Testwiki:Reference desk/Archives/Language/2024 March 5

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March 5

Does anyone know what this charcter is?

At s:Page:Cyclopaedia, Chambers - Volume 1.djvu/351, in the second column in the original text, in the second paragraph of the section on the equal sign (the one starting with Template:Tqq, the sixth paragraph to start from the top of the page) there is a weird symbol that looks like a backwards ∝. Does anyone know if this is represented in unicode? I can't find anything, but it must have been somewhat common, since the publisher of the book would have had to have it in print (the book was published in 1728). 🌺 Cremastra (talk) 21:57, 5 March 2024 (UTC)

This page describes mathematical notation used by Descartes: [1]. He introduced some notations that are standard today, but the backwards "∝" for equality is one that didn't catch on. I can't find it in Unicode or in any modern usage. Here's a book with more history on Descartes' equals sign and our modern one: [2]. --Amble (talk) 23:18, 5 March 2024 (UTC)

(Edit Conflict) The relevant paragraphs state '= is the Sign of Equality' ... 'Des Cartes in lieu of it uses ∝'.

Equals sign states:

So I suppose it might be a sloppily OCR-recognized Template:Char or Template:Char), unless someone would be a bigger expert on Descartes. 惑乱 Wakuran (talk) 23:23, 5 March 2024 (UTC)

I read the same paragraph in equals sign, and had the same thought, but OCR mistakes don't really make sense in an original text. I think I'll extract an image from it and insert it into the transcribed text for now. Thanks, 🌺 Cremastra (talk) 00:15, 6 March 2024 (UTC)

Or you could do this: Template:Rotate text. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:39, 6 March 2024 (UTC)

Or this: ∝ ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:10, 6 March 2024 (UTC)

Ah, hadn't thought of that, thanks. 🌺 Cremastra (talk) 13:31, 6 March 2024 (UTC)

When books were manually typeset using movable type, the typesetter could insert a type piece turned upside down, rotated by 180°, or rotate it by just 90°, which explains why many $\mathrm{\infty }$ symbols in older printed books are not rotationally symmetric, like Template:Serif : they are the figure Template:Serif on its side. This can explain its use here if Template:Serif was available in type.  --Lambiam 11:16, 6 March 2024 (UTC)

Florian Cajori's A History of Mathematical Notations says that Descartes "probably intended" his equality sign "to represent the first two letters in the [Latin] word aequalis" (so in effect it was meant as an ae-ligature like æ), but the symbol that was typeset was probably the sign for Taurus, rotated anticlockwise 90°.

By the way, the double horizontal line for an equals sign is usually credited to Robert Recorde.

--142.112.220.50 (talk) 18:28, 6 March 2024 (UTC)

Courtesy link: A History of Mathematical Notations#External links. 2A02:C7B:210:BA00:8458:F303:FDB1:5E14 (talk) 19:00, 6 March 2024 (UTC)

Amble already linked the book (and indeed the relevant passage) in the first response to this query, above. Deor (talk) 21:09, 6 March 2024 (UTC)

Thomas Harriot's symbol may have been substantially different from our present symbol,^[3] more like $\mathrm{\top }\mathrm{\perp }\mathrm{\top }\mathrm{\perp }.$ More info (based on Cajori) can also be found in MacTutor's Earliest Uses of Symbols of Relation. Recorde may not have been the very first, and he used his Template:Serif only in his 1557 book The Whetstone of Witte, in the lengthy, somewhat cumbersome form "=====". It is unclear when the use of our Template:Serif of much shorter but of equally Template:Serif became widespread.  --Lambiam 22:53, 6 March 2024 (UTC)

There's a story that during WW2 someone adapted typewriters for various Asian languages, and in Burmese he got one of the letters upside-down. When he became aware of his error, he offered to correct it but was told, never mind, it is now an accepted variant. —Tamfang (talk) 19:49, 7 March 2024 (UTC)