This, unsurprisingly, is also related to mermaids.

Spearguns using rubber bands and the like are popular underwater weapons, so slingshots would be useful to mermaids. The problem is, these require(?) vulcanized rubber, which was invented in the 19th century.

I'm wondering if there is any way you could get this, or a similar material sooner, or stumble onto it someway. This may be more plausible than it sounds.

Invention of Vulcanized Rubber

The legend goes that Goodyear, who was not college trained, accidentally spilt rubber and sulfur onto a hot stove, and noticed it become a strong material. He claimed it was no such thing, but if it is technically possible that could happen, any alchemist messing with sulfur and rubber might discover this, and mermaids may gain access to such an invention.

But, I really need a more expert opinion on this, to know if it's really plausible, or how it could come about. As a side note, rubber use in Europe appears to have started in the 18th century, not sure why there wasn't any sooner.

Effects on the Ancient World?

There is also, as a side question, how this would affect the ancient world if vulcanized rubber (and rubber trees) were discovered. But this is less important to me, as I mostly want to know about its plausibility for it to happen.

  • $\begingroup$ Vulcan mermaids... that's a surprise. $\endgroup$
    – user6760
    Oct 16, 2016 at 12:07
  • $\begingroup$ Where would mermaids get rubber from? $\endgroup$ Oct 16, 2016 at 14:38
  • $\begingroup$ @Bellerophon From whoever is selling it, I suppose. They might come onto lands with rubber, someway. $\endgroup$
    – J. Doe
    Oct 16, 2016 at 18:05
  • $\begingroup$ Europeans only started using rubber in the 18th and 19th centuries because before that it was nearly only found in the Americas. google.co.uk/url?sa=t&source=web&rct=j&url=http://… $\endgroup$ Oct 18, 2016 at 13:44

3 Answers 3


Assuming that you have access to rubber producing trees and a culture with some concept of technology and experimentation developing vulcanization is reasonably plausible. Elemental sulphur occurs naturally and has been known since antiquity.

This sort of discovery is helped by having a tradition of alchemy (or some local equivalent) which is the 'mix it up and see what happens' school of discovery and while not in itself science is a good starting point for chemistry and materials science to develop from.

It is also worth noting that even 'accidental' discoveries rely on the person making that discovery to be of the right turn of mind to a) notice that it might be useful and b) be able to follow it up and work out how it happened and how to reproduce it.

Edit (for more detail)

A good example of this is the development of the metallurgy of steel. Blacksmiths were able to produce heat treated steel tools long before the actual mechanism of hardening and tempering steel was understood in a scientific sense. This is helped by the fact that blacksmiths were among the first specialist artisans and as such spent their entire careers working with metal. This represents a middle ground between properly rigorous scientific research and the implausibility of accidentally discovering a complex technical process.

  • $\begingroup$ Thank you, Chris. This makes sense. I'll look into it a bit more, but I think that as you say, it seems quite plausible science fiction. $\endgroup$
    – J. Doe
    Oct 17, 2016 at 20:50

Rather than rubber or other material that stretches significantly, use a tortion spring like a Roman catapult.


In the photo you can see that this is made from ordinary rope. It only stretches a tiny amount when twisted. They used line made from the archilles tendon of cattle. Anything that functions as rope will work to some degree, but may wear out quickly.

More generally, see that you don’t need ellastic like in a modern speargun. Any kind of compressive, tension, or bending-moment can be bent [pun intended] to the task, by using simple mechanics to couple the energy storage to the desired motion.

Maybe they’ll use the bending of chiton shell material to form a bow, inspired by the mantis shrimp.

  • $\begingroup$ I'm afraid I'm not sure how to apply this. If you apply pressure to shell, it can resist a lot of force, but it doesn't really store and expel that energy. youtu.be/ePCI7BTlEnY?t=36m13s There might be some design of chiton or shell that can accomplish this. I simply don't know how such a thing would work. Bull tendons, or penises, or some other biological matter might be suitable in giving comparable power and durability in underwater and cold conditions. If so, that solves the issue of rubber. I'll try to look into sinew string properties. $\endgroup$
    – J. Doe
    Oct 16, 2016 at 18:15
  • 2
    $\begingroup$ The mantis shrimp uses the chitin shell around the arm to power its famous blow. Maybe you can find a video of the show where this is explained. Ancient bows included composites made from animal horn on one side. $\endgroup$
    – JDługosz
    Oct 16, 2016 at 20:49
  • 1
    $\begingroup$ Byssus threads, which are made by molluscs like mussels are incredibly strong. Apparently people used to make 'sea silk' out of them: en.wikipedia.org/wiki/Sea_silk Scientists get very excited about the properties of byssus: telegraph.co.uk/news/science/science-news/10197664/… $\endgroup$
    – DrBob
    Oct 17, 2016 at 17:37
  • $\begingroup$ Great find, Dr. Bob! I'll have to look into this material. It sounds a lot like rubber, and it sounds like it could be durable and water resistant, maybe temperature resistant as well. Also, thanks to JD, I will look into articles on the pistol shrimp to see if that tech could be used for slingshots. $\endgroup$
    – J. Doe
    Oct 17, 2016 at 19:51

Strictly answering your question about vulcanized rubber, it is impractical for merfolk to develop vulcanized rubber.

  1. Rubber (at least the natural kind) comes from trees in the rainforest. Merfolk don't really have access to that.

  2. Elemental sulfur is not present in seawater. Sulfur is common, but is locked up in sulfate salts. You need elemental sulfur to vulcanize rubber, and the merfolk won't have access to it.

  3. Rubber must be vulcanized at about 170$^\circ$ for 10 minutes. You can't get things to 170$^\circ$ in seawater, so the process would have to be done in an air pocket or vacuum. It seems unlikely that the merfolk will develop a complex chemical manufacturing process that can't be done in their home enviornment (underwater)

All in all, the merfolk should find an alternative elastic to provide mechanical power for spear-slings.

  • $\begingroup$ I wasn't thinking of the mermaids farming and processing it from tree sap to a finished product, but gaining it from allied human traders. Thanks for the factoids on the difficulty of producing it in water, all the same. $\endgroup$
    – J. Doe
    Oct 17, 2016 at 19:44
  • 1
    $\begingroup$ @J.Doe I see. Well the reason that Europeans took so long to develop vulcanize rubber is that natural rubber is from the Amazon, its useful properties were not discovered until the 1750s, and it wasn't commonly used until the 19th century. Vulcanization was discovered only about a hundred years after rubber discovery, so it might be plausible that vulcanization would be invented by a tropical civilization at an earlier technology level. $\endgroup$
    – kingledion
    Oct 17, 2016 at 19:49
  • $\begingroup$ Yeah, hopefully that is possible. I'll do more research into it, and see how plausible it would be. Thanks. $\endgroup$
    – J. Doe
    Oct 17, 2016 at 20:06

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