IV. The pressure upon the poles of the electric arc

Abstract

Suspending one pole of a carbon arc and keeping the other pole fixed it was found that there was an apparent repulsion between them. There is in fact a pressure upon each electrode which tends to separate them. The first part of this paper is devoted to the experimental methods of estimating this pressure, the second to a discussion of its origin. Part I.—Experimental. Three series of observations have been made, the original observations and preliminary series by Duffield in 1912, the second series in conjunction with Burnham, and the third in conjunction with Davis. In spite of the very small forces examined the three series agree within reasonable limits. The general form of the apparatus (fig. 1) was the same in each series, though there were important differences in the dispositions of the carbons in different sets of experiments.