Discussion on “arc phenomena” (Collis), San Francisco, Cal., Sept. 16, 1915. (see proceedings for September, 1915)

E. B. Merriam (by letter): Mr. Collis has given us some very interesting data concerning arcs as influenced by the shape of contacts in oil circuit breakers. It will be observed, however, that his results were obtained with comparatively small currents and moderate operating pressures, i.e., 200 to 300 amperes at 6600 volts. Consequently, the arcs produced were comparable in magnitude with the contacts used and a very decided mutual influence should be expected.