( 592 ) 
seen. Plate I, Fig. 6 shows these lines for the doublet and the quartet; 
especially with D s the effect is very marked. 
12. Observations in directions inclined to the field. 
According to Lorentz’s elementary theory of magnetic division one 
generally observes in a direction, which is oblique under an angle 
with the lines of force, a triplet with elliptically polarized outer 
components *). 
The ellipse, which characterizes the state of polarization of the 
components with period T a -f- v, is the projection on the wave-front 
of the circle perpendicular to the field, in which the electron with 
period T 9 -\-v is moving, v is a small quantity. The direction of 
the motion of the moving electron also determines the motion in 
the ellipse. The ratio of the axes is as I to cos&. For the other 
outer component with period T 0 —v holds mutatis mutandis the same 
reasoning. 
The central line with the unmodified period T 0 always remains 
linearly polarized. The vibrations of the middle component are in 
the plane determined by the ray and the line of force and the 
amplitude of the vibrations is proportional to sin 
If we put # = 0, i. e. in the case of the longitudinal effect, only 
circular motions remain. 
All this applies to very narrow spectral lines in a strong field, 
the distance of the components being much greater than their width. 
According to Yoigt and Lorentz we must expect some interesting 
particularities if this restriction be discarded. We return to this point 
later on. 
As a general rule the deductions from the elementary theory are 
verified. Also in the case of the quartet and the sextet the outer 
components become elliptically polarized, as has been observed already 
by Righi s ). 
In contradiction with the elementary theory, though not strictly 
applicable to the case, is the very slight diminution of intensity of 
the middle components of the quartet even for & = 45°. 
13. Observations at & = 60°. 
If the observation is made with a caicspar rhomb, the image 
l > cf. RlGHI l. c. 
2) Riem’s observations L e. all refer to an angle of nearly 55°, the angle at 
which according to the elementary theory the three components of the triplet are 
of equal intensity. 
