[i am bored (OP)]

I heard back in medieval times they used a incendiary called Greek fire which is either fired by bow or catapult. it is lit then fired and after its fired it cannot be put out with water. in fact it makes it worse i would like to know what and how this is made and how they extinguished it if they couldn't use water .

[DoctorBeaver]

It was used mainly by the Byzantines in sea battles. It's formula was a closely guarded secret and remains so to this day.

From Wikipedia http://en.wikipedia.org/wiki/Greek_fire

Theophanes records that Greek fire was invented c. 670 in Constantinople by Kallikinos (Callicinus), an architect from Heliopolis in the Byzantine Iudaea Province.[2] Historian James Partington thinks it likely that "Greek fire was really invented by the chemists in Constantinople who had inherited the discoveries of the Alexandrian chemical school".[3] Many accounts note that the fires it caused could not be put out by pouring water on the flames—on the contrary, the water served to intensify or spread them, suggesting that 'Greek fire' may have been a 'thermite-like' reaction, possibly involving a quicklime or similar compound. Others have posited a flammable liquid that floated on water, possibly a form of naphtha or another low-density liquid hydrocarbon, as petroleum was known to Eastern chemists long before its use became widespread in the 1800s.

[Bored chemist]

There are things that can't be put out with water. The usual way to put them out is to wait for them to burn out. Sometimes dumping dry salt or sand on them will do the job.

[i am bored (OP)]

oh ok

[lightarrow]

It was used mainly by the Byzantines in sea battles. It's formula was a closely guarded secret and remains so to this day.

From Wikipedia http://en.wikipedia.org/wiki/Greek_fire

Theophanes records that Greek fire was invented c. 670 in Constantinople by Kallikinos (Callicinus), an architect from Heliopolis in the Byzantine Iudaea Province.[2] Historian James Partington thinks it likely that "Greek fire was really invented by the chemists in Constantinople who had inherited the discoveries of the Alexandrian chemical school".[3] Many accounts note that the fires it caused could not be put out by pouring water on the flames—on the contrary, the water served to intensify or spread them, suggesting that 'Greek fire' may have been a 'thermite-like' reaction, possibly involving a quicklime or similar compound. Others have posited a flammable liquid that floated on water, possibly a form of naphtha or another low-density liquid hydrocarbon, as petroleum was known to Eastern chemists long before its use became widespread in the 1800s.

I think the second hypothesis is more reasonable: making aluminum or magnesium were almost certainly out of their possibilities.

[another_someone]

Why not just a mix of hydrocarbon and oxidiser (e.g. saltpetre), and maybe some iron filings or iron dust, or maybe phosphorous added in?  The oxidiser would make it pretty difficult to put out, with water or even by smothering; and the addition of phosphorous would make it self igniting (although it may make handling it more difficult).

[Bored chemist]

And the interesting question is then "How did the ancients Greeks make phosphorus?"
Lets face it, if you were not aware of things like naphtha, a burning liquid that floats on water and keeps burning would look like magic. You wouldn't need to add nitre or iron.

[another_someone]

And the interesting question is then "How did the ancients Greeks make phosphorus?"

It was used mainly by the Byzantines in sea battles. It's formula was a closely guarded secret and remains so to this day.

From Wikipedia http://en.wikipedia.org/wiki/Greek_fire

Theophanes records that Greek fire was invented c. 670 in Constantinople

Scarcely ancient Greece, but clearly early medieval Greece.

http://en.wikipedia.org/wiki/Phosphorus#History

Phosphorus (Greek phosphoros was the ancient name for the planet Venus, but in Greek mythology, Hesperus and Eosphorus could be confused with Phosphorus) was discovered by German alchemist Hennig Brand in 1669 through a preparation from urine, which naturally contains considerable quantities of dissolved phosphates from normal metabolism. Working in Hamburg, Brand attempted to distill some salts by evaporating urine, and in the process produced a white material that glowed in the dark and burned brilliantly. Since that time, phosphorescence has been used to describe substances that shine in the dark without burning.

Yes, this was almost exactly a millennium later; but was the technology used by Brand in 1669 so out of reach of the Byzantines in 670?  Could not the Byzantines have previously discovered the same, but shrouded in secrecy, the discovery was lost and awaited rediscovery a millennium later?

[i am bored (OP)]

isnt it possible they could have used sodium, lit it on fire then launched it

[another_someone]

isnt it possible they could have used sodium, lit it on fire then launched it

I can't see metallic sodium being available at such a date.

Metallic sodium was discovered in 1807, and required electrolysis, and thus could not have been discovered before the discovery of electricity.

[DoctorBeaver]

George - although the Byzantines were renown for using it, it was actually first used in ancient Greece.

[another_someone]

George - although the Byzantines were renown for using it, it was actually first used in ancient Greece.

The quoted Wikipedia article above indicates otherwise.

I have to admit that I too had thought of it as an earlier invention, but none of the references I can find support this.

[DoctorBeaver]

I found a reference the other day to it that stated that although it was believed to have been invented by the Greek Byzantines, an ancient Greek historian had mentioned it.

I can't find the reference now  []

[Bored chemist]

"Yes, this was almost exactly a millennium later; but was the technology used by Brand in 1669 so out of reach of the Byzantines in 670?  Could not the Byzantines have previously discovered the same, but shrouded in secrecy, the discovery was lost and awaited rediscovery a millennium later?"


Yes, and they might have discovered sodium too but kept this hidden. Can we really rule out a nuclear reactor? Well, not unless you can say that you have gone over every bit of the Byzantine empire with a geiger counter.
On the other hand, rather than inventing possible "lost civilisation" type answers why not just beleive what's reasonably likely?

[another_someone]

"Yes, this was almost exactly a millennium later; but was the technology used by Brand in 1669 so out of reach of the Byzantines in 670?  Could not the Byzantines have previously discovered the same, but shrouded in secrecy, the discovery was lost and awaited rediscovery a millennium later?"


Yes, and they might have discovered sodium too but kept this hidden. Can we really rule out a nuclear reactor? Well, not unless you can say that you have gone over every bit of the Byzantine empire with a geiger counter.
On the other hand, rather than inventing possible "lost civilisation" type answers why not just beleive what's reasonably likely?

No - the point I was making was: is there any precondition to having discovered phosphorous that we believe was absent in Byzantine technology?

The point about metallic sodium is that there was a precondition which was required, and access to such a precondition (the discovery of electricity) has such wide implications in other technologies that would have changed the entire technological base of the civilisation, that we can reasonably say that the precondition is very unlikely to have existed for the discovery of metallic sodium in Byzantine civilisation.

In 1669, phosphorous was discovered by evaporation of urine.  At face value, the preconditions for such a discovery being the use of fire, and access to urine, seems not to have been out of reach of the Byzantines.  If you are going to tell me that there is some complexity to this process that requires another technical innovation that was not yet available to the Byzantines, then I will accept that as making it improbable that they would have discovered phosphorous - but I am not presently aware of what that other technical precondition might be.

If all the technical preconditions to the discovery of phosphorous had been met prior to 670, then in theory the material could have been discovered at any time prior to 1669, and may have indeed been discovered and rediscovered, possibly several times over, without people properly understanding, or documenting, their discovery.

[DoctorBeaver]

Could it have been pitch mixed with something? As far as I'm aware, you can't put out a pitch fire with water.

[i am bored (OP)]

pitch fire?

[Bored chemist]

"In 1669, phosphorous was discovered by evaporation of urine. "
No it wasn't, there's more to it than just evaporation.

"The point about metallic sodium is that there was a precondition which was required, and access to such a precondition (the discovery of electricity) has such wide implications in other technologies that would have changed the entire technological base of the civilisation"
The sort of furnace you need to get phosphorus would have showed up nearly as well in the historical record as electricity would. It is possible (at least thermodynamicly) to reduce sodium carbonate to sodium with charcoal. The temperature required is less than that needed to produce phosphorus.

"As far as I'm aware, you can't put out a pitch fire with water."
Well I don't see why not- it might be messy and spatter a lot but you could do it.

[lightarrow]

"In 1669, phosphorous was discovered by evaporation of urine. "
No it wasn't, there's more to it than just evaporation.

"The point about metallic sodium is that there was a precondition which was required, and access to such a precondition (the discovery of electricity) has such wide implications in other technologies that would have changed the entire technological base of the civilisation"
The sort of furnace you need to get phosphorus would have showed up nearly as well in the historical record as electricity would. It is possible (at least thermodynamicly) to reduce sodium carbonate to sodium with charcoal. The temperature required is less than that needed to produce phosphorus.

Using the standard industrial process, yes (calcium phosphate + charcoal + silica), but I wonder if it's difficult the same (in terms of temperatures needed) using other phosphates.

[another_someone]

"In 1669, phosphorous was discovered by evaporation of urine. "
No it wasn't, there's more to it than just evaporation.

"The point about metallic sodium is that there was a precondition which was required, and access to such a precondition (the discovery of electricity) has such wide implications in other technologies that would have changed the entire technological base of the civilisation"
The sort of furnace you need to get phosphorus would have showed up nearly as well in the historical record as electricity would. It is possible (at least thermodynamicly) to reduce sodium carbonate to sodium with charcoal. The temperature required is less than that needed to produce phosphorus.

Using the standard industrial process, yes (calcium phosphate + charcoal + silica), but I wonder if it's difficult the same (in terms of temperatures needed) using other phosphates.

What kind of temperatures are we talking about, and how does this relate to the temperatures that would have been commonplace in metal ore reduction?

Do you have any ideas as to what technical developments happened between 670 and 1669 to allow this increase in furnace temperature?