( 546 ) 
us now imagine that at the moment ¢, the molecule I collides with 
the molecule III. Between t, and ¢; + @ the value a will then 
be very great. Afterwards that quantity will be reduced to an aver- 
T 
age value; but at the moment t + ae the wave emitted by mole- 
5 s d* ag 
cule I will arrive at molecule II and will cause SPEK ‘to have an 
abnormally great value between tj + 2 and ¢, + En +- 0, Between 
L r da 
the moments t + 2 pe and 4 + 2 <5 + 0 the value of ey will 
be again abnormally great and so on. This solution is certainly not 
contained in the function-solution. 
Therefore before we assume the theory of GALITZIN of the broad- 
ening of the lines of the spectrum as proved, we should have to 
make a separate examination, in order to investigate in how far 
we may assume that the motion of the molecules may be represented 
approximately by the function-solution, and in how far the roots 
which GaLiTzin has not found, have influence on the phenomenon. 
In this investigation we should have to start from the hypothesis 
about the way in which the molecules are made to vibrate. 
I shall however, not occupy myself further with this problem, 
but I shall try to solve the more intricate problem of vibrators 
which are in motion, in order to investigate, if a connection may 
be found between the ponderomotorie forces of radiation and the 
molecular forces. The solution of this problem I have had in view 
from the very beginning. 
Astronomy. — “The 14-monthly period of the motion of the pole 
of the earth from determinations of the azimuth of the meri- 
dian marks of the Leiden observatory from 1882 —1896”. 
By J. Weeder (Communicated by Prof. H. G. van DE 
SANDE BAKHUYZEN). 
1. From the motion of the poles of the earth over the earth’s 
surface results not only a variation of the geographical latitude of 
each place, but also a variation of the direction of the meridian; 
hence the azimuth of each direction varies accordingly. 
If in seconds of are # and y express the deviations of the north pole 
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