Maelzel's metronome Magdeburg hemispheres Magnetic coil Magnetic field of a circular current Magnetic field of a solenoid Magneto-electric apparatus Magneto-electric machine Magnets Mascart's electrometer Manometric capsule Mariner's compass with Cardan's suspension Mariner's compass with Cardan's suspension Marconi's system of wireless telegraphy Mascart's electroscope Mascart's insulator Maxwell's pendulum Meidinger's cell Melloni's bench for the radiant heat Metallic plates

Metallic thermometer (Breguet) Microphone for radio communication Micrometer Micrometric screw Micrometric slit Microscope cathetometer Model of alternator Model of calliper Model of rectilinear Vernier Model of the eye Models of rotors Mohr's balance Morse stations Mousson's recongelation apparatus Moving coil ammeter and voltmeter Moving coil ammeter and voltmeter with basis Moving coil galvanometer Müller's apparatus for the laws of the reflection Müller's apparatus for the laws of the refraction