Fountain PEN is a pen of silver, brass, or other metal, so contrived as to contain a considerable quantity of ink, and let it flow out by degrees, to supply the writer a long time without his being under the necessity of taking fresh ink.
The Geometric PEN is an instrument by which a right line, a circle, an ellipse, and other mathematical figures, may be described by a circular motion. It was first invented and explained by Suardi, in a work entitled Nuovo Instrumento per la Descrizione di diverse Curve antiche e moderne. Several writers had observed the curves arising from the compound motion of two circles, one moving
round the other; but Suardi first realized the principle, and reduced it to practice.