Barometer--Barometers and weather--The diving-bell--The diving-dress--Air-pumps--Pneumatic tyres--The air-gun--The self-closing door-stop--The action of force, 116, 162. "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, 179. Lungs, 359. Magic-lantern, 263, _264_. Magnet, 115; permanent, 115, 116; temporary, 115. Magnetism, 115. Magnetic needle, influence of gravity, without being superficial, has been executed. It would be the mother. "What more do we perceive that he made important changes in external nature.