Geometry for Entertainment (1950) | Hacker News Reader

Geometry for Entertainment (1950)

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178 pointsthe-mitr47 comments

This one is new to me. I still have my copies of Physics for Entertainment and Mathematics can be fun by the same author - Yakov Perelman. I owe my superfast stereogram decoding skills ( < 2 seconds most of the times ) to him :)

Here's an interesting tidbit from his wikipedia page - He is not related to the Russian mathematician Grigori Perelman, who was born in 1966 to a different Yakov Perelman. However, Grigori Perelman told The New Yorker that his father gave him Physics for Entertainment, and it inspired his interest in mathematics

The book is no more. It has been taken down, and I cannot find it anywhere.

Could you kindly email it to me? I will be grateful.

I read “Physics For Fun” by the same author (translated to Kannada, my native tongue) in highschool. Terrific book. I would read it all the time, would open a random page and read a few articles.

This was at a time when India-Russia friendly relations were at their peak so in order to carry out cultural exchange Indian government funded translating a ton of Russian books to local languages here. Sadly the initiative seems to be dead as I don’t find such books anymore.

a lot of Indian geeks of my generation grew up on "mathematics can be fun". amazing book.

I read the same book, also in Kannada. It was bought by my father when he was in high school. Of all the science books I have read, this one was more engaging and had a bigger impact on me growing up.

My father said he used to buy lot of soviet translations because they were cheap but the content was of high quality. Even after 30 years, when I picked them up, they were clearly distinct, including the Art, print quality and binding.

I read much of the book, too, but translated to Bengali, in High School. I borrowed it from my Chemistry teacher who was in his late-sixties then.

My father had some excellently produced Russian fairy tales translated to English.

It was printed in Russia, by Raduga Publication.

Such books with thick pages, full color images, and custom fonts didn’t exist back then (1970s) in India. They were prized possessions.

Now there are volunteer efforts to digitize such books for nostalgia reasons [0][1].

And due to USSR-India cultural exchanges people of those generations were exposed to Dostoyevsky, Tolstoy, Pushkin, Gogol, Solzhenitsyn, and many more. Many sexagenarians still seem to quote from them!

[0]: https://mirtitles.org/tag/bengali/

[1]: https://sovietbooksinbengali.blogspot.com/p/blog-page_1.html

The name of the "translator" didn't strike me as one that a native speaker of either Russian or English would have.

Sure enough:

  I have made use of machine translations for the bulk of the text, and the results are quite satisfactory. At times, I have used several translation services to ensure I am on the right track and that the meaning is not lost in translation. Though, of course, there might be places where I have not translated correctly. I learnt to read the Russian in a very rudimentary way in the process.

Fascinating!

Damitr Mazanav doesn’t (modulo some variation in transliteration into Roman characters) sound Russian to you?

edit: looking at the introduction written by the translator, he/she appears to be possibly… Indian?

It’s weirdly close to Dmitry Mazanov, though, which would seemingly be a reasonable Russian name.

No, it doesn't.

Mitr in Hindi means friend.

Mazanav sounds like "majha naav", which means "my name" in Marathi, the language spoken in Mumbai (which is where the translator seems to live / have lived).

So, in summary - my name is the friend. Hello Mitr!

Translator here:

"Damitr" is literally the acronym for my name and Maza-nav माझा नाव in Marathi means my name.

Translator here:

It is literally the acronym for my name and Maza-nav माझा नाव in Marathi means my name.

You have to quote "my name" to protect it from evaluation :)

The translation is really bad. The very first paragraph is practically nonsensical. There are several sentences that are either badly wrong or maybe russian idioms translated directly. Machine translation is ok for a rough idea but it's not good enough to put out in the world and call a translation.

You're right that the first paragraph is bad - but it's uncharacteristically bad. Maybe the translator/editor was still warming up his workflow at the start and never went back to revise it for some reason.

I think you'll find the bulk of the book to be much better. At the very least, the English prose itself flows beautifully. And clearly the typesetting and restoration of the illustrations are truly top-notch. The first few pages are really an aberration.

Considering the project is open source at https://gitlab.com/mirtitles/perelman-geometry, I'm tempted by the obviously-high level of effort to help patch up a lot of these problems in the early chapters.

Translator-typesetter here, yes you are right, I was to revisit the intial few pages and was "warming up" this was one of my first attempt. Will do so in the upcoming revision

It's somehow became trend to make statements that there hasn't been good physics/math/etc books in the past and that's why many are so bad at these subjects. Perelman is a very good counterargument to use with everyone grown up in Soviet Union. His books are really legendary among 50+ people and I still have all of them on my book shelf.

any other gems from https://archive.org/details/mir-titles ?

You can look for other works by Perelman in the collection. Also there are several popular science/mathematics books.

I am the maintainer/curator of the mirtitles blog

धन्यवाद, looking through VA Uspensky and PS Alexandroff currently.

> with everyone grown up in Soviet Union.

also in India. Generations of people have been inspired by his books.

I've actually seen the opposite trend: that modern textbooks are bad, and therefore the students are as well.

I thought the quality of many of these old Soviet books was well known. Gel'fand's Algebra, for example.

Typo in page 281: The mnemonic in French has almost all offsets wrong because it considers "j'aime" as one word instead of two. If anyone feels like making a pull request, the source is at [1].

Correct:

  Que j'aime à faire apprendre un nombre utile aux sages !
  3   1 4    1 5     9         2  6      5     3   5
  ...

[1] https://gitlab.com/mirtitles/perelman-geometry/-/blob/master...

Also "Jmmortel" in the following sentence (unless that J character was chosen for stylistic reasons).

That looks like a misspelling of "Immortel" to me

Thanks! will update. -- I am the translator-typesetter

The archive.org page now says "This item is no longer available. Items may be taken down for various reasons, including by decision of the uploader or due to a violation of our Terms of Use." What's that about?

Ah.. I remember purchasing a Yakov Perelman's math puzzle book many years ago (as a high schooler).

Just heard about this. Let's see...

Edit: Access to files is available here at the git repo

  https://gitlab.com/mirtitles/perelman-geometry

The book is no more. It has been taken down, and I cannot find it anywhere.

Could anyone kindly email it to me? I will be grateful.

Here

https://gitlab.com/mirtitles/perelman-geometry

Thank you!

1950?

according to https://math.ru/lib/81 , (1950) 206pp [edition of 150k copies]

Is this the original edition? The layout is fantastic for its age.

No, this is a 2024 translation into English from Russian. The original is at https://archive.org/details/20220910_perelman_geometry/

I am perpetually annoyed by the argument "the Sun's rays are parallel" made here and many other places. They tell you to take a single point on the sun, and draw a big skinny triangle from there to different points on the Earth, showing that the angle is very small.

But any child can look at the sun (with eye protection :) and see that it is a disc, not a point of light. The disc is about 0.5 degrees, which is not so small.

So, two rays emanating from opposite ends of the Sun and arriving at your eye are clearly not "effectively parallel." Of course, 0.5 degrees often is small enough to not matter in some contexts, but it's just annoying to me that the "start from a single point on the Sun" reasoning is used to draw a conclusion that flies in the face of simple observation.

Sorry, rant over (:

It's much easier to solve physical problems when you make as many simplifying assumptions as possible. These reduce the complexity of the problem and the amount of error-prone bookkeeping, without, in context, materially affecting the outcome.

We all inevitably make a wide variety of assumptions of this type constantly when we work with any real-world system. They are a basic requirement for doing science and engineering. Literally every achievement of our technological society is built on top of a heap of simplified models of reality which are imperfect but usually good enough for the purpose demanded of them. We should celebrate them rather than moaning about them.

And then, in the appropriate context where it is meaningful, we can peel back our models and examine a richer situation.

Oh absolutely. I have no objection to the approximation. I have an objection to the shoddy reasoning put forth in its favor.

If they said "0.5 degrees is small enough to ignore in this case" that would be fine. But instead they give this argument about how the angle is 0.00138 arc seconds, when that's clearly not the full story.

What chapter has that? I didn't see it searching the gitlab.

I was talking about page 10 of the PDF [1], in Chapter 1 (odd, the original link in this HN post is now taken down).

The part starting: "The rays of the Sun falling on the Earth can be considered parallel because..."

As another commenter pointed out, the following paragraphs do mention the penumbra and solar disk, but I feel like the reasoning put forth in that initial paragraph is simply wrong (though common), even if it's briefly expanded upon afterwards. Or maybe it's just an artifact of the translation that it comes across sounding more authoritative than it is.

[1] https://gitlab.com/mirtitles/perelman-geometry/-/raw/master/...

It's not wrong. It's just casually presented and not perfectly precise. the Chapter is about applting geometry in the real world, not idealized mathematical models.

It is standard in empirical science to focus on first order effects, and then to address 2nd-order effects, which the book does in the following pages.

Page 10 is a talking about how the angle of shadow is independent of subject position (human or pole), on the order of ~10m, and so we can treat all shadows at the same moment in time in the local area as similar. (Obviously shadows are not similar when comparing someone in Russia to someone in Mexico at the same time.) This is in contrast to a shadow from a streetlamp, where the angle changes from 45 degrees to 80 degrees over the span of a few meters of relative subject position.

This is true, and the 0.5-degree error due to the size of the sun is not important to the overall result, which is already appromixate to a similar level of precision, and is the same for all subjects.

electrons flow in a wire

acceleration is constant

light travels at c

and other lies. the whole thing is a sham i tell you!!

electrons _do_ flow in a wire?

According to which set of physical laws?

those of our universe

> But any child can look at the sun (with eye protection :) and see that it is a disc, not a point of light. The disc is about 0.5 degrees, which is not so small.

Page 11-12 explicitly discusses "sun-as-a-disk", the resulting shadow penumbra and other sources of inaccuracies.

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