Problem: Background: Jonas Edward Salk (; October 28, 1914 - June 23, 1995) was an American medical researcher and virologist. He discovered and developed one of the first successful polio vaccines. Born in New York City, he attended New York University School of Medicine, later choosing to do medical research instead of becoming a practicing physician. In 1939, after earning his medical degree, Salk began an internship as a physician scientist at Mount Sinai Hospital.
Context: Salk preferred not to have his career as a scientist affected by too much personal attention, as he had always tried to remain independent and private in his research and life, but this proved to be impossible. "Young man, a great tragedy has befallen you--you've lost your anonymity", the television personality Ed Murrow said to Salk shortly after the onslaught of media attention. When Murrow asked him, "Who owns this patent?", Salk replied, "Well, the people I would say. There is no patent. Could you patent the sun?" The vaccine is calculated to be worth $7 billion had it been patented. However, lawyers from the National Foundation for Infantile Paralysis did look into the possibility of a patent, but ultimately determined that the vaccine was not a patentable invention because of prior art.  Salk served on the board of directors of the John D. and Catherine T. MacArthur Foundation.  Author Jon Cohen noted, "Jonas Salk made scientists and journalists alike go goofy. As one of the only living scientists whose face was known the world over, Salk, in the public's eye, had a superstar aura. Airplane pilots would announce that he was on board and passengers would burst into applause. Hotels routinely would upgrade him into their penthouse suites. A meal at a restaurant inevitably meant an interruption from an admirer, and scientists approached him with drop-jawed wonder as though some of the stardust might rub off."  For the most part, however, Salk was "appalled at the demands on the public figure he has become and resentful of what he considers to be the invasion of his privacy", wrote The New York Times, a few months after his vaccine announcement. The Times article noted, "at 40, the once obscure scientist ... was lifted from his laboratory almost to the level of a folk hero." He received a presidential citation, a score of awards, four honorary degrees, half a dozen foreign decorations, and letters from thousands of fellow citizens. His alma mater, City College of New York, gave him an honorary degree as Doctor of Laws. But "despite such very nice tributes", The New York Times wrote, "Salk is profoundly disturbed by the torrent of fame that has descended upon him.... He talks continually about getting out of the limelight and back to his laboratory... because of his genuine distaste for publicity, which he believes is inappropriate for a scientist."  During a 1980 interview, 25 years later, he said, "It's as if I've been a public property ever since, having to respond to external, as well as internal, impulses.... It's brought me enormous gratification, opened many opportunities, but at the same time placed many burdens on me. It altered my career, my relationships with colleagues; I am a public figure, no longer one of them."
Question: how did it prove to be impossible?
Answer: Airplane pilots would announce that he was on board and passengers would burst into applause.

Background: Robert Owen (; 14 May 1771 - 17 November 1858) was a Welsh textile manufacturer, philanthropic social reformer, and one of the founders of utopian socialism and the cooperative movement. Owen is best known for his efforts to improve the working conditions of his factory workers and his promotion of experimental socialistic communities.
Context: Although Owen made brief visits to the United States, London became his permanent home and the centre of his activities in 1828. After an extended period of friction with William Allen and some of his other business partners, Owen relinquished all of connections to New Lanark. He is often quoted as comment Allen at the time, "All the world is queer save thee and me, and even thou art a little queer". Having invested most of his personal fortune in the failed New Harmony communal experiment, Owen was no longer a wealthy capitalist; however, he remained the head of a vigorous propaganda effort to promote industrial equality, free education for children, and adequate living conditions in factory towns. In addition, he delivered lectures in Europe and published a weekly newspaper to gain support for his ideas.  In 1832 Owen opened the National Equitable Labour Exchange system, a time-based currency in which the exchange of goods was effected by means of labour notes; this system superseded the usual means of exchange and middlemen. The London exchange continued until 1833; a Birmingham branch operated for only a few months until July 1833. Owen also became involved in trade unionism. He briefly served as the leader of the Grand National Consolidated Trade Union (GNCTU) before its collapse in 1834.  Socialism first became current in British terminology in the discussions of the Association of all Classes of all Nations, which Owen formed in 1835 and served as its initial leader. Owen's secular views also gained enough influence among the working classes to cause the Westminster Review to comment in 1839 that his principles were the actual creed of a great portion of them. However, by 1846, the only long-lasting result of Owen's agitation for social change, carried on through public meetings, pamphlets, periodicals, and occasional treatises, remained the co-operative movement, and for a time even that seemed to have utterly collapsed.
Question: what did the exchange system do
Answer:
a time-based currency in which the exchange of goods was effected by means of labour notes;