Perpetual motion machine of the first kind
Perpetual motion machine of the first kind is a machine that can do work indefinitely without an energy input.
From ancient, people has been captivated by this concept. The examples include the “closed-cycle water mill” proposed by the English physician Robert Fludd in 1618. In this machine, the energy created by water by falling from a reservoir onto a mill wheel is used to return the water back to reservoir, thus keeping the machine in perpetual motion. This kind of machine is impossible, since it violates the first law of thermodynamics. The energy delivered by water falling never exceeds the energy required to return water back to reservoir.