942 
§ 3. In order to form a better judgment of the value found 
for the quadrupole moment of oxygen we must still investigate 
whether the magnetic attraction between the paramagnetic oxygen 
molecules contributes considerably to B. In this case the quadru- 
pole moment ought to be smaller than the value found above with 
neglect of this attraction. Calculation proves however that this 
is not the case. 
According to Weiss and Piccard’) oxygen should possess 14 
magnetons per molecule. This involves a magnetic moment of the 
O,-molecule 
: . ie OO, 
In Comm. Leiden Suppl. n°. 25 $ + has been shown that 
u = 9,47 X 10-19 should be required in order to explain the molecular 
attraction. The real magnetic moment has only zb of this value. 
Taking into consideration, that the statistically remaining molecular 
attraction is proportional to u“, we see that the contribution of the 
magnetic moment to the molecular attraction does not come into 
consideration here. 
§ 4. We must expressly point out that the calculations of this 
communication (as well as those for H,, Leiden Suppl. n°. 39) are 
based on the supposition that the molecules collide as solid spheres 
with constant diameter. If this were not the case and if the behaviour 
at a collision should correspond to a value of o depending on the 
temperature, this would become manifest in B by terms also depend- 
ing on 7. The dependency of B on 7’ would then no longer be 
due to molecular attraction exclusively as in this Comm. For the 
same reason the values of the quadrupole moments would possibly 
have to be altered considerably. . 
.1).P. Weiss and A. Piccarp. C. R. 155 (1912), p. 1984. 
