A Manual of Natural Philosophy ...

air-pump angle aperture apparent magnitude appear atmosphere attraction axis ball becomes bottom called centre of gravity centrifugal force colors concave concave lens convex convex lens cord course crystalline lens cylinder diameter diminished direction discharge distance double-convex lens downward earth effect elasticity electricity equal excited experiment eye-glass fall feet figure fluid focus force friction inches inclined plane instrument insulated inverted length Let A B lever Leyden jar liquid magnet manner means mercury metallic mirror motion move needle north pole object observed particles pass perpendicular person piston plane plate polarized portion position pounds pressure prime conductor prism produced pulley quantity QUESTION ray of light reflected refracted represented retina rise screw sealing-wax seen shown side solid sound south pole space specific gravity spectrum substance supposed surface suspended telescope tion upper usually valve velocity vessel vibrations weight wheel wire