Actinometer, [120]

Alternating current, [82], [100]

Ammonia, [123]

Angle of stylus, [24], [78]

Aniline dye, [123]

Arcing, [27], [82]

Arc lamps, [15], [120], [121]

Atmospherics, [61], [85]

Ballasting resistance, [100]

Belin, [47]