PROFESSOR THOMSON ON THE ELECTRO-DYNAMIC QUALITIES OF METALS. 751 
part of the magnetic field ; and the conclusion was, that the conducting power of the 
plate, when magnetized, became greater across than along the lines of magnetization, 
which was confirmed by every repetition and variation of the experiment. Now it 
is obvious that the intensity of magnetization must have been on the whole greater 
in the parts of the disc next the poles : hence a diminution of conductivity across 
the lines of magnetization, to the same extent as that which we know from Experi- 
ment 1 . exists along them, would give a contrary effect to that now observed ; and it 
follows that the electric conductivity is in reality greater across than along the lines 
of magnetization in magnetized iron. 
177. This experiment was witnessed by Mr. Joule, and afforded a full confirma- 
tion of the conclusion (§ 172 ) which had been established by Experiment 5 . above, 
and which follows from Experiment 1 . and Experiment 6 ., considered together. The 
effects of applying pieces of hot wood equatoreally or axially to the disc were very 
clearly observed, and were always similar to those described above (§ 166 ), indicating 
a greater resistance to the parts of the current crossing the hot region than to those 
passing through the comparatively cool parts of the iron. 
