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Rainmaking, also known as artificial precipitation or artificial rainfall, is the act of attempting to artificially induce or increase precipitation, usually to stave off drought. According to the clouds' different physical properties, this can be done using airplanes or rockets to sow to the clouds with catalysts such as dry ice, silver iodide and salt powder, to make clouds rain or increase precipitation, to remove or mitigate farmland drought, to increase reservoir irrigation water or water supply capacity, or to increase water levels for power generation. In the United States, rainmaking was attempted by traveling showmen. It was practiced in the old west, but may have reached a peak during the dust bowl drought of the American West and Midwest in the 1930s. The practice was depicted in the 1956 film ''The Rainmaker''. Attempts to bring rain directly have waned with development of the science of meteorology, the advent of laws against fraud and increased communication technology, with some exceptions such as cloud seeding and forms of prayer including rain dances, which are still practiced today. Prayer for more rain is also a cross cultural practice in Christians and Muslims in areas where people keep "traditional" non-scriptural religions. In the Christian areas the Defteras (learned clerics of the Orthodox Christian Church) believed to have the wisdom to arrest the rain, to bring hail to farms of individuals who refuse to comply with religious rules as well as to bring more rains when the rainy season fell short of giving the usual amount of rain needed for growing cereals. The term is also used metaphorically to describe the process of bringing new clients into a professional practice, such as law, architecture, consulting, advertising, or investment banking—in general, processes that bring money into a company. It is also used to describe a Confidence trick where the scammer takes money from the victim to influence a system over which they have no real control, but a random chance of the outcome happening anyway. ==Cloud seeding== Since the 1940s, cloud seeding has been used to change the structure of clouds by dispersing substances into the air, potentially increasing or altering rainfall. In spite of experiments dating back to at least the start of the 20th century, however, there is much controversy surrounding the efficacy of cloud seeding, and evidence that cloud seeding leads to increased precipitation on the ground is highly equivocal. One difficulty is knowing how much precipitation might have fallen had any particular cloud not been seeded. Operation Popeye was a US military rainmaking operation to increase rains over Vietnam during the Vietnam War in order to slow Vietnamese military truck activity in the region. Rainmaking is not climate engineering, which seeks to alter climate, but a form of weather modification, as it seeks only to change local weather. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「rainmaking」の詳細全文を読む スポンサード リンク
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