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Constantine the Great was the first Christian emperor of Rome. By his adoption of Christianity, and by his various policies encouraging its growth, he played a major role in transforming it from a persecuted sect into the dominant religion of Europe.
Constantine was born about 280, in the town of Naissus (present day Nis), in what is now Yugoslavia. His father was a high-ranking army officer, and Constantine spent his younger days in Nicomedia, where the court of the Emperor Diocletian was situated.
Diocletian
abdicated in 305, and Constantine's father, Constantius, became the ruler of the western half of the Roman Em
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pire. When Constantius died the following year, Constantine was proclaimed emperor by his troops. Other generals, however, disputed his claim, and a series of civil wars followed. These ended in 312 when Constantine defeated his remaining rival, Maxentius, at the Battle of the Milvian Bridge, near Rome.
Constantine was now the undisputed ruler of the western half of the Empire;
however, another general, Licinius, ruted the eastern half. In 323, Constantine attacked and defeated Licinius also, and from then until his death in 337 was sole ruler of the Roman Empire.
It is uncertain just when Constantine became converted to Christianity. The most usual story is that on the eve of the Battle of the Milvian Bridge, Constantine saw a fiery cross in the sky, together with the words "By this sign shalt thou conquer." Regardless of how or when he was converted, Constantine became deeply dedicated to the advancement of Christianity. One of his early actions was the Edict of Milan, under which Christianity became a legal and tolerated religion. The Edict also provided for the return of Church property which had been confiscated during the preceding period of persecution, and it established Sunday as a day of worship.
The Edict of Milan was not motivated by general feelings of religious toleration. On the contrary, Constantine's reign may be said to mark the beginning of the official persecution of the Jews that was to persist in Christian Europe for so many centuries.
Constantine never established Christianity as the official state religion. However, by his legislation and other policies, he did much to encourage its growth. During his reign it became obvious that conversion to Christianity enhanced one's prospects for promotion to a high government position, and his decrees gave the Church various useful privileges and immunities. Also, construction of several of the world's most famous church buildings—such as the Church of the Nativity in Bethlehem, and the Church of the Holy Sepulchre in Jerusalem—was commenced during his reign.
Constantine's role as the first Christian emperor of Rome
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would by itself entitle him to a place on this list. However, several of his other actions have also had far-reaching consequences. For one thing, he rebuilt and greatly expanded the old city of Byzantium, renamed it Constantinople, and made it his capital. Constantinople (which is today called Istanbul) was to become one of the great cities of the world; it remained the capital of the Eastern Roman Empire until 1453, and for centuries thereafter was the capital of the Ottoman Empire.
Constantine also played a significant role in the internal history of the Church.
To deal with a dispute between the followers of Arius and Athanasius (two Christian theologians who had advanced conflicting doctrines), Constantine convoked the Council of Nicaea (in 325), the first general council of the Church. The council, in which Constantine took an active part, resolved the dispute by its adoption of the Nicene Creed, which became orthodox Church doctrine.
More important still was some of his civil legislation. Constantine introduced laws which made certain occupations (e.g., butchers, bakers) hereditary. He also issued a decree under which coloni (a class of tenant farmers) were forbidden to leave their land. In modern terms, this decree converted the coloni into serfs, permanently attached to the land. This and similar legislation helped to lay the foundations for the entire social structure of medieval Europe.
Constantine chose not to be baptized until he was on his deathbed, but it is clear that he had been converted to Christianity long before that. It is equally plain that the spiritual content of Christianity had eluded him completely. Even by the standards of the day, he was ruthless and cruel—and not merely to his enemies. For reasons that are unclear, he had his wife and his eldest son put to death in 326.
It might be argued that Constantine's adoption of Christianity did not really change the course of history, but merely ratified the inevitable. After all, although the Emperor Diocletian (who ruled 284-305) had conducted a vigorous persecution of Christianity, his
attempt to suppress the religion was unsuc
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cessful, for by that time Christianity was far too strong to be stamped out by even the fiercest measures. When one considers the failure of Diocletian's efforts to extirpate Christianity, one suspects that Christianity might eventually have triumphed even without Constantine's intervention.
Such speculations are interesting, but inconclusive. It is hard to be sure what might have happened without Constantine. It is quite plain, though, that with his encouragement, Christianity rapidly expanded in both numbers and influence. From the creed of a small minority it became, within a century, the predominant and established religion of the largest empire on earth.
Clearly, Constantine was one of the great pivotal figures of European history. He has been ranked higher than better known figures such as Alexander the Great, Napoleon, and Hitler because of the enduring influence of his policies.
The Scottish inventor James Watt, the man who is often described as the inventor of the steam engine, was the key figure of the Industrial Revolution.
Actually, Watt was not the first man to build a steam engine. Similar devices were described by Hero of Alexandria in the 1st century. In 1698, Thomas Savery patented a steam engine that was used for pumping water, and in 1712 an Englishman, Thomas Newcomen, patented a somewhat improved version. Still, the Newcomen engine had such a low efficiency that it was useful only for pumping water out of coal mines.
Watt himself became interested in the steam engine in 1764, while repairing a model of Newcomen's device. Watt, although he had received only one year's training as an instrument maker, had great inventive talent. The improvements which he made upon Newcomen's invention were so important that it is fair to consider Watt the inventor of the first practical steam engine.
Watt's first great improvement, which he patented in 1769,
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was the addition of a separate condensing chamber. He also insulated the steam cylinder, and in 1782 he invented the double- acting engine. Together with some smaller improvements, these innovations resulted in an increase in the efficiency of the steam engine by a factor of four or more. In practice, this increase of efficiency meant the difference between a clever but not really very useful device, and an instrument of enormous industrial utility.
Watt also invented (in 1781) a set of gears for converting the reciprocal motion of the engine into a rotary motion. This device greatly increased the number of uses to which steam engines could be put. Watt also invented a centrifugal governor (1788), by which the speed of the engine could be automatically controlled; a pressure gauge (1790);
a counter; an indicator; and a throttle valve, in addition to various other improvements.
Watt himself did not have a good head for business. However, in 1775 he formed a partnership with Matthew Boulton, who was an engineer and a very capable businessman.
Over the next twenty-five years, the firm of Watt and Boulton manufactured a large number of steam engines, and both partners became wealthy men.
It would be difficult to exaggerate the importance of the steam engine. True, there were many other inventions which played a role in the Industrial Revolution. There were developments in mining, in metallurgy, and in many sorts of industrial machinery. A few of the inventions, such as the fly shuttle (John Kay, 1733) or the spinning jenny (James Hargreaves, 1764) had even preceded Watt's work. The majority of the other inventions, however, represented small improvements, and no one of them alone was vital to the Industrial Revolution. It was quite different with the steam engine, which played an absolutely crucial role, and without which the Industrial Revolution would have been vastly different. Previously, although some use had been made of windmills and waterwheels, the main source of power had always been human muscles. This factor severely limited the productive capacity of industry. With the invention
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of the steam engine, however, this limitation was removed. Large quantities of energy were now available for production, which accordingly increased enormously.
The oil embargo of 1973 made us aware of how severely a shortage of energy can
Watt's double-acting steam engine, 1769.
hamper an industrial system, and this experience might, in some slight degree, give us an idea of the importance to the Industrial Revolution of Watt's inventions.
Aside from its usefulness as a source of power for factories, the steam engine had many other important applications. By 1783, the Marquis de Jouffroy d'Abbans had successfully used a steam engine to power a boat. In 1804, Richard Trevithick built the first steam locomotive. Neither of those early models was
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commercially successful. Within a few decades, however, the steamboat and the railroad were to revolutionize both land and water transportation.
The Industrial Revolution occurred at about the same time in history as the American and French revolutions. Though it might not have seemed obvious at the time, today we can see that the Industrial Revolution was destined to have a far greater impact on the daily lives of human beings than either of those important political revolutions. James Watt, accordingly, has been one of the most influential persons in history.
Watt, as a boy, notices the condensation of steam.
23 FARADAY
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This is the age of electricity. It is true that our era is sometimes called the space age and sometimes called the atomic age; however, space travel and atomic weapons, whatever their potential importance, have relatively little impact upon our everyday lives. But we use electrical devices constantly. In fact, it seems safe to say that no technological feature so completely permeates the modern world as does the use of electricity.
Many men have contributed to our mastery of electricity:
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Charles Augustine de Coulomb, Count Alessandro Volta, Hans Christian Oersted, and Andre Marie Ampere are among the most important. But towering far above the others are two great British scientists, Michael Faraday and James Clerk Maxwell. Though the work of the two men was in part complementary, they were in no sense collaborators, and each man's individual achievements entitle him to a high place on this list.
Michael Faraday was born in 1791, in Newington, England. He came from a poor family and was largely self-educated. Apprenticed to a bookbinder and bookseller at the age of fourteen, he used the opportunity to read extensively. When he was twenty, he attended lectures given by the famous British scientist, Sir Humphry Davy, and was fascinated. He wrote to Davy, and eventually got a job as his assistant. Within a few years, Faraday was making important discoveries of his own. Although he lacked a good background in mathematics, as an experimental physicist he was unsurpassed.
Faraday's first important innovation in electricity was made in 1821. Two years earlier, Oersted had found that the needle of an ordinary magnetic compass would be deflected if an electric current flowed in a nearby wire. This suggested to Faraday that if the magnet were to be held fixed, the wire might move instead. Working on this hunch, he succeeded in constructing an ingenious device, in which a wire would rotate continuously in the vicinity of a magnet as long as an electric current flowed through the wire. In fact, what Faraday had invented was the first electric motor, the first device to use an electric current to make a material object move. Primitive as it was, Faraday's invention was the ancestor of all the electric motors in use in the world today.
This was a tremendous breakthrough. However, its practical usefulness was limited, as long as there was no method of generating electric currents other than the primitive chemical batteries of
the day. Faraday was convinced that there must be some way of using magnetism to generate electricity, and he kept looking for such a method. Now, a stationary magnet will not in
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duce an electric current in a nearby wire. But in 1831, Faraday discovered that if a magnet is passed through a closed loop of wire, a current will flow in the wire while the magnet is moving. This effect is called electromagnetic induction, and the discovery of the law governing it ("Faraday's law") is generally considered to be Faraday's greatest single achievement.
This was a monumental discovery, for two reasons. First, Faraday's law is of fundamental importance in our theoretical understanding of electromagnetism.
Second, electromagnetic induction can be used to generate continuous electric currents, as Faraday himself demonstrated by building the first electric dynamo.
Although the modern electric generators that supply power to our cities and factories are far more sophisticated than Faraday's device, they are all based on the same principle of electromagnetic induction.
Faraday also made contributions to the field of chemistry. He devised methods for liquefying gases, and he discovered various chemical substances, including benzene. Of greater importance is his work in electrochemistry (the study of chemical effects of electric currents). Faraday's careful experiments established the two laws of electrolysis which are named after him, and which form the foundations of electrochemistry. He also popularized much of the important terminology used in that field, such as anode, cathode, electrode, and ion.
It was Faraday who introduced into physics the important idea of magnetic lines of force and electric lines of force. By emphasizing not the magnets themselves but rather the field between them, he helped prepare the way for many advances in modern physics, including Maxwell's equations. Faraday also discovered that if polarized light is passed through a magnetic field, its polarization will be altered.
This discovery is significant, because it was the first indication that there is a relationship between light and magnetism.
Faraday was not only brilliant, but also handsome, and he was a very popular lecturer on science. Nevertheless, he was modest and singularly indifferent to fame, money, and honors.
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He declined a knighthood, and also declined an offer to become president of the British Royal Society. He had a long, happy marriage, but no children. He died in 1867, near London.
Faraday lectures at the Royal Institution on December 27, 1855.