A firm specialising in gas sensor technology set up by two academics in the late 1970s is set to make them multi-millionaires when it is floated on the Stock Exchange in June with a valuation of around Pounds 80 million. Chemists John Finbow and Bryan Hobbs created the firm, City Technology, while based at City University, London. They led a management buy-out of the firm in 1993 which took it out of the university.