930 
also the two parts of which 9 is composed, have been given sepa- 
rately, namely : 
Qv?(n? +2)? 2 (n*+2) Di 
Pa ane : = 
Oen i Pa Yen (»,?—v?)? 
In this it should be borne in mind that every value of the 
series (I) is built up of the average of six determinations, those of 
the second series being derived from one determination. In the 
former greater accuracy is, therefore, to be expected. 
At the same time the influence which the two free frequencies 
have on the constant of rotation, appears from the table. We see 
that that of the ultraviolet frequency at moderate distance by far 
preponderates. 
We can compare the dispersion of the constant of rotation found 
here with H. Breqeerer)’s determinations *). He found for the relative 
values of the constant of rotation 
@ D E b F G h 
o/op = 0,637 1,000 1,590 1,730 2,271 4,828 5,450 
while from the formula found above for series (I) follows: 
0,688 1,000 1,538 1,661 2,177 3,967 . 5,259 
The dispersion found here is, therefore, considerably less than 
BECQUEREL’S, 
We can then try to represents BreQquerer’s five values of n by 
a formula 
taking for v,? first the value 47,485.10°°, then 48,161.10*°. These 
calculations too have been carried out by the method. of least 
Observed Calculated 
n BE FE 
a LL | I | Il 
G 1,5948 0,33970 0,33966 | 0,33968 
D 1,6043 0,34407 0,34413 | 0,344 11 
EE: 1,6171 0,34996 0,34997 0,34995 
I 1,6293 0,35548 0,35547 0,35546 
G 1,6557 0,36726 0,36723 0,36726 
1) H. Becguerer, Ann. de Ch. et de Ph. (5) 12 p. 35 (1877). 
