Changes in Temperature and Distribution of Magnetism. 2S5 
The magnetic moments were also determined by swinging the magnets 
at the two temperatures in a known field. The experiments were per¬ 
formed with great care and gave the following results: 
Magnets. 
A. 
B. 
M, A . 
Moment at 14° C. 
2359 
2091 
^ ,J -1 4. 
Moo - . 
Moment at 99. 6 5 C. 
2197 
1947 
9 9.5 . 
M. Moo r 
Loss... 
166 
146 
- LTJ -1 4 ' LTJ ' 9 9 _ 5 • • • • 
Ml 4 M 99 5 
Proportional loss.. 
M 14 •••• 
0.0686 
0.0687 
Intensity at 14° C. 
339 
298 
Intensity at 99. °5 C. 
316 
277 
The difference between these two sets of values is considerable, in the 
case of magnet A the variation amounts to two per cent. This may be 
due to the fact that only an approximation could be made to the mo¬ 
ments of inertia of the magnets because of the holes in the ends, where 
a slight error would affect the result materially, the distance from the 
center being 15 cm. The moments of inertia were calculated by divid¬ 
ing the magnet into two parts, an inner core and an outer shell extend¬ 
ing beyond the core at both ends. On the other hand it is to be noticed 
]y[ _ m 
that the ratios —h*—!!_§_ differ by less than one part in 300. In this 
Mi 4 
ratio the moment of inertia of the magnet is eliminated. I think on 
the whole that the accuracy of the work is fairly well shown. 
IV. DISCUSSION OF RESULTS. 
The result of the experiment may be stated as follows: If a magnet 
be heated after it has been brought into the permanent state, the pro¬ 
portional loss in distribution is greatest at the ends and least in the 
middle. A glance at the table on pages 282-83, or at the curves on plate XI, 
will show this. The same fact may be stated in other words as follows: 
The proportional change in the number of lines of induction passing 
through a cross-section of the magnet is greater, the nearer the section 
is to the end, as is shown by column seven in the table on page 282-83. This 
