About volcanos and earthquakes.--The sun.--On comets.--The weather and weather prophets.--Celestial measurings and weighings.--On light: pt. I. Reflexion, refraction, dispersion, colour, absorption. pt. II. Theories of light, interferences, diffraction. pt. III. Double refraction, polarization.--On sensorial vision.--The yard, the pendulum, and the metre.--On atoms.--A dialogue.--On the origin of force.--On the absorption of light by coloured media, viewed in connexion with the undulatory theory.--On the estimation of skill in target shooting.