Sounds crazy but early engines ran on "city gas," generated by roasting coal. Liquid fuels like gasoline improved our lot in Combustion Life, but there have been many experiments to get the most out of it. How close are we to perfect combustion? How do we get liquid fuel--which will not burn--to turn to vapor that will burn? So many questions that Kevin and Mark set out to answer. Let's get into the molecules, shall we?