shown by Small Particles on a Nernst Glower, 213 
simply a sinking of the metal into the material of the glower 
without apparent motion in either direction, but with some 
metals the process involves vigorous action, and shows a very 
definite tendency to proceed in one direction, depending on 
the current (see Table I.). Fluxing may be carried to a point 
where the conduction in the glower becomes largely metallic 
instead of electrolytic, and that part of the glower in con- 
sequence becomes relatively cool. Continued heating at a high 
temperature will vaporize most of such metals out of the 
glower. 
The second case, which is possibly one of only apparent 
diffusion, has been observed with platinum, rhodium, and 
palladium, and is probably characteristic of the less oxidizable 
metals. It consists in the formation of a discoloured streak 
or " tail " extending out from the drop along the surface of 
the glower and ending in a point. In the cases noted it has 
been directed against the current flow, when direct current 
was used (i. e. opposite to the direction of mass motion), while 
with alternating current it is found on both sides of the 
globule. In the case of platinum, it will occur at temperatures 
a hundred degrees or more below the melting-point, although 
the formation is more rapid at higher temperatures. Micro- 
scopic examination of such a platinum trace shows the surface 
of the glower covered with what is apparently a very thin 
layer of platinum for perhaps a millimetre from the globule. 
Nevertheless, chemical tests kindly made by Professor Lenher 
have so far failed to prove positively that the " tail " is metallic 
platinum ; but the minute amount of material present makes 
chemical examination extremely difficult. 
Undoubtedly these cases of diffusion, inasmuch as they are 
unidirectional and depend on the current, imply the existence 
of forces related to those which must cause the mass motions 
above described, but it is impossible to say at present just 
what this relation is ; for there seems to be no fixed relation 
between the directions of diffusion and of mass motion in the 
various cases. 
Conclusion. 
It seems probable that the motions of both solid and molten 
particles are due to the same causes ; furthermore, that the 
forces involved, such as they are, are localized at the point 
of contact of the particle and glower. If we consider this 
fact in connexion with that before noted of the sticking of 
the particle to the glower, involving as it does considerable 
forces of cohesion between the metal and the glower, we 
may perhaps suggest a general explanation of the phenomena. 
