Magnetism, [202]

Matter, constitution of, [5]

Megohm, [172]

Microfarad, [104]

Mil-ampere, [71]

Mil-henry, [83]

Modulation, [145], [230], [237], [239]

Molecule, kinds of, [6];
motion of, [35]

μv, [190]

Multiplex telegraphy, [258];
telephony, [258]