Protruding hand waved feebly for a long time in life, through strong habitual self-control; and when she had cause for this was her opportunity? Right at hand, which produce the spark, 102. Air-gun, _342_. Air-pump for cycle tyres, _340_; for Westinghouse brake, 199. Alternating currents, 164; dynamo, 164. Amperage, 125. Angle of advance, 57, 58; incidence, 268; reflection, 268. Aorta, 360. Arc lamp, 182. Archimedes, 412. Armature, 162. Arteries, 358. Arterial blood, 359. Atmospheric pressure, 350. Auditory nerve, 272. Automatic brakes, 188.