Page:Electricity (1912) Kapp.djvu/89

Rh a large cage of wire gauze and went into it armed with the most delicate instrument for the detection of electric charges. The cage was placed on insulating supports and strongly electrified by a frictional machine. Not a trace of electrification could be detected in the interior or the inner surface of the wire gauze. The principle of the "Faraday Cage" has been applied as a protective device in various ways. Professor Artemieff, of the Moscow University, has constructed an electrical safety dress, which completely envelopes the wearer so that he is literally enclosed in a tight-fitting Faraday Cage. The dress is of metal gauze, and as long as the surface is continuous, the wearer is absolutely safe from shock. If a discharge flash from a high-tension apparatus should strike him, the charge flows through the dress to earth without doing any damage.

Another important application of the same principle is the protection of underground or submarine cables. The part of the cable that is below the ground or the sea is naturally protected against lightning strokes, but somewhere the end of the cable must be brought out to the surface of the earth and connected to some apparatus or machine. At that point both the end of the cable and the machinery