Volts before Volta
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Sino-Platonic Papers is pleased to announce the publication of its three-hundred-and-seventy-seventh issue:
“The Baghdad Battery: Experimental Verification of a 2,000-Year-Old Device Capable of Driving Visible and Useful Electrochemical Reactions at over 1.4 Volts,” by Alexander Bazes.
ABSTRACT
The “Baghdad Battery” has posed an archaeological enigma for over eighty years. Discovered at the Parthian site of Khujut Rabu (first century ce), this famous artifact’s utilitarian yet highly specific design tailors so clearly to the requirements of an electrochemical cell that it is difficult to conceive of another use for it. Although efforts have been made to recreate this battery (König 1938, Keyser 1993, MythBusters 2005), prior experiments have failed to (1) account for all aspects of the artifact’s design and (2) make a device that has enough power to be evidently useful for people two thousand years ago. The result of these previous recreations has thus been to cast doubt upon whether the Baghdad Battery was, in fact, a battery at all. The present study’s recreation dispels this doubt by accounting for two previously neglected aspects of the artifact’s design, namely the use of solder and the function of the ceramic jar, which together form a previously unrecognized second source of voltage for the device: an aqueous tin-air battery. This “outer cell,” which is integrally connected in electrical series with the device’s already well-understood “inner cell” (comprising copper and iron), enables the Baghdad Battery to generate over 1.4 volts: an electric potential capable of driving a number of useful (and highly noticeable) electrochemical reactions, including electroplating, etching, and the electrolysis of water into hydrogen and oxygen gas. The present study’s result therefore provides the strongest evidence to date for people in the Near East having had a working knowledge of electrochemistry nearly two millennia before Alessandro Volta’s experiments with the voltaic pile.
Keywords: Baghdad Battery, Parthian Galvanic Cell, tin-air battery, aqueous metal-air battery, ancient electrochemistry
Selected readings
- "Unit utility" (6/25/25) –in the comments
- "Annals of word rage" (5/2/09)
- "The dormitive virtue of root-power quantities" (8/29/13)
Alexander Bazes said,
January 4, 2026 @ 2:46 pm
As a possible direction for future research, I find it intriguing that the Baghdad Battery and similar artifacts date from the time and place where the earliest Syriac writings on alchemy were emerging. The opening of the Emerald Tablet, for example, strikes me as describing a spiritual theory of electrical phenomena in both the atmosphere and in living beings, with strong parallels to Taoist writings on qi. A battery may be mundane to us now, but I believe 2,000 years ago it could have had profound implications for people's understanding of the universe and their place within it.
Alexander Bazes said,
January 4, 2026 @ 3:47 pm
The opening of 内業 (Inward Training), for example, I have always found to be quite evocative of the Emerald Tablet:
1. The vital essence of all things:
2. It is this that brings them to life.
3. It generates the five grains below
4. And becomes the constellated stars above.
5. When flowing amid the heavens and the earth
6. We call it ghostly and numinous.
7. When stored within the chests of human beings,
8. We call them sages.
凡物之精
此則為生
下生五穀
上為列星
流天地間
謂之鬼神
蔵於胸中
謂之聖人
Roth, Harold David. 内業: Inward Training (nei-yeh) and the Foundations of Taoist Mysticism. Columbia University Press, 1999. (46-47)
For comparison, here is a 1929 translation of a version of the Emerald Tablet from Jabir ibn Hayyan:
0) Balinas mentions the engraving on the table in the hand of Hermes, which says:
1) Truth! Certainty! That in which there is no doubt!
2) That which is above is from that which is below, and that which is below is from that which is above, working the miracles of one.
3) As all things were from one.
4) Its father is the Sun and its mother the Moon.
5) The Earth carried it in her belly, and the Wind nourished it in her belly,
7) as Earth which shall become Fire.
7a) Feed the Earth from that which is subtle, with the greatest power.
8) It ascends from the earth to the heaven and becomes ruler over that which is above and that which is below.
14) And I have already explained the meaning of the whole of this in two of these books of mine.
[Holmyard 1923: 562.]
Peter Grubtal said,
January 5, 2026 @ 3:35 am
The wiki page on this will need updating then, because it's uniformly negative on the battery hypothesis, with apparently cogent technical arguments.
Hopefully those who edited the current wiki page will check the technical arguments in the platonic papers article, because they're above my and a lot of people's heads.
~flow said,
January 5, 2026 @ 8:18 am
Can recommend this thoughtful piece: "The Enigmatic 'Battery of Baghdad': This 2,000-year-old find is considered by some scientists to be an electrical power source. Did it really work?" by Gerhard Eggert (in: *Skeptical Inquirer* May/June 1996) https://cdn.centerforinquiry.org/wp-content/uploads/sites/29/1996/05/22165042/p31.pdf
Of particular interest regarding the critical treatment of the Battery hypothesis by the Wikipedia article is the observation that we don't have finds from the time that are electroplated.
Alexander Bazes said,
January 5, 2026 @ 10:18 am
~flow, thank you for that link, although let's remember that the Skeptical Inquirer has a self-stated bias and must cater to certain expectations from its readers. I believe you will find that my article addresses most of the concerns raised by Eggert.
Although I see electroplating as one possible use for this device, at 1.4 volts the Baghdad Battery would have been capable of driving any number of electrochemical processes, which would not necessarily have left direct evidence (for example, if the byproducts of these reactions were consumables such as hydrochloric or sulfuric acid). I am not a chemist, so I hope professionals will recreate my experiment and see what they can do with 1.4 volts. I speculate that something may have been done with electrolysis of water by fuming hydrogen bubbles over sulfur, etc. This was, after all, where early Syriac alchemical writing was emerging. People were absolutely experimenting with metals and salts.
The discovery that the Baghdad Battery actually functioned as two batteries in one also may explain other similar artifacts discovered where the iron rod is missing. A metal tube, lye, and a porous clay pot will get you a metal-air battery (the BB's "outer cell.")
Philip Taylor said,
January 5, 2026 @ 10:45 am
I am following this thread with considerable interest, in part because there was a time in my life when I saw my future career as being a research chemist, and I am not sceptical in the least, merely fascinated. But I have one question for Alexander, if I may ? Alexander, both in your comment above and in your original paper you make reference to "lye", which you define in your paper as potassium hydroxide (KOH). Now the word "lye" is not commonly used in British English, so although I thought I knew what was meant, I wanted to be sure. And Google (amongst other "authorities") tells me that "lye" can be KOH or NaOH (sodium hydroxide). My question is therefore simply "(a) do we know which of these two compounds (if either) was used in the Baghdad battery, and (b) if the other were used, would it make any significant difference ?".
Alexander Bazes said,
January 5, 2026 @ 10:53 am
It is also important to note that these artifacts are quite rare. With only one Baghdad Battery found (the other artifacts being of different design), I'm not sure how surprised we should be not to have physical evidence of what it was used for—whether that be electroplating or something else.
Similar artifacts found at the archaeological site of Csestiphon (several centuries later than the Baghdad Battery) were found in a magician's house, along with other ritual implements. I think that most likely these specialized devices were within the domain of magi/ritual practitioners, and that we are thus best served looking for evidence of how an ancient knowledge of electricity might have influenced the development of alchemical thought.
Alexander Bazes said,
January 5, 2026 @ 11:07 am
Hi Philip,
Thank you for your comment. I really wish the artifact had not been stolen from the Baghdad Museum during the Iraq War so X-ray fluorescence could be done—and then I can be proven totally wrong!
Potassium hydroxide, which was historically rendered from potash, is one of the oldest chemicals known to man, so that is why I thought it would be a likely/reasonable electrolyte to test out. I honestly don't know whether sodium hydroxide would work. (My understanding is that lye originally referred only to KOH and only later came also to refer to NaOH).
Alexander Bazes said,
January 5, 2026 @ 11:52 am
*Correction: "āšipu" was the term I was looking for that describes ritual practitioners.
Philip Taylor said,
January 5, 2026 @ 2:01 pm
Fine, thank you Alexander, and all understood. And I join with you in deploring the theft of this remarkable artifact from the Baghdad Museum during the Iraq War.