On Burning Oil, Part 2

Here's a little "myth-busting" experiment you can do easily in your own home. Recall that medieval lamp oil was just olive oil (or more rarely some other vegetable, fish oil, etc.). Here I've put together a "flask" of such oil, some matches, a little bit of string, and poured some of the oil on a plate:

Consider the following as representative of a torch applied to a pool of oil on a dungeon floor. Is it possible to get that pool ignited by applying a flame? No way! I emptied a whole book of matches on multiple attempts (photo shots) like this:

But if I take a little bit of string, dip the end in some oil, and light it like a wick, can I use it as a lamp? Quite easily!

I left this burning away happily for the better part of an hour. I can carry it around the house and even light up my always-dark bedroom with it reasonably well. (Actually, it's still going next to me as I write these words.) I've really got no idea how long it would take to burn away (can't see any noticeable difference in the wick or the pool). After an hour, for argument's sake, I tried to ignite the whole pool again -- Not gonna happen!

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  1. I'm not quite sure, if it wouldn't burn if you toss an actual torch into it - wich wasn't something more than cloth drenched in oil around a stick - presumably much hotter than a matchstick...
    I built one once, but i never tried it with an oil puddle. Damn!

  2. Excellent research. Of course, the throwing and smashing might aerate some of the oil. Plus, your target may have flammable clothing or fur.

  3. So are you going to mix crude oil and resins together in your next bedroom to test the Greek Fire hypothesis?

  4. D&D oil is Hollywood kerosene.

    I light my charcoal grill with a piece of paper soaked in olive oil becasue it creates a long burning wick which is sure to light the darned charcoal...60-70% of the time.

  5. One thing that struck me reading this and the prior posts, which is kind of on a related subject.

    Burning web spell webs. I've noted a few times in recent games, both our online experiment and in Paul's campaign, that players seem to assume that setting something caught in a web spell alight is akin to dousing them in petroleum and lighting them up. (Remember the big fustercluck in the Wardicon campaign between Boudoin and Dumas in that webbed up tunnel?)

    This just strikes me as another bit of cinematic assumptions about fire creeping into the game. It'd be hard to do a Mythbusters on it, tho.

    I guess cobwebs or actual spider webs are just so tenuous they burn quickly, but I don't think that equates to raging infernos.

    A party would be more in danger of getting blown up by heavy dust in the air, as exploding silos full of grain or flour often attest.

    Still, inneresting subject, and I too am glad to see flaming oil abuse discredited.

  6. Paul & rorshchhamster -- I'm pretty sure that neither of those things would work. The presence of any flammable vapor "is a function of that liquid's temperature" (Wikipedia: Flash point). So a hotter source won't ignite the whole pool -- unless the oil itself was uniformly heated to 300+ degrees in advance. And throwing the liquid into the air won't change anything, either (in fact, it seems most likely that would smother any existing lamp wick).

    My current understanding of a wick or a torch is that there's enough non-saturated material to burn and hold the fire in close proximity to the oil, thereby heating it locally and then burning it in turn. Like, historically one thing that actually would work is how "Chinese made early grenades out of oil-soaked hemp and cotton, which were ignited and thrown by mangonels." (Wikipedia: Early thermal weapons). In fact, Gygax has an adventurer named Jaer armed like that in module T1-4 (p. 112 & 114; throw 3", damage 1-4). God help me.

    Alex -- Normally I'd say "no way" because I'm flat-out afraid of fire. But apparently my resolution for the new year is to be more pyromaniacal, and so-far-so-good. :-D

  7. BigFella -- Another good point, I agree! Again you can see the legacy evolve: in OD&D Vol-2 it was just "A Flaming Sword will slash through them in one turn." [p. 35] And then by AD&D is expanded to lighting the whole mass of fire and doing damage to those stuck in it [PHB p. 72].

  8. JDJarvis said: "Hollywood kerosene."

    I like that. :-)

  9. Also, consider the use of boiling oil for various purposes.

    Surely this would never have been common, if there were likely to be problems from having so much hot oil in close proximity to fire.

    On the other hand, Wikipedia's article on thermal weapons says: "Another use of oil can be seen in the naval battle of La Rochelle during the Hundred Years' War; the Castilians sprayed oil on the decks of English ships then ignited it by shooting flaming arrows down.[73]"

    Perhaps you should talk to your local fire department, and ask if they'd supervise while you do some experiments. ;^)

  10. Hey Jon -- I agree with your main point there. That particular quoted case seems suspect, what with the rest of the evidence around it. Another tidbit I found interesting from the same article was this:

    "Since the smoke point of oil is lower than its boiling point, the oil was only heated and not boiled."

  11. Umm, well, that's all well and good and somewhat interesting, and I'm sure you are right that olive oil won't burst into flame, but that's a very different kettle of fish from the oil in the D&D equipment lists. D&D torch and lamp fuel in the books is specificly "lamp oil" which you can find in any hardware store and which is a refined grade of Kerosene. Lest there be any doubt, Gygax did also specified that it was meant to be the familiar kerosene lamp oil in at least one place I've seen. Lamp oil does indeed burn quite well when ignited by a fire.

  12. DHBoggs -- Going to have to mostly disagree with you there. Medieval lamp oil really was olive oil. Kerosene wasn't invented until 1846 by a Canadian geologist.

    However, a quote that Gygax intended D&D oil to be kerosene sounds like it would be very interesting! Do you have a link/reference?

  13. Knowledge is power my friend.

    "In OD&D the 1st level PCs did do several things to help extend their chnaces--hire men-at-arms, use missile weapons (including flaming lamp oil, that is kerosene), and run away when things appeared to be too dangerous to stay and fight." - Gary Gygax quoted http://www.enworld.org/forum/archive-threads/193204-gary-gygax-q-part-xiii-58.html

    Also, distilled petroleum based oils (crude kerosenes) have actually been around since at least the early middle ages, mostly in the middle-east and asia and not so much europe, but even so they are not so out of place in a pre modern fantasy setting.

    Still, I like your exeriential archaeology approach. :)

  14. ^ That's a great quote! Thank you for looking that up.

  15. Delta, just found your blog and loved this post. Cracked me up because there is at least one oil flask toss per game night. I think this post would crush their spirits. Anyway, joined up and looking forward to going through more of your posts.

  16. Tim -- Thanks for the kind words! Hope there's some other stuff here that also serves as "fuel" for your game. :-)

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