102 



HENRY A. EOWLAND 



TABLE III. 

 BAB -39 INCH DIAMETER. AT END OF BAR. 



The horizontal line in the figure represents values of L, and the verti- 

 cal ordinates are values of Q' g . The full line gives the observed dis- 

 tribution, and the dotted line that according to the formula. 



15 10 5 O 



FIG. 2. Distribution at end of bar. 



The formula gives the distribution very nearly for all points except 

 those near the end. The formula indicates that Q' f decreases contin- 

 ually toward the end; but by experiment we see that it increases near 

 this point. On first seeing this, I thought that it was due to some 

 residual magnetism in the bar; but after repeating the experiment 

 several times with proper care, I soon found that this was always the 

 case. I give the following explanation of it : In the f ormulse we have 

 assumed R', the resistance of the medium, to be a constant; now this 

 resistance includes that of the lines of force as they pass from the rod 

 through the medium and thus back to the other end of the rod ; and of 



