944 THE BELL SYSTEM TECHNICAL JOURNAL, OCTOBER 1951 



molten metal blown out from the arc crater by the pressure of metal vapor. ^"^ 

 The metal from the crater is deposited in a rim about it and upon the 

 negative electrode. There is considerable roughening of the negative elec- 

 trode but none of its metal has been found upon the anode. This roughen- 

 ing indicates, no doubt, that a small fraction of the energy is dissipated 

 directly upon the cathode. Estimates of the amount of metal transferred 

 from positive to negative, made after many thousands of closure arcs, have 

 shown that about 1 per cent of the metal from an anode crater reaches the 

 cathode. Microscopic examination of the surfaces after a single arc reveals 

 that the transferred metal upon the cathode seems to be much greater in 

 amount than the 1 per cent found after many arcs. There is thus a distinct 

 disagreement between the results of transfer measurements after many 

 arcs and what one sees upon the surface of the cathode after a single arc. 



Measurements of the present paper could be accounted for by assuming 

 that most of the energy of a closure arc is dissipated upon the anode in 

 melting and boiling metal, and that the energy is then located in this dis- 

 placed metal with 58 per cent of it finally freezing on the anode and 42 per 

 cent on the cathode. This tentative conclusion agrees with microscopic ob- 

 servations upon the electrodes after a single closure arc but is in sharp 

 disagreement with the results of measurements of transfer of metal resulting 

 from many arcs. 



At the time this paper is being written it is felt that more penetrating 

 experiments are called for, and in particular transfer measurements upon 

 both active and inactive surfaces under experimental conditions which are 

 better controlled than any which have been made previously. 



" L. H. Germer andF. E. Haworth, Phys. Rev. 73, 1121 (1948) and Reference 11, Figs. 

 5 and 6. 



