Grasshopper escapement it in his prototype marine chronometers, H1 - H3, and Justin and Benjamin Vulliamy made a small number of regulators using Harrison's design, but generally it remains today what it was in Harrison's time: a brilliant, unique curiosity. A unique public clock built as a tribute to John Harrison's grasshopper escapement, the Corpus Clock, was unveiled at Corpus Christi College, Cambridge University, in Cambridge, England on 19 September 2008. Industrialist John Taylor spent £1 million building the mechanical clock. Feeling that Harrison's escapement was not well enough known, the clock's grasshopper escapement is exposed on the top of the clock,
Mechanical energy isolated system remains constant in time, as long as the system is free of friction and other non-conservative forces. In any real situation, frictional forces and other non-conservative forces are present, but in many cases their effects on the system are so small that the principle of conservation of mechanical energy can be used as a fair approximation. Though energy cannot be created or destroyed in an isolated system, it can be converted to another form of energy. In a mechanical system like a swinging pendulum subjected to the conservative gravitational force where frictional forces like air drag and friction