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109-421: After the periodical ceased publication in 1952, The Electrician ' s corporation continued on its book publishing business, printing works on physics and electrical engineering, until 1959. The Electrician was originally established in 1861, it was discontinued after about three years. In 1878 a new journal with the same title was launched and thereafter published weekly. The Electrician billed itself in

218-546: A 'strongman' was often the best solution. Athens fell under a tyranny in the second half of the 6th century BC. When this tyranny was ended, the Athenians founded the world's first democracy as a radical solution to prevent the aristocracy regaining power. A citizens' assembly (the Ecclesia ), for the discussion of city policy, had existed since the reforms of Draco in 621 BC; all citizens were permitted to attend after

327-500: A coalition of 31 Greek city states, including Athens and Sparta, determined to resist the Persian invaders. At the same time, Greek Sicily was invaded by a Carthaginian force. In 480 BC, the first major battle of the invasion was fought at Thermopylae , where a small rearguard of Greeks, led by three hundred Spartans, held a crucial pass guarding the heart of Greece for several days; at the same time Gelon , tyrant of Syracuse, defeated

436-609: A council of elders (the Gerousia ) and magistrates specifically appointed to watch over the kings (the Ephors ). Only free, land-owning, native born men could be citizens entitled to the full protection of the law in a city-state. In most city-states, unlike the situation in Rome , social prominence did not allow special rights. Sometimes families controlled public religious functions, but this ordinarily did not give any extra power in

545-528: A decisive victory, and in 447 lost Boeotia again. Athens and Sparta signed the Thirty Years' Peace in the winter of 446/5, ending the conflict. Despite the treaty, Athenian relations with Sparta declined again in the 430s, and in 431 BC the Peloponnesian War began. The first phase of the war saw a series of fruitless annual invasions of Attica by Sparta, while Athens successfully fought

654-414: A force law for the interaction between elements of electric current, Ampère placed the subject on a solid mathematical foundation. A theory of electromagnetism, known as classical electromagnetism , was developed by several physicists during the period between 1820 and 1873, when James Clerk Maxwell 's treatise was published, which unified previous developments into a single theory, proposing that light

763-436: A group of city-states allied themselves to defend Greece, the vast majority of poleis remained neutral, and after the Persian defeat, the allies quickly returned to infighting. Thus, the major peculiarities of the ancient Greek political system were its fragmented nature (and that this does not particularly seem to have tribal origin), and the particular focus on urban centers within otherwise tiny states. The peculiarities of

872-436: A link between human-made electric current and magnetism was Gian Romagnosi , who in 1802 noticed that connecting a wire across a voltaic pile deflected a nearby compass needle. However, the effect did not become widely known until 1820, when Ørsted performed a similar experiment. Ørsted's work influenced Ampère to conduct further experiments, which eventually gave rise to a new area of physics: electrodynamics. By determining

981-474: A magnetic field transforms to a field with a nonzero electric component and conversely, a moving electric field transforms to a nonzero magnetic component, thus firmly showing that the phenomena are two sides of the same coin. Hence the term "electromagnetism". (For more information, see Classical electromagnetism and special relativity and Covariant formulation of classical electromagnetism .) Today few problems in electromagnetism remain unsolved. These include:

1090-446: A magnetic needle using a Voltaic pile. The factual setup of the experiment is not completely clear, nor if current flowed across the needle or not. An account of the discovery was published in 1802 in an Italian newspaper, but it was largely overlooked by the contemporary scientific community, because Romagnosi seemingly did not belong to this community. An earlier (1735), and often neglected, connection between electricity and magnetism

1199-452: A nearby compass needle to move. At the time of discovery, Ørsted did not suggest any satisfactory explanation of the phenomenon, nor did he try to represent the phenomenon in a mathematical framework. However, three months later he began more intensive investigations. Soon thereafter he published his findings, proving that an electric current produces a magnetic field as it flows through a wire. The CGS unit of magnetic induction ( oersted )

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1308-474: A powerful influence on ancient Rome , which carried a version of it throughout the Mediterranean and much of Europe. For this reason, Classical Greece is generally considered the cradle of Western civilization , the seminal culture from which the modern West derives many of its founding archetypes and ideas in politics, philosophy, science, and art. Classical antiquity in the Mediterranean region

1417-760: A result of Epaminondas ' liberation of Messenia from Spartan rule, the helot system there came to an end and the helots won their freedom. However, it did continue to persist in Laconia until the 2nd century BC. For most of Greek history, education was private, except in Sparta. During the Hellenistic period, some city-states established public schools . Only wealthy families could afford a teacher. Boys learned how to read, write and quote literature. They also learned to sing and play one musical instrument and were trained as athletes for military service. They studied not for

1526-492: A role in chemical reactivity; such relationships are studied in spin chemistry . Electromagnetism also plays several crucial roles in modern technology : electrical energy production, transformation and distribution; light, heat, and sound production and detection; fiber optic and wireless communication; sensors; computation; electrolysis; electroplating; and mechanical motors and actuators. Electromagnetism has been studied since ancient times. Many ancient civilizations, including

1635-413: A sewing-needle by means of the discharge of Leyden jars." The electromagnetic force is the second strongest of the four known fundamental forces and has unlimited range. All other forces, known as non-fundamental forces . (e.g., friction , contact forces) are derived from the four fundamental forces. At high energy, the weak force and electromagnetic force are unified as a single interaction called

1744-523: A special type of slaves called helots . Helots were Messenians enslaved en masse during the Messenian Wars by the state and assigned to families where they were forced to stay. Helots raised food and did household chores so that women could concentrate on raising strong children while men could devote their time to training as hoplites . Their masters treated them harshly, and helots revolted against their masters several times. In 370/69 BC, as

1853-508: A unified concept of energy. This unification, which was observed by Michael Faraday , extended by James Clerk Maxwell , and partially reformulated by Oliver Heaviside and Heinrich Hertz , is one of the key accomplishments of 19th-century mathematical physics . It has had far-reaching consequences, one of which was the understanding of the nature of light . Unlike what was proposed by the electromagnetic theory of that time, light and other electromagnetic waves are at present seen as taking

1962-722: A war with the Roman Republic in the late 3rd century. Although the First Macedonian War was inconclusive, the Romans, in typical fashion, continued to fight Macedon until it was completely absorbed into the Roman Republic (by 149 BC). In the east, the unwieldy Seleucid Empire gradually disintegrated, although a rump survived until 64 BC, whilst the Ptolemaic Kingdom continued in Egypt until 30 BC when it too

2071-684: A year, the Thirty had been overthrown. The first half of the fourth century saw the major Greek states attempt to dominate the mainland; none were successful, and their resulting weakness led to a power vacuum which would eventually be filled by Macedon under Philip II and then Alexander the Great. In the immediate aftermath of the Peloponnesian war, Sparta attempted to extend their own power, leading Argos, Athens, Corinth, and Thebes to join against them. Aiming to prevent any single Greek state gaining

2180-572: Is an interaction that occurs between particles with electric charge via electromagnetic fields . The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interactions of atoms and molecules . Electromagnetism can be thought of as a combination of electrostatics and magnetism , which are distinct but closely intertwined phenomena. Electromagnetic forces occur between any two charged particles. Electric forces cause an attraction between particles with opposite charges and repulsion between particles with

2289-573: Is commonly considered to have begun in the 8th century BC (around the time of the earliest recorded poetry of Homer) and ended in the 6th century AD. Classical antiquity in Greece was preceded by the Greek Dark Ages ( c.  1200 – c.  800 BC ), archaeologically characterised by the protogeometric and geometric styles of designs on pottery. Following the Dark Ages was

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2398-411: Is compatible with special relativity. According to Maxwell's equations, the speed of light in vacuum is a universal constant that is dependent only on the electrical permittivity and magnetic permeability of free space . This violates Galilean invariance , a long-standing cornerstone of classical mechanics. One way to reconcile the two theories (electromagnetism and classical mechanics) is to assume

2507-465: Is debated. Herodotus was succeeded by authors such as Thucydides , Xenophon , Demosthenes , Plato and Aristotle . Most were either Athenian or pro-Athenian, which is why far more is known about the history and politics of Athens than of many other cities. Their scope is further limited by a focus on political, military and diplomatic history, ignoring economic and social history. The archaic period, lasting from approximately 800 to 500 BC, saw

2616-458: Is mountainous, and as a result, ancient Greece consisted of many smaller regions, each with its own dialect, cultural peculiarities, and identity. Regionalism and regional conflicts were prominent features of ancient Greece. Cities tended to be located in valleys between mountains, or on coastal plains, and dominated a certain area around them. In the south lay the Peloponnese , consisting of

2725-400: Is named in honor of his contributions to the field of electromagnetism. His findings resulted in intensive research throughout the scientific community in electrodynamics. They influenced French physicist André-Marie Ampère 's developments of a single mathematical form to represent the magnetic forces between current-carrying conductors. Ørsted's discovery also represented a major step toward

2834-508: Is no one-to-one correspondence between electromagnetic units in SI and those in CGS, as is the case for mechanical units. Furthermore, within CGS, there are several plausible choices of electromagnetic units, leading to different unit "sub-systems", including Gaussian , "ESU", "EMU", and Heaviside–Lorentz . Among these choices, Gaussian units are the most common today, and in fact the phrase "CGS units"

2943-411: Is often used to refer specifically to CGS-Gaussian units . The study of electromagnetism informs electric circuits , magnetic circuits , and semiconductor devices ' construction. Ancient Greece Ancient Greece ( Ancient Greek : Ἑλλάς , romanized :  Hellás ) was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to

3052-454: Is studied, for example, in the subject of magnetohydrodynamics , which combines Maxwell theory with the Navier–Stokes equations . Another branch of electromagnetism dealing with nonlinearity is nonlinear optics . Here is a list of common units related to electromagnetism: In the electromagnetic CGS system, electric current is a fundamental quantity defined via Ampère's law and takes

3161-479: Is unclear exactly how this change occurred. For instance, in Athens, the kingship had been reduced to a hereditary, lifelong chief magistracy ( archon ) by c. 1050 BC; by 753 BC this had become a decennial, elected archonship; and finally by 683 BC an annually elected archonship. Through each stage, more power would have been transferred to the aristocracy as a whole, and away from a single individual. Inevitably,

3270-407: Is widely known as the "father of history": his Histories are eponymous of the entire field . Written between the 450s and 420s BC, Herodotus' work reaches about a century into the past, discussing 6th century BC historical figures such as Darius I of Persia , Cambyses II and Psamtik III , and alluding to some 8th century BC persons such as Candaules . The accuracy of Herodotus' works

3379-674: The Archaic Period , beginning around the 8th century BC, which saw early developments in Greek culture and society leading to the Classical Period from the Persian invasion of Greece in 480 BC until the death of Alexander the Great in 323 BC. The Classical Period is characterized by a "classical" style, i.e. one which was considered exemplary by later observers, most famously in the Parthenon of Athens. Politically,

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3488-710: The Archaic period , the Greek population grew beyond the capacity of the limited arable land of Greece proper, resulting in the large-scale establishment of colonies elsewhere: according to one estimate, the population of the widening area of Greek settlement increased roughly tenfold from 800 BC to 400 BC, from 800,000 to as many as 7 + 1 ⁄ 2 -10 million. This was not simply for trade, but also to found settlements. These Greek colonies were not, as Roman colonies were, dependent on their mother-city, but were independent city-states in their own right. Greeks settled outside of Greece in two distinct ways. The first

3597-699: The Battle of Aegospotami , and began to blockade Athens' harbour; driven by hunger, Athens sued for peace, agreeing to surrender their fleet and join the Spartan-led Peloponnesian League. Following the Athenian surrender, Sparta installed an oligarchic regime, the Thirty Tyrants , in Athens, one of a number of Spartan-backed oligarchies which rose to power after the Peloponnesian war. Spartan predominance did not last: after only

3706-673: The Byzantine period. Three centuries after the decline of Mycenaean Greece during the Bronze Age Collapse , Greek urban poleis began to form in the 8th century BC, ushering in the Archaic period and the colonization of the Mediterranean Basin. This was followed by the age of Classical Greece , from the Greco-Persian Wars to the death of Alexander the Great in 323 BC, and which included

3815-576: The Delian League gradually transformed from a defensive alliance of Greek states into an Athenian empire, as Athens' growing naval power intimidated the other league states. Athens ended its campaigns against Persia in 450, after a disastrous defeat in Egypt in 454, and the death of Cimon in action against the Persians on Cyprus in 450. As the Athenian fight against the Persian empire waned, conflict grew between Athens and Sparta. Suspicious of

3924-698: The Golden Age of Athens and the Peloponnesian War . The unification of Greece by Macedon under Philip II and subsequent conquest of the Achaemenid Empire by Alexander the Great spread Hellenistic civilization across the Middle East. The Hellenistic Period is considered to have ended in 30 BC, when the last Hellenistic kingdom, Ptolemaic Egypt , was annexed by the Roman Republic . Classical Greek culture , especially philosophy, had

4033-595: The Greeks and the Mayans , created wide-ranging theories to explain lightning , static electricity , and the attraction between magnetized pieces of iron ore . However, it was not until the late 18th century that scientists began to develop a mathematical basis for understanding the nature of electromagnetic interactions. In the 18th and 19th centuries, prominent scientists and mathematicians such as Coulomb , Gauss and Faraday developed namesake laws which helped to explain

4142-740: The Paeonians due north, the Thracians to the northeast, and the Illyrians , with whom the Macedonians were frequently in conflict, to the northwest. Chalcidice was settled early on by southern Greek colonists and was considered part of the Greek world, while from the late 2nd millennium BC substantial Greek settlement also occurred on the eastern shores of the Aegean , in Anatolia . During

4251-424: The chemical and physical phenomena observed in daily life. The electrostatic attraction between atomic nuclei and their electrons holds atoms together. Electric forces also allow different atoms to combine into molecules, including the macromolecules such as proteins that form the basis of life . Meanwhile, magnetic interactions between the spin and angular momentum magnetic moments of electrons also play

4360-564: The electroweak interaction . Most of the forces involved in interactions between atoms are explained by electromagnetic forces between electrically charged atomic nuclei and electrons . The electromagnetic force is also involved in all forms of chemical phenomena . Electromagnetism explains how materials carry momentum despite being composed of individual particles and empty space. The forces we experience when "pushing" or "pulling" ordinary material objects result from intermolecular forces between individual molecules in our bodies and in

4469-408: The permeability as a dimensionless quantity (relative permeability) whose value in vacuum is unity . As a consequence, the square of the speed of light appears explicitly in some of the equations interrelating quantities in this system. Formulas for physical laws of electromagnetism (such as Maxwell's equations ) need to be adjusted depending on what system of units one uses. This is because there

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4578-506: The poleis grouped themselves into leagues, membership of which was in a constant state of flux. Later in the Classical period, the leagues would become fewer and larger, be dominated by one city (particularly Athens , Sparta and Thebes ); and often poleis would be compelled to join under threat of war (or as part of a peace treaty). Even after Philip II of Macedon conquered the heartlands of ancient Greece, he did not attempt to annex

4687-599: The quantized nature of matter. In QED, changes in the electromagnetic field are expressed in terms of discrete excitations, particles known as photons , the quanta of light. Investigation into electromagnetic phenomena began about 5,000 years ago. There is evidence that the ancient Chinese , Mayan , and potentially even Egyptian civilizations knew that the naturally magnetic mineral magnetite had attractive properties, and many incorporated it into their art and architecture. Ancient people were also aware of lightning and static electricity , although they had no idea of

4796-464: The 146 BC conquest of Greece after the Battle of Corinth. Macedonia became a Roman province while southern Greece came under the surveillance of Macedonia's prefect ; however, some Greek poleis managed to maintain a partial independence and avoid taxation. The Aegean Islands were added to this territory in 133 BC. Athens and other Greek cities revolted in 88 BC, and the peninsula was crushed by

4905-583: The Carthaginian invasion at the Battle of Himera . The Persians were decisively defeated at sea by a primarily Athenian naval force at the Battle of Salamis , and on land in 479 BC at the Battle of Plataea . The alliance against Persia continued, initially led by the Spartan Pausanias but from 477 by Athens, and by 460 Persia had been driven out of the Aegean. During this long campaign,

5014-649: The Classical Period was dominated by Athens and the Delian League during the 5th century, but displaced by Spartan hegemony during the early 4th century BC, before power shifted to Thebes and the Boeotian League and finally to the League of Corinth led by Macedon . This period was shaped by the Greco-Persian Wars , the Peloponnesian War , and the Rise of Macedon . Following the Classical period

5123-525: The Corinthian empire in northwest Greece and defended its own empire, despite a plague which killed the leading Athenian statesman Pericles . The war turned after Athenian victories led by Cleon at Pylos and Sphakteria , and Sparta sued for peace, but the Athenians rejected the proposal. The Athenian failure to regain control of Boeotia at Delium and Brasidas ' successes in northern Greece in 424 improved Sparta's position after Sphakteria. After

5232-668: The Greek city-states. It greatly widened the horizons of the Greeks and led to a steady emigration of the young and ambitious to the new Greek empires in the east. Many Greeks migrated to Alexandria, Antioch and the many other new Hellenistic cities founded in Alexander's wake, as far away as present-day Afghanistan and Pakistan , where the Greco-Bactrian Kingdom and the Indo-Greek Kingdom survived until

5341-460: The Greek colonies Syracusae ( Συράκουσαι ), Neapolis ( Νεάπολις ), Massalia ( Μασσαλία ) and Byzantion ( Βυζάντιον ). These colonies played an important role in the spread of Greek influence throughout Europe and also aided in the establishment of long-distance trading networks between the Greek city-states, boosting the economy of ancient Greece . Ancient Greece consisted of several hundred relatively independent city-states ( poleis ). This

5450-578: The Greek colony Sybaris in southern Italy, its allies, and the Serdaioi. In 499 BC, the Ionian city states under Persian rule rebelled against their Persian-supported tyrant rulers. Supported by troops sent from Athens and Eretria , they advanced as far as Sardis and burnt the city before being driven back by a Persian counterattack. The revolt continued until 494, when the rebelling Ionians were defeated. Darius did not forget that Athens had assisted

5559-420: The Greek system are further evidenced by the colonies that they set up throughout the Mediterranean , which, though they might count a certain Greek polis as their 'mother' (and remain sympathetic to her), were completely independent of the founding city. Inevitably smaller poleis might be dominated by larger neighbors, but conquest or direct rule by another city-state appears to have been quite rare. Instead

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5668-815: The Greeks began 250 years of expansion, settling colonies in all directions. To the east, the Aegean coast of Asia Minor was colonized first, followed by Cyprus and the coasts of Thrace , the Sea of Marmara and south coast of the Black Sea . Eventually, Greek colonization reached as far northeast as present-day Ukraine and Russia ( Taganrog ). To the west the coasts of Illyria , Southern Italy (called " Magna Graecia ") were settled, followed by Southern France , Corsica , and even eastern Spain . Greek colonies were also founded in Egypt and Libya . Modern Syracuse , Naples , Marseille and Istanbul had their beginnings as

5777-423: The Greeks were very aware of their tribal origins; Herodotus was able to extensively categorise the city-states by tribe. Yet, although these higher-level relationships existed, they seem to have rarely had a major role in Greek politics. The independence of the poleis was fiercely defended; unification was something rarely contemplated by the ancient Greeks. Even when, during the second Persian invasion of Greece,

5886-535: The Ionian revolt, and in 490 he assembled an armada to retaliate. Though heavily outnumbered, the Athenians—supported by their Plataean allies—defeated the Persian hordes at the Battle of Marathon , and the Persian fleet turned tail. Ten years later, a second invasion was launched by Darius' son Xerxes . The city-states of northern and central Greece submitted to the Persian forces without resistance, but

5995-483: The League of Corinth following the death of Philip, Alexander began his campaign against Persia in 334 BC. He conquered Persia, defeating Darius III at the Battle of Issus in 333 BC, and after the Battle of Gaugamela in 331 BC proclaimed himself king of Asia. From 329 BC he led expeditions to Bactria and then India; further plans to invade Arabia and North Africa were halted by his death in 323 BC. The period from

6104-737: The Roman general Sulla . The Roman civil wars devastated the land even further, until Augustus organized the peninsula as the province of Achaea in 27 BC. Greece was a key eastern province of the Roman Empire, as the Roman culture had long been in fact Greco-Roman . The Greek language served as a lingua franca in the East and in Italy , and many Greek intellectuals such as Galen would perform most of their work in Rome . The territory of Greece

6213-458: The ability to disturb a compass needle. The link between lightning and electricity was not confirmed until Benjamin Franklin 's proposed experiments in 1752 were conducted on 10   May 1752 by Thomas-François Dalibard of France using a 40-foot-tall (12 m) iron rod instead of a kite and he successfully extracted electrical sparks from a cloud. One of the first to discover and publish

6322-579: The ancient Greeks did not think in terms of race . Most families owned slaves as household servants and laborers, and even poor families might have owned a few slaves. Owners were not allowed to beat or kill their slaves. Owners often promised to free slaves in the future to encourage slaves to work hard. Unlike in Rome, freedmen did not become citizens. Instead, they were mixed into the population of metics , which included people from foreign countries or other city-states who were officially allowed to live in

6431-666: The center, while in the east lay Boeotia , Attica , and Megaris . Northeast lay Thessaly , while Epirus lay to the northwest. Epirus stretched from the Ambracian Gulf in the south to the Ceraunian Mountains and the Aoos river in the north, and consisted of Chaonia (north), Molossia (center), and Thesprotia (south). In the northeast corner was Macedonia , originally consisting Lower Macedonia and its regions, such as Elimeia , Pieria , and Orestis . Around

6540-455: The course of the archaic period. Already in the seventh century, the right of all citizen men to attend the assembly appears to have been established. After a failed coup led by Cylon of Athens around 636 BC, Draco was appointed to establish a code of laws in 621. This failed to reduce the political tension between the poor and the elites, and in 594 Solon was given the authority to enact another set of reforms, which attempted to balance

6649-473: The course of the eighth and seventh century. According to Spartan tradition, this constitution was established by the legendary lawgiver Lycurgus . Over the course of the first and second Messenian wars , Sparta subjugated the neighbouring region of Messenia , enserfing the population. In the sixth century, Greek city-states began to develop formal relationships with one another, where previously individual rulers had relied on personal relationships with

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6758-574: The culmination of political and social developments which had begun in the Greek dark age, with the polis (city-state) becoming the most important unit of political organisation in Greece. The absence of powerful states in Greece after the collapse of Mycenaean power, and the geography of Greece, where many settlements were separated from their neighbours by mountainous terrain, encouraged the development of small independent city-states. Several Greek states saw tyrants rise to power in this period, most famously at Corinth from 657 BC. The period also saw

6867-461: The death of Alexander the Great in 323 BC until the death of Cleopatra , the last Macedonian ruler of Egypt, is known as the Hellenistic period. In the early part of this period, a new form of kingship developed based on Macedonian and Near Eastern traditions. The first Hellenistic kings were previously Alexander's generals, and took power in the period following his death, though they were not part of existing royal lineages and lacked historic claims to

6976-423: The deaths of Cleon and Brasidas, the strongest proponents of war on each side, a peace treaty was negoitiated in 421 by the Athenian general Nicias . The peace did not last, however. In 418 BC allied forces of Athens and Argos were defeated by Sparta at Mantinea . In 415 Athens launched an ambitious naval expedition to dominate Sicily; the expedition ended in disaster at the harbor of Syracuse , with almost

7085-502: The deep connections between electricity and magnetism that would be discovered over 2,000 years later. Despite all this investigation, ancient civilizations had no understanding of the mathematical basis of electromagnetism, and often analyzed its impacts through the lens of religion rather than science (lightning, for instance, was considered to be a creation of the gods in many cultures). Electricity and magnetism were originally considered to be two separate forces. This view changed with

7194-674: The dominance that would allow it to challenge Persia, the Persian king initially joined the alliance against Sparta, before imposing the Peace of Antalcidas ("King's Peace") which restored Persia's control over the Anatolian Greeks. By 371 BC, Thebes was in the ascendancy, defeating Sparta at the Battle of Leuctra , killing the Spartan king Cleombrotus I , and invading Laconia. Further Theban successes against Sparta in 369 led to Messenia gaining independence; Sparta never recovered from

7303-409: The domination of politics and concomitant aggregation of wealth by small groups of families was apt to cause social unrest in many poleis . In many cities a tyrant (not in the modern sense of repressive autocracies), would at some point seize control and govern according to their own will; often a populist agenda would help sustain them in power. In a system wracked with class conflict , government by

7412-654: The early 1860s as "a weekly journal of Telegraphy, Electricity, and Applied Chemistry" and was published by Thomas Piper. The new Electrician that appeared in the late 1870s was published by James Gray on behalf of the proprietors, John Pender and James Anderson of the Eastern Telegraph Company, the biggest cable firm of the day and had a somewhat different focus. It described itself as "a weekly illustrated journal of electrical engineering, industry and science" and also featured more theoretical aspects of electrical engineering such as electromagnetism . In

7521-726: The east to the Indian king Chandragupta Maurya in exchange for war elephants, and later lost large parts of Persia to the Parthian Empire . By the mid-third century, the kingdoms of Alexander's successors was mostly stable, though there continued to be disputes over border areas. The great capitals of Hellenistic culture were Alexandria in the Ptolemaic Kingdom and Antioch in the Seleucid Empire . The conquests of Alexander had numerous consequences for

7630-562: The effects of modern physics , including quantum mechanics and relativity . The theoretical implications of electromagnetism, particularly the requirement that observations remain consistent when viewed from various moving frames of reference ( relativistic electromagnetism ) and the establishment of the speed of light based on properties of the medium of propagation ( permeability and permittivity ), helped inspire Einstein's theory of special relativity in 1905. Quantum electrodynamics (QED) modifies Maxwell's equations to be consistent with

7739-552: The elites of other cities. Towards the end of the archaic period, Sparta began to build a series of alliances, the Peloponnesian League , with cities including Corinth , Elis , and Megara , isolating Messenia and reinforcing Sparta's position against Argos , the other major power in the Peloponnese. Other alliances in the sixth century included those between Elis and Heraea in the Peloponnese; and between

7848-531: The end of classical antiquity ( c.  600 AD ), that comprised a loose collection of culturally and linguistically related city-states and other territories. Prior to the Roman period , most of these regions were officially unified once under the Kingdom of Macedon from 338 to 323 BC. In Western history , the era of classical antiquity was immediately followed by the Early Middle Ages and

7957-619: The end of the first century BC. The city-states within Greece formed themselves into two leagues; the Achaean League (including Corinth and Argos) and the Aetolian League (including Sparta and Athens). For much of the period until the Roman conquest, these leagues were at war, often participating in the conflicts between the Diadochi (the successor states to Alexander's empire). The Antigonid Kingdom became involved in

8066-609: The entire army killed, and the ships destroyed. Soon after the Athenian defeat in Syracuse, Athens' Ionian allies began to rebel against the Delian league, while Persia began to once again involve itself in Greek affairs on the Spartan side. Initially the Athenian position continued relatively strong, with important victories at Cyzicus in 410 and Arginusae in 406. However, in 405 the Spartan Lysander defeated Athens in

8175-540: The exact borders of the Hellenistic kingdoms were not settled. Antigonus attempted to expand his territory by attacking the other successor kingdoms until they joined against him, and he was killed at the Battle of Ipsus in 301 BC. His son Demetrius spent many years in Seleucid captivity, and his son, Antigonus II , only reclaimed the Macedonian throne around 276. Meanwhile, the Seleucid kingdom gave up territory in

8284-576: The existence of a luminiferous aether through which the light propagates. However, subsequent experimental efforts failed to detect the presence of the aether. After important contributions of Hendrik Lorentz and Henri Poincaré , in 1905, Albert Einstein solved the problem with the introduction of special relativity, which replaced classical kinematics with a new theory of kinematics compatible with classical electromagnetism. (For more information, see History of special relativity .) In addition, relativity theory implies that in moving frames of reference,

8393-435: The existence of self-sustaining electromagnetic waves . Maxwell postulated that such waves make up visible light , which was later shown to be true. Gamma-rays, x-rays, ultraviolet, visible, infrared radiation, microwaves and radio waves were all determined to be electromagnetic radiation differing only in their range of frequencies. In the modern era, scientists continue to refine the theory of electromagnetism to account for

8502-618: The field of electrical engineering and was regularly quoted and cited in Nature , Scientific American , and elsewhere. Between 1889 and 1895 an American journal also called The Electrician was published in New York by Williams & Co. Often referred to as the American Electrician , it was merged into another electrical engineering periodical, Electrical World . Electromagnetism In physics, electromagnetism

8611-516: The form of quantized , self-propagating oscillatory electromagnetic field disturbances called photons . Different frequencies of oscillation give rise to the different forms of electromagnetic radiation , from radio waves at the lowest frequencies, to visible light at intermediate frequencies, to gamma rays at the highest frequencies. Ørsted was not the only person to examine the relationship between electricity and magnetism. In 1802, Gian Domenico Romagnosi , an Italian legal scholar, deflected

8720-435: The formation and interaction of electromagnetic fields. This process culminated in the 1860s with the discovery of Maxwell's equations , a set of four partial differential equations which provide a complete description of classical electromagnetic fields. Maxwell's equations provided a sound mathematical basis for the relationships between electricity and magnetism that scientists had been exploring for centuries, and predicted

8829-469: The founding of Greek colonies around the Mediterranean, with Euboean settlements at Al-Mina in the east as early as 800 BC, and Ischia in the west by 775. Increasing contact with non-Greek peoples in this period, especially in the Near East, inspired developments in art and architecture, the adoption of coinage, and the development of the Greek alphabet. Athens developed its democratic system over

8938-576: The government. In Athens, the population was divided into four social classes based on wealth. People could change classes if they made more money. In Sparta, all male citizens were called homoioi , meaning "peers". However, Spartan kings, who served as the city-state's dual military and religious leaders, came from two families. Women in Ancient Greece appear to have primarily performed domestic tasks, managed households, and borne and reared children. Slaves had no power or status. Slaves had

9047-547: The increasing Athenian power funded by the Delian League, Sparta offered aid to reluctant members of the League to rebel against Athenian domination. These tensions were exacerbated in 462 BC when Athens sent a force to aid Sparta in overcoming a helot revolt, but this aid was rejected by the Spartans. In the 450s, Athens took control of Boeotia, and won victories over Aegina and Corinth. However, Athens failed to win

9156-435: The knives took up the nails. On this the whole number was tried, and found to do the same, and that, to such a degree as to take up large nails, packing needles, and other iron things of considerable weight ... E. T. Whittaker suggested in 1910 that this particular event was responsible for lightning to be "credited with the power of magnetizing steel; and it was doubtless this which led Franklin in 1751 to attempt to magnetize

9265-478: The lack of magnetic monopoles , Abraham–Minkowski controversy , the location in space of the electromagnetic field energy, and the mechanism by which some organisms can sense electric and magnetic fields. The Maxwell equations are linear, in that a change in the sources (the charges and currents) results in a proportional change of the fields. Nonlinear dynamics can occur when electromagnetic fields couple to matter that follows nonlinear dynamical laws. This

9374-616: The late nineteenth century, The Electrician Printing and Publication Company Limited was established and began publishing shorter electrical engineering texts including well-known early electrical engineering titles such as Oliver Heaviside 's Electromagnetic Theory (1893-1912), Oliver Lodge 's The Work of Hertz and Some of His Successors (1894), and many others. Some of these publications were based on papers presented elsewhere and published in full in The Electrician . The new series of The Electrician quickly established itself in

9483-514: The loss of Messenia's fertile land and the helot workforce it provided. The rising power of Thebes led Sparta and Athens to join forces; in 362 they were defeated by Thebes at the Battle of Mantinea . In the aftermath of Mantinea, none of the major Greek states were able to dominate. Though Thebes had won the battle, their general Epaminondas was killed, and they spent the following decades embroiled in wars with their neighbours; Athens, meanwhile, saw its second naval alliance, formed in 377, collapse in

9592-442: The mechanisms behind these phenomena. The Greek philosopher Thales of Miletus discovered around 600 B.C.E. that amber could acquire an electric charge when it was rubbed with cloth, which allowed it to pick up light objects such as pieces of straw. Thales also experimented with the ability of magnetic rocks to attract one other, and hypothesized that this phenomenon might be connected to the attractive power of amber, foreshadowing

9701-495: The mid-350s. The power vacuum in Greece after the Battle of Mantinea was filled by Macedon, under Philip II . In 338 BC, he defeated a Greek alliance at the Battle of Chaeronea , and subsequently formed the League of Corinth . Philip planned to lead the League to invade Persia, but was murdered in 336 BC. His son Alexander the Great was left to fulfil his father's ambitions. After campaigns against Macedon's western and northern enemies, and those Greek states that had broken from

9810-429: The molecular scale, including its density, is determined by the balance between the electromagnetic force and the force generated by the exchange of momentum carried by the electrons themselves. In 1600, William Gilbert proposed, in his De Magnete , that electricity and magnetism, while both capable of causing attraction and repulsion of objects, were distinct effects. Mariners had noticed that lightning strikes had

9919-451: The objects. The effective forces generated by the momentum of electrons' movement is a necessary part of understanding atomic and intermolecular interactions. As electrons move between interacting atoms, they carry momentum with them. As a collection of electrons becomes more confined, their minimum momentum necessarily increases due to the Pauli exclusion principle . The behavior of matter at

10028-529: The period of Christianization during the later 4th to early 6th centuries AD, consummated by the closure of the Academy of Athens by Justinian I in 529. The historical period of ancient Greece is unique in world history as the first period attested directly in comprehensive, narrative historiography , while earlier ancient history or protohistory is known from much more fragmentary documents such as annals, king lists, and pragmatic epigraphy . Herodotus

10137-410: The power of the rich and the poor. In the middle of the sixth century, Pisistratus established himself as a tyrant, and after his death in 527 his son Hippias inherited his position; by the end of the sixth century he had been overthrown and Cleisthenes carried out further democratising reforms. In Sparta, a political system with two kings, a council of elders , and five ephors developed over

10246-408: The publication of James Clerk Maxwell 's 1873 A Treatise on Electricity and Magnetism in which the interactions of positive and negative charges were shown to be mediated by one force. There are four main effects resulting from these interactions, all of which have been clearly demonstrated by experiments: In April 1820, Hans Christian Ørsted observed that an electrical current in a wire caused

10355-617: The reforms of Solon (early 6th century), but the poorest citizens could not address the assembly or run for office. With the establishment of the democracy, the assembly became the de jure mechanism of government; all citizens had equal privileges in the assembly. However, non-citizens, such as metics (foreigners living in Athens) or slaves , had no political rights at all. After the rise of democracy in Athens, other city-states founded democracies. However, many retained more traditional forms of government. As so often in other matters, Sparta

10464-420: The regions of Laconia (southeast), Messenia (southwest), Elis (west), Achaia (north), Korinthia (northeast), Argolis (east), and Arcadia (center). These names survive to the present day as regional units of modern Greece , though with somewhat different boundaries. Mainland Greece to the north, nowadays known as Central Greece , consisted of Aetolia and Acarnania in the west, Locris , Doris , and Phocis in

10573-518: The right to have a family and own property, subject to their master's goodwill and permission, but they had no political rights. By 600 BC, chattel slavery had spread in Greece. By the 5th century BC, slaves made up one-third of the total population in some city-states. Between 40–80% of the population of Classical Athens were slaves. Slaves outside of Sparta almost never revolted because they were made up of too many nationalities and were too scattered to organize. However, unlike later Western culture ,

10682-471: The same charge, while magnetism is an interaction that occurs between charged particles in relative motion. These two forces are described in terms of electromagnetic fields. Macroscopic charged objects are described in terms of Coulomb's law for electricity and Ampère's force law for magnetism; the Lorentz force describes microscopic charged particles. The electromagnetic force is responsible for many of

10791-448: The state. City-states legally owned slaves. These public slaves had a larger measure of independence than slaves owned by families, living on their own and performing specialized tasks. In Athens, public slaves were trained to look out for counterfeit coinage , while temple slaves acted as servants of the temple's deity and Scythian slaves were employed in Athens as a police force corralling citizens to political functions. Sparta had

10900-695: The territories they controlled. The most important of these rulers in the decades after Alexander's death were Antigonus I and his son Demetrius in Macedonia and the rest of Greece, Ptolemy in Egypt, and Seleucus I in Syria and the former Persian empire; smaller Hellenistic kingdoms included the Attalids in Anatolia and the Greco-Bactrian kingdom . In the early part of the Hellenistic period,

11009-515: The territory or unify it into a new province, but compelled most of the poleis to join his own Corinthian League . Initially many Greek city-states seem to have been petty kingdoms; there was often a city official carrying some residual, ceremonial functions of the king ( basileus ), e.g., the archon basileus in Athens. However, by the Archaic period and the first historical consciousness, most had already become aristocratic oligarchies . It

11118-626: The time of Alexander I of Macedon , the Argead kings of Macedon started to expand into Upper Macedonia , lands inhabited by independent Macedonian tribes like the Lyncestae , Orestae and the Elimiotae and to the west, beyond the Axius river , into Eordaia , Bottiaea , Mygdonia , and Almopia , regions settled by Thracian tribes. To the north of Macedonia lay various non-Greek peoples such as

11227-539: Was a notable exception to the rest of Greece, ruled through the whole period by not one, but two hereditary monarchs. This was a form of diarchy . The Kings of Sparta belonged to the Agiads and the Eurypontids, descendants respectively of Eurysthenes and Procles . Both dynasties' founders were believed to be twin sons of Aristodemus , a Heraclid ruler. However, the powers of these kings were held in check by both

11336-460: Was a situation unlike that in most other contemporary societies, which were either tribal or kingdoms ruling over relatively large territories. Undoubtedly, the geography of Greece —divided and sub-divided by hills, mountains, and rivers—contributed to the fragmentary nature of ancient Greece. On the one hand, the ancient Greeks had no doubt that they were "one people"; they had the same religion , same basic culture, and same language. Furthermore,

11445-406: Was an electromagnetic wave propagating in the luminiferous ether . In classical electromagnetism, the behavior of the electromagnetic field is described by a set of equations known as Maxwell's equations , and the electromagnetic force is given by the Lorentz force law . One of the peculiarities of classical electromagnetism is that it is difficult to reconcile with classical mechanics , but it

11554-752: Was conquered by the Romans. The Aetolian league grew wary of Roman involvement in Greece, and sided with the Seleucids in the Roman–Seleucid War ; when the Romans were victorious, the league was effectively absorbed into the Republic. Although the Achaean league outlasted both the Aetolian league and Macedon, it was also soon defeated and absorbed by the Romans in 146 BC, bringing Greek independence to an end. The Greek peninsula came under Roman rule during

11663-417: Was in permanent settlements founded by Greeks, which formed as independent poleis. The second form was in what historians refer to as emporia ; trading posts which were occupied by both Greeks and non-Greeks and which were primarily concerned with the manufacture and sale of goods. Examples of this latter type of settlement are found at Al Mina in the east and Pithekoussai in the west. From about 750 BC

11772-475: Was reported by a Dr. Cookson. The account stated: A tradesman at Wakefield in Yorkshire, having put up a great number of knives and forks in a large box ... and having placed the box in the corner of a large room, there happened a sudden storm of thunder, lightning, &c. ... The owner emptying the box on a counter where some nails lay, the persons who took up the knives, that lay on the nails, observed that

11881-602: Was the Hellenistic period (323–146 BC), during which Greek culture and power expanded into the Near and Middle East from the death of Alexander until the Roman conquest. Roman Greece is usually counted from the Roman victory over the Corinthians at the Battle of Corinth in 146 BC to the establishment of Byzantium by Constantine as the capital of the Roman Empire in 330 AD. Finally, Late Antiquity refers to

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