title: When Huygens and Mariotte agree.
abstract: Edme Mariotte in the seventeenth century attributed halos to tiny ice prisms in the atmosphere. Christiaan Huygens attributed them to tiny spheres or cylinders. The two seemingly incompatible theories largely agree in their predictions for the common halos. This article explains why.
authors.affiliation: University of Alaska, Department of Mathematics 6660, Fairbanks, Alaska 99775-6660, USA. ffwrt@uaf.edu
authors.forename: Walter
authors.initials: W
authors.lastname: Tape