Although the electric arc is perhaps the oldest field in elec- tronics, it is still one of the least well understood. The beautiful and complex phenomena accompanying the conduction of electricity in gases have led to the development of spectroscopy (and thus of atomic structure and quantum theory), discovery of isotopes, of the electron itself, of X-rays and thus to Moseley's discovery of atomic number, to the discovery of electron emission, and thus to modern electronic technology as well as to much of modern physics. The properties of the plasma state of matter, which until relatively...