The #paperOfTheDay is the most bizarre one I have read in the whole #dailyPaperChallenge so far: It's "Geometrisches zur Abzählung der reellen Wurzeln algebraischer Gleichungen" from 1892. It is well known that a polynomial equation of order n has exactly n complex solutions. The present article deals with the question how many of these are real: Consider for example a quadratic equation, its curve is a parabola, and a parabola can have zero, one, or two intersections with the y=0 axis. These cases can be distinguished by a calculation, without drawing the curve. More generally, in equations of higher order, these things become more involved, but Klein argues that they still correspond to concrete questions in geometry.
What is so special about this article is where it appeared: In the book "Katalog mathematischer und mathematisch-physikalischer Modelle, Apparate und Instrumente", published by the Deutsche Mathematiker-Vereinigung. That is, in 1892 the German mathematical association published a printed book about mechanical calculation devices and physical equipment, which also contained a few pure #mathematics research articles. The common theme of all this is that it is in some way related to visualization or geometric realization of mathematics.