Nicomedes's Mechanism for Constructing a Conchoid

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This Demonstration gives Nicomedes's (c. 180 BC) mechanism for constructing a conchoid. The mechanism consists of three rulers. Two are perpendicular; the horizontal one has a slot and the vertical one has a fixed peg at . The third ruler, , has a fixed peg at that slides along and a slot that lets it slide along .


You can vary the distance between the points and B and the length .


Contributed by: Izidor Hafner (November 2012)
Open content licensed under CC BY-NC-SA




[1] T. L. Heath (ed.), The Works of Archimedes, New York: Dover Publications, 2002, p. cvii.

[2] D. E. Smith, History of Mathematics, Vol. II, New York: Dover Publications, 1958, pp. 299–300.

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