Needle capacity apparatus Newton's coloured rings Newton's disk Newton's tube Nicholson's areometer Nobili's galvanometer Norrenberger's apparatus Oersted's experiment Optical bench for showing the teory of telescopes Pacinotti's magneto-electric machine Pacinotti's ring winding Palmer's micrometer Pellat's apparatus Piezometer Phosphorescent substances

Photocell Plane angular mirrors and parallel mirrors Pneumatic oil pump, Fleuss type Pneumatic pump Pneumatic tinderbox Polyprism Polyphase motors Porro's telescope Precision scales Prismatic glass tanks Psycrometer