21
$\begingroup$

In a world of my story, which is loosely based on medieval times, fire disappeared. Are there any sources of lighting without fire that would be possible in a medieval setting?

It is a fantasy book and magic does exist and is widely used to create light. But I'm looking for non magical ways to do it.

$\endgroup$
  • 5
    $\begingroup$ Fire disappeared is a confusing concept. Are you saying the chemical reaction that creates the effect of fire has stopped working? Or are you saying people have forgotten how to make fire? Because if it's the first, then the Earth is going to die as the core cools down and solidifies. Earth loses it's magnetic fields and then loses it's atmosphere. $\endgroup$ – Trevor Jul 9 at 18:03
  • 22
    $\begingroup$ @TrevorD the earth is not heated by fire, the end of fire would kill most life on earth however since the chemistry behind fire and aerobic metabolism are exactly the same. $\endgroup$ – John Jul 9 at 18:15
  • 5
    $\begingroup$ 10 answers and only 2 upvotes! Consider upvoting a question you like enough to post an answer. $\endgroup$ – Willk Jul 9 at 20:07
  • 6
    $\begingroup$ @TrevorD I agree - the boundary of what is considered "fire" needs to be defined. Magnesium/Phosphor burning, any oxidization. Or do things still oxidize, but without emitting much light? Then life could go on, but fireflies would also lose the ability to shine... We need a clear cut definition of how "fire stopped working" $\endgroup$ – Falco Jul 10 at 8:48
  • 5
    $\begingroup$ without a better description of what constitutes "fire" this is not answerable. $\endgroup$ – John Jul 10 at 16:08

18 Answers 18

26
$\begingroup$

In terms of what was known before, say, the 18th century, there were very limited sources of what we'd normally consider rather dim light, but fire wasn't the absolutely only light source (not counting the sun, moon -- as it was thought to give its own light in pre-Renaissance times -- and stars).

Glowing insects were the commonest, and brightest. Fireflies can be nearly bright enough to (briefly) read by, if you can get even two or three of them near your page (their tendency to blink in synchronus is both helpful, because they're brighter, and unhelpful, because it'll be bright then completely dark). Firefly larvae are "glow worms" -- and I'm not certain whether they glow steadily or flash like fireflies.

Other sources of phosphorescence, like certain fungi (foxfire), are very faint -- easily bright enough to see in a dark forest, but not really bright enough to see by.

I can't say whether it was known in pre-scientific times or not, but the mineral sphalerite (zinc sulfide) is moderately common in some regions. It's the material that's incorporated into "glow in the dark" paints and plastics -- it will absorb light energy and then release it over time, though it can't be "kept" and only lasts minutes to an hour or so unless there's a source of either UV radiation or something else (this was used in radium clock dial paint, excited by the radiation from the actual radium).

Pure phosphorus was made by alchemists well before the 18th century, and glows from slow oxidation even when stored in water -- but I'm not sure this wouldn't be a form of the lost fire.

Another possibility is electric light. There is (slight, controversial) evidence that electricity had been created during the Bronze Age -- the Baghdad Battery was a wine jar that contained a rolled core consisting of dissimilar metals separated by fabric; it would have functioned as a simple electric cell if filled with wine or vinegar. Speculation is that it was used for electroplating, to allow dishonest jewelers to pass off cheap base metal goods as solid precious metal. However, there are various ways this low voltage electricity could be turned into light without requiring the ability to produce tungsten or platinum alloys (to take the heat).

One possibility is electroluminescence; this requires 100 Volts or so (which is a big bunch of battery jars), but could be made from minerals and metals that were available before the 18th century, if someone knew how (or stumbled on the effect -- say, a jeweler plating a ring that already has a tourmaline mounted).

$\endgroup$
  • 2
    $\begingroup$ Re: glow-worms. I've only seen one, and showed it to an entomologist from the local zoo's insect exhibit and he had never seen one before, so I suspect they're difficult to collect. From what I recall, it had a few small glowing patches, nothing like a mature firelfy. $\endgroup$ – Rob Crawford Jul 10 at 19:51
  • 2
    $\begingroup$ There are different varieties of glow worms in different parts of the world. As I recall, New Guinea has some that are especially large and bright. I've seen pictures of a species referred to as a "train worm" because its lights are arranged along both sides. Unless you life in firefly country, however, you aren't likely to find glow worms -- and even if you do, you have to be outdoors, at night, the right time of year (there's a few week period, once a year, I think, when they're active, before they turn into fireflies). $\endgroup$ – Zeiss Ikon Jul 10 at 21:19
  • $\begingroup$ Rather than just blinking, the chemicals in a firefly will glow continuously for quite a while if the fly is crushed. Bug paste in a jar could create a pretty good light source. $\endgroup$ – user4574 Jul 10 at 22:47
  • $\begingroup$ Phosphorescent compounds will glow if heated. I have personally witnessed this one when bonding glow-in-the-dark fabric paint with a hot iron. $\endgroup$ – user4574 Jul 10 at 22:49
14
$\begingroup$

Proper medieval artificial light sources rely only on fire, or on trapped fireflies.

Though it is not exactly a medieval technology, really dedicated alchemists (and a twist in the story) might come with the invention of the glowing sticks.

A glow stick is a self-contained, short-term light-source. It consists of a translucent plastic tube containing isolated substances that, when combined, make light through chemiluminescence, so it does not require an external energy source. The light cannot be turned off and can only be used once. Glow sticks are often used for recreation, but may also be relied upon for light during military, police, fire, or EMS operations. They are also used by military and police to mark ‘clear’ areas.

$\endgroup$
  • 3
    $\begingroup$ glow sticks are not something they are going to be making without modern chemistry. $\endgroup$ – John Jul 9 at 18:13
  • 1
    $\begingroup$ The problem with fireflies is that they don't exist everywhere, and where they do exist, they can be very seasonal. For instance, they were (and perhaps still are) quite common in the late spring to early summer in the northeast, but AFAIK aren't found west of the Rockies. $\endgroup$ – jamesqf Jul 9 at 18:17
  • 2
    $\begingroup$ the "translucent plastic tube" might be a tiny little problem for a medieval world... $\endgroup$ – Tom Jul 10 at 4:41
  • 3
    $\begingroup$ @John Phosphorus was created by alchemists in 1669 - not quite medieval, but still pretty far away in time from "modern chemistry". $\endgroup$ – Headcrab Jul 10 at 5:34
  • 1
    $\begingroup$ Plastic tube is not the problem. Instead of tube use glass container to which you add chemicals from different glass container. Bioluminesce is doable if you have fireflies $\endgroup$ – SZCZERZO KŁY Jul 10 at 9:43
6
$\begingroup$

During daytime, they can use glass bottles with water, plugged in holes in roof as sort of light bulbs for home illumination.

https://www.instructables.com/id/How-to-build-a-SOLAR-BOTTLE-BULB/

Also with systems of mirrors and lenses its possible to illuminate, for example, cellars and mines using light of Sun.

Unfortunately, at night, you have to use candles, and fires.

$\endgroup$
  • $\begingroup$ How about moonlight? With mirrors and lenses you could probably aim moonlight at the glass bottle - probably not as effective, but maybe good enough? $\endgroup$ – Rachey Jul 10 at 13:41
  • $\begingroup$ @rachey even if we assume the system is bright enough, and forget someone would have to keep adjusting all the mirrors all night, you still have the issue of what to do on moonless nights. $\endgroup$ – John Dvorak Jul 10 at 14:21
  • $\begingroup$ @JohnDvorak Of course, I meant it as something like a single candle equivalent, for example as a bedside lamp in a house, for reading a book for example. Moonless night? No extra light for you. $\endgroup$ – Rachey Jul 10 at 14:29
  • 1
    $\begingroup$ One major problem with the system of mirrors to direct the light of the sun is that the sun moves WAY faster than we typically think. Mythbusters did a show about this a while back and they found that it worked, but every mirror in the array had to be recalibrated very frequently (like, every 15 minutes frequently). $\endgroup$ – bvoyelr Jul 10 at 15:01
6
$\begingroup$

Glow in the dark paint.

The brightest glow in the dark paint is supposed to be visible in the dark for 30 hours, which is plenty to get your peasants through the night.

enter image description here

A lamp like this would be clearly visible and would not require fire or electricity. Just charge it up during the day, and the photoluminescence should go all night.

According to Encyclopedia Britannica, glow-in-the-dark was first synthesized in 1603. It technically isn't medieval (5th-15th century), but it's still pretty close.

$\endgroup$
2
$\begingroup$

hammering ironHammered iron.

https://www.youtube.com/watch?v=tXF60MOWUeY Cold iron can be hammered until it is glowing red hot. That is a little bit of light. Also the hammering throws off sparks which also produce some light.

Not sure anyone is going to read a book with light like this but it might be a cool thing for a story - someone whaling on an iron rod until it glows then using it to light the way.

$\endgroup$
  • 3
    $\begingroup$ As cool as this would be, cold forging is a lot of work for very little light $\endgroup$ – Garret Gang Jul 9 at 20:29
  • 1
    $\begingroup$ Yes, this is a lot of work to get a minuscule bit of light. Nevertheless, you can optimize the basic principle: Do work, convert it into heat that's trapped within a very constrained location, and you have a glowing light source. For instance, you could build something like a stationary bicycle that uses the power of your legs to turn a rod of iron, rubbing its tip against the tip of another rod of iron (smooth surfaces, so very little abrasion). That would be a quite workable 200 Watts source of light a heat. $\endgroup$ – cmaster Jul 9 at 21:50
  • 1
    $\begingroup$ Maybe a waterwheel driving a hammer. It would be a loud light. $\endgroup$ – Willk Jul 9 at 22:31
  • 2
    $\begingroup$ But the sparks are fire, aren't they? That is, they are small bits of iron reacting with oxygen, as you would see if you've ever used an oxy acetylene torch for cutting iron & steel: en.wikipedia.org/wiki/Oxy-fuel_welding_and_cutting $\endgroup$ – jamesqf Jul 10 at 5:37
  • 1
    $\begingroup$ @jamesqf - the question of sparks is a good one; seriously. The glowing of the iron is because of the kinetic energy of the hammer being captured as heat; that would work in a vacuum. Are sparks an extreme case of the same thing, or it is the metal burning? Sparks go from nothing to glowing hot in a split second when hit. Steel wool does not burn like that in air. $\endgroup$ – Willk Jul 10 at 12:08
2
$\begingroup$

There are a few natural sources of light, which could be harnessed if you really need to.

Lightning produce light. If lightning storms are something common in your setting, it's not unthinkable that someone (maybe with some help from magic) has learnt to harness such power to use as light source. Not sure realistic, but hey, it's a magical world...

Sparks. Technically fire (?), but not a real flame. Imagine how much sparks come from a wheeled wetstone when sharpening a knife. Now make it smaller and portable, with a smaller blade attached. Takes a bit of effort, but could be a source of dim light.

Bioluminescent animals and plants. From common fireflies, to rare fishes found on in the deepest trenches on the ocean floor, all the way to some kinds of plankton and algae or shrooms. All sources of dim light. Since it's a living being, it's going to requires some taking care of, or constant replacement.

Moonlights is obviously an option. Maybe your world has multiple moons, making full moons a much more common event.

Magic. I know you said u don't want magic sources, but what about "natural" sources that came to be thanks to magic? Maybe some crystal or other mineral (possibly not radioactive or toxic) that sheds some light? Maybe a glowing small animal, something hamster-sized or larger. Or maybe there's simply some glowing liquid (naturally, or by alchemical means). It's magic, doesn't need to have an evolutionary purpose or even sense!

$\endgroup$
  • $\begingroup$ The pressure at the bottom of the Mariana trench is 1000 atm. Good luck trying to keep your pet anglerfish from splattering across the wagon. I think it's still a challenge in modern days if you want something transparent. And that still ignores the issue of feeding. $\endgroup$ – John Dvorak Jul 10 at 14:29
2
$\begingroup$

On medieval tech? It's a very simple answer: no.

Just about every answer above involves tech well beyond the medieval period, or ways of producing light that don't actually produce enough light to be of any use. Sounds like you're reliant on magic, short of handwavium like "Koomatka fruit glow with a bright bluish-green light, and are widely used for lamps."

$\endgroup$
  • $\begingroup$ Using bio-luminescent plants or animals is really only handwavium if you are trying to say that the setting is on Earth, not just like Earth. Since we know plants and animals can glow, it's not a stretch to say otherworldy life could glow brighter, longer or at different times. An "unknown" mineral could serve the same purpose, alone or as a reaction like "xyzite pebbles glow as they dissolve in vinegar." $\endgroup$ – techturtle Jul 10 at 19:19
2
$\begingroup$

You might find a way to modify Archimedes' heat ray for your purposes. Essentially, one or more mirrors would be used to reflect sunlight (or light from another source, I suppose) to illuminate a given location. Further, you could use a series of lenses to magnify or diffuse the light as needed.

$\endgroup$
1
$\begingroup$

One could heat a well-insulated mass of metal by using a solar mirror, and then use the black-body glow of the metal when the sun goes down. You could get yellow light at sunset, fading to a deep, soft red as the metal cooled.

The insulation would be layered, with porous pottery at the innermost layer and something more like horsehair on the outside. Insulation is important to reduce the losses, and help the metal heat faster and cool more slowly.

$\endgroup$
  • $\begingroup$ I'm curious why the down-vote? Mirrors, pottery, and metal (iron) are available in medieval technology. $\endgroup$ – cmm Jul 10 at 13:43
  • $\begingroup$ Attaining such high temperatures from sunlight is not easy. I've been doing minor research, planning, and tinkering with it recently and find it possible but difficult. With a small setup, I don't think I've topped 300F yet. With a very large collection area directed to a small spot, it has been made to work by others. YMMV a lot. +1 $\endgroup$ – Loduwijk Jul 10 at 14:17
  • $\begingroup$ There's a problem with this: while the metal is emitting a little bit of visible light, it's emitting a lot of infrared. It's a bit tough to find "insulation" that passes visible light and reflects infrared. The net result is that the metal cooks anything nearby, and cools off quickly, probably far more quickly than the sky darkens. $\endgroup$ – jeffB Jul 10 at 15:39
  • $\begingroup$ Also, I doubt the glowing of the metal would last past sunset. As the sun starts going down, you loose most of your heating ability and red hot metal doesn't stay hot for that long. I don't see it lasting longer than twilight itself. $\endgroup$ – JPhi1618 Jul 10 at 15:41
1
$\begingroup$

Bioluminescent fungi aka foxfire. It's nowhere near bright enough to be a torchlight, but you may be able to have it cultured brighter. A specific one would the bitter oyster fungus. (Tastes nasty, apparently.)

$\endgroup$
1
$\begingroup$

Magma emits a very beautiful light at night. Might be helpful if you don't mind living near a volcano. You may even scoop some lava from a nearby volcano and hold it in a ceramic or tugsten container, making your very own lava lamp (drumroll).

And while you may not have fire, if you scratch two iron rods really hard you still have sparks. One could crete contraptions which rub iron against iron and give off a little light as well.

Finally, since you are using the tag, you can take a page from Terry Pratchett's Discoworld's light dams:

An architectural and engineering feat in the Great Nef desert, designed and built by Goldeneyes Silverhand Dactylos.

While not described in the text, it would appear from context that these are otherwise conventional dams, strategically located in the Nef desert to trap and channel the sluggish Discworld light, so that it can be exported and/or sold on to other parts of the Disc that need it more than a desert does. The further details of the technology/technomancy involved have so far not been disclosed to us. The Light Dams and their devisor make an appearance in The Colour of Magic.

$\endgroup$
  • 1
    $\begingroup$ I could be wrong, but I think a lump of isolated lava would crust over and stop glowing pretty quickly. $\endgroup$ – JPhi1618 Jul 10 at 15:39
  • 1
    $\begingroup$ @JPhi: I can imagine a guy reading a book, getting up every once a while to give the lump of lava on the tripod a couple of good whacks with the hammer to shatter the crust and "reset" the reading light. It's sort of what people used to do trimming the wick in the candle or oil lamp (completely burning wicks are a surprisingly recent invention). And lava is not fire--there is no combustion going on, just black-body radiation, same as a lightbulb filament, only cooler and thus dimmer and redder. $\endgroup$ – Ralf B Jul 26 at 17:05
1
$\begingroup$

Some ideas for light sources that do not involve lighting something on fire:

  1. Bioluminescence (Fire flies in a jar, jellyfish in a jar)

  2. The moon or sun with a mirror network to redirect light.

  3. Chemical reactions that give off light, for example Zinc Atoms and Nitrous Oxide: When zinc atoms react with nitrous oxide, N2O, the reaction is chemiluminescent.

$\endgroup$
0
$\begingroup$

https://en.wikipedia.org/wiki/Phosphorus was discovered in the 17th century, and by an alchemist trying to produce a philosophers stone so might fit with the time period.

You'd still want to burn it though so depending on your definition of 'fire' it may not count. It burns with a brilliant white light iirc, so would at least look completely different to wood/charcoal fires.

$\endgroup$
  • $\begingroup$ 17th century was way after the middle ages. $\endgroup$ – Renan Jul 10 at 15:14
  • $\begingroup$ yes but one can imagine bringing this earlier in time as I don't think it relies on anything particularly 17C , iirc he basically boiled urine $\endgroup$ – jk. Jul 10 at 15:26
0
$\begingroup$

Radioluminescence

This is not a medieval technology but i can't see a real no-go technological limitation for that era.

Radioluminescent light sources usually consist of a radioactive substance mixed with, or in proximity to, a phosphor.

The only issue is the low light intensity.

$\endgroup$
  • $\begingroup$ Can the downvoter explain why this answer is wrong? $\endgroup$ – theGarz Jul 11 at 6:50
-1
$\begingroup$

Well, it's certainly not historical, but it might be doable with tech that they could have used. A Mercury lamp.

If handed the requirements I can't think of any step that is impossible, though admittedly improbable and no reason for them to invent the tech themselves.

Glass tubing -- Difficult, but at least possible - would be very expensive in comparison to modern manufacturing techniques.

Mercury -- The knew have to produce this.

Electricity - Making batteries does not require advanced chemistry techniques.

You need high voltage. You could put enough batteries in series, but it will take a lot - you need about 250 volts DC to get a mercury lamp started that operates at 120 V.

There are still hard details. E.g., as the mercury heats up and converts to plasma, the resistance of the lamp drops, increasing current and heats in a positive feedback loops that leads to self-destruction. No modern circuitry to rescue you from this problem, but by integrating a variable resistance element in the circuit (hand controlled) until operating temperature is reached you could be OK as the resistance of the batteries in the circuit would provide some negative feedback of the current.

Mercury lights produce a lot of ultraviolet, which are normally filtered out (in one form or another) in lighting applications. You can go blind if you get too much. Can't think of a simple way to block UVA (glass blocks most UVB) using middle age tech off the top of my head.

I should add that producing glass tubes without fire would be rather difficult, but I consider using magic to produce the glass if necessary still qualifies as not using fire to produce light. I am also assuming a low-pressure version of the mercury lamp similar to the original produced in 1860

$\endgroup$
  • $\begingroup$ Glass tubing won't cut it -- it softens at too low a temperature. You need fused quartz, which is not something a medieval glassblower could make. $\endgroup$ – Mark Jul 9 at 19:56
  • $\begingroup$ @mark - not all mercury lamp use a quartz tube to contain the arc. $\endgroup$ – Gary Walker Jul 10 at 11:45
-1
$\begingroup$

There are natural rocks that glow in the dark (after charged from other light).

https://www.forbes.com/sites/trevornace/2018/09/17/michigan-man-discovers-strange-glowing-rocks-in-the-upper-peninsula/#2f1544d723ff

If your world has these rocks readily available, it's possible that fire for light wasn't really a need at all.

$\endgroup$
  • $\begingroup$ Formerly pale, flat, unlit rocks and minerals turn vibrant orange, pink, and green when the overhead lights are turned out and the black-light turned on. Rocks or other pigment that fluoresce in UV light is not the same as "glow in the dark". $\endgroup$ – JPhi1618 Jul 10 at 15:44
  • $\begingroup$ Updating the link - had the wrong rocks I guess, but they do exist. $\endgroup$ – Kyle J V Jul 10 at 15:52
-1
$\begingroup$

With a lot of vinegar (for the batter and pickles), it is theoretically possible to produce enough electricity to make a pickle (or any other material that glows hot from electric resistance, like a non-flammable thread) glow.

https://www.youtube.com/watch?v=aab8VjzuXyM https://www.scienceworld.ca/resources/activities/vinegar-batteries

$\endgroup$
-1
$\begingroup$

As some of the comments have hinted, "fire" is more general than you think. If fire doesn't work any more, it's extremely unlikely that life can work either -- fire is based on (exothermic) oxidation, convection (which is based on gas laws and gravity), and radiant energy. Take away any of those things, and you're left with an environment that bears no resemblance to ours.

If you want to hand-wave something that makes fire impossible, you might as well keep waving and invent some other light source that suits the needs of your story.

$\endgroup$
  • $\begingroup$ Did you intend to post this as a comment? $\endgroup$ – Mark Jul 10 at 19:47
  • $\begingroup$ @Mark No, and I'll edit it to make that clearer. It looks like I'm having some trouble getting the hang of Worldbuilding answers, though. $\endgroup$ – jeffB Jul 10 at 20:24

Not the answer you're looking for? Browse other questions tagged or ask your own question.