Hot answers tagged

170

Euler did write this, but it was not a mistake! Euler's statement was correct under his own definition of the notation that he was using. I looked at the PDF version of Elements of Algebra linked to in SCappella's answer. Reading Section I, Chapter XIII, I found that Euler wrote that most numbers have two square roots, which matches the definition of the ...


151

The Romans built the aqueducts -- as well as bridges, piers, and colossal buildings -- out of concrete. Stone and brick were usually just exterior casings for the concrete structural core. And the secret of super-durable Roman concrete was indeed lost for centuries. Modern concrete uses a paste mixture of water and Portland cement (a fine powder made from ...


93

TL;DR: Rated (old) urban legend Based on this website, this story dates from as far back as 1897, from a magazine called "The Strand". This appears in section which looks like a collection of various jokes and "fancy stories". You can find the original article below (the one about the claim is in the bottom left corner): It reads: This story has been ...


87

Yes. It is real, and filmed originally in colour, as is, not colourised later. General Edwin Graf von Rothkirch und Trach, the author of this clip, (alternative version to the one in question) was an avid amateur photographer and movie maker. As such he followed the developements of colour motion picture technology, which was invented in the 19th century, ...


84

The Twitter thread gives an explicit source for this letter, 'A Reluctant Icon: Letters to Neil Armstrong'. by James R. Hansen. This book exists, from Purdue University Press, ISBN 9781557539694 The publisher's blurb says: Artfully curated by James R. Hansen, A Reluctant Icon: Letters to Neil Armstrong is a companion volume to Dear Neil Armstrong: Letters ...


82

No. They used a sentence that includes "mathematica" and condemns and forbids it, but they were not using a modern definition of "mathematician", which gives the sentence a very different interpretation. A Latin Dictionary defines "mathematicus" as: măthēmătĭcus […] A. Măthēmătĭcus 1. A mathematician 2. An astrologer (post-Aug.) Also compare ...


82

Q Has a virus ever escaped a high-level virus lab? Yes, depending on definitions. How deadly pathogens have escaped the lab — over and over again Most appropriate candidates for an inappropriately cherry picking and restrictive reading of the claim in question: the 1977 "red flu" occurring from China or Russia is thought o be most likely a failed ...


68

As it usually is the issue with those questions: what counts as someone being killed by the Soviet Union changes the answer. And that is supposing we have reliable numbers of the cause of deaths in the first place. Soviet archives were only released in 1991, as such it was extremely difficult to assess the situation before then. It is also particularly ...


43

Strictly speaking, the quoted claim is most immediately one about Hans Sloane's writings. So if this is an accurate description of what Sloane wrote, Olusoga is telling the truth. Olusoga is not specific about which writings he is referring to. At least some of Sloane's writings are relatively easy to find online, but so far, I'm not able to pinpoint quotes ...


37

A similar text was published on Instagram on April 29, 2020 by Véronique de Bure, a French author and one of the directors for Flammarion, a well-known French publishing house. Un texte similaire a été publié sur Instagram le 29 avril 2020 par Véronique de Bure, une auteure française et directrice littéraire chez Flammarion. Translation of the accompanying ...


35

I think the author did derive this from a real description of "candy." However, I find no support for the novel's depiction of Leningrad's books being decimated by people eating the bindings. The real "sweet dirt" or "candy" was sugar-infused dirt mixed with various types of glues available in households of the time. Judging by ...


34

The knowledge of how to build aqueducts was not lost. See Vitruvius and Frontinus among other texts. Some few techniques that were more practical knowledge among workers might not have been written down, though. Musk is totally wrong here. The real reason people after the Romans didn't build aqueducts is not that they couldn't. It's because if you don't ...


32

It's hard to prove a negative, but here are some points against its authenticity: This 12-volume edition of Madame de Sévigné's letters doesn't have any letter dated 30 April 1687 (the date given in the link). My French isn't so good, but I didn't immediately see any mention of plague in the letters around that date. This shorter, searchable edition doesn'...


32

Yes. But he did not have to do that in such a clandestine, private manner. Using "admit" in the question title is a bit leading. He — among many others, it was absolutely no secret — wrote to that effect publicly from at least 1979 onwards. Der angestrebte 'Mokkatasseneffekt', das war der Wunsch der währungsstarken Länder zur Verteilung der durch ...


25

Euler did argue that √-2 √-3 = √6. Whether this is a mistake depends a lot on context. This appears in Euler's 1770 publication Elements of Algebra in Section I., Chapter XIII. (pdf link). Moreover, as √a multiplied by √b makes √ab, we shall have √6 for the value of √-2 multiplied by √-3; and √4, or 2, for the value of the product of √-1 by √-4. Thus ...


22

For the US, we have pretty detailed record keeping of how many slaves were imported, but for North Africa we do not. The number of African slaves imported to the US is about 300,000, only a fraction of the approximately 12.5 million that were brought to the Americas in total. As for the number of white slaves brought to North Africa, it depends on whose ...


18

This answer focuses specifically on Queensland's capital Brisbane, since its history is best documented, but the general principles would have applied to other towns as well. 1) Is it true that these streets were used to curfew indigenous Australians? Yes, it is -- but the naming predates the policy. More specifically, boundaries were defined to set the ...


18

@hdhondt's comment on the question made me aware that I totally missed the image is embedded in a thread and it's about the book "A Reluctant Icon: Letters to Neil Armstrong" . It seems the letter of the teacher is from 2000, so Neil does indeed mean the Internet. That makes the whole story quite plausible.


16

I found a full account of pre-computerized reservation systems on Wikipedia's Reservisor article. The account is sourced to a single book, which I cannot get due to worldwide library closures, but compared to the accounts in the question it has far more details on what made the binoculars necessary. At the time, bookings were handled by a system known as &...


16

Was it cheaper to starve a slave to death and to replace him than it was to provide him with food? It depends on what you mean with "starve". Starve has two meanings according to Merriam-Webster: 1a : to perish from lack of food - b : to suffer extreme hunger Definition #1 If we were to take the first definition, the claim would come down to: A slave was ...


15

Yes. But a lot of context is needed to understand that list and the list makers intentions, methods and intellectual capabilities. Imprecise. Very imprecise, but yes, if it is meant as "locations", not countries. And if given an actual list of places where this is said to have happened, it is quite an anachronistic or more often ahistorical ...


15

TL;DR: It's complicated... Evidence shows that Hitler genuinely tried to become vegetarian in the early 30s, with some failings at times due to occasional consumption of ham, liver dumplings or some of the chefs adding meat without telling him. Ian Kershaw - historian notable in particular for his biographies on Hitler and nazi Germany - published several ...


15

tl;dr: The words "Hakenkreuz" and "swastika" describe one and the same symbol, one time in Sanskrit and English, one time in German. Some believe that this 'is' an ancient Germanic symbol, some that it 'is' an ancient Indic. Both these schools argue with archaeology and unbroken tradition, Both claim that this is inherited from a not ...


10

1) Did Galileo teach sciencific theories which were not yet proven? The Jesuit Cardinal Robert Bellarmine thought that there was not sufficient proof in his time. He wrote, in his 12 April 1615 letter to the Carmelite priest Fr. Foscarini* (my emphases): I say that if there were a true demonstration that the sun is at the center of the world and the ...


9

John Brown was a militant abolitionist. He led a militia in the "Bleeding Kansas" crisis - a conflict over the question of whether the Kansas territory would allow slavery or not. He later organized the Harpers Ferry raid, an attempt to initiate a slave rebellion in the South. Wikipedia has a well-sourced article on the funding of the raid which ...


9

This looks like a made up claim, perhaps for educational purposes. I found it made in Paul Sloanes: "Lateral Thinking Puzzles", 1991. On page 24, "Historical Puzzles, 3.7 War Aims" and that exact solution on p83. No source given, just a puzzle to teach stats. (Like re-used here.) Biggest problem in this detail: The British helmet went ...


8

The Bisbee Deportation described in the book, in which Harry C. Wheeler "arrested" 1200 striking miners at machine gun point and then abandoned them in the desert is well attested by other sources. In 1917, during another strike at the Bisbee mines, he deputized and armed two thousand citizens, and sent them out at dawn to arrest striking miners and ...


7

As a partial answer, according to the 1987 book Systems and Theories of Psychology, volume 2, page 410: We conclude our discussion of the Stroop effect with a story for whose veracity we cannot vouch. It seems a man was accused of being a Russian agent, a charge which he vehemently denied. He claimed to know nothing even of the Russian language. His ...


7

The oldest example of the quote that I see is the 10 December 1903 Christian Register at page 1455: It is told of the younger Pitt that, in looking round for more earners and still more to meet the demands for more money and still more to carry on the war with Napoleon, the great statesman said, "We must yoke up the children to work in the factories." ...


7

A quick glance through those Wikipedia pages that exist for strikes and even "labor wars" quickly confirm these numbers. One example for such wars would be the Illinois coal wars with around 24 deaths. During the Copper Country Strike of 1913–1914, a number of above 83 people from the 'labor' side died. Another of these wars even featured machine ...


Only top voted, non community-wiki answers of a minimum length are eligible