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Benjamin Franklin - Реферат

that "vitreous" and "resinous" electricity were not different types of electrical fluid (as electricity was called then) but the same electrical fluid under different pressures (See electrical charge). He is also often credited with labeling them as positive and negative respectively. In 1750 he published a proposal for an experiment to prove that lightning is electricity by flying a kite in a storm that appeared capable of becoming a lightning storm. On May 10, 1752, Thomas Francois d'Alibard of France conducted Franklin's experiment (using a 40-foot-tall iron rod instead of a kite) and extracted electrical sparks from a cloud. On June 15, Franklin conducted his famous kite experiment and also successfully extracted sparks from a cloud (unaware that d'Alibard had already done so, 36 days earlier). Franklin's experiment was not written up until Joseph Priestley's 1767 History and Present Status of Electricity; the evidence shows that Franklin was insulated (not in a conducting path, as he would have been in danger of electrocution in the event of a lightning strike). (Others, such as Prof. Georg Wilhelm Richmann of St. Petersburg, Russia, were spectacularly electrocuted during the months following Franklin's experiment.) Franklin, in his writings, displays that he was aware of the dangers and offered alternative ways to demonstrate that lightning was electrical, as shown by his invention of the lightning rod, an application of the use of electrical ground. If Franklin did perform this experiment, he did not do it in the way that is often described (as it would have been dramatic but fatal). Instead he used the kite to collect some electric charge from a storm cloud, which implied that lightning was electrical. See, for example, the 1805 painting by Benjamin West of Benjamin Franklin drawing electricity from the sky.
In recognition of his work with electricity, Franklin was elected a Fellow of the Royal Society and received its Copley Medal in 1753. The cgs unit of electric charge has been named after him: one franklin (Fr) is equal to one statcoulomb.
Franklin established two major fields of physical science, electricity and meteorology. In his classic work (A History of The Theories of Electricity & Aether), Sir Edmund Whittaker (p. 46) refers to Franklin's inference that electric charge is not created by rubbing substances, but only transferred, so that "the total quantity in any insulated system is invariable." This assertion is known as the "principle of conservation of charge."
As a printer and a publisher of a newspaper, Franklin frequented the farmers' markets in Philadelphia to gather news. One day Franklin inferred that reports of a storm elsewhere in Pennsylvania must be the storm that visited the Philadelphia area in recent days. This initiated the notion that some storms travel, eventually leading to the synoptic charts of dynamic meteorology, replacing sole dependence upon the charts of climatology.
In 1751 Franklin and Dr. Thomas Bond obtained a charter from the Pennsylvania legislature to establish a hospital. Pennsylvania Hospital was the first hospital in what was to become the United States of America.
This political cartoon by Franklin urged the colonies to join together during the French and Indian War (Seven Years' War).
In politics he proved very able both as an administrator and as a controversialist; as an office-holder, he made use of his position to advance his relatives, though doing so was all but expected in a world dominated by political patronage. His most notable service in domestic politics was his reform of the postal system, but his fame as a statesman rests chiefly on his diplomatic services in connection with the relations of the colonies with Great Britain, and later with France. It was during this period that Franklin was involved in the creation of not only the aforementioned first volunteer fire department and free public library, but also many other civic enterprises.
In 1754 he headed the Pennsylvania delegation to the Albany Congress. This meeting of several colonies had been requested by the Board of Trade in England to improve relations with the Indians and defense against the French. Franklin proposed a broad Plan of Union for the colonies. While the plan was not adopted, elements of it found their way into the Articles of Confederation and the Constitution.
In 1757 he was sent to England to protest against the influence of the Penn family in the government of Pennsylvania, and for five years he remained there, striving to enlighten the people and the ministry of the United Kingdom as to colonial conditions. At Oxford University Franklin was awarded an honorary doctorate for his scientific accomplishments and from then on went by "Doctor Franklin." He also managed to secure a post for his illegitimate son, William Franklin, as Colonial Governor of New Jersey.
In 1756, Franklin became a member of the Society for the encouragement of Arts, Manufactures & Commerce (now Royal Society of Arts or RSA, which had been founded in 1754) whose early meetings took place in coffee shops in London's Covent Garden district, close to Franklin's main London residence in Craven Street (the only one of his residences to survive and which is currently undergoing renovation and conversion to a Franklin museum). After his return to America, Franklin became the Society's Corresponding Member and remained closely connected with the Society. The RSA instituted a Benjamin Franklin Medal in 1956 to commemorate the 250th anniversary of Franklin's birth and the 200th anniversary of his membership of the RSA.
In 1758, the year in which he ceased writing for the Almanac, he printed "Father Abraham's Sermon," one of the most famous pieces of literature produced in Colonial America.
Franklin noted a principle of refrigeration by observing that on a very hot day, he stayed cooler in a wet shirt in a breeze than he did in a dry one. To understand this phenomenon more clearly Franklin conductedexperiments. On one warm day in Cambridge England in 1758, Franklin and fellow scientist John Hadley experimented by continually wetting the ball of a mercury thermometer with ether and using bellows to evaporate the ether. With each subsequent evaporation, the thermometer read a lower temperature, eventually reaching 7 °F (-14 °C). Another thermometer showed the room temperature to be constant at 65 °F (18 °C). In his letter "Cooling by Evaporation" Franklin noted that "one may see the possibility of freezing a man to death on a warm summer's day."
Later years
On his return to America, he played an honorable part in the Paxton affair, through which he lost his seat in the Assembly, but in 1764 he was again dispatched to England as agent for the colony, this time to petition the King to resume the government from the hands of the proprietors. In London he actively opposed the proposed Stamp Act, but lost the credit for this and much of his popularity because he secured for a friend the office of stamp agent in America. This perceived conflict of interest, and the resulting outcry, is widely regarded as a deciding factor in Franklin's never achieving higher elected office. Even his effective work in helping to obtain the repeal of the act did not regain his popularity, but he continued his efforts to present the case for the Colonies as the troubles thickened toward the crisis of the Revolution. This also led to an irreconcilable conflict with his son, who remained ardently loyal to the British Government.
Franklin, an engraving from a painting by Duplessis
In 1767 he crossed to France, where he was received with honor; but before his return home in 1775 he lost his position as postmaster through his share in divulging to