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1 Torricelli, Evangelista
SUBJECT AREA: Photography, film and optics[br]b. 15 October 1608 Faenza, Italyd. 25 October 1647 Florence, Italy[br]Italian physicist, inventor of the mercury barometer and discoverer of atmospheric pressure.[br]Torricelli was the eldest child of a textile artisan. Between 1625 and 1626 he attended the Jesuit school at Faenza, where he showed such outstanding aptitude in mathematics and philosophy that his uncle was persuaded to send him to Rome to a school run by Benedetto Castelli, a mathematician and engineer and a former pupil of Galileo Galilei. Between 1630 and 1641, Torricelli was possibly Secretary to Giovanni Ciampoli, Galileo's friend and protector. In 1641 Torricelli wrote a treatise, De motugravium, amplifying Galileo's doctrine on the motion of projectiles, and Galileo accepted him as a pupil. On Galileo's death in 1642, he was appointed as mathematician and philosopher to the court of Grand Duke Ferdinando II of Tuscany. He remained in Florence until his early death in 1647, possibly from typhoid fever. He wrote a great number of mathematical papers on conic sections, the cycloid, the logarithmic curve and other subjects, which made him well known.By 1642 Torricelli was producing good lenses for telescopes; he subsequently improved them, and attained near optical perfection. He also constructed a simple microscope with a small glass sphere as a lens. Galileo had looked at problems of raising water with suction pumps, and also with a siphon in 1630. Torricelli brought up the subject again in 1640 and later produced his most important invention, the barometer. He used mercury to fill a glass tube that was sealed at one end and inverted it. He found that the height of mercury in the tube adjusted itself to a well-defined level of about 76 cm (30 in.), higher than the free surface outside. He realized that this must be due to the pressure of the air on the outside surface and predicted that it would fall with increasing altitude. He thus demonstrated the pressure of the atmosphere and the existence of a vacuum on top of the mercury, publishing his findings in 1644. He later noticed that changes in the height of the mercury were related to changes in the weather.[br]Bibliography1641, De motu gravium.Further ReadingT.I.Williams (ed.), 1969, A Biographical Dictionary of Scientists, London: A. \& C.Black.Chambers Concise Dictionary of Scientists, 1989, Cambridge.A Dictionary of Scientific Biography, 1976, Vol. XIII, New York: C.Scribner's Sons.A.Stowers, 1961–2, "Thomas Newcomen's first steam engine 250 years ago and the initial development of steam power", Transactions of the Newcomen Society 34 (provides an account of his mercury barometer).W.E.Knowles Middleton, 1964, The History of the Barometer, Baltimore.RLHBiographical history of technology > Torricelli, Evangelista
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2 Emigration
Traditionally, Portugal has been a country with a history of emigration to foreign lands, as well as to the overseas empire. During the early centuries of empire, only relatively small numbers of Portuguese emigrated to reside permanently in its colonies. After the establishment of the second, largely Brazilian empire in the 17th century, however, greater numbers of Portuguese left to seek their fortunes outside Europe. It was only toward the end of the 19th century, however, that Portuguese emigration became a mass movement, at first, largely to Brazil. While Portuguese-speaking Brazil was by far the most popular destination for the majority of Portuguese emigrants in early modern and modern times, after 1830, the United States and later Venezuela also became common destinations.Portuguese emigration patterns have changed in the 20th century and, as the Portuguese historian and economist Oliveira Martins wrote before the turn of the century, Portuguese emigration rates are a kind of national barometer. Crises and related social, political, and economic conditions within Portugal, as well as the presence of established emigrant communities in various countries, emigration laws, and the world economy have combined to shape emigration rates and destinations.After World War II, Brazil no longer remained the favorite destination of the majority of Portuguese emigrants who left Portugal to improve their lives and standards of living. Beginning in the 1950s, and swelling into a massive stream in the 1960s and into the 1970s, most Portuguese emigrated to find work in France and, after the change in U.S. immigration laws in the mid-1960s, a steady stream went to North America, including Canada. The emigration figures here indicate that the most intensive emigration years coincided with excessive political turmoil and severe draft (army conscription) laws during the First Republic (1912 was the high point), that emigration dropped during World Wars I and II and during economic downturns such as the Depression, and that the largest flow of Portuguese emigration in history occurred after the onset of the African colonial wars (1961) and into the 1970s, as Portuguese sought emigration as a way to avoid conscription or assignment to Africa.1887 17,0001900ca. 17,000 (mainly to Brazil)1910 39,0001912 88,000 (75,000 of these to Brazil)1930ca. 30,000 (Great Depression)1940ca. 8,8001950 41,0001955 57,0001960 67,0001965 131,0001970 209,000Despite considerable efforts by Lisbon to divert the stream of emigrants from Brazil or France to the African territories of Angola and Mozambique, this colonization effort failed, and most Portuguese who left Portugal preferred the better pay and security of jobs in France and West Germany or in the United States, Venezuela, and Brazil, where there were more deeply rooted Portuguese emigrant communities. At the time of the Revolution of 25 April 1974, when the military coup in Lisbon signaled the beginning of pressures for the Portuguese settlers to leave Africa, the total number of Portuguese resident in the two larger African territories amounted to about 600,000. In modern times, nonimperial Portuguese emigration has prevailed over imperial emigration and has had a significant impact on Portugal's annual budget (due to emigrants' remittances), the political system (since emigrants have a degree of absentee voting rights), investment and economy, and culture.A total of 4 million Portuguese reside and work outside Portugal as of 2009, over one-third of the country's continental and island population. It has also been said that more Portuguese of Azorean descent reside outside the Azores than in the Azores. The following statistics reflect the pattern of Portuguese emigrant communities in the world outside the mother country.Overseas Portuguese Communities Population Figures by Country of Residence ( estimates for 2002)Brazil 1,000,000France 650,000S. Africa 600,000USA 500,000Canada 400,000Venezuela 400,000W. Europe 175,000 (besides France and Germany)Germany 125,000Britain (UK) 60,000 (including Channel Islands)Lusophone Africa 50,000Australia 50,000Total: 4,010,000 (estimate)
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