were of continuing importance to later Byzantine, Islamic and European science. The first is the astronomical treatise now known as the Almagest, although it was originally entitled the "Mathematical Treatise" (Μαθηματικὴ Σύνταξις, Mathēmatikē Syntaxis) and then known as the "Great Treatise" (Ἡ Μεγάλη Σύνταξις, Ē Megálē Syntaxis). The second is the Geography, which is a thorough discussion of the geographic knowledge of the Greco-Roman world. This manuscript was used by Christopher Columbus as the map for his westward-bound path to Asia, in which he discovered the hitherto unknown lands of the Americas. The third is the astrological treatise in which he attempted to adapt horoscopic astrology to the Aristotelian natural philosophy of his day. This is sometimes known as the Apotelesmatika (Ἀποτελεσματικά) but more commonly known as the Tetrabiblos from the Greek (Τετράβιβλος) meaning "Four Books" or by the Latin Quadripartitum.

Dioptrique

La dioptrique (in English Dioptrique, Optics, or Dioptrics), is a short treatise published in 1637 included in one of the Essays written with Discourse on the Method by Rene Descartes. In this essay Descartes uses various models to understand the properties of light. This essay is known as Descartes' greatest contribution to optics, as it is the first publication of the Law of Refraction.

First Discourse: On Light

The first discourse captures Descartes' theories on the nature of light. In the first model, he compares light to a stick that allows a blind person to discern his environment through touch. Descartes says:

Descartes' second model on light uses his theory of the elements to demonstrate the rectilinear transmission of light as well as the movement of light through solid objects. He uses a metaphor of wine flowing through a vat of grapes, then exiting through a hole at the bottom of the vat.

Second Discourse: On Refraction

Descartes uses a tennis ball to create a proof for the laws of reflection and refraction in his third model. This was important because he was using real-world objects (in this case, a tennis ball) to construct mathematical theory. Descartes' third model creates a mathematical equation for the Law of Refraction, characterized by the angle of incidence equalling the angle of refraction. In today's notation, the law of refraction states,

Al-Kindi

Abu Yūsuf Yaʻqūb ibn ʼIsḥāq aṣ-Ṣabbāḥ al-Kindī (Arabic: أبو يوسف يعقوب بن إسحاق الصبّاح الكندي‎, Latin: Alkindus) (c. 801–873 AD), known as "the Philosopher of the Arabs", was a Muslim Arab philosopher, polymath, mathematician, physician and musician. Al-Kindi was the first of the Muslim peripatetic philosophers, and is unanimously hailed as the "father of Islamic or Arabic philosophy" for his synthesis, adaptation and promotion of Greek and Hellenistic philosophy in the Muslim world.

Al-Kindi was a descendant of the Kinda tribe. He was born in Basra and educated in Baghdad. Al-Kindi became a prominent figure in the House of Wisdom, and a number of Abbasid Caliphs appointed him to oversee the translation of Greek scientific and philosophical texts into the Arabic language. This contact with "the philosophy of the ancients" (as Greek philosophy was often referred to by Muslim scholars) had a profound effect on his intellectual development, and led him to write hundreds of original treatises of his own on a range of subjects ranging from metaphysics, ethics, logic and psychology, to medicine, pharmacology, mathematics, astronomy, astrology and optics, and further afield to more practical topics like perfumes, swords, jewels, glass, dyes, zoology, tides, mirrors, meteorology and earthquakes.

Business

A business, also known as an enterprise, agency or a firm, is an entity involved in the provision of goods and/or services to consumers. Businesses are prevalent in capitalist economies, where most of them are privately owned and provide goods and services to customers in exchange for other goods, services, or money. Businesses may also be social not-for-profit enterprises or state-owned public enterprises targeted for specific social and economic objectives. A business owned by multiple individuals may be formed as an incorporated company or jointly organised as a partnership. Countries have different laws that may ascribe different rights to the various business entities.

Business can refer to a particular organization or to an entire market sector, e.g. "the music business". Compound forms such as agribusiness represent subsets of the word's broader meaning, which encompasses all activity by suppliers of goods and services. The goal is for sales to be more than expenditures resulting in a profit.

Business (disambiguation)

A business is an organization involved in the trade of goods, services, or both, with consumers.

Business may also refer to:

See also

Business (TV channel)

Business (later – Ukrainian Business Channel, UBC) – first Ukrainian specialized TV channel for business-community. Established in 2007.

History

Audience

Main audience – business people. Currently TV channel has an audience of over two million potential viewers of cable and satellite network in the capital and throughout Ukraine.

External links