hilden's

Updated: April 30, 2025

To solar light, an artificial one has been preferred. D'Acquapendentus' bottle has given way to the convex lens, and to concave, spherical, and parabolic mirrors, etc. De Hilden's speculum has been replaced by cylindrical, conical, bivalve, and other forms of the instrument.

Various - Scientific American Supplement, No. 488, May 9, 1885