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Mr. Mask
2013-10-22, 06:15 AM
There was a thread rather like this about a year back, used for fielding questions that didn't suit the Got a Real Weapons or Armour Question? thread. I'll restart it.


NOTE: Be careful of topics such as real world politics, religion, etc.. IN consideration of the forum's rules.


As a beginning question... how many livers and other organs would a centaur have? Considering they have two torsos, it's left me wondering how their biology would function.

Topus
2013-10-22, 09:20 AM
Interesting question.
I think you can double all the organs, assuming you have to sustain a very complex creature that probably came up from a symbiotic or parasitic process rather than an environmental pushed evolution.
So you have two hearts to adequately pump the blood, four lungs to adequately oxygenate tissues, and yes two livers for doubled metabolic processes.
I will go also for two distinct digestive systems, one omnivorous and one herbivorous. They should have larger nostrils and nose to inhale a bigger quantity of air, and they should have larger mouth to contain teeth for ripping and teeth for grinding.
Maybe they should have a valve that redirects the bolus to two distinct esophagi depending on the source of food. Thus they should two distinct intestines one "omnivorous" and one "herbivorous".
Of course two anuses, one in the usual position horses have it, for herbivorous intestine, and one between the two frontal legs for omnivorous intestine.
I think they should have a single brain, located in the head, usually prolonging in the spine, that goes through the entire human and horse torsos.
Maybe the brain should have a third portion with a bigger corpus callosum connecting the three "trisphere".
Then, how they thermoregulate? Humans are able to sweat, but horses don't.
I think centaur should have a larger number of sweat glands, innervating also the horse body (thus making them more resistant than normal horses).
At last, about genitals, i've thought about a complex system about centaurs having both humans and horse genitals.
To generate a centaur they have to fecundate two different egg cells, with two different sexual intercourses. Then the fecundated egg cells meet in between of the two torsos. If they are both fecundated they merge and grow into a "centaur" uterus bearing a baby centaur. If not the fecundated egg migrate into the human or horse uterus to grow a baby human or a baby horse. So, female centaurs do have three uterus, and they can bear a centaur, a horse, or a baby, or any combination of the three at the same time.
This could lead to an interesting development in centaurs societies.

hymer
2013-10-22, 09:24 AM
The thread (http://www.giantitp.com/forums/showthread.php?t=296276) you remember isn't gone. At the time of writing this, it's on the first page. :smallsmile:

GraaEminense
2013-10-22, 09:35 AM
Obligatory "does that count as real-world...?" post.

Not a proper biologist, but...

Form follows function. Based on appearances, it seems likely that the centaur has dual organs to some degree. To what degree, hard to say: I would expect most of the digestive system to be in the horse part (since the human part can´t fit a large enough stomach for both) since neither horse nor human have multiple stomachs. Actually there´d be room to spare, since the centaur would need a pretty human-like diet (no horse-teeth) and so wouldn´t need the full horse-scale system to utilize grass and the like.

Lungs would probably be dual, since the human bit is too small for the necessary horse-lungs while the huge human brain wants ready and short-distance air supply.

I´d expect dual hearts, one main horse-heart for the heavy work and a secondary human one to, again, keep the brain and the rest of the human bits well circulated.

Also, there really needs to be a reason for the human torso to look human, and protecting lungs and heart is what it does.

The rest of the bits, like liver and kidney, I really can´t think of a reason for multiplying. Just increase the horsey ones a bit and it should be good.

Interesting side note: Horses can´t vomit. With a horsey digestive system, neither can the centaur (and the stomach is oh so far away from the mouth, too). Would make alchohol poisoning a real cause for concern, so perhaps dual livers after all.

hymer
2013-10-22, 09:51 AM
Vomiting can be facilitated by having things pass through both stomachs. Grass and such needs to go on for digestion (an organ like a gizzard would be useful to chew cud without actaully needing to send it all the way to the mouth), and things that need to go back up gets checked out in the humanoid stomach before going too far.

TheStranger
2013-10-22, 10:26 AM
Two of most things sounds reasonable, but I'm not 100% sure how lungs would work. Basically, human lungs aren't nearly large enough for a horse-sized body. But running an airway all the way to horse lungs in the lower body seems problematic as well. I'm not sure how the muscular action to make that happen would work (humans and horses have very different breathing mechanics while running). And then you've got to ask how the airway would pass all the way through the human torso, and whether it would be large enough to pass enough air for the horse lungs. You'd need a very large mouth and neck to make that work, I think.

It might actually be less problematic to treat the entire human torso like an oddly-shaped neck for the horse body. Nothing in there but bone and muscle; all the biology happens further down. Getting oxygenated blood the extra distance to the brain could be tricky, but seems to work for giraffes (for instance). A human brain admittedly needs more oxygen, but I think it's plausible anyway. If necessary, handwave with a very robust heart and/or extra red blood cells.

So you'd end up with broad faces and thick necks to allow enough airflow (and food intake), but relatively slender upper bodies (you can compensate with more muscle if you want to offset that).

Doomchicken
2013-10-22, 10:58 AM
May I suggest having the organs be in the lower third of the human's body and the front third of the horse's body? That seems like a logical midpoint to me.

Garimeth
2013-10-22, 05:50 PM
Posted this in another thread similar to this but it was ignored...


Economics questions regarding commodity production and population support. Semi homebrewing a 13th Age game I am trying to balance the following community's populations in order to support them all and all of the agricultural needs. Society has paved roads in between major cities, a good weather almanac to predict sailing and occupies an area of 103k square miles. I tried balancing this off of the 3e DMG figures, but this seems way off to me, any help is appreciated.


Axis: the metropolis seat of the Empire, near the sea and with a waterway leading to the city.
Population 275,000

Glitterhaegen: mercantile capitol, entry point for dwarven goods entering the empire, located on the central sea, major trade hub.
Population: 75,000

Tramore: A holding located on the highway in-between Axis and Glitterhaegen, Tramore is only noteworthy because its farms are able to support the number of travelers who use it as a waypoint – causing it to become the unofficial pit-stop between the two cities.
House Martens: The Governor’s Son Kenneth Martens, 34, manages his estates here.
Population: 1,800 in Tramore, with another 5,800 in the surrounding agricultural area.
Major Exports: Commerce.

Greenhill: The produce grown here supports all of Glitterheagen. The land is unusually productive, and McDurglebadger has special enchanted greenhouses that allow him to grow year-round all manner of exotic spices and fruits found nowhere else in the empire.
House McDurglebadger: Managed by his Steward Master Bildgman.
Populations: 4,200 in Greenhill itself, 35,600 in the surrounding farming villages.
Major Exports: Agriculture

Delos: Delos is the only major holding in the Bitterwood, unless you count Shadow Port. Delos is mostly supported by the lumber trade and there are three very productive mills. The other portion of income is derived from animal hides and meats.
Lord Quentaine: Managed by his steward Master Quinn, a halfling. Delos is not a profitable holding.
Population: 1,200
Major Exports: Lumber, Leather

Kashel: The primary source of revenue here is metal from the mines in the Giantwalk. Most of the workers here work the mines, but there are a few small farms as well. The two famous taverns here have something of a feud going between which establishment brews the better beer.
House Gratina: The affairs are managed by Lady Marta.
Population: 4,700 in Kashel itself, and another 6,200 throughout the province.
Major Exports: Iron, steel, tin, copper, and gold.

Ruskil: Located on the plains in between the northern Bitterwood and Calamity, Ruskil is the seat of House Rahon. Famed for having the best horses, and riders, in the empire many of its citizens have served in the Legion’s cavalry. Ruskil is a pastoral community consisting mostly of shepherds, cattle farms, horse breeders, and fishermen.
House Rahon:
Population:2,100 in Ruskil itself, with another 12,400 spread out around the countryside.
Major Exports: Horses, Lumber, wool, leather, cheese, and beef

Ballina: (on a peninsula just south of the empire's capitol)
House Alrian
Population: 5,000 in Ballina and another 27,000 in the surrounding areas.
Major Exports: Agriculture, sailing vessels,


I adjusted these figures from the OP based off of some info I found on France from around the time of the rennaissance and figure magic makes up for the lack of ren tech and science. Thoughts? I doubt my players will care, but I care.

Mr. Mask
2013-10-22, 11:45 PM
Garimeth: I estimate it being about as accurate as you can get, without help from an economics specialist.


Centaur: A lot of good ideas and points here.

Stranger's point about lungs makes me wonder if the main set of lungs would be within the horse, but a second set, smaller than a man's lungs would exist within the human torso, mainly to supply quick oxygen to the brain, and to serve as a back up if the horse lungs' efficiency drops. Of course, as pointed out with Giraffes, this isn't necessary.

We have to decide when recreating the mythological centaur with real biology, is how closely we want to adopt the legends and appearance of the original. Not having a human set of organs within the human torso, for example, could create a very uncanny-valley appearance. That would make them unique among cartoon centaurs.

Topus' idea of adopting the Cretan style of centaur already would separate them from the norm.


One thing to consider from the idea of dual organs, is what happens if one set of organs lose much of their efficiency or stop? If the horse lungs can't breathe, I don't feel the human set would be enough for running? If the human set stopped, the horse set could likely keep the body going at reasonable efficiency, but though it might be highly uncomfortable for the brain?

Having the mass of a horse as well as dual organs, could lead to the centaur being an extremely tough combatant.

Brother Oni
2013-10-23, 06:59 AM
A couple of points regarding centaur biology:

The only way I can see the spine functioning, is if the horse's spine plugs into the human's pelvis. This requires some creative jointing with regard to the horse's front legs to a humanoid pelvis, but that's a minor concern in comparison.

Another comment is that I believe most greek depictions of centaurs had them as extremely fond of meat (particularly human flesh) to the point that I wouldn't be surprised if they were obligate carnivores.
A high protein and fat diet gives the centaur more energy to function (a neccessity considering its mass), thus negating any requirement to have a herbivorous digestive tract (which is so long since grass has a low energy density), including additional modification for teeth (lots of constantly self replacing flat grinding molars) and sheer time most herbivores spend processing plant material (chewing the cud).

The teeth of omnivores are generally unsuited for chewing grass as a primary food source, since there's no need for canines, plus all that silica puts a lot of wear and tear on the molars.

The extended GI tract permits a centaur to extract more energy from their meat rich high energy diet, thus giving them an advantage over other obligate carnivores. This also has the side effect of only needing one anus.

About the only modification I'd make is to the centaur's teeth - increased number of canines and less molars for all the meat eating. I don't think Topus' suggestions are wrong, just a different way of looking at it.
I see no reason why the two types of centaur couldn't 'exist' and it'd certainly be a surprise (not to mention interesting, exotic and more than a bit squicky) for players.


With regard to thermoregulation, horses sweat just fine. They just don't have same capability of thermoregulation as humans due to their higher mass resulting in a smaller volume:surface area ratio, thus reduced endurance comparatively speaking.

Topus
2013-10-23, 11:16 AM
With regard to thermoregulation, horses sweat just fine. They just don't have same capability of thermoregulation as humans due to their higher mass resulting in a smaller volume:surface area ratio, thus reduced endurance comparatively speaking.
Thank you for your clarification, i was convinced they don't sweat at all, maybe that kind of scientific urban legend any non expert relies on :)
Oh and by the way, it seems some serious research (http://www.improbable.com/airchives/paperair/volume12/v12i5/centaur-12-5.pdf) (worth the ig-nobel attention) has been done about centaurs physiology :P

Mr. Mask
2013-10-23, 12:55 PM
Carnivorous centaurs was strange to me, considering they're part horse. Although, considering your point about how useful it would be... I guess it's better to go with the original lore (are there any carnivorous hoofed creatures?).


Topus: Hey, it's short too. Thanks Topus!

Brother Oni
2013-10-23, 01:18 PM
Thank you for your clarification, i was convinced they don't sweat at all, maybe that kind of scientific urban legend any non expert relies on :)

Horse sweat is very well documented, although due to a protein excreted by the horse, it's not the same salty liquid we associated with humans: Horse sweat and latherin (http://www.horsetalk.co.nz/health/horsesweat-161.shtml#axzz2iZQrY6FW).
http://i.istockimg.com/file_thumbview_approve/15155927/2/stock-photo-15155927-horse-sweat.jpg


Carnivorous centaurs was strange to me, considering they're part horse. Although, considering your point about how useful it would be... I guess it's better to go with the original lore (are there any carnivorous hoofed creatures?).

There are modern hoofed omnivores (boar and pigs), who will more than happily kill and hunt prey animals or other sources of meat.

There are a number of extinct species which were hoofed and may be potentially omnivorous or carnivorous.

In legend, some depictions of the cleaning of the Augean stables (Heracles' fifth labour), the horses within were carnivorous.

hamishspence
2013-10-23, 01:19 PM
There are modern hoofed omnivores (boar and pigs), who will more than happily kill and hunt prey animals or other sources of meat.

It also crops up in some species of deer.

SimonMoon6
2013-10-23, 01:48 PM
Once, in a game where everybody (or almost everybody) was playing monsters from Savage Species, one of my fellow players was playing a centaur. The DM promptly told him that "horses can't control when they [excrete solid waste]", so this PC was going to have the same problem.

Is this a true statement? Would it apply to a centaur? Or was this DM full of "solid waste"?

(This certainly made me not want to play a centaur in this any of this DM's games. Fortunately, I was playing an air elemental.)

Topus
2013-10-23, 03:12 PM
Horse sweat is very well documented, although due to a protein excreted by the horse, it's not the same salty liquid we associated with humans: Horse sweat and latherin (http://www.horsetalk.co.nz/health/horsesweat-161.shtml#axzz2iZQrY6FW).
http://i.istockimg.com/file_thumbview_approve/15155927/2/stock-photo-15155927-horse-sweat.jpg
Oh, now i understand why they say that horses make a foam when they are pushed to the limit:smalleek:



In legend, some depictions of the cleaning of the Augean stables (Heracles' fifth labour), the horses within were carnivorous.
It was one of Heracles labours but it was the eighth, Diomedes' Mares.


The DM promptly told him that "horses can't control when they [excrete solid waste]", so this PC was going to have the same problem. They don't care when and where to defecate, but i don't think they have no control on the sphincter.

Brother Oni
2013-10-23, 06:16 PM
It was one of Heracles labours but it was the eighth, Diomedes' Mares.


Ooops, my bad. I knew it was one of his. :smallredface:


Once, in a game where everybody (or almost everybody) was playing monsters from Savage Species, one of my fellow players was playing a centaur. The DM promptly told him that "horses can't control when they [excrete solid waste]", so this PC was going to have the same problem.

A horse doesn't learn as it's not as intelligent as a human and hence doesn't see the need to control where its waste is released.

Humans aren't born with innate control of their sphincter - that's something taught during early childhood. I see no reason why an intelligent (and comparatively civilised) centaur couldn't learn to do the same (whether a nomadic centaur born on the open plains would have a reason to, is a separate and valid question).

If a DM tried that on me without a valid reason, then I'd argue that humans are equally non-toilet trained and hence crap themselves whenever they have an involuntary bowel movement.

Randel
2013-10-24, 04:40 AM
Regarding centaurs, I'm pretty sure centaurs would have unusually long arms if the want to be able to pick stuff up off the ground or to reach the other parts of their body. I'm pretty sure it would be impossible for the human part to dress the horse part in armor properly without outside assistance otherwise.


What if the centaurs arms are more like elephant trunks with the ability to stretch and bend in such a ways that they can reach the rest of their body?

Mr. Mask
2013-10-24, 04:48 AM
What if the centaurs arms are more like elephant trunks with the ability to stretch and bend in such a ways that they can reach the rest of their body? What does TV tropes call that again? Nightmare Fuel?

Fair point regardless. I wonder if you could allow them to turn their human torso almost 180 degrees, so that they could more easily attend to their horsish half.

Considering most animals can't attend to themselves the ways humans can, it doesn't appear strictly necessary.

CombatOwl
2013-10-24, 06:03 AM
There was a thread rather like this about a year back, used for fielding questions that didn't suit the Got a Real Weapons or Armour Question? thread. I'll restart it.


NOTE: Be careful of topics such as real world politics, religion, etc.. IN consideration of the forum's rules.


As a beginning question... how many livers and other organs would a centaur have? Considering they have two torsos, it's left me wondering how their biology would function.

90% sure the answer is magic.

Brother Oni
2013-10-24, 06:48 AM
Fair point regardless. I wonder if you could allow them to turn their human torso almost 180 degrees, so that they could more easily attend to their horsish half.

Given a human pelvis, it's perfectly possible. I'm not seeing how the IG Nobel version can even hold itself upright (unless it can dislocate its spine, the human part is always going to be held at a forward angle).



Considering most animals can't attend to themselves the ways humans can, it doesn't appear strictly necessary.

I agree on this, although it could be an incentive for centaurs to form social groups, so they can groom or otherwise help each other.

With regard to armour, anything more complicated than a mail shirt typically required assistance to put on (knights are often armoured by their squires), so I see no issue with them helping each other put barding on their horse parts.

Likewise picking stuff off the ground isn't much of an issue - horses can kneel or otherwise lie/rest on the ground.


90% sure the answer is magic.

There's a thread in Friendly banter which was trying to find the source of a quote regarding the suspension of disbelief and one that sticks out is "you can ask an audience to believe the impossible, but not the improbable".

The impossible part is the existance of centaurs in the first place (magic!). The improbable part is how such a creature would live and function (verisimilitude).

Mr. Mask
2013-10-24, 08:22 AM
Oni: You're voicing my thoughts. Admittedly on the point of family units, it's a bit of a problem if you want to have Centaurs who live solitarily--but then, it's not such a problem that you'd be denied such stories (they might be forced to look for help, and be in risk of dying from injuries they couldn't attend to themselves).


I wonder about how armoured centaur warriors would be. Unlike horses who have no say in how much barding they have if any, Centaurs will be pretty concerned about their large target of a body. They'd armour themselves as much as they could afford to, with thought to not over-encumber themselves. Leaves questions of how well you can armour a horse if you were trying your best.

erikun
2013-10-24, 04:54 PM
I've always been curious about merfolk, specifically how to streamline them for swimming purposes. Legs haven't been so much of a concern, as they can easily be set up to behave like tails, but it does bring up the question of how awkwardly their feet/legs would end up due to fins.

One thing that I've never quite settled in my mind are the arms, though. Would fins on the arms point towards the hands, and held at their sides while swimming? Fins point back towards the shoulder doesn't seem to make sense, as you wouldn't hold your arms forward all the time I'd think. Would they have webbing or a membrane between arms and chest, like a humanoid bat? Would that even be useful underwater?

Darklord Bright
2013-10-24, 06:46 PM
I'm not entirely sure if this is the right place to ask a question about Geography, but I'm not sure there really is another around here, and the question doesn't warrant its own thread.

So a setting I've been developing takes place primarily within an area of one of my maps which appears, from my modern knowledge, to be a large caldera not unlike Yellowstone. It's got the ring of mountains, and an indent in the middle that's fairly wide and largely flat at the centre, with warm pools and such.

The problem is, I'm not sure what to call it. 'Caldera' seems inappropriate, because the people living there don't really have the knowledge or the word to identify it as such. 'Valley' just feels like an incorrect term given the general size of the place, and 'Crater' doesn't really sound like what you'd call a geographical area people have lived in for generations.

Anyone able to help with this?

Brother Oni
2013-10-24, 07:23 PM
Leaves questions of how well you can armour a horse if you were trying your best.

Very heavily:

http://upload.wikimedia.org/wikipedia/commons/4/48/Dresden-Zwinger-Armoury-Armor.02.JPG

Note that a centaur doesn't have to carry an armoured man on the middle of its back, plus with four legs, it can support a heavier load, so this would be fairly plausible in my opinion:

http://www.john-howe.com/portfolio/gallery/data/media/36/CentaurArmour.jpg

http://www.john-howe.com/portfolio/gallery/data/media/36/Armour.jpg


Note that we're wandering into the realms of the weapons and armour thread now. :smalltongue:



One thing that I've never quite settled in my mind are the arms, though. Would fins on the arms point towards the hands, and held at their sides while swimming? Fins point back towards the shoulder doesn't seem to make sense, as you wouldn't hold your arms forward all the time I'd think. Would they have webbing or a membrane between arms and chest, like a humanoid bat? Would that even be useful underwater?

You may be interested in looking up monofins, which essentially make people swim like how I would imagine a merfolk would: link (http://www.youtube.com/watch?v=JCtbpm5asg0).

Some research indicates that the arms would indeed be held forward to improve streamlining, since the human head and shoulders aren't particularly good at slipping through the water.

This would suggest that a membrane between the arms and chest like a bat wouldn't be particularly useful, since it would need to be taut to provide its effect, which would only be possible in the arms extended position. In all other situations, I would think it would contribute significant drag, or at least I haven't seen any monofin wearers using a suit with fins under the arms.



The problem is, I'm not sure what to call it. 'Caldera' seems inappropriate, because the people living there don't really have the knowledge or the word to identify it as such. 'Valley' just feels like an incorrect term given the general size of the place, and 'Crater' doesn't really sound like what you'd call a geographical area people have lived in for generations.

If caldera is a too specific and technical term, then I don't think any other technical geological term would be suitable or known to the people.

Why not 'Hot Water Valley' or an actual place name? I believe the Romans didn't have a specific word for volcano until after the Mount Vesuvius eruption - they just called them fire bearing mountains.

TheStranger
2013-10-24, 08:00 PM
You may be interested in looking up monofins, which essentially make people swim like how I would imagine a merfolk would: link (http://www.youtube.com/watch?v=JCtbpm5asg0).

Some research indicates that the arms would indeed be held forward to improve streamlining, since the human head and shoulders aren't particularly good at slipping through the water.

This would suggest that a membrane between the arms and chest like a bat wouldn't be particularly useful, since it would need to be taut to provide its effect, which would only be possible in the arms extended position. In all other situations, I would think it would contribute significant drag, or at least I haven't seen any monofin wearers using a suit with fins under the arms.
That video looks just about right to me. I think hands forward is the most streamlined position to swim with a human torso, and I don't think an underarm membrane would add anything. Not that merfolk wouldn't sometimes swim in other postures, but that would be for reasons other than efficiency. You could maybe add some partially webbed fingers, but other than that I can't see any way to modify the human upper body for better swimming while keeping the merfolk aesthetic. And the more I think about it, the less convinced I am that webbed fingers would actually be helpful.

Darklord Bright
2013-10-24, 08:09 PM
If caldera is a too specific and technical term, then I don't think any other technical geological term would be suitable or known to the people.

Why not 'Hot Water Valley' or an actual place name? I believe the Romans didn't have a specific word for volcano until after the Mount Vesuvius eruption - they just called them fire bearing mountains.

This is a point, though it's mostly so I have something to refer to it as in the text. I don't want to call it a caldera, so I might just continue to refer to it as a valley, since otherwise I'd have to call it by its name every time I referenced it.

fusilier
2013-10-24, 08:53 PM
This is a point, though it's mostly so I have something to refer to it as in the text. I don't want to call it a caldera, so I might just continue to refer to it as a valley, since otherwise I'd have to call it by its name every time I referenced it.

"Caldera" means something like "cauldron" -- it's a reference to the shape, so you could call it a cauldron, or a bowl (bowl's are usually smaller), etc.

AMFV
2013-10-24, 09:00 PM
I'm not entirely sure if this is the right place to ask a question about Geography, but I'm not sure there really is another around here, and the question doesn't warrant its own thread.

So a setting I've been developing takes place primarily within an area of one of my maps which appears, from my modern knowledge, to be a large caldera not unlike Yellowstone. It's got the ring of mountains, and an indent in the middle that's fairly wide and largely flat at the centre, with warm pools and such.

The problem is, I'm not sure what to call it. 'Caldera' seems inappropriate, because the people living there don't really have the knowledge or the word to identify it as such. 'Valley' just feels like an incorrect term given the general size of the place, and 'Crater' doesn't really sound like what you'd call a geographical area people have lived in for generations.

Anyone able to help with this?

Well Calderas are pretty difficult to identify as anything once they've erupted. They usually don't have have much that would identify them. Frequently they'll have domes that will grow later, which happened at Campi Felegrei. Mostly what they would call it would probably depend on if they saw the mountain before the dome collapse occurred, if there was a dome collapse.

You could call it something based on the type of rocks present and their weathering (Yellowstone, Blackrock (World of Warcraft, I know but still same concept), the color could range from grays (composite, andesitic type composition) to dark colors (glassy rhyolitic eruptions, which are pretty rare on Earth).

What about something like "The Devil's Valley" a lot of hot spot regions have names associated with hell or dragons because of the smoke and mist that a geologically active region can produce. "The Valley of 10,000 Smokes" is another example of an appropriately named area, although not a caldera, but the result of an eruption.

Also how active is the region and how violent are eruptions, as I'm sure that would have a lot of impact on the name, if it's a major Caldera like Yellowstone it may erupt rarely, if it's part of a bigger system like Campi Felegrei, you may see other volcanism in the area, which you don't see as much around yellowstone, a lot depends on the nature and depth of the magma chamber.

What type of environment were you imagining, because that way I can give you some more information about what sort of volcanism might be involved. Is it part of a range? Do you want it to be on a subduction zone, or to be hot spot volcanism? If it's like Yellowstone you're probably wanting hotspot Volcanism.

You can add some Volcanic necks and cinder cones and such to the landscape too, instead of necessarily naming the big region, I'd add that sort of extra detail, maybe a few smaller mountains, resulting from the magma chamber moving, that way you have more interesting things to name. Also since it's a complex system you can have some variation in the magma types and eruptive events. Add in some flood basalts maybe, especially on a large scale, so that the players will be aware of the size of the volcanic activity.

Well I could go on, let me know if you want to know anything else about volcanism or hotspots or whatever, since that's kind of my thing.

Jay R
2013-10-24, 09:02 PM
As a beginning question... how many livers and other organs would a centaur have? Considering they have two torsos, it's left me wondering how their biology would function.

From C.S. Lewis's The Silver Chair:

A Centaur has a man-stomach and a horse-stomach. And of course both want breakfast. So first of all he has porridge and pavenders and kidneys and bacon and omelette and cold ham and toast and marmalade and coffee and beer. And after that he tends to the horse part of himself by grazing for an hour or so and finishing up with a hot mash, some oats, and a bag of sugar. That's why it's such a serious thing to ask a Centaur to stay for the weekend. A very serious thing indeed.

Doesn't anybody do research any more?

Mr. Mask
2013-10-25, 12:41 AM
Oni: Bodies can be armoured quite thickly, but I don't know of any cases of armoured horse legs. If your horse gets crippled, that's too bad. If you're part of the horse... crippled legs are very bad.


R: Always a pleasure when someone quotes C.S. Lewis' works.

Zavoniki
2013-10-25, 01:13 AM
So I have two related questions, one about Greek History and one about Steam Engines.

I heard about this Greek Scientist who apparently invented the Steam Engine early. He apparently though it was only a cool toy and the technology was forgotten. However this got me thinking about what would happen if you introduced Steam Engines into Greece as an idea for a roleplaying campaign. Unfortunately I don't know enough about Greek history to know when I would set this to make an interesting campaign.

I'm also not entirely sure how the Greeks would use a Steam Engine assuming they had one. My first thought was trains but I'm not sure the Greeks had the other technology necessary for trains/would need them anyways. The second thought was ships, but again I'm not sure what that would entail.

Lorsa
2013-10-25, 03:43 AM
So I have two related questions, one about Greek History and one about Steam Engines.

I heard about this Greek Scientist who apparently invented the Steam Engine early. He apparently though it was only a cool toy and the technology was forgotten. However this got me thinking about what would happen if you introduced Steam Engines into Greece as an idea for a roleplaying campaign. Unfortunately I don't know enough about Greek history to know when I would set this to make an interesting campaign.

I'm also not entirely sure how the Greeks would use a Steam Engine assuming they had one. My first thought was trains but I'm not sure the Greeks had the other technology necessary for trains/would need them anyways. The second thought was ships, but again I'm not sure what that would entail.

The problem with steam engines isn't that it is very hard to figure out how they work in theory, which may have been possible in ancient Greece, it's how to build them. In order for a steam engine to be efficient you need pretty good engineering, which is something that they didn't have. So if you DO introduce steam engines in ancient Greece, what you need to remember is that the engineering knowledge required will basically mean a lot of other things are also possible and basically you would start the industrial revolution 2000 years earlier.

But yeah, if you can build an efficient steam engine, you can build a train, and a boat and a factory and...

The problem with technology is that it's often connected.

erikun
2013-10-25, 04:17 AM
Also, note that steam power would need to do something in order to become useful enough to really warrant production. You aren't going to see an empire devote resources to creating steam-powered grain mills, because any waterwheel on a river can do much the same thing. Greek steam-trains would require the manufacture of enough metal to create rails, and so on.

The result would definitely change how Greece looked back then.


You may be interested in looking up monofins, which essentially make people swim like how I would imagine a merfolk would: link (http://www.youtube.com/watch?v=JCtbpm5asg0).

Some research indicates that the arms would indeed be held forward to improve streamlining, since the human head and shoulders aren't particularly good at slipping through the water.

This would suggest that a membrane between the arms and chest like a bat wouldn't be particularly useful, since it would need to be taut to provide its effect, which would only be possible in the arms extended position. In all other situations, I would think it would contribute significant drag, or at least I haven't seen any monofin wearers using a suit with fins under the arms.
Thank you very much for this! It certanly looks interesting. I think I'll look around a bit more at it, as well.

TuggyNE
2013-10-25, 04:19 AM
The problem with steam engines isn't that it is very hard to figure out how they work in theory, which may have been possible in ancient Greece, it's how to build them. In order for a steam engine to be efficient you need pretty good engineering, which is something that they didn't have. So if you DO introduce steam engines in ancient Greece, what you need to remember is that the engineering knowledge required will basically mean a lot of other things are also possible and basically you would start the industrial revolution 2000 years earlier.

To be fair, steam engines were pretty horribly inefficient even when they were introduced — something around 2% or so, I think.

BWR
2013-10-25, 05:29 AM
On the subject of centaurs, one can always adopt Philipo José Farmer's version from his World of Tiers series.


They were indeed centaurs, although not quite as the painters of Earth had depicted. This was not surprising. The Lord, when forming them in his biolabs, had had to make certain concessions to reality. The main adjustment had been regulated by the need for oxygen. The large animal part of a centaur had to breathe, a fact ignored by the conventional Terrestrial representations. Air had to be supplied not only to the upper and human torso but to the lower and theriomorphic body. The relatively small lungs of the upper part could not handle the air requirements.

Moreover, the belly of the human trunk would have stopped all supply of nourishment to the large body beneath it. Or, if the small belly was attached to the greater equin digestive organs to transmit food, diet was still a problem. Human teeth would quickly wear out under the abrasion of grass.

Thus the hybrid beings coming so swiftly and threateningly towardthe men did not quite match the mythical creatures that had served as their models. The mouths and necks were proportionaltelylarge to allow intake of enough oxygen. In place of the human lungs was a bellows-like organ which drovethe air through a throat-like opening and thence into the great lungs of the hippoid body- These lungs were larger than a horse's for the vertical part increased the oxygen demands. Space for the bigger lungs was made by the removeal of the larger herbivore digestive organs and substitution of a smaller carnivore stomach. [...]

The equine part was about the size of an Indian pony of Earth. [...]The horse-hair covered all but the face. This was almost twice as large as a normal-sized man's and was broad, high-cheekboned and bignosed.

(As an aside, the books are well worth reading)

snowblizz
2013-10-25, 05:59 AM
So I have two related questions, one about Greek History and one about Steam Engines.

I heard about this Greek Scientist who apparently invented the Steam Engine early. He apparently though it was only a cool toy and the technology was forgotten. However this got me thinking about what would happen if you introduced Steam Engines into Greece as an idea for a roleplaying campaign. Unfortunately I don't know enough about Greek history to know when I would set this to make an interesting campaign.

I'm also not entirely sure how the Greeks would use a Steam Engine assuming they had one. My first thought was trains but I'm not sure the Greeks had the other technology necessary for trains/would need them anyways. The second thought was ships, but again I'm not sure what that would entail.
Should be this one I think:
http://en.wikipedia.org/wiki/Aeolipile

You'll note it's quite small. I don't think trains are feasible, most importantly (technical issues aside) in the sense that they'd make no sense to an ancient Greek. Go overland? The tough route? To some place you aren't very welcome to anyway? What city state would pay for tracks to another city state? It's not an accident that trains really kicked off in the US with large expanses of land to travel over, once off the waterways.

A ship, so a steam engine instead of rowers, would make a bit more sense. But then you have this huge honking fire aboard, which was the main argument against early steam ships. What captain would want that.

The other big problem is societal, there's free slave labour so what use for machines? To that we add the issue of imagination. From our perspective the conclusions of one thing are inevitable, but it is not for those whose world-view is much narrower. It's usually the crazy inventor who takes things along not always the original inventor. Took Europeans to take gunpowder and guns/cannons to new heights. Then again we tend to undervalue the knowledge of ancients.
Almost all of steam punk revolves around this selective brilliance/ignorance (they can build and effectively utilize one thing, but totally ignore others).

If we decide to accept that it could be possible to make a somewhat larger and sophisticated version of what it seems they really did, the questions is indeed why. Getting rid of the aforementioned slaves perhaps? A Sparta less reliant on a huge slave labour-force they had to control. A much greater Athenian steam-galley navy. Less rowers, less people, longer voyages due to more seldom needed provision stops.
Most likely though, more automated entertainment devices... which they apparently had.

Brother Oni
2013-10-25, 07:05 AM
Oni: Bodies can be armoured quite thickly, but I don't know of any cases of armoured horse legs. If your horse gets crippled, that's too bad. If you're part of the horse... crippled legs are very bad.

There's records of anti-cavalry 'horse cutting blades' such as the Zhanmado (http://en.wikipedia.org/wiki/Zhanmadao), which is intended to slice through a horse's legs as it gallops past, yet I can find no record of horse leg armour to counter it.

I suspect the reason for horses' legs not being armoured is the same reason why infantry tend to neglect lower leg armour - it saps endurance/performance too much and is a big hassle to wear.

This is also assuming that you don't get impaled on a spear/lance by a 'ride by' skirmishing attack by the centaur, who's going to have considerably more control over his own legs than a cavalryman is of their horse.

Actually that raises an interesting question - could a rider and horse manoeuver and fight better than a centaur when at speed?
A rider has the advantage of the horse being able to watch where they're going while he concentrates on combat. The equal disadvantage is that it's a horse that's concentrating on where they're going.

snowblizz
2013-10-25, 07:28 AM
Actually that raises an interesting question - could a rider and horse manoeuver and fight better than a centaur when at speed?
A rider has the advantage of the horse being able to watch where they're going while he concentrates on combat. The equal disadvantage is that it's a horse that's concentrating on where they're going.

Isn't one of the guiding principles of a trained warhorse that it doesn't have it's own ideas of where to go. It wouldn't run over cliffs or into obstacles I'd think but I don't think a centaur would either.

Where a rider would have an advantage is in reach around the body, since he's centrally located he can more easily engage targets to the side-rear than the "front loaded" centaur.

Actually fighting at speed though is more a question of impaling/swiping at enemies as you pass by so I don't think there'd be large advantages either way. I'd say a small advantage centaur in the galloping at full towards/through enemies impaling/swinging but a large advantage knight in a close in melee where the centaur would seem more disadvantaged by reach issues.

Mr. Mask
2013-10-25, 08:11 AM
Oni: I don't guess it's possible to know what the casualty rates are like comparing horses and their riders?

Did some searching, and found out horse greaves are possible, and there are a couple of known examples of it. I don't know how it effects performance, but we can expect that it works at the usual cost (that being worse, as mobility is a strong-point of cavalry). More common is to have a skirt of mail which pretty well reaches the ground.


Blizz: Moreover, they don't need to fight with their horse to get stuff done (even well-trained, horses are sadly thick).

A centaur having control of his own legs would have an easier time making sure the front of him was to his aggressors (he would naturally be skilled at this just from moving around, picking stuff up, being used to his own body). They might be the cream of cavalry. Being able to move how the like, and to unleash kicks if someone gets too close behind or to the side (at the front, they'll just cut you in two rather than kick).

Really, I wish I knew the casualty rates of horses among cavalry. Centaurs are part of the horse... you can't replace their lower half if that goes down.

Hjolnai
2013-10-25, 08:34 AM
Another consideration for centaurs is that they can't fall off themselves. If they fight lance-to-lance, they're safe from being unhorsed, but they do risk spinal injury instead. If the spine is strong enough, this should be an advantage, but if it's not...

snowblizz
2013-10-25, 08:50 AM
Really, I wish I knew the casualty rates of horses among cavalry. Centaurs are part of the horse... you can't replace their lower half if that goes down.

That's a difficult one as cavalry over the years means a lot of things. What is certain that horses are much much less durable than humans.

Some documentaries of WW1 and WW2, possible Napoleonic times mentioned how how men grumbled, tightened their belts and moved on while horses just gave up and died. So "off the battle filed" horses are worse off it seems to privations, whereas I think diseases were harder on men. A centaur at least would have the psychological benefits of a man, being able to "tough it out".

For battles I'm not sure. Keeping in mind that for a considerable time the horse was valuable enough that you might want to avoid damaging it. Kill the rider and you get a valuable horse! Wouldn't surprise me if cavalry avoided damaging horses in purpose. Because that always to me seems the the answer to any cavalry charge. Shoot the horse.

Here's some numbers I found googling quickly.

By 1917 the British Army were employing over 530,000 horses and 230,000 mules. Large numbers of horses were killed and wounded during the war. Others became lame or sick. The British Army discovered they needed to buy about 15,000 horses a month to maintain the number they needed. It has been calculated that almost half a million horses owned by the British Army were killed during the First World War.


Horses in the Boer War

Note: Based on a comparison of Army pay rates, one pound (£1) sterling in 1900 is equal to approximately $(AU)1,000 in 2011.

Animals were an important part of the logistics for the Boer War, drawn from across the British Empire as well as Europe and the Americas. 360,000 horses out of a total of 519,000, had to be shipped into South Africa. 106,000 mules and donkeys out of a total of 151,000 were also brought into the region for the war.

The number of horses killed in the war was at the time unprecedented in modern warfare. For example, in the Relief of Kimberley, French's cavalry rode 500 horses to their deaths in a single day. The wastage was particularly heavy among British forces for several reasons: overloading of horses with unnecessary equipment and saddlery, failure to rest and acclimatise horses after long sea voyages and, later in the war, poor management by inexperienced mounted troops and distant control by unsympathetic staff. The average life expectancy of a British horse, from the time of its arrival in Port Elizabeth, was around six weeks.

Horses were on occasion slaughtered for their meat. During the Siege of Kimberley and Siege of Ladysmith, horses were consumed as food once the regular sources of meat were depleted. The besieged British forces in Ladysmith also produced chevril, a Bovril-like paste, by boiling down the horse meat to a jelly paste and serving it like beef tea.

The Horse Memorial in Port Elizabeth is a tribute to the 300,000 horses that died during the conflict.

Husbandry was not a strong point during the Boer War, horses endured extreme hardship and died in unprecedented numbers. 60% of the horses died in combat or as the result of mis-treatment as opposed to 3% of human combatants.

3,000 Estimated number of horses killed at the Battle of Gettysburg

Segev
2013-10-25, 01:19 PM
You know, a centaur with a rider would be a "best of both worlds" scenario in some ways, despite a few oddities that might impede functionality. But of most interest, perhaps, is that a rider could utterly trust the centaur to be aware of forward direction. Maybe riders could mount backwards, and thus be a rear-guard, fighting "back-to-back" despite having a definite and easily controlled forward motion.

Insofar as reaching the whole of the body, it was rightly pointed out that horses and other animals have difficulty attending various parts of themselves, too. A centaur's tail would serve just as would a horse's, but being tool-users like men, they likely would develop some aids for grooming and attending themselves. I mean, we have back-scratchers for humans; I imagine centaurs could come up with similar.

Of interesting question is whether they would go naked, go clad, or would wear only "torso clothes." If they share human sensibilities about both humans and horses, they likely would do that last, because females would wish to cover themselves and males likely would want at least some additional covering. THere's also the fact that humans wear clothing for protection from the elements, while horses have horse-hair to help with that to a degree. And without specialized tools, "horse pants" would be hard to don by oneself.

Still, if they have human sensibilities, they might want to cover their nether-regions for modesty's sake. Or maybe not; the arrangement of body parts might just mean they use posture for modesty. Or maybe all centaurs favor skirt-like acoutrements that cover the rump region and are easily draped with a well-practiced toss of the arms and adjusted with careful twitches of the tail.

I tend to favor an "internal organs appropriate to partial body type" sort of view. I don't imagine centaurs graze, however, but simply rather eat large salad portions as appetizers. Their dual stomachs efficiently pass plant matter downwards with minimal digestion, and retain meat and protiens in the humanoid stomach. Their lower stomach may substitute volume for complexity, and might even serve as a sort of "camel's hump" device for storing food over a longer period. They either eat regularly in somewhat large amounts, or they feast infrequently, going for long periods of fasting on their stores. This allows them to traverse the plains without needing to carry much food, as long as their destination has plenty.

I also imagine them to actually have separate kidneys and livers and the like, just to more efficiently distribute the load for the larger overall body.

Their lungs, again, are dual. But here, I imagine they have a dual cycle. Inhale to their first set of lungs, then exhale from that down to the larger ones. Then the larger ones, on a slower cycle, exhale all the way back up. So they take multiple inhalations, then a long exhalation. When in danger of blacking out, they can short circuit it for long gasps of air to oxyginate the blood going to the brain. When doing very long exertion, the pathway to the larger lungs opens wider and their breathing synchronizes (with training) so that trained runners can keep both filling efficiently. It means that there's a lot moer to training a centaur in running, as it's not a natural braething cycle that is the most efficient for endurance running. Like horses, they're more natural at sprinting (wherein, for really hard pushes, they can hold their upper breath for a bit and let the brain subsist on oxygen obtained from the lower lungs).


As for armor, it would impede their running, but protecting their legs could be done with skirts. Heavy cloth or reinforced metal extending forward and back a bit to accommodate the leg motions would do well. Making them kind-of walking tanks.

fusilier
2013-10-25, 02:37 PM
So I have two related questions, one about Greek History and one about Steam Engines.

I heard about this Greek Scientist who apparently invented the Steam Engine early. He apparently though it was only a cool toy and the technology was forgotten. However this got me thinking about what would happen if you introduced Steam Engines into Greece as an idea for a roleplaying campaign. Unfortunately I don't know enough about Greek history to know when I would set this to make an interesting campaign.

I'm also not entirely sure how the Greeks would use a Steam Engine assuming they had one. My first thought was trains but I'm not sure the Greeks had the other technology necessary for trains/would need them anyways. The second thought was ships, but again I'm not sure what that would entail.

I think it's terribly impractical to get useful work out of the ancient greek style of steam engine -- which is basically a kind of steam jet (Aeolipile). It probably would have required a lot of development, and possibly new metallurgical skills, to build to anything approaching a Newcomen engine. I don't think it would have been impossible, but there doesn't seem to have been much impetus in developing such things.

Mr. Mask
2013-10-25, 02:51 PM
Blizz: Horses dying outside battle muddles the issue. Still, that's some nice data. You did an excellent job collecting that.


Segev: When you need them agile, they go in as they are with fantastic coordination. When you want them for heavy fighting or to unload as many arrows as possible, you put riders on them.

I don't know much about riding backwards, so I can't say.

Clothing is more effected by climate than culture (culture will exert its influence over time, hence heatstroke from Victorian dresses in the tropics). How resistant the human parts of a centaur are is the factor, as well as the local temperature. If human-like, they'd definitely wear clothing in colder climates. If they wear partial clothing, they'll also be able to cloth their horse halves should the elements provoke them to do so. Same applies to kentaurides.

Good points all around. Centaurs don't get enough of a spotlight in fiction.

Darklord Bright
2013-10-25, 05:44 PM
Well I could go on, let me know if you want to know anything else about volcanism or hotspots or whatever, since that's kind of my thing.

The name of the actual area is not really something I'll have a problem with, it was deciding what to call it when speaking casually. I've settled on referring to it as "the valley" whenever I don't need to be specific about the name, which is most of the time.

On the topic of volcanism, I'm not entirely sure. I do know that I intend there to be geysers, and there's a few warm pools around. The soil around the large central lake (which I've described as hotter towards the center - whether or not that actually makes sense, I like the fantasy) is also frequently described as red or orange.

Other than that, I've actually fully made up a bunch of flora and fauna, so it's not easy to discern from the kind of trees or plants or animals around. It's based on a caldera, but it's still very much a fantasy setting set on a slightly alien world.

Is there anything you can discern from that? Like I said, most of it is pure fantasy, but it would be cool if there was a believable explanation in there, especially if it helped me add more details to the setting.

AMFV
2013-10-25, 05:52 PM
The name of the actual area is not really something I'll have a problem with, it was deciding what to call it when speaking casually. I've settled on referring to it as "the valley" whenever I don't need to be specific about the name, which is most of the time.

On the topic of volcanism, I'm not entirely sure. I do know that I intend there to be geysers, and there's a few warm pools around. The soil around the large central lake (which I've described as hotter towards the center - whether or not that actually makes sense, I like the fantasy) is also frequently described as red or orange.

Other than that, I've actually fully made up a bunch of flora and fauna, so it's not easy to discern from the kind of trees or plants or animals around. It's based on a caldera, but it's still very much a fantasy setting set on a slightly alien world.

Is there anything you can discern from that? Like I said, most of it is pure fantasy, but it would be cool if there was a believable explanation in there, especially if it helped me add more details to the setting.

Well the lake being hotter towards the center may or may not make a lot of sense, you could definitely have a vent in that area of the lake that would spew out warm gasses, also the gasses could definitely affect the coloration of the lake, but it's probably easier to have some kind of non-photosynthetic algae that live in the lake feeding off the gasses, similar to what you have in deep oceanic vents, which could explain the odd coloration. I wouldn't use some kind of thing in the lake, or it could be something at the base of the lake, and it has very few things living in it.

Red or orange soil is typically mafic and is therefore rich in iron and magnesium, it tends to be slightly less fertile for growing as compared to other igneous rocks. I would make it part of a flood basalt and then have the lakes have formed through other processes, possibly the vent filled in in most of the spots and was exposed by the lake.

Darklord Bright
2013-10-25, 06:14 PM
Red or orange soil is typically mafic and is therefore rich in iron and magnesium, it tends to be slightly less fertile for growing as compared to other igneous rocks. I would make it part of a flood basalt and then have the lakes have formed through other processes, possibly the vent filled in in most of the spots and was exposed by the lake.

I will admit, I don't... fully understand what you're saying here regarding basalt and such, but I think I may still be able to work with it. I'm not certain how much of this would really come up in the setting details, but would this then mean that it would be harder to grow anything nearer to the bank of the lake?

If I'm reading you right, you'd recommend a large warm vent in the centre of the lake, and algae that feeds off the gasses and also gives the lake an odd colouration? Also, the red soil was more immediately around the lake in the original design than everywhere... or is that part of what you're talking about, too?

tomandtish
2013-10-25, 08:34 PM
So I have two related questions, one about Greek History and one about Steam Engines.

I heard about this Greek Scientist who apparently invented the Steam Engine early. He apparently though it was only a cool toy and the technology was forgotten. However this got me thinking about what would happen if you introduced Steam Engines into Greece as an idea for a roleplaying campaign. Unfortunately I don't know enough about Greek history to know when I would set this to make an interesting campaign.

I'm also not entirely sure how the Greeks would use a Steam Engine assuming they had one. My first thought was trains but I'm not sure the Greeks had the other technology necessary for trains/would need them anyways. The second thought was ships, but again I'm not sure what that would entail.

An even bigger problem to be faced isn't generating the steam power. That's actually the easier part. Doing it safely... ahh, there's the rub.

Boiler explosions can be huge. For a long time the general perception of persons working with steam power wasn't "These people are geniuses!". It was "These people are NUTS!".

So depending on how new the technology is, it may be viewed with awe, suspicion, or both. Those who work with it may be "visionaries", "maniacs" or both.

Topus
2013-10-26, 04:17 AM
By the way, the etymology of the word centaur may leads to the meaning of "bulls killer", so they may have some bonus against minotaurs :)

fusilier
2013-10-26, 02:24 PM
An even bigger problem to be faced isn't generating the steam power. That's actually the easier part. Doing it safely... ahh, there's the rub.

Boiler explosions can be huge. For a long time the general perception of persons working with steam power wasn't "These people are geniuses!". It was "These people are NUTS!".

So depending on how new the technology is, it may be viewed with awe, suspicion, or both. Those who work with it may be "visionaries", "maniacs" or both.

A lot of the very early successful steam engines ran at very low pressures (like a Newcomen engine) -- probably for that reason. Denis Papin invented the safety valve in the late 1600s for his early versions of pressure cookers (they apparently exploded, or at least rent apart at the seams). Savery's steam engines (which just relied upon the force of steam alone), also blew themselves to pieces often, but it looks like they didn't so much explode as come apart at the seams.

Once steam locomotives became established, there was a desire to push the technology and there were many boiler explosions -- although sometimes those happen due to firebox collapse and not excessive steam pressure. Modern operating guidelines for steam boilers are usually very thick books, because of the century or two of experience with boilers failing!

erikun
2013-10-26, 07:42 PM
I will admit, I don't... fully understand what you're saying here regarding basalt and such, but I think I may still be able to work with it. I'm not certain how much of this would really come up in the setting details, but would this then mean that it would be harder to grow anything nearer to the bank of the lake?

If I'm reading you right, you'd recommend a large warm vent in the centre of the lake, and algae that feeds off the gasses and also gives the lake an odd colouration? Also, the red soil was more immediately around the lake in the original design than everywhere... or is that part of what you're talking about, too?
As I understand it, he means that soil directly from volcanic activity has a lot of metals (a.k.a. salts) in it. These metals mean that it is difficult for plants to grow in the soil. A much more reasonable explanation would be that a river feeds into the lake in the area, which has brought dirt in that is better for plants to grow in.

Soil that isn't brown tends to be missing a lot of important minerals necessary to grow plants well, and tends to have stuff in it that doesn't allow plants to grow well. This is why stuff like red clay is frequently under a thick layer of dirt. It is also why, when you see places with wildly different colored dirt/rocks, you generally don't see vegetation growing in them.

As for the lake, there could be several reasons for its coloration. Colored algae would do it, although it would make the lake someplace you wouldn't want to swim. Minerals in the water could do it. The water could be so clear you could see color from rocks at the bottom, although that would be worrying about why nothing was alive in it. You could also have your own fantasy reason, such as magical luminous algae/planketon that thrives off the heat in the lake, or fish that produce a spectrum in the water they swim through. Or just that the underwater vent releases magic rather than magma, which has tinted the water and surrounding shoreline. (That could explain why the dirt, and possibly even the trees, are a different color.)

AMFV
2013-10-27, 08:55 PM
I will admit, I don't... fully understand what you're saying here regarding basalt and such, but I think I may still be able to work with it. I'm not certain how much of this would really come up in the setting details, but would this then mean that it would be harder to grow anything nearer to the bank of the lake?

If I'm reading you right, you'd recommend a large warm vent in the centre of the lake, and algae that feeds off the gasses and also gives the lake an odd colouration? Also, the red soil was more immediately around the lake in the original design than everywhere... or is that part of what you're talking about, too?

Well if you have recently erupted material, it probably won't be red-orange or green colored as that's a result of oxidation or reduction. You could have some orange if the material had been up there for a while. You could have the material be some kind of sedimentary fossil remains, which is what I was suggesting, especially if the lake was higher at some point.

Another option is to have the sand be mostly composed of Garnet, which would be extremely unlikely on Earth, given relative proportions of garnet. If you have more garnet though it's certainly possible to do that in a different location.

It could also be some kind of staining, separate from active Volcanism in the region. which could be caused by composition of rainfall or some kind of plant life in the region.

Red Bear
2013-11-06, 07:07 PM
I have a question about flammable substances and explosive substances.
Is a flammable substance automatically an explosive substance?
For example Gasoline is flammable, but car explodes in movie, the same goes for rum (e.g. pirates of the caribbean movie).

So does a barrel of rum really explode if ignited? What about a barrel of lamp oil? If they do, what is the critical quantity to trigger an explosion?

TuggyNE
2013-11-06, 07:17 PM
I have a question about flammable substances and explosive substances.
Is a flammable substance automatically an explosive substance?
For example Gasoline is flammable, but car explodes in movie, the same goes for rum (e.g. pirates of the caribbean movie).

So does a barrel of rum really explode if ignited? What about a barrel of lamp oil? If they do, what is the critical quantity to trigger an explosion?

Not usually. That's mostly Hollywood physics.

Now, if you spread particles or droplets of a flammable substance in the air, you can turn pretty much anything that burns into a thermobaric bomb, but that generally requires considerable effort to properly disperse them. And a barrel of rum will not be dispersed that way, so no quantity will be sufficient to make it explode.

warty goblin
2013-11-06, 07:44 PM
Not usually. That's mostly Hollywood physics.

Now, if you spread particles or droplets of a flammable substance in the air, you can turn pretty much anything that burns into a thermobaric bomb, but that generally requires considerable effort to properly disperse them. And a barrel of rum will not be dispersed that way, so no quantity will be sufficient to make it explode.

Gasoline evaporates at most temperatures you encounter day to day, so with sufficient exposure to air it is highly explosive, no work needed.

I don't think even aerosolized alcohol could be considered explosive though. Back when I worked in food service, a frequent source of amusement involved taking a mouthful of almond extract (90% alcohol) and spewing it at an open flame. It burned quite impressively, but was hardly an explosion. Finer droplets would probably burn more fiercely, but there's only so much a person could do with their mouth, particularly when said mouth went instantly numb upon contact with the extract.

On that note, there's a fantastic little trick you can do to get a little fuel-air burn with materials you have around the house. Take some candle wax, boil it, then add water. Snow works even better. Try to stand clear, and only do this outside. I've lost eyebrows.

TuggyNE
2013-11-06, 08:18 PM
Gasoline evaporates at most temperatures you encounter day to day, so with sufficient exposure to air it is highly explosive, no work needed.

Well, sort of. There's a reason a lot of careful research goes into cylinder and carburetor/fuel injector design, and it's because gasoline works best when it's properly aerosolized; a full gas can will almost never explode, but a (nearly) empty one will much more easily, because it's not merely had enough time to evaporate, but has the right proportions with the air.

warty goblin
2013-11-06, 08:28 PM
Well, sort of. There's a reason a lot of careful research goes into cylinder and carburetor/fuel injector design, and it's because gasoline works best when it's properly aerosolized; a full gas can will almost never explode, but a (nearly) empty one will much more easily, because it's not merely had enough time to evaporate, but has the right proportions with the air.

There's plenty of room between optimal mix, and mixed well enough to blow up the idiot who struck a spark next to the gas. In my ongoing effort to not be an idiot and keep at least a majority of my bodyparts, I tend to treat this as a very wide window.

TuggyNE
2013-11-06, 10:47 PM
There's plenty of room between optimal mix, and mixed well enough to blow up the idiot who struck a spark next to the gas. In my ongoing effort to not be an idiot and keep at least a majority of my bodyparts, I tend to treat this as a very wide window.

Sure, which is why empty gas cans can explode, but it's not automatic either, especially not if all you have is a full container of some fuel.

Jay R
2013-11-06, 11:25 PM
A lot fewer things are explosive than most people think.

For instance, gun powder is not explosive. It just creates a lot of gas, very quickly. To get an explosion, you need to confine it in a gas-tight container. (This is why a firecracker that's broken open only fizzes.)

Most explosions you see on film are gasoline explosions, because they look spectacular. My wife has gotten bored with me complaining about the gasoline explosives where they don't belong, like in the climax of The Mask of Zorro. We were once watching a movie in which a gas station blew up, and she asked, "Well, is it all right if that one was a gasoline explosion?

tomandtish
2013-11-07, 08:07 PM
Most explosions you see on film are gasoline explosions, because they look spectacular. My wife has gotten bored with me complaining about the gasoline explosives where they don't belong, like in the climax of The Mask of Zorro. We were once watching a movie in which a gas station blew up, and she asked, "Well, is it all right if that one was a gasoline explosion?

Actually, if it was the whole station (inckuding the underground tanks) and not just a pump or two, then probably not. Even most gas station explosions in movies are not reali life scenarios. They have 4 automatic shutoffs built into the pump itself*, another in the tank, and of course the attendent can kill power to the unit. It pretty much takes explosives directed at the concrete itself to get at the tanks.

*Fun fact: my maternal grandfather held the patent on one of these until he sold it to Texaco.

Segev
2013-11-08, 12:48 PM
The difference between "flammable" and "explosive" is interesting.

In particular, an explosion is usually a result of a detonation. A detonation is something which expands faster than the sound waves its expansion generates. Most unconfined flammable materials instead deflagrate. Gunpowder, even gasoline, will ignite and burn quickly, but they do so more slowly than the sound wave generated by the expanding air travels.

Detonations - explosions - are potent because the expanding energy-wave compresses the air into a concussive shockwave which causes the famed damage.

The reason confining a deflagration can lead to an explosion is because the expansion is stopped at the edges of the confine, allowing pressure to build. When the pressure gets too high, the confinement bursts and the expansion suddenly happens VERY rapidly, faster than the sound wave, and we have an explosion.

This is why gunpowder works fine for shooting bullets: the pressure-build-up is not a detonation, but it's very rapid and, by the time it reaches the exit point of the barrel, the expansion of the shock wave is faster than the sound, and we get gunshot sounds.

As a final side note, liquid gasoline is not particularly flammable. But, as others have noted, gasoline evaporates at lower-than-room-temperatures. And gasoline fumes ARE highly flammable. This is why, if you see gasoline burning, it looks like the flames are coming from a bit above the surface: they are. The fumes on top are burning, but the gas itself usually isn't.

warty goblin
2013-11-08, 03:27 PM
The difference between "flammable" and "explosive" is interesting.

In particular, an explosion is usually a result of a detonation. A detonation is something which expands faster than the sound waves its expansion generates. Most unconfined flammable materials instead deflagrate. Gunpowder, even gasoline, will ignite and burn quickly, but they do so more slowly than the sound wave generated by the expanding air travels.

Detonations - explosions - are potent because the expanding energy-wave compresses the air into a concussive shockwave which causes the famed damage.

The reason confining a deflagration can lead to an explosion is because the expansion is stopped at the edges of the confine, allowing pressure to build. When the pressure gets too high, the confinement bursts and the expansion suddenly happens VERY rapidly, faster than the sound wave, and we have an explosion.

This is why gunpowder works fine for shooting bullets: the pressure-build-up is not a detonation, but it's very rapid and, by the time it reaches the exit point of the barrel, the expansion of the shock wave is faster than the sound, and we get gunshot sounds.


During my insufferable smartass phase of college (read: college) I found this deeply amusing because the weapons policy forbid anything that used explosives to shoot a projectile. As I was fond of pointing out, this left me free to have pretty much whatever I wanted stashed in my room.

Not that anybody paid a bit of mind to the weapons policy anyway. I know of at least one person who kept a goddamn katana in their room, and swords were expressly forbidden.

fusilier
2013-11-08, 04:33 PM
I have a different understanding of it:

There are materials that "burn" and there are materials that "detonate" -- gunpowder burns, it doesn't detonate -- the primer used to set off gunpowder usually detonates.

An explosive material, I think, is one that can be used as an explosive. Gunpowder can be used as an explosive, even though it doesn't detonate, and usually if burned in unconfined space won't generate much pressure.

That's my recollection of what the terminology means. Chemically they burn or detonate, exploding refers to the physical effect, but I could be mistaken.

--EDIT--
According to the wikipedia entry on "detonation", a detonation involves a supersonic exothermic front -- if it doesn't reach a supersonic speed it's a "deflagration". Sometimes it transitions, but the article is unclear as to what happens in guns (which can propel their projectiles faster than speed of sound).
--EDIT--

Red Bear
2013-11-15, 02:38 PM
Is it possible to estimate the volume of a ship? (air excluded) ships like a Viking longship or a caravel.

Bonus question: up to 1500 A.D. what has been the smallest ship capable of traversing the atlantic ocean?

fusilier
2013-11-15, 05:45 PM
Is it possible to estimate the volume of a ship? (air excluded) ships like a Viking longship or a caravel.

Displacement should be a function of volume -- sounds like you are looking for the displacement of an unladen ship. I believe there were ways of estimating that, but I don't know them.


Bonus question: up to 1500 A.D. what has been the smallest ship capable of traversing the atlantic ocean?

I think caravels routinely made the journey, some of which could be quite small -- the primary question would be if they could carry sufficient supplies for the trip. That I'm more unsure of -- the caravels may have usually travelled in convoys and supplies could be carried on a larger nao or carrack for the whole fleet.

During the Portuguese explorations around Africa, the naos and carracks apparently couldn't make the return trips (the winds made it almost impossible), so they would primarily explore with caravels, and used naos as disposable supply ships. When the supplies were used up, they simply stripped them and abandoned them.

The Spanish in the mid to late 16th century actually sailed galleys across the Atlantic, where they were used in anti-piracy actions in the Caribbean with much success. It's impressive, not because galleys were particularly small, but they usually didn't operate well in mid-ocean.

warty goblin
2013-11-15, 06:06 PM
Displacement should be a function of volume -- sounds like you are looking for the displacement of an unladen ship. I believe there were ways of estimating that, but I don't know them.


Displacement in a ship is the weight of water it displaces. Which, as Archimedes tells us, is equal to the weight of the ship. Actually estimating that is somewhat tricky as a rule, though a decent lowball would be to figure out the volume of hull material used in the ship, then multiply by its density. Increase by any cargo you're carrying.

The volume of a ship is a rather nebulous term. Do you mean volume of a hold? The usual technique is to partition a solid into a number of pieces whose volumes are easy to estimate, then sum up.

Red Bear
2013-11-15, 06:29 PM
Displacement in a ship is the weight of water it displaces. Which, as Archimedes tells us, is equal to the weight of the ship. Actually estimating that is somewhat tricky as a rule, though a decent lowball would be to figure out the volume of hull material used in the ship, then multiply by its density. Increase by any cargo you're carrying.


yes if I knew the weight of water displaced by an empty caravel I could multiply it by the average density of wood and I would have a good estimate.

For modern vehicles the dry weight is usually written somewhere, but I don't know where to find it for a caravel.



The volume of a ship is a rather nebulous term. Do you mean volume of a hold? The usual technique is to partition a solid into a number of pieces whose volumes are easy to estimate, then sum up.

I looked up "hold" in a dictionary but I didn't find a meaning that worked in this context. I mean the volume of all the wood that makes up a ship.

warty goblin
2013-11-15, 06:51 PM
yes if I knew the weight of water displaced by an empty caravel I could multiply it by the average density of wood and I would have a good estimate.

Wait, you're looking for the actual volume occupied by the materials of a ship? Why?

Lacking the displacement though, you're still free to estimate via dividing up the ship into sections whose volume can be calculated by well known formulas. Barring that you're faced with a numerical approximation to a series of very irregular integrals (hello Monte Carlo!), or else I believe there's computer software that produces volume estimates as well.


I looked up "hold" in a dictionary but I didn't find a meaning that worked in this context. I mean the volume of all the wood that makes up a ship.
Hold as in cargo hold.

Red Bear
2013-11-15, 08:06 PM
Wait, you're looking for the actual volume occupied by the materials of a ship? Why?


The reason is very trivial: I wanted to know what ship could be shrinked with the spell "Shrink Item (http://www.d20pfsrd.com/magic/all-spells/s/shrink-item)" :smallsmile:

Cealocanth
2013-11-15, 10:09 PM
The reason is very trivial: I wanted to know what ship could be shrinked with the spell "Shrink Item (http://www.d20pfsrd.com/magic/all-spells/s/shrink-item)" :smallsmile:

With only 2 cubic feet of material for the spell, if you're trying to shrink the ship to proper dimensions then the best you're going to get is a toy ship or a kayak built for a gnome.

fusilier
2013-11-16, 04:37 AM
Displacement in a ship is the weight of water it displaces. Which, as Archimedes tells us, is equal to the weight of the ship. Actually estimating that is somewhat tricky as a rule, though a decent lowball would be to figure out the volume of hull material used in the ship, then multiply by its density. Increase by any cargo you're carrying.

The volume of a ship is a rather nebulous term. Do you mean volume of a hold? The usual technique is to partition a solid into a number of pieces whose volumes are easy to estimate, then sum up.

Volume of the hold would be the "tonnage" if I'm not mistaken? There's several different ways of calculating that and some historical methods that aren't used anymore. Often it relates to cargo capacity, and therefore taxation was involved.

It gets a bit confusing because displacement is often described in "tons". You are correct that displacement is the weight, but assuming you know the density of the material, you should be able to work backward to get volume. However, you need to know the displacement to begin with.

fusilier
2013-11-16, 04:45 AM
The wikipedia entry for Columbus's Santa Maria (a nao), gives an estimated displacement (150 tons), and a "tons burthen" of 108 tons. The tons burthen is the cargo capacity estimate.

http://en.wikipedia.org/wiki/Santa_Mar%C3%ADa_(ship)

The Pinta and the Nina were caravels, but the wikipedia pages for them only list the tons burthen. While it would be tempting to attempt to give them a similar ratio of tons to displacement, caravels had different hull shapes than carracks/naos. There are several replicas of all his ships, you may want to try to research them for displacement figures.

Red Bear
2013-11-16, 07:17 AM
With only 2 cubic feet of material for the spell, if you're trying to shrink the ship to proper dimensions then the best you're going to get is a toy ship or a kayak built for a gnome.

it's 2 cubic feet per caster level, so I can shrink up to 40 cubic feet at high levels.


The wikipedia entry for Columbus's Santa Maria (a nao), gives an estimated displacement (150 tons), and a "tons burthen" of 108 tons. The tons burthen is the cargo capacity estimate.


Does this mean we can estimate that the dry weight of a caravel is 42 tons?

TheStranger
2013-11-16, 07:30 AM
I have to say, if I were your DM, and you told me that you should be allowed to shrink the volume of the wood in the ship rather than the volume of the completed ship, I'd throw a DMG at you.

hymer
2013-11-16, 09:38 AM
Here fusilier went to all this trouble... *sigh* Good on him, though.

Red Bear
2013-11-16, 10:39 AM
I have to say, if I were your DM, and you told me that you should be allowed to shrink the volume of the wood in the ship rather than the volume of the completed ship, I'd throw a DMG at you.

I'm only excluding air. I don't think there is much non-wood that makes up a ship.


Here fusilier went to all this trouble... *sigh* Good on him, though.
yeah, I'm feeling a little guilty... but even if the reason for my question was a spell I found his answer interesting.

TheStranger
2013-11-16, 11:01 AM
I'm only excluding air. I don't think there is much non-wood that makes up a ship.

If you can sell your DM on that ruling, more power to you. This isn't the thread for RAW debates, I just wanted to point out that the spell may not do what you think it does.

snowblizz
2013-11-16, 11:40 AM
I'm only excluding air. I don't think there is much non-wood that makes up a ship.

Actually there is. A lot of rope for one. Miles of it for a large ship.

The complete gang of standing and running rigging alone for one 400-ton brig launched at Portland, Maine, in 1865 was 3.8 miles long.

For a pocket ship I think you'd want to look at the Viking Longship. Less complex shape, less "enclosed space". Also Polynesians travelled vast distances over the Pacific in large two hulled canoe-like (I think) vessels.

TheMeMan
2013-11-16, 02:01 PM
it's 2 cubic feet per caster level, so I can shrink up to 40 cubic feet at high levels.



Does this mean we can estimate that the dry weight of a caravel is 42 tons?

I think you may be massively overestimating what 40 cubic feet entails.

A stack of boards 1 ft wide, by 1 foot deep, by 40 feet long is 40 cubic feet. if each board is 1 inch wide (Which is probalby the low end for an ocean going vessle), then you have 12 boards in that stack that are 1 inch thick, 1 foot wide, and 40 feet long. Which likely isn't enough to make any sort of vessel that I know of. Even if you halve the length to make a really tiny vessel, that leaves you with 24 boards of 20 feet long. It's possible to make *something* out of that, but not much.

This isn't, over course, considering the rigging or sails necessary which could take up a huge chunk of the cubic feet necessary.

fusilier
2013-11-16, 04:21 PM
Does this mean we can estimate that the dry weight of a caravel is 42 tons?

Unfortunately, no. First that was for a larger nao, not a caravel. Second, it's not clear whether the displacement refers to a fully laden ship (see below). Finally the relationship between "tons burthen" and "displacement" isn't that straightforward. There's a variety of ways of coming up with tonnage, modern ones are estimates sometimes based upon certain ratios, which assume a certain design. Historical tonnage is actually more precise, as they literally loaded the ship with casks to see how many it could take -- but you have to know which units were being used, and authors often aren't clear on that subject.

The statistic you are looking for is the "light displacement", that's the weight of the ship alone, with no crew or stores aboard. "Displacement" usually refers to a fully crewed ship with all stores aboard -- but not necessarily all cargo -- that's the "loaded displacement". So the term "displacement" can be ambiguous if the context isn't made clear.

I checked up a source that I had, Galleys and Galleons, it pointed out that while displacement calculations didn't start to be used until the late 1600s, the design of medieval and renaissance ships were pretty consistent, so we can estimate the displacement from one or two factors (length, width, depth or tonnage). It also noted that the caravels that were sailed to India were probably 80-130 tons.

The GURPS: Low-tech (3rd-edition), book has a chart of water vehicles including an 80 foot Caravel:

The empty weight is a little less than 20 tons, and the cargo capacity works out to 56 tons. Which leads to a loaded displacement of almost 76 tons. The numbers don't all work out precisely, but it's probably a similar size to the caravels that accompanied Columbus on his first journey to America.

[GURPS books are awesome for this kind of stuff]

TheStranger
2013-11-16, 05:41 PM
For additional reference, 20 tons of wood is somewhere in the neighborhood of 30 cubic yards (though it varies greatly by type of wood). Which is in the ballpark of 800 cubic feet, so you're an order of magnitude away from being able to shrink the wood alone.

Many common woods range from 25-40 lbs/cubic foot. So a level 20 caster could, at best, shrink a boat weighing around 1500 lbs (assuming your DM will only count the wood volume, not the dimensions of the boat). Which, as suggested above, might be a smallish Viking longship.

Beleriphon
2013-11-17, 10:18 AM
--EDIT--
According to the wikipedia entry on "detonation", a detonation involves a supersonic exothermic front -- if it doesn't reach a supersonic speed it's a "deflagration". Sometimes it transitions, but the article is unclear as to what happens in guns (which can propel their projectiles faster than speed of sound).
--EDIT--

Gunpowder, or more specifically black powder, is a low velocity explosive when confined. In a proper sense it isn't an explosive in the same way dynamite is an explosive. Anything than propels a round out of a barrel of a weapon is a propellant and have radically different properties than explosives. Although in sufficient quantities an propellant in a confined space can cause an explosion.

Jay R
2013-11-17, 11:49 AM
Gunpowder, or more specifically black powder, is a low velocity explosive when confined. In a proper sense it isn't an explosive in the same way dynamite is an explosive. Anything than propels a round out of a barrel of a weapon is a propellant and have radically different properties than explosives. Although in sufficient quantities an propellant in a confined space can cause an explosion.

Put a can of peas in a fire, and the can will explode. That does not make peas an explosive substance. Similarly, gunpowder is not an explosive substance. But it creates lots of gas really quickly when it burns, so put it in an gas-tight enclosed cartridge, grenade, or firecracker, and the expanding gases will cause the container to explode.

TheMeMan
2013-11-17, 11:55 AM
Many common woods range from 25-40 lbs/cubic foot. So a level 20 caster could, at best, shrink a boat weighing around 1500 lbs (assuming your DM will only count the wood volume, not the dimensions of the boat). Which, as suggested above, might be a smallish Viking longship.

I don't even think a longship is small enough. Karvis were the smallest longships, and they were still around 56 feet long at the smallest. Considering my calculation above, there simply isn't enough wood in 40 cubic feet to encompass that. Really, there isn't much wood to be had in 40 cubic feet at all, and I doubt one could make an ocean going ship with so little space alotted.

fusilier
2013-11-17, 05:39 PM
Put a can of peas in a fire, and the can will explode. That does not make peas an explosive substance. Similarly, gunpowder is not an explosive substance. But it creates lots of gas really quickly when it burns, so put it in an gas-tight enclosed cartridge, grenade, or firecracker, and the expanding gases will cause the container to explode.

Aren't the technical terms: Detonate and Deflagrate? Explosion, and "explosive" can have a looser or different definition?

Gunpowder (specifically what's now called "black powder"), is generally considered to be the world's first "explosive". There are plenty of other things that "burn", but when put into a confined space won't "explode" -- in fact they may not burn at all. Gunpowder is not just a propellant, it was used in mining as a general explosive as well. It's not too bad as one, but nitroglycerin and dynamite were better. It also has some rather unusual properties when compared to later smokeless propellants.

Tyndmyr
2013-11-18, 04:49 PM
Aren't the technical terms: Detonate and Deflagrate? Explosion, and "explosive" can have a looser or different definition?

Gunpowder (specifically what's now called "black powder"), is generally considered to be the world's first "explosive". There are plenty of other things that "burn", but when put into a confined space won't "explode" -- in fact they may not burn at all. Gunpowder is not just a propellant, it was used in mining as a general explosive as well. It's not too bad as one, but nitroglycerin and dynamite were better. It also has some rather unusual properties when compared to later smokeless propellants.

That's correct. It's determined by if the blast wave breaks the sound barrier or not.

Now, you can make an explosion via a pressure chamber from things that are not normally explosive. A small amount of gunpowder, unpressurized, will burn in a reasonably safe manner. That same gunpowder, when compressed within a metal chamber, will propel a bullet at supersonic speeds.

Colloqually, we tend to use the word explode much looser, though. So, "a can of peas exploded" is a pretty reasonable phrase.