diving vessel built by the Swiss scientist Jacques Piccard (Piccard, Jacques) that suspended itself automatically at predetermined depths. The first mesoscaphe was built for the 1964 Swiss National Exhibition in Lausanne and designed as a tourist submarine for 40 passengers. Although it could descend to more than 600 m (2,000 feet), most of the mesoscaphe's 1,100 descents into Lake Geneva during 1964 and 1965 reached only about 90 m (300 feet). A second and smaller mesoscaphe, equipped to remain submerged a month or more, was submerged in Florida and drifted underwater to Nova Scotia in a successful study of the Gulf Stream in the late 1960s.