Wikipedia:Reference desk/Archives/Science/2016 May 4

= May 4 =

Newton trying to convince people that energy is physical
Hi all - is it true that Newton found it difficult to convince others that energy is physical, in the same way that people find it hard to think of information as physical? If so, can someone cite some references? Thanks Adambrowne666 (talk) 02:38, 4 May 2016 (UTC)
 * This is a bit philosophical. I'm not a student of Newton or anything, I did some university physics, but I'm not sure any physicist considers "energy" it self to be physical. In fact I find this is one of the biggest misconception held by most people; that energy IS a physical "thing", that you can have a jar full of "energy" or a ball of "energy" can fly through space, or that the human body has some "energy field", or that there is such a thing as "pure energy". Energy is a property of physical things or systems, it's not it self a physical "thing". Vespine (talk) 03:54, 4 May 2016 (UTC)
 * Unless of course you mean Mass–energy_equivalence then I take back all of the above, but Newton predates that by a few centuries. Vespine (talk) 03:55, 4 May 2016 (UTC)


 * Yeah, maybe I'm putting it wrong - what I mean is, I've heard that Newton had difficulty in getting people to think of energy as a thing - a property that can be discussed in the same way that weight is... Am I getting closer? Adambrowne666 (talk) 04:12, 4 May 2016 (UTC)
 * Riiight. Ok, i think I understand. I have not heard about it specifically related to Newton, are you perhaps thinking of Caloric theory? Vespine (talk) 05:20, 4 May 2016 (UTC)
 * Did Newton's even have a conception of energy? I'm not sure that he did. I thought that energy was largely developed as a concept in the 19th Century, in part because of heat–kinetic energy equivalence noted in the steam engine, and in part from Hamilton's reformulation of mechanics. — Preceding unsigned comment added by Star trooper man (talk • contribs) 10:18, 4 May 2016 (UTC)


 * "Earlier workers, including Newton and Voltaire, had all believed that "energy" (so far as they understood the concept at all) was not distinct from momentum and therefore proportional to velocity." From Conservation_of_energy. More good stuff in that section too. SemanticMantis (talk) 13:57, 4 May 2016 (UTC)


 * I would have thought that the problem was the reverse of that. Newton was an alchemist - and some of those guys (but evidently not Newton) believed in Phlogiston theory - where phlogiston is a physical substance (albeit with a negative mass!) that had properties somewhat similar to the modern concept of "energy".  So I'd have expected Newton to have to work hard to demonstrate that energy was not a physical thing - but merely a measurement akin to "mass", "charge" or "temperature". SteveBaker (talk) 01:05, 5 May 2016 (UTC)


 * Take the idea that the sun warms the ocean and causes water to evaporate. Then some of that water falls upon high ground and forms a river which runs downhill and works a mill. which grinds corn. Today, we all understand that energy is being transferred from one form to another, but is conserved. If it is cold, less rain is formed, and less wheat is ground. This everyday notion of the conservation and transformation of energy is so common today that we forget that is was an alien concept before Newton. Philosophers assumed that different types of natural events had their own way of doing things, Celestial objects worked according to their own laws, very different those which were found on Earth. The vitalist forces which made life possible were set apart from those which determined the weather. The notion that energy permeates very different systems, and is conserved, that is, cannot be created or destroyed suddenly made a single calculus the measure of ALL things, and thus was, probably, the foundation of modern science. I presume that this is what is meant by the OP talking of energy being physical. Myles325a (talk) 05:21, 5 May 2016 (UTC)

Thanks for your answers, all - it's clearly a case of memory being a peeling wallpaper over the walls of the vast chamber of forgetting - still, it's good to have it cleared up Adambrowne666 (talk) 01:01, 6 May 2016 (UTC)

Why is a kidney dish so shaped?
The WP page for this: Kidney dish provides a few pictures, and notes that bowl" is a shallow basin with a kidney-shaped footprint". I immediately imagined that they must be equipped with some ambulatory prowess, and wondered if such were kept under lock and key when they were not being used. Perhaps, the mundane "base" might have sufficed. The article notes that the dish is shaped so it can be held against a curved surface such as a torso, and collect blood more efficiently than a dish with straight sides could. Fine. But I had long thought that some shapes for dishes render them more stable, and less inclined to tip over, and others are inherently unstable. The kidney dish, I had long-thought, was one of the former. Can anyone throw some light on this? I believe that dishes with circular bases are the most unstable. But have there been any experiments with dishes being pushed, jolted and tilted to see which shape is the most stable? Myles325a (talk) 07:28, 4 May 2016 (UTC)
 * AFAIK (which isn't a reliable source) the shape is indeed from that of blood-letting bowls, where the concave edge made them useful for catching the most blood (or whatever else is falling out of a patient). The rest is convention and the fact that even when a kidney-shaped bowl isn't useful for a particular task, it isn't a drawback and it allows them to stack with the other kidney-shaped bowls. Instrument trays though are rectangular, as they make better use of space on a small trolley.
 * I think the shape is based on the upper rim, not the base, and that stability doesn't enter into it. Stability is mostly about the steepness of the sides (shallow sides make a narrow base and that does reduce stability). Shallow sides also make for more splashback. Nursing 101 of course explains why not to try to catch vomit in any shallow dish-shaped bowl. Andy Dingley (talk) 10:32, 4 May 2016 (UTC)


 * Here is a circular bowl (with a circular base) that is very stable. http://www.academy.com/shop/pdp/ruffin-it-stainless-steel-dog-bowl-018946848p--1 It depends on more than just the footprint. 196.213.35.146 (talk) 10:36, 4 May 2016 (UTC)

OP Myles325a back live. Thanks number man, this lovely image is that of a dog bowl, where the rim curves inward, not straight up or outward, probably because that set up helps contain the food within the bowl as the dog wrestles with and devours it. Is this configuration more or less stable than bowls with rims which curve outwards, or is it all the same? I would opt for the former because, while the centre of gravity remains the same as with the inward-pointing rim, the outward-pointing rim is inherently more unstable. For example, the dog could suddenly press down on the outward rim tipping the bowl towards him. This cannot happen with the inward-pointing rim bowl. I would hazard a guess and say that while the centre of gravity’s position is important to stability, it is NOT the be all and end all of the matter. The inward-pointing rim bowl has its mass distributed over a smaller area, making it harder to upset. Myles325a (talk) 04:04, 5 May 2016 (UTC)


 * Any rigid body resting on a flat surface is in a stable state if its Center of mass lies over its base area. Round vases, bottles, dishes etc. with circular bases are not inherently unstable but vary in their critical tippling angles $$A$$ which measure how far they can be tipped to one side and still return to their upright position.
 * $$A = arctan ( r / h )$$
 * where $$r$$ is radius of the base, $$h$$ is height of the center of mass. A tall bottle with a small base has small $$A$$ and is only weakly stable since a slight tilt will topple it; conversely a symmetrical solid Cone object that has large $$r$$ with small $$h$$ has large $$A$$ so it is difficult to topple. A kidney dish has largest $$A$$ (is least liable to topple) when it is empty because filling the dish raises $$h$$. The dish's resistance to toppling is least ($$A$$ is small) in the direction of its short dimension. The characteristic curvature in its long dimension makes almost no difference to its overall stability. AllBestFaith (talk) 12:01, 4 May 2016 (UTC)

OP Myles325a back live. Thanks, AllBestFaith, you have done more to address this quest ion than anyone else. Leaving aside the maths, it is obvious that (say) a vase with a circular base and with a low perimeter is more stable than one with the identical base but with a tall perimeter, as per your bottle example. Note that both vases have the same centre of gravity. Thus this thought experiment shows that centre of gravity is not the only feature influencing stability. But my query is not directly concerned with the matter of how rims affect stability, which has been settled by your answer, it is more concerned with how the layout of the base affects stability. So we could assume for all cases under consideration, the rim is straight up, and its height is derived as a function of the area of its base. (And of course, they are all made of the same material Myles325a (talk) 04:19, 5 May 2016 (UTC)

OP Myles325a – This just in. AllBestFaith, you note that “A kidney dish ...(is least liable to topple) when it is empty... Let me see if I have got this right. You would intuitively expect a full bottle to be more stable than an empty one, as its weight makes it harder to tip over. But then, a dish with a big base relative to its low perimeter might well be inherently unstable. Think of carrying a frying pan full of water. The greater the area of the pan’s base, the more likely it is that the water will begin to slosh about and spill. But these considerations are perhaps sidetracked by questions of fluid dynamics. If we put sand rather than water in the pan, it would be far more stable. Myles325a (talk) 04:35, 5 May 2016 (UTC)


 * A kidney dish has a flat bottom so shouldn't tip over because of instability. --TammyMoet (talk) 14:05, 4 May 2016 (UTC)


 * The answer to the question is this sentence in the article: "The shape of the dish allows it to be held against the patient's body to catch any falling fluids or debris." ←Baseball Bugs What's up, Doc? carrots→ 14:15, 4 May 2016 (UTC)


 * I remember being in 6th grade or thereabouts and reading about medical and surgical practice. When I read about "kidney dishes" in the hospital I assumed it was designed for a surgeon to deposit an excised kidney in, and wondered if there were specific named dishes for each organ which might be removed. ("Nurse! Bring me a spleen dish, an appendix dish and a gall bladder dish!") Edison (talk) 16:03, 4 May 2016 (UTC)
 * Shocked doctor: "No, no nurse, I said Remove the patient's SPECTacles" AllBestFaith (talk) 22:54, 4 May 2016 (UTC)
 * I've always rather fancied getting some kidney dishes to serve kidneys in. Soup goes in a soup bowl, gravy in a gravy boat, so why shouldn't kidneys get their own dish? DuncanHill (talk) 22:59, 4 May 2016 (UTC)
 * What kind of dish are you going to use for the spotted dick, and will you put two appropriate vessels of Rocky Mountain oysters in a bag along side? DMacks (talk) 23:29, 4 May 2016 (UTC)

OP Myles325a rides again. Thanks, Edison; this is kinda a cross twixt an eggcorn and a mondegreen. I rem the Walrus and the Carpenter poem from “Through the Looking Glass”. A couple of lines from there go: “To talk of many things: / Of shoes--and ships--and sealing-wax--...For many years I thought it was “ceiling wax”, which I assumed was some special compound like fine plaster to coat the rosette around a pendulous light. It is pure felicity that a misconception like that should occur via Lewis’ work, which plays extensively with such constructions.

I think that I have nutted out a bit more of this problem. A circle is the most compact way of containing a given area. So it is the most unstable. If you take the same area (a hamburger patty) and spread it out (a sausage) it becomes more stable. The kidney dish is a more stable way of organizing the base area because it spreads the outer circumference of the dish. So a U is more stable than a O. And if we twisted one side of kidney dish to face the opposite direction, it would form an S, and that would be even more stable. If you do not think this is plausible, think of a circular base of a radius of (say) 10 centimeters. Now imagine taking that circular base and extruding it so it forms a long rectangle that is only a centimeter wide. Is not that shape very stable. Now imagine taking this long rectangle and making it into a loose spiral that has a radius much larger than the original circle. This kind of base would be very stable indeed. It becomes impossible to think of how it could be tipped over. Myles325a (talk) 05:26, 5 May 2016 (UTC)


 * And to top it off, we can fill in the needlessly unused spaces in that long spiral and make it a circle, so it is most stable of all. :) ... I have no idea, I really don't ... :) Wnt (talk) 21:06, 5 May 2016 (UTC)

Symbol & in Html
what is the html code to get this symbol & ???--Ip80.123 (talk) 09:56, 4 May 2016 (UTC)
 * . See more at &. PrimeHunter (talk) 10:25, 4 May 2016 (UTC)


 * Also, see ampersand, which is what the symbol is called. ←Baseball Bugs What's up, Doc? carrots→ 13:29, 4 May 2016 (UTC)

Recovering data from Iphone soaked in salt water
This question would apply to Iphones or other digital devices with memory chips which are recovered after being immersed in water or recovered from a wet environment. Two 14 year old boys went fishing in the Atlantic ocean in a small boat and were lost at sea. The boat was found months later and hundreds of miles away complete withe their celphone, which had been soaked in salt water. A news article said it might be impossible to recover any stored data such as videos, voice memos, notes, GPS locations, or numbers dialled, since it was claimed 'the entire phone had to be functioning" to recover data. It is said to be a "newer model" Iphone, and might have the same passcode issue as the terrorist iphone which the FBI had someone hack. My basic question is, why couldn't the Mobile DDR be unsoldered, cleaned, and downloaded to a backup storage, so there is no possibility of deleting the contents from too many attempts at the passcode, and then brute force attempts be made in cracking the passcode. If the cloned chip is erased after 10 attempts, reload the source data and try the next 10 sequential passcodes. This could easily be automated, and 10000 attempts should take way  less than a day. Are there other chips which store data on an Iphone which make it different than any other Iphone of the same model fresh in the box? In other words, does the memory chip only function with its fellow chips from the original phone? Is a "recent model Iphone" passcode restricted to 4 digits, or can it be longer and more varied? How well sealed are present-day chips against ingress of water into the plastic encapsulation? I would expect there are many cases where someone wants to retrieve data from memory chips which have been immersed in saltwater, and there are reports of data recovery after "days" of immersion in saltwater. In this case it was "months." Are memory chips tested at all for maximum data survival while immersed? Edison (talk) 16:39, 4 May 2016 (UTC)
 * This and This imply it is not as simple as you make it out to be. -- Jayron 32 16:45, 4 May 2016 (UTC)
 * I didn't "make it out to be simple." I just asked why if was impossible even in principal.Is it possible to unsolder a chip from a circuitboard in an Iphone, if you have the training and tools? Having achieved that step, the question is whether the data on the chip can be transferred to another memory chip. Someone found a digital camera which had been dropped in the ocean 4 years earlier, and had no trouble recovering all the data, after a good cleaning. In criminal cases where a phone was buried or tossed into the bay, or if loved ones were drowned in a boat accident, small plane crash or hurricane, someone might be interested enough to pay someone to do even painstaking steps to recover data. The news story said that one would have to power up the original Iphone to recover the data, and I'm asking if that is correct. Is the Mobile DDR chip that much more fragile in saltwater than the camera chip which was downloaded after 4 years in the ocean? Edison (talk) 17:11, 4 May 2016 (UTC)
 * As I read this question, Edison is specifically asking about iPhone, rather than about a generic modern digital device at large. Per the publicly available iOS Security Guide, "Every iOS device has a dedicated AES 256 crypto engine built into the DMA path between the flash storage and main system memory, making file encryption highly efficient."  Clearly, a highly-capable and well-trained, well-funded organization could have the equipment to carefully disassemble the hardware... but even if you were able to remove the nonvolatile storage hardware without damaging it - and if the hardware was undamaged by exposure to the natural elements - the contents are strongly encrypted.  One would not be able to trivially decrypt the content, and even with a brute-force attack, it would be very difficult to recover any data.  The nature of strong encryption implies that one would not even be able to locate the data that was securely encrypted: the user's protected data would be completely indistinguishable from empty space on the file-system unless you could break that encryption.  Nimur (talk) 18:47, 4 May 2016 (UTC)
 * Beyond what Nimur has said, you seem to be confusing different things. As the article you linked to says Mobile DDR is a form Dynamic random-access memory i.e. Volatile memory. While there has been some observed Data remanence in certain forms of DRAM for minutes or hours, and longer if cooled, none of these are likely in the scenario you outlined or really most scenarios with a phone. Perhaps the only likely would be if the phone is still on and you think there's something useful in the RAM. However it's very risky since you risk damaging something and the the earlier link makes me wonder if you even have any hope of recovery (most phones now use mobile DDR derived from DDR3 or may be even DDR4 AFAIK). In truth even if you could recover, the difficulty of access etc means it's going to be very rare anyone attempts to recover data from mobile DDR. Remember you have to do it quick before the data is no longer recoverable probably in a cooled environment.  Recovering data from the non volatile flash memory storage is a different matter. But as has been said by Nimur, recovering the data is of limited utility if you can't decrypt it. And depending on the design of the phone, decrypting it may be very difficult if all you have is the flash memory content and not whatever was in some other chip which may store part of the decryption system. You will have to bruteforce the whole key rather than simply the password, passphrase, PIN or whatever.  Nil Einne (talk) 19:59, 4 May 2016 (UTC)
 * So while it was recently proven it might not be "IMPOSSIBLE" to crack an iPhone's security features, it took, probably THE most well resourced intelligence agency in the world several months to get into one phone, for reasons of, literally, national security. We still have NO idea how they actually did it. For all we know it might have included a secret deal with apple, or even an apple "mole". It seems unlikely anyone would be in a similar position and willing to spend the same amount of resource to get some data from the phones of 2 people who were confirmed lost at sea. Vespine (talk) 01:46, 5 May 2016 (UTC)


 * The FBI isn't an intelligence agency. Also, they have stated publicly in broad terms how they got in; they bought an exploit from an Israeli cracking firm. Obviously it's up to whether you believe them, but the story is very plausible. There are dozens of these firms that specialize in finding exploits. Basically all software is buggy and full of undiscovered security holes. For instance, here's the latest massive security hole in widely used software, just revealed the other day. --71.110.8.102 (talk) 05:58, 5 May 2016 (UTC)
 * I'm not certain if precisely who they bought it from was ever revealed see e.g.  . However who they paid seems to be mostly beside the point. And Vespine's comment suggests some confusion about what the FBI actually did. As far as we know, all they seem to have done is gotten around the artificial time and trial limitations allowing them to keep trying PINs fairly quickly, which is what they wanted Apple to do for them     . This exploit is largely irrelevant to what's proposed by Edison namely simply removing the flash chip. I don't think we know precisely how it works, there was some very early speculation here  but what the FBI have since disclosed suggests there's no physical modification of the phone needed. Since the problem seems to be at least partially that it's likely some components are damaged, I guess you could move the flash and security chip to another phone of the exact same design if they were working fine. And this probably won't work partially because of software. In that case you may need an exploit similar to the San Bernadino case. But that's a lot of ifs. Nil Einne (talk) 09:34, 5 May 2016 (UTC)
 * BTW, I should perhaps clarify that I'm in agreement with Vespine's basic point namely that the cost involved means there's a fair chance no one is going to be willing to do it. I'm just saying that concentrating on the security aspect is likely missing the point. It's probably a factor in that it means having gone through all that efforts, there's a reduced chance of recovery and a risk of more costs. (Although realisticly even without the security aspect, it's still likely to be very difficult to predict if you'll get anything useful and how hard it'll be.) But it's also a long way before you even get there. Nil Einne (talk) 20:06, 6 May 2016 (UTC)
 * "71.110.8.102:The FBI isn't an intelligence agency.". The opening line of our FBI article: The Federal Bureau of Investigation (FBI) is the domestic intelligence and security service. I admit I have not researched in depth exactly how it was cracked, my point was: it was. Vespine (talk) 23:16, 5 May 2016 (UTC)

Cookies in a Tin - Nitrogen?
High-quality (sometimes imported) cookies (any language variant) are sometimes sold in a tin that is sealed with a plastic-like or cellophane-like sealing material, which is easily ripped off when opening the tin. I remember that, in the past, occasionally when such a container was opened, there was a slight hissing sound. That would have indicated that the tin had been evacuated and that the cookies were vacuum-packed to ensure freshness. (Is there a pun to vacuum-packing? How can nothing be packed in a tin?  Well, the cookies are not nothing, just packed in nothing.)  Sometimes these days there is no sound on breaking the seal, but the cookies are fresh several months after the tin was sold. Presumably the original reason for evacuating the tin was that oxygen can react with the cookies and cause them to become stale. If there is no sound on breaking the seal, that suggests that the tin wasn't evacuated. My question is: Are the cookies preserved by packing them in nitrogen or carbon dioxide? I can see that any reaction with carbon dioxide would be slower than with oxygen, and with nitrogen would be even slower. (While monatomic nitrogen is an extremely reactive gas, diatomic nitrogen is about as inactive as a gas can be that isn't truly an inert gas, because the dinitrogen triple bond is one of the strongest bonds known in chemistry. That is, those nitrogen atoms really "want" each other.)  When a tin of cookies or other food is sealed, is nitrogen used to ensure freshness? Robert McClenon (talk) 16:49, 4 May 2016 (UTC)


 * This article looks interesting. As does This video.  -- Jayron 32 16:52, 4 May 2016 (UTC)


 * These how it's made-type videos are like Qoyaanisqatsi, but without the moralism. Asmrulz (talk) 23:03, 4 May 2016 (UTC)


 * In fact, it is more important to keep out moisture and light - though an inert gas may be used in some cases (it rather depends on the type of biscuit). 81.132.106.10 (talk) 17:20, 4 May 2016 (UTC)


 * Jayron32 deliver good references as usual. Lets consider the question of whether a cookie tin could have a full vacuum inside. An old standard science experiment to demonstrate the pressure of the atmosphere, around 14 pounds per square inch, was to boil water in a 1 gallon metal can with a screw-top, made of steel of similar thickness to a cookie tin. Once the small amount of water in the bottom was boiling good, and the can was full of steam, the heat was shut off and the cap was screwed on. Immediately the can was crushed nearly flat, as the steam condensed and there was no pressure inside to counter the atmospheric pressure outside. The lamer experiment today uses an empty unsealed Coke can with stem inside which is crushed when inverted i a pan of cold water. But similar to your experience, I have purchased ground coffee in a plastic cylindrical container, with a metallized plastic seal on the top. When the plastic is punctured, air hisses INTO the can and the concavity of the seal is reduced. Maybe they ship it with some of the air removed, or with some of the air removed and nitrogen replacing it.Maybe the ground coffee resists the crushing of the container. I wouldn't expect cookies to resist can crushing at all. If the gas in it is nitrogen, though, I don't see the point of the reduced pressure. To save nitrogen? Edison (talk) 17:35, 4 May 2016 (UTC)


 * Stem? DuncanHill (talk) 23:02, 4 May 2016 (UTC)


 * Highly unlikely a tin could withstand full atmospheric pressure with a vacuum inside. The cookies would crumble because of the pressure changes too. But a small pressure differential may be created if the cookies are put in the tin at a high altitude or slightly warm. Water vapour present in the tin may be absorbed by the cookies, creating 1 kPa or so underpressure before the air in the tin is dry.
 * If any preservative gases were added to the tin it should be mentioned on the packaging. At least, in Europe it should be mentioned. Look for statements like "packaged under a protecting atmosphere" or whatever it is exactly in english or your language. Have a look at packaging gas and E number, in the range 938–949. PiusImpavidus (talk) 19:24, 4 May 2016 (UTC)


 * Yes, a hissing sound is associated with reduced pressure packing but inert gases can be used in combination. Where there is no hissing for cookies containers I hazard a guess that its argon and its E number may not appear. Being mono-atomic it changes the partial pressure of water vapor ensuring the cookies (or whatever) stay dry (desiccates bacteria too). The best answer would be to get it from the horses-mouth. The packaging will have either a web address or customer care-line number, consumer services department or something. Google the company to find their contact us details and send them an email. When I worked in industry we often received these sort of odd-ball inquires and we answered them the best we could. It was viewed as an important part of PR. So I can guarantee you, that you will get a reply.--Aspro (talk) 21:10, 4 May 2016 (UTC)


 * Note that the hissing sound during opening doesn't necessarily mean it was stored under reduced pressure intentionally. Either it might just have happened to be in a slightly different air pressure environment when it was sealed than when it was opened, or the act of opening the package may itself increase the volume, and thus decrease the pressure, as pulling the cork out of a wine bottle does. StuRat (talk) 14:58, 5 May 2016 (UTC)


 * The hissing also seems to be evidence the container was well sealed, and presumably helps reinforce the customer's trust in the hygiene of the product. This is also OR, but I note StuRat's idea above, though reasonable, suggests we should see an outflow of air frequently from products packed at sea level (especially since so much comes by ship).  Yet I've never seen an outflow of air, because everyone associates it with botulism beans and such.  In good, out bad, and that seems reflected in the marketplace. Wnt (talk) 21:10, 5 May 2016 (UTC)


 * It's rather shameful that nobody mentioned the vacuum packing article before now, which says potato chips may be packed in nitrogen. Wnt (talk) 10:25, 8 May 2016 (UTC)

Somme river flooding
Hello,

How often and how severely does the Somme river in France flood? Where can I find data on this? — Preceding unsigned comment added by 140.233.173.140 (talk) 20:46, 4 May 2016 (UTC)
 * Our article Somme (river) has statistics for the past few decades, and the French article fr:Somme (fleuve) has more data. From the latter: « Les crues, quant à elles, sont rarement importantes, sauf en cas de saturation de la nappe phréatique, comme ce fut le cas en avril 2001. » - approximately translated "Floods, on the other hand, are rarely significant, except when saturation of the water table occurs, as was the case in April 2001". Tevildo (talk) 23:18, 4 May 2016 (UTC)

So, for example, around how often do significant floods occur? (significant as in may have caused significant damage to a medieval town) I'm a bit confused by the data. — Preceding unsigned comment added by 140.233.173.140 (talk) 01:02, 5 May 2016 (UTC)
 * This has a timeline (page 6) and this discusses things to some extent. I googled inondation somme Thincat (talk) 08:28, 5 May 2016 (UTC)