FTP, name this device, imagined by its Scottish creator as an intelligent gatekeeper between two vessels of gas who willfully separated fast and slow molecules into different vessels.
Its use in perpetual motion machines was undermined around 1950, when physicist Leon Brillouin [bree-ou-AN] showed that the increased change resulting from its actions would exceed, in magnitude, the decrease in change brought about by its actions.  This unit chooses between fast and slow molecules, and even though the fast molecules, once sectioned off into their own chamber, would have excess energy to do work, it would still create entropy.  Hypothesized in 1871 it allows for the violation of the second law of thermodynamics.  FTP, name this device, imagined by its Scottish creator as an intelligent gatekeeper between two vessels of gas who willfully separated fast and slow molecules into different vessels.
Its use in perpetual motion machines was undermined around 1950, when physicist Leon Brillouin [bree-ou-AN] showed that the increased change resulting from its actions would exceed, in magnitude, the decrease in change brought about by its actions.  
Maxwell's demon or Maxwell's devil