254 
2m 
7 
/ is the magnetization which the body would have in the case 
y —0 and 9 —0. We may safely assume, that this value scarcely 
differs from the magnetization that would exist when 6 and g were 
different from zero. Thus 
2m | 
Dy = — I. 
? 
Substituting this in (6), we find 
2m 1 1 
sin O = -— —1I — —.- co lh pleted tet eee 
m À (f= A 5 ( ) 
According to this formula it wonld be possible to reach an in- 
finite value of si 6 by making C and A equal to each other. It 
is true that a strong magnetization can only be obtained by using 
a rather long rod of iron, but notwithstanding this the difference 
('—A may be made as small as we like by adjusting non-mag- 
netizable masses in a proper way. In reality however this ideal 
case can never be realised. The principal reason for this is, that 
the point of suspension will never coincide with the centre of 
gravity, but will always lie at a small distance say q from the latter. 
In this case, contrary to what we have supposed, the force of 
gravity will produce a couple acting on the body. Taking C—A—O 
and writing P for the weight of the body we now get instead 
of (5a. 
J2 
G : 
— Py sin = B; + Dy cos 6 Be aig ig Sea a a 
so that the condition for the stationary state becomes 
Introducing 
and the time of oscillation ¢ for vibrations about O Y under influence 
of gravity, a time that is given by 
we find finally 
Pd 
