﻿874 Dr. E. N. da C. Andrade on the Carriers of 



current, large compared with the usual metallic current, was 

 obtained without any field being applied. The direction of 

 this current corresponded to the assumption that negative 

 charges were received by the strip, and was, no doubt, due 

 to electrons shot out by the net (which from its fineness was 

 much hotter than the strip) being received by the strip. If 

 the net w r as insulated and earthed through the galvanometer, 

 a current was observed if an earthed strip was present in the 

 flame ; if the strip was insulated or absent no current was 

 obtained. In this case there must be approximate equili- 

 brium between the accumulated electrons in the flame and 

 those given out by the net, but as soon as an earthed strip 

 is in the flame the electrons can escape as they are produced, 

 and fresh ones are given out by the net, producing the 

 observed current. 



If the net is earthed, and the strip connected through the 

 galvanometer to earth at a distance of about 1'5 cm. from it, 

 the introduction of a bead of salt(SrCl 2 ) into the flame makes 

 no appreciable difference to the observed current unless the 

 luminous metallic vapour is in contact with the net, when 

 the current observed from the strip is very much increased 

 (four or five fold). If the strip in the flame is directly 

 earthed, and the net earthed through the galvanometer, when 

 the streak of luminous metallic vapour is brought into con- 

 tact with the net, the current observed is increased in a 

 similar manner. This show T s that the impact of the metallic 

 atoms of the vapour against the platinum must be able to 

 liberate electrons in large quantities from the metals. The 

 process may, of course, be considered not as direct impact, 

 but as " Nahewirkung " (see P. Lenard, Annalen derPliysik, 

 [4] xvii. 1905, p. 244). 



§ 6. The Faster Carriers come only from the edge cf the 

 Luminous Vapour. 



To see if the fast moving positive carriers were driven out 

 from throughout the volume of the metallic vapour, or only 

 from the edge of the luminous streak remote from the 

 positive electrode, as was suspected, a second bead of salt 

 was brought into the flame between the first bead and the 

 positive electrode, and level with the first bead. It was 

 found, with the platinum strip in various positions, to produce 

 no appreciable increase in the galvanometer deflexion. 

 Hence it may be assumed that the faster carriers do not 

 proceed from the volume of the vapour, but travel out from 

 the neighbourhood of the edge only. This is most important 

 for our theoretical considerations. 



