Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: i am bored on 09/09/2007 04:02:04
-
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 .
-
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 (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.
-
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.
-
oh ok
-
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 (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.
-
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).
-
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.
-
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 (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?
-
isnt it possible they could have used sodium, lit it on fire then launched it
-
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.
-
George - although the Byzantines were renown for using it, it was actually first used in ancient Greece.
-
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.
-
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 [:(]
-
"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?
-
"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.
-
Could it have been pitch mixed with something? As far as I'm aware, you can't put out a pitch fire with water.
-
pitch fire?
-
"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.
-
"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.
-
"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?
-
"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?
The industrial process happens in electric oven, so the temperatures are higher than 2000°C, but reducing (still with C) other phosphates, the temperatures should be much less, around 900°C, according to some informations taken from the web (don't know if true).Do you have any ideas as to what technical developments happened between 670 and 1669 to allow this increase in furnace temperature?
Always been bad in hystory...
-
ok go on
-
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?
The industrial process happens in electric oven, so the temperatures are higher than 2000°C, but reducing (still with C) other phosphates, the temperatures should be much less, around 900°C, according to some informations taken from the web (don't know if true).Do you have any ideas as to what technical developments happened between 670 and 1669 to allow this increase in furnace temperature?
Always been bad in hystory...
Looking at the most obvious high temperature reduction technology in use at that time, the history of iron, it does seem that the move from bloomeries to the use of blast furnes happened during the middle ages.
http://en.wikipedia.org/wiki/Blast_furnace#Medieval_Europe
The oldest known blast furnaces in the West were built in Dürstel in Switzerland, the Märkische Sauerland in Germany, and Sweden at Lapphyttan where the complex was active between 1150 and 1350. At Noraskog in the Swedish county of Järnboås there have also been found traces of blast furnaces dated even earlier, possibly to around 1100. These early blast furnaces, like the Chinese examples, were very inefficient compared to those used today. The iron from the Lapphyttan complex was used to produce balls of wrought iron known as osmonds, and these were traded internationally - a possible reference occurs in a treaty with Novgorod from 1203 and several certain references in accounts of English customs from the 1250s and 1320s. Other furnaces of the 13th to 15th centuries have been identified in Westphalia.
Knowledge of certain technological advances was transmitted as a result of the General Chapter of the Cistercian monks, including the blast furnace, as the Cistercians are known to have been skilled metallurgists. According to Jean Gimpel, their high level of industrial technology facilitated the diffusion of new techniques: "Every monastery had a model factory, often as large as the church and only several feet away, and waterpower drove the machinery of the various industries located on its floor." Iron ore deposits were often donated to the monks along with forges to extract the iron, and within time surpluses were being offered for sale. The Cistercians became the leading iron producers in Champagne, France, from the mid-13th century to the 17th century, also using the phosphate-rich slag from their furnaces as an agricultural fertilizer.
Archaeologists are still discovering the extent of Cistercian technology. At Laskill, an outstation of Rievaulx Abbey and the only medieval blast furnace so far identified in Britain, the slag produced was low in iron content. Slag from other furnaces of the time contained a substantial concentration of iron, whereas Laskill is believed to have produced cast iron quite efficiently. Its date is not yet clear, but it probably did not survive Henry VIII's Dissolution of the Monasteries in the late 1530s, as an agreement (immediately after that) concerning the 'smythes' with the Earl of Rutland in 1541 refers to blooms. Nevertheless, the means by which the blast furnace spread in medieval Europe has not finally been determined.
Early modern blast furnaces: origin and spread
The direct ancestor of those used in France and England was in the Namur region in what is now Belgium. From there, they spread first to the Pays de Bray on the eastern boundary of Normandy and from there to the Weald of Sussex, where the first furnace (called Queenstock) in Buxted was built in about 1491, followed by one at Newbridge in Ashdown Forest in 1496. They remained few in number until about 1530 but many were built in the following decades in the Weald, where the iron industry perhaps reached its peak about 1590. Most of the pig iron from these furnaces was taken to finery forges for the production of bar iron.
The first British furnaces outside the Weald were not built until the 1550s, but many were built in the remainder of that century and the following ones. The output of the industry probably peaked about 1620, and was followed by a slow decline until the early 18th century. This was apparently because it was more economic to import iron from Sweden and elsewhere than to make it in some more remote British locations. Charcoal that was economically available to the industry was probably being consumed as fast as the wood to make it grew.
On the other hand, it seems the Chinese were about 2000 years ahead of the Europeans in that respect, and I do not believe one can dismiss the possibility that some of the technology migrated from China to Byzantine (who did not use it for iron production because they had not mastered the post processing of the cast iron) earlier than it arrived in western or northern Europe.
http://en.wikipedia.org/wiki/History_of_ferrous_metallurgy#Early_Developments_in_China
Archaeologists and historians debate whether bloomery-based ironworking ever spread to China from the Middle East. Around 500 BC, however, metalworkers in the southern state of Wu developed an iron smelting technology that would not be practiced in Europe until late medieval times. In Wu, iron smelters achieved a temperature of 1130°C, hot enough to be considered a blast furnace which could create cast iron. At this temperature, iron combines with 4.3% carbon and melts. As a liquid, iron can be cast into molds, a method far less laborious than individually forging each piece of iron from a bloom.
Cast iron is rather brittle and unsuitable for striking implements. It can, however, be decarburized to steel or wrought iron by heating it in air for several days. In China, these ironworking methods spread northward, and by 300 BC, iron was the material of choice throughout China for most tools and weapons. A mass grave in Hebei province, dated to the early third century BC, contains several soldiers buried with their weapons and other equipment. The artifacts recovered from this grave are variously made of wrought iron, cast iron, malleabilized cast iron, and quench-hardened steel, with only a few, probably ornamental, bronze weapons.
During the Han Dynasty (202 BC–AD 220), Chinese ironworking achieved a scale and sophistication not reached in the West until the eighteenth century. In the first century, the Han government established ironworking as a state monopoly and built a series of large blast furnaces in Henan province, each capable of producing several tons of iron per day. By this time, Chinese metallurgists had discovered how to puddle molten pig iron, stirring it in the open air until it lost its carbon and became wrought iron. (In Chinese, the process was called chao, literally, stir frying.) By the 1st century BC, Chinese metallurgists had found that wrought iron and cast iron could be melted together to yield an alloy of intermediate carbon content, that is, steel. According to legend, the sword of Liu Bang, the first Han emperor, was made in this fashion. Some texts of the era mention "harmonizing the hard and the soft" in the context of ironworking; the phrase may refer to this process. Also, the ancient city of Wan (Nanyang) from the Han period forward was a major center of the iron and steel industry. Along with their original methods of forging steel, the Chinese had also adopted the production methods of creating Wootz steel, an idea imported from India to China by the 5th century AD
So, while I agree that developments in western and northern Europe had probably not yet reached a point where these high temperatures were regularly reached; it does seem clear that in China, temperatures of 1130°C and been reached by 500BC (over 1000 years before the innovation of Greek fire, in 670AD), and the question still must remain is maybe some of this technology had not been brought to Constantinople, and although the Byzantines had not understood its application in iron making, they may have unexpectedly found it applicable to other technologies.
-
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 .
The classic illustration of Greek Fire comes from a 10th century (IIRC) Byzantine MS:
http://www.greece.org/Romiosini/gr_fire.gif
which shows the fire emerging from a tube already ignited, not unlike a modern flame-thrower. I have not been able to substantiate the claims that it was auto-igniting on impact.
The Greeks certainly knew about the pitch balls that often rose from the Dead Sea (a major commercial product of the time),
http://198.62.75.1/www1/ofm/fai/FAImpded.html
and distillation was not unheard of in that era, either:
http://en.wikipedia.org/wiki/Distillation#History
Distilling the pitch at low temperatures (<100° C) would produce a volatile petroleum byproduct (known by many names such as ligroin, petroleum ether, white gas, etc.)
http://en.wikipedia.org/wiki/Petroleum_ether
The higher-boiling fraction of petroleum distillates we now call kerosene was developed soon afterwards:
http://en.wikipedia.org/wiki/Kerosene
The Greeks certainly knew of the innovations in hydraulics of Hero of Alexandria
http://en.wikipedia.org/wiki/Hero_of_Alexandria
Whatever the flammable substance was, it conceivably could have been contained in a pottery jar with a burning wick (like a modern Molotov cocktail) and launched by means of either a scorpion or a trebuchet or other such catapult (aslthough some would have been very awkward to put on a boat).
http://en.wikipedia.org/wiki/Ballista
http://en.wikipedia.org/wiki/Catapult
Use of such a weapon would have been most effective on the sea, where the petroleum ether would spread rapidly along the water, still flaming, making even a near miss effective, belying the old adage "'Close' only counts with Horseshoes and hand grenades."
I view the major innovation as the development of the flame-thrower as a delivery system rather than the development of a flame as a weapon of war. It gave one side an insurmountable tactical advantage.
It is even possible that an oxidizer such as Egyptian nitrates
http://books.google.com/books?id=2CRCAAAAMAAJ&pg=PA763&lpg=PA763&dq=luxor+nitrates&source=web&ots=hWzIwNsVyc&sig=poFZa2OuZnXPwYb1BMGYoL383bk
were added to make a slurry, accelerating the burning. The most significant features of "Greek Fire" were that water would not extinguish it (much as petroleum fires today), that it was a projectile of pure fire rather than a problematic thrown torch or flaming arrow, which could be readily dealt with by the recipient, and that it had a tremendous demoralizing effect on the enemy.
tadchem
Richmond, VA
-
whoa lots of infomation
-
From Wikipedia
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.
Could it be some sort hydrocarbon? Burning oil, paraffine and stearine are liquid in an the burning state and have an huge explosive reaction if water is being added. As you can see in this youtube clip watch?v=Ln5egDJxJm0]
-
More than likely bees wax and pine resin. Some of our glues today for labeling once lit really cannot be put out. What makes the sight so horrific is that the amounts can be an almost invisible film, once heated they really do not wish to be put out. Even a thin film once lit, can emit balls of fire, with a rather unsettling crack. As if an electrochemical reaction is taking place.
Sincerely,
William McCormick