Hmmm, it's different. And it's also slightly more defensible as a method of time travel. After all, we can already "travel through time" simply be evoking memories, and deep memories can be accessed by "mind-altering" drugs, I guess.
Only thing is, it's not really visual. For a time travel movie, you've just got to have an exotic contraption with lights and moving parts that make strange noises, etc.. The money scene is always when the machine starts up and things start to happen. And I've already started making that prop.
As for the fuel fumes, there's an example in the third "Back To The Future" movie, when the bartender sloppily pours a whiskey into a shot glass and some of it spills on to the bartop. White fumes instantly rise around the glass. I guess the bar was treated with something that would react when the "whiskey" hit it, but I don't know what they used. Obviously it must have been a harmless substance, because the actor was right up close to it.
Thanks for your thoughts anyway, Michel.
SMF, I'm thinking more along the lines of a small wisp of vapour rising from the beaker/test tube/bottle when the two chemicals are mixed.
Something like the vapour that comes from acid, but without the stinging and the ow it hurts me factor!