1320 
ence of the wall, added to the reciprocal effect of the molecules 
(correlation) the axes will show a preference for lying in horizontal 
planes. In the horizontal plane itself, however, each direction is 
equivalent. 
Now. when we excite a perpendicular magnetic field, it tries to 
turn the molecules in a direction perpendicular to the plane of 
preference in virginal state; and the first result will be a disturb- 
ance of the order existing in the virginal state and therefore an 
increase of the extinction. Soon however a magnetic field of suffi- 
cient intensity will bring about a higher order i.e. a smaller 
extinction as is shown at C in fig. 2. A weak magnetic field 
however will only diminish the originally existing order i. e. increase 
of the extinction (see fig. 5). But a strong magnetic field has also to 
overcome the resistance of the reciprocal influence between the 
originally horizontally directed particles; therefore the slow rising 
towards C (fig. 2) is quite intelligible; whereas after F (fig. 2) 
a quicker rising can be explained, as the state of the matter there 
is such that no preference for directions parallel to the wall of glass 
is shown even at a very small distance from it. 
Let us now proceed to consider the case represented in fig. 3. 
In the virginal state (B) the molecules were lying by preference in 
the horizontal planes, the exciting of the horizontal magnetic field 
(C) not only increases this preference, but moreover calls into exist- 
ence in that horizontal lane a direction of preference. From this 
it follows that there can be no question of a temporary rising of 
the extinction at the exciting of a horizontal field. 
The different conduct at the removal of the field can be ex- 
plained too. 
After the removal of the vertical field (D and H in fig. 2) the 
heat motion has free play as no direction of preference exists at 
some distance of the walls. The directing influence of the wall 
restores but. slowly the original order by means of the mutual 
influences of the molecules. In the mean time (compare FG in fig. 4) 
if the field which has disturbed the order, is weak, the wall will 
sooner be able to recover the original state. Totally different is the 
case after the removal of the horizontal field (D and H in fig. 8). 
Here the influences proceeding from the wall, united with the mutual 
action of the molecules, practically maintain the higher order 
originated by the field. 
The fact that the commutation of the magnetic field has no influence 
on the extinction shows that the particles themselves possess no 
polar peculiarities. A research which Mr. Rocneru is working out 
