I found this picture.


An old mathematician has devised this tool. It is about conic sections.

What does it do? I can't figure out.

Maybe only Arab users can answer this question. The script is written in Arabic.

I understand some of the words such as "برکار" which means compass. And "تام" meaning universal; complete.

It seems this is designed to draw any conic section. But is that possible?

From the translation of the text in the picture, it turned out to be a universal conic section drawer compass.

Now my question is how does it do that?

the most relevant place to ask this, I think, must be here. Because here may be some people who have seen this tool once.

  • 1
    $\begingroup$ You may want to take a look at the two pictures at the bottom of this page. This question sounds more relevant to the history of math and science. Anyway, I found the persian article to be more informative (Yes, I could read it) $\endgroup$ – polfosol Jan 5 '17 at 16:14
  • $\begingroup$ @polfosol The two pictures are very small. And the Wikipedia article doesn't talk about the principle upon which this apparatus was made. I think understanding the way this thing works is more related to math rather than history of math, compatriot! $\endgroup$ – AHB Jan 5 '17 at 18:37

This is a compass, a device for drawing circles by rotating a pencil. The marks measure the angle of the compass (and thus the radius of the circle). The original image can be found on Wikimedia commons.

  • $\begingroup$ Just a simple compass? $\endgroup$ – AHB Jan 5 '17 at 14:59
  • $\begingroup$ Probably, that's what the description says, and I don't see any way to change the angle evenly while drawing, so it can likely only draw circles. $\endgroup$ – zzz Jan 5 '17 at 15:01
  • $\begingroup$ Why two protractors then? $\endgroup$ – AHB Jan 5 '17 at 15:02
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    $\begingroup$ Wikipedia presents it as being a "perfect compass to draw conic sections". Since an ordinary compass can't draw conic sections other than a circle, there must be more to it. References 6 through 10 in the Wikipedia article seem to lead to more detailed descriptions of it. @AHB. $\endgroup$ – Henning Makholm Jan 5 '17 at 15:03
  • 1
    $\begingroup$ My bad, the leg can indeed be moved while drawing. hal.archives-ouvertes.fr/hal-00658217/en $\endgroup$ – zzz Jan 5 '17 at 15:05

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