Dear NicholasW: I wonder how good pumps they had. A really good pump can convert enough work into heat to give one a blister. If one puts a finger over air outlet of a bicyle pump, pushes plunger to get maxixmum pressure, and then allow a small air leak, there is enough heat released to be quite painful. A mixture with both naphrha and sulfur might have low flash point. A modern flame thrower has to have some kind of an igniter. I wonder if Greeks had any think like punk that could burn slowly enough to last until it was needed, to ignite the stream of the flammable materials.