Talk:Water clock

Headings
Converted to lowercase headings, as per Manual_of_Style.--Semioli 14:17, 24 July 2006 (UTC)

Invention
There is contradictory information in the introduction of the article and the "Egypt" section regarding the invention of the water clock. The introduction claims that it is unknown who invented the water clock or where, but the "Egypt" section provides a person and place. —Preceding unsigned comment added by 68.46.110.248 (talk) 07:10, 8 November 2009 (UTC)

Royal Gorge
No mention of the water clock at the entrance to Royal Gorge, CO, USA?

It is now mentioned.

Hill reference concerning "Toledo"
This reference discusses the water clock constructed in around 1050 by the astronomer al-Zarqali on the banks of the Tagus in Toledo Spain, not "To". I have the reference if anyone is still uncertain about its title.

Isn't a gnomon just part of a sundial?
What am I missing here:

"Water clocks, along with the sundials, are possibly the oldest time-measuring instruments, with the only exceptions being the gnomon and day-counting tally stick."

Isn't a gnomon just the main part of a sundial? In which case why is the gnomon an exception to "Water clocks, along with the sundials"? -- That's a great question. A gnomon is a part of a sundial, but this isn't its only purpose. For example, if you take a stick and put it in the ground vertically and watch its shadow move over the course of the day, the stick is called a gnomon. Most writers on early timekeeping will refer to this method as the earliest way in which man observed the movement of time. Is a stick in a ground a sundial? No, sundials are usually a bit more complex and use a gnomon as just one of its parts. In some cases, you'll even see an obelisk refered to as a gnomon. There is one change that should, however, be made to the article though, and that is adding the word "vertical" before gnomon. Your question made me reread Turner, which is where I got the information. Some how, it was ommitted...I hope this answers your question. If not, let me know and I will attempt to research it more (time permitting). I just really trust Turner, he's a very good source.

I just looked at the Wiki gnomon article. The article really lacks a good historical background.

What about sand glasses and candles for measuring time?
I would have thought sand glasses and candles would have been in very common use before the pendulum clock was invented. In which case I doubt the accuracy of this:

"While never reaching the level of accuracy based on today's standards of timekeeping, the water clock was the most accurate and commonly used timekeeping device for millennia, until it was replaced by the more accurate pendulum clock in 17th century Europe." ---

The accuracy of the water clock increased dramatically over 2,000 years ago by Ctesibius of Alexandria and the Han dynasty in China. Ctesibius introduced mechanical gearing with temporal hours, automata, and a feedback control system. I have never heard of a sand glass or candle clock that could match timekeeping on this level. Have you? I'd love to see it if you have! So, the "the most accurate" part, I believe is quite accurate.

As far as the second part, "commonly used" goes, I can see this as being generally debatable among scholars, but far from being a source of contention. I'd like to hear what historians have to say on this. But I don't see this as a big issue. If you can prove otherwise, change it.

Hydrochronometer
I suggest the article Hydrochronometer be merged with Water clock. Biscuittin 07:57, 20 July 2007 (UTC)

- I suggest it be stand alone. Speciific water clocks like Su Song's clock and the elephant clock warrent their own article. I think that this is no differnt. However, it should at least be mentioned in the Modern water clock designs section.

I included a link on the Hydrochronometer page for the source info, but that article really needs to be expanded.

England section and other recent edits
Topics that are loosely related to the Wiki article do not belong. I suggest recent editors refer to Wikipedia's topics: Relevance of content and Policies and guidelines.--jimmaciejewski —Preceding unsigned comment added by Jimmaciejewski (talk • contribs) 04:36, 3 September 2007 (UTC)

too many references
This page needs to have far fewer references or way more text to be brought in line with wikipedia's guidelines. If you don't know about them, reply here and I'll find them for you. Pdbailey 22:01, 1 December 2007 (UTC) --

How many refs are allowed in accordance to Wiki's guidelines? I'd love to add more content, as much more is needed. The problem is time. Even going through and selectively removing some refs could be laborious. I'm probably the most qualified to do so, since most of the content and refs came from me. Guidelines would be helpful. It's too bad though, because these are really good - it's like a dream for anyone doing research on the subject; half the work is done. Jimmaciejewski —Preceding comment was added at 04:24, 2 December 2007 (UTC)

Babylon or Babylonia?
Are the early water clocks from Babylonia, or just the city of Babylon? The article says Babylon (the capital of Babylonia), but I find it hard to believe that the technology wouldn't have spread. Twilight Realm (talk) 00:03, 21 October 2008 (UTC)

Inflow, outflow?
Could someone explain what these mean in regard to water clocks?? The article mentions them as if they are obvious. Not to me at least. APW (talk) 09:06, 17 January 2010 (UTC)

The simplest way to explain it is this...Inflow has 2 vessels and Outflow has only 1 vessel. With the Inflow, you have one vessel where water flows into the other, and the other is used to actually measure time usually by a floating device). The Outflow can either be a timer, which was used in ancient Rome and Greece, especially for timing lawyer's speeches (pictured at the top of the page of the article); or, an actual clock, as was the case in ancient Egypt with the Karnak example. The Egyptian water clock had indicators inside the walls of the clock to tell the time. Hope that helps! Jimmaciejewski (talk) 00:33, 20 April 2010 (UTC)

What is a water clock?
This page is interesting, but after reading it I still have no idea what a water clock is. I feel as though this page should be titled History of the Water Clock, and there should be another article here whose primary purpose is to explain what a water clock is, and how different types of water clocks work. Jun-Dai (talk)
 * I totally agree! i came here to learn what a water clock is, and how one works, and what the common types of designs are... and i still don't know the answers to any of these questions! InsertCleverPhraseHere InsertTalkHere 01:28, 16 December 2015 (UTC)

Iran
I moved this from the page for now:


 * use of water clock in Iran dated back to 2500 years ago and it had been used primarily to distribute share of water of shareholder of qanat in desert of Iran especially in qanat or kareez of gonabad. but later it was also used to determine exact holy days of pre islamic religion such as: newrouz and chelah or yalda means longest - shortest and equal days and nights of the years. Ancient water clock used in qanat of gonabad 2500 years ago.JPG    in Islamic period then it was also used to announce the exact time of prayers.

because it seems dubious. First, there are no refs. Second, the picture claims to be of a pre-islamic clock, but it is self-taken and it isn't clear what it is. I'd guess it is merely a bowl similar to such a thing. I'm dubious about the claim that it was used to determine shortest and longest days William M. Connolley (talk) 11:21, 6 January 2012 (UTC)

Viscosity
Right now there is in the article the claim that because of temperature dependent viscosity water clocks cannot be accurate. But viscosity only gets interesting in hydrodynamics at low Reynolds numbers.
 * $$ \mathrm{Re} = {{\rho v L} \over {\mu}} = {{v L} \over {\nu}}$$

For water the kinematic viscosity $$\nu\approx 10^{-6}$$ m²/s, so unless the water clock is build on micrometer scale it should be dominated by inertial forces, with viscosity being irrelevant – and at that scale pressure changes as a result of surface tension will get important too. Typical Reynolds numbers in water clocks are more likely in the range 2000–10000, with the big modern ones (I once saw the one in Berlin) near 100000 (yes, I know they are actually pendulum-controlled). Or am I missing something? PiusImpavidus (talk) 20:11, 30 July 2013 (UTC)

Viscosity is not necessary the main factor that influences the accuracy of the water clock, which I supported with a reference and edited to make the claims in the rest of the text in the section more clear in which case the claims would apply. However the old content of the section was never supported by other citations, so there's more work to be done. Janjs (talk) 01:13, 14 April 2016 (UTC)

Fenjaan accuracy
I have removed the statement "Water clocks, or Fenjaan, in Persia reached a level of accuracy comparable to today's standards of timekeeping." This is uncited and directly contradicted by the lede which says "While never reaching a level of accuracy comparable to today's standards of timekeeping, the water clock was the most accurate and commonly used timekeeping device for millennia" and by the "Temperature" section which says "ancient water clocks (unlike the modern pendulum-controlled one described above) cannot have been reliably accurate by modern standards." Mnudelman (talk) 22:47, 3 January 2014 (UTC)

External links modified
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Requested move 16 December 2015

 * The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section. 

The result of the move request was: Not moved due to lack of support below. Additionally this article does go beyond simply history, although barely. Tiggerjay (talk) 01:46, 23 December 2015 (UTC)

Water clock → History of the water clock – This article does not describe how a water clock works at all, but rather is only about the history of water clocks, a new article should be made to discuss different types of water clocks and how they work. InsertCleverPhraseHere InsertTalkHere 01:41, 16 December 2015 (UTC)

Alternatively, a very large overhaul of this article to include that information is necessary. For now, anyone coming to this page to find out how water clocks work will be very disappointed (as I was). Unfortunately this article seems to have been written by people who clearly understand how a water clock works and how the different designs compare to each other, but neglected to include any of that information in the article. This article is better titled the 'History of water clocks' given the information currently contained within it. InsertCleverPhraseHere InsertTalkHere 01:41, 16 December 2015 (UTC)
 * Oppose. The article may need additional information but there's no need to rename it. -- Necrothesp (talk) 15:16, 16 December 2015 (UTC)
 * As I said, that is another option. Currently the title is very inappropriate given the content. InsertCleverPhraseHere InsertTalkHere 17:39, 16 December 2015 (UTC)
 * Wikipedia is an open project that is always being expanded. Narrow naming isn't especially helpful, given this is the only article we have on water clocks. -- Necrothesp (talk) 09:26, 17 December 2015 (UTC)
 * I don't agree. as it stands this article is not what it claims to be about. Unless someone has the expertise and offers to do the work necessary to change the article to match the title, it should be changed to reflect the article content until such time as it is expanded. InsertCleverPhraseHere InsertTalkHere 23:06, 17 December 2015 (UTC)


 * Weak oppose - I don't necessarily agree with changing the page name to accommodate its contents because if a user expanded the page outside of the "history" scope, it would not be relevant to the newly titled page. Meatsgains (talk) 00:32, 19 December 2015 (UTC)


 * The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

What is a water clock, revisited
Re the concern that the article is too heavy with history, and doesn't offer basic information about the subject: the close on the move discussion notes that the article does go beyond simply history, although barely. Could the article be improved by moving the section "Temperature, water viscosity, and clock accuracy" to the top, from its current position at the very bottom? Also, comments from in 2010  show that the desired information may be scattered among the copious historical sections. Maybe a paragraph or two extracting information focussed on the technical would help, too. Willondon (talk) 02:54, 23 December 2015 (UTC)

Chronological order standardised/emphasised
The articles here on clocks seem to be in a tangle that adversely impacts chronological understanding, as well as overall development and quality. The article [Clocks] begins with sundials though with no dating information (except a ref to "ancient times") and follows this with a section on water clocks that are stated as being the oldest. The [History of Timekeeping] article begins with Egypt while much later showing China provides the earliest example of (water) clocks. This article begins with Persia .... though I've corrected that so that at least here the regional sections are now in conventional chronological order (oldest first). LookingGlass (talk) 10:16, 28 May 2017 (UTC)

External links modified
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Many grammar and syntax errors in section "Uses of water clocks"
I was doing some research for a project and noticed the above section is very poorly written but I lack the knowledge or time to fix it beyond minor edits.

Can someone please help out?

DaddyDevito (talk) 22:48, 5 February 2020 (UTC)

Some contradictions in article
The introduction claims that water clocks were invented in Athens Greece, yet states that they were present in civilizations predating it (Mesopotamian, Persian, and Chinese civilizations). Can someone clear that up? DaddyDevito (talk) 22:47, 5 February 2020 (UTC)

definitions of 'clock' versus 'timer'
I think it should be noted in the article that the earliest, simplest "water clocks", consisting of two vessels, actually served as timers only. That is, they were capable of measuring an interval of time, but could not actually be used to determine the time of day, as does a real clock. That only became possible when the inflow clock was invented by Ktesibios (see ScienceDirect dot com ) Another useful source is an old History Channel documentary titled "Ancient Discoveries", which I just viewed and prompted me to post this comment. They show a shot of a real klepsydra on display in an Athens museum, which they attest was unearthed from a well in the Athens agora. They state it was used to allot time to lawyers arguing in the law court. For those interested I highly recommend this documentary if you can find one for sale. Last I saw they were going on Amazon for something like 50 or 60 bucks.

BTW another thing that show mentions is that water clocks are the origin of the expression "running out of time". I checked the web and can't find any possible cites for this. I'm tempted to put it in the article, but I'm not so sure about what the opinion is about using a History Channel doc. as a sources. Comments anyone? Wikkileaker (talk) 14:25, 16 March 2020 (UTC)

Calisthenes reference
I have removed some claims attributed to Callisthenes regarding water clocks in Persia circa 328, these were justified in the peer review. The only reason to ever reinstate this claim would be if we can find any of the follwing:


 * An extant work by Callisthenes where he mentions Persian water clocks, the period of this work should be between 330 BC (Battle of the Persian Gate) and Callisthene's death (328 or 327 BC).
 * An extinct work of Callisthenes of the same 330-327BC period, later referenced by another historic author.
 * With caveats like "Some authors consider.." (and a secondary source backing it up) if the citation appears in Alexander Romance historically attributed to Callisthenes, but now known to not be his work.

--TZubiri (talk) 02:29, 16 December 2020 (UTC)

Problem with Needham references
Could someone reconcile or consolidate the Needham references (Science & Civilisation in China) on this page? The dates of publication look wrong. Volume 4 is listed twice in the references with the dates 1986 and 2000, but the records I can find show the publication year as 1965. Volume 3 was originally published in 1959. The 1986 edition in Taipei is probably a reprint or later edition, but it should still list the original publication date to make it clear that it's the same book. And then I can find no record of a 2000 edition at all, even with the ISBN provided. Some of the later volumes of the series, not cited here, were indeed published more recently, but often with other contributors or editors (note that the the author died in 1995). Someone familiar with the material might be able to fix this or clarify. R Prazeres (talk) 16:49, 10 April 2022 (UTC)

Water clock
Japanese

Egypt Perrisan 196.189.16.125 (talk) 11:23, 30 September 2022 (UTC)

How the Clepsydra work in Shiva Temple
The principal deity in all Shiva temples is a Linga, a tall circular cylinder smothered at the top like a hemisphere and embedded into / enclosed by a flat circular disc tapering at one corner with an indent or a gradual slope for free outflow of water. Above the Shivalinga, there will be a clepsydra hanging from four corners or by four hinges. From a small aperture at its bottom, sealed by the Bael leaf to regulate the outflow, water drips onto the Linga in drops continuously. Water contained in the clepsydra will be emptied in a civil day (time between two continuous sunrises at a place) or sixty (60) ghatis. [According to Aryabhata I, the Earth revolves 1 minute arc in 4 seconds or one-sixth of a Vinadi. And a Vinadi is that length of time taken by a man in normal condition to pronounce sixty (60) long vowels with a moderate flow of voice/ six respirations.]

Nauduri Murty (talk) 07:48, 23 January 2023 (UTC)

Egyptian image
The caption of the Egyptian image says "Fragment of a basalt water-clock, with evaporation time markers on interior as dots on djed and was hieroglyphs. Late period, 30th Dynasty. From Egypt. The Petrie Museum of Egyptian Archaeology, London" But there are neither djed nor was hieroglyphs on the block in the photo and the surface is clearly convex. I'm unsure whether the image is showing us the exterior of the clock or if the label is actually referring to something else in the cabinet. Either way it is (a) not a very helpful image and (b) based on a handwritten note by an unknown individual! An image of a complete, published Egyptian clock would be far better! Furius (talk) 19:14, 9 March 2024 (UTC)