Fire has almost a mythic status among many people. Notice how often, in fantasy works, the four-elements view of the Ancient Greeks (fire, earth, water, air) is taken up? Pity there isn't a 92-element view instead. A hydrogen wizard (as opposed to a generic "fire wizard") would be awesome.

This article is interesting. I'm unimpressed by the suggestion that it could be bat guano - it's less probable than the idea that it was evidence of human activity, as human fires were much more common and mundane and thus had more opportunities to leave traces. If they found evidence of bat remains in the cave, that would make that suggestion (of guano combustion) more plausible.

I wonder what the invention of fire would have been like. Perhaps humans originally saw it caused by lightning storms or droughts, and occasionally picked it up for use. Then our ancestors and their contemporaries began to collect and store such fires, feeding them for long-term use. Then, they created "spawn" fires by taking burning branches from the original fires, and so pass it on. Finally, they learned how to make their own. After that, perhaps we had a long technological history experimenting with different fuels. Maybe there were thousands of kinds of fires recruited for a variety of purposes.

I feel almost guilty when I flick on the gas stove and think how easily and thoughtlessly I can just use the fire. Sometimes, I think we give our forebears too little credit.