II. Manometric observations in the electric arc

Abstract

The experiments recorded in my former paper, entitled “Studies on the Electric Arc," together with the numerous observations made conjointly with Professor Liveing on the spectrum of the arc discharge between carbon electrodes in different gases, led me to ascertain if the interior of the gaseous envelope of the ordinary arc showed any peculiarities of pressure. Pressure might be caused by the motion of the gas particles, the transit of material from pole to pole, electric action, or indirectly by chemical combinations taking place in the arc. As any effect due to the above causes must necessarily be very small, a delicate manometer capable of measuring easily the 1/100th of a millimetre of water pressure had to be employed.