"Linking up," 65. Locks, 430; Barron, 433; Bramah, 437; Chubb, 433, 434; Hobbs, 437; simplest, _431_; tumbler, _432_; Yale, _436_. Locking gear for signals, 205. Locomotive, electric, 178; advantages of, 84. Maudslay, Henry, 363. Maxim, Sir Hiram, 348. Micrometer free wheel, 441. Micro-photography, 265. Microscope, 254; compound, 261, _263_; in telescope, 257; simple, _254_. Mineral oil, 392. Mirror, parabolic, 261, _262_; plane, _267_. Morse, 132, 145; code, 128; inker, 142; sounder, 132. Motor car, the, 92; electric, 177. Mouth.