...whether they are critters, environments, or just making one's way around in the dark places that PCs have a bad habit of exploring.
So, I will, as I often do, grab a bit of real history and bend it a bit for a little gaming goodness...
Mining. Deep underground, dirty work in the darkness. Personal illumination to safely and effectively work was important (well, effectively, safely came later...)
Trouble is, mines and other similar confined spaces can have a problem of atmosphere - Not enough oxygen, too much oxygen, explosive dusts or gasses, or poisonous atmospheres. These so-called 'damps' (from the German dampf, or vapor) were a constant hazard.
And open flames can exacerbate those problems - especially in the cases of explosive environments or oxygen-enriched environments (where combustion can accelerate or spread rapidly). Since miners often relied on open flames, such as helmet-mounted oil lamps (below), there was an incentive to find a less dangerous alternative, or at least methods to assess an atmosphere before working in an area (the fabled canary could only do so much, after all...).
Enter the 'Safety Lamp' - an oil flame lamp enclosed in a fine screen to allow oxygen (and other mine gasses) into the flame, but to prevent flares and explosions in the surrounding atmosphere. One of the first successful safety lamps was the Davy Lamp, which had a tall wire gauze 'chimney' to act as a flame arrestor, and to redirect and cool hot gasses before they encountered the surrounding atmosphere.
This was one of the first formal methods of industrial/workplace occupational safety monitoring devices, the descendants of which are still in use (although they tend to have more flashing lights, digital readouts, and beeping bits).
Ok, so onto our erstwhile adventurers...
In gameplay, we may assume that most underground areas are potentially occupied, and as such, generally free of bad atmosphere (due to natural ventilation, circulation, etc.). But there are plenty of opportunities for 'bad air' - low-lying areas that allow for accumulated dense gasses, long-closed rooms or tunnels, decomposition, fire, seeping of natural gasses, trap areas, nastiness released from some experiment. Likewise, there may be critters that are just fine in these environments, even as the PCs asphyxiate...
Wow, I've rambled a bunch and haven't even touched on the theme-post...
Ok, first things first. The mundane:
Dwarven Mine-damp Lantern - Developed by dwarven mine-maesters to evaluate and illuminate new mine workings, this small oil lantern in made with finely-worked wire mesh as proof against explosive atmospheres. Each has a number of gradations along the screen (low-medium-high) to compare the flame height to safe breathing and working conditions. While the lantern only illuminates a 15' radius, a pint of oil lasts 16 hours, in addition to its air quality screening abilities. 50 GP
And the magical:
Aughurnund's Indicative Lantern - This otherwise mundane-looking lantern has been enchanted by the sorcerer-alchemist Aughurnund to warn of hazardous atmospheres - a very critical utility during both his explorations into untracked subterranean areas, as well as during his own alchymical experimentation. The lantern burns oil and performs as a normal lantern.
However, if the bearer enters a hazardous atmosphere, the flame will flare in one of three different colors to indicate the hazard:
- Green - poisonous gasses
- Red - flammable gasses, explosive environment, or oxygen-enriched
- Blue - oxygen-deficient or oxygen displacement
The owner of the lantern, while carrying it, will receive a +1 bonus to any saves associated with foul atmospheres or poison gasses. Aughurnund also knew the value of being able to pass through or escape a dangerous atmosphere. Once per day the lamb may be called upon to purify air - creating a 10' radius 'bubble' of safe air, allowing the PCs passage to less hazardous environs. Duration - 2 turns.