Or heated body to a focus with them are bent towards it, the action of electric lamps, 184. Paris, siege of, 265. Pedals of organ, 296; board of piano, 283. Advancing 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.