1412 
wires can be thin on account of the low temperature. There were 
two resistances of the same kind in the cryostat, one of 50 2 and 
the other of 130 2, the section of the tubes was about 0.004 mm? 
and 0.0015 mm’. They were intended to investigate the influence 
of the section of the tubes upon the phenomena examined, a thing 
that had been aimed at already before (see § 2) but did not succeed 
and the preparation of the narrowest one in particular had given 
great difficulties. It gave way during the experiment, so that the 
question of the influence of the section had again to be solved later 
on (see § 5). The experiments which were of chief importance for 
the matter under consideration were made in Dec. 1911 with the 
smallest of the two resistances, the section of the narrow resistance 
tube was here a little smaller than the mean in the resistance which 
was used for the experiments in Comm. N°. 124c. 
On the whole the results were the same as by previous measure- 
ments. Although great care’) was again given to the distillation of 
the mercury with the help of liquid air’), the mercury legs, as has 
(which made it easy to add mercury which the contraction during the freezing 
made necessary), and bell-shaped tubes Hy were placed over the extremities in 
which the platinum wires Hg' etc. are sealed, which connect the resistance to the 
current sources and the measuring apparatus. Platinum amalgam (see note 2, p. 4) 
need not be feared in this case, so that the complication of the inverted forks 
was superfluous. 
We do not need here to enter into particulars of precautions such as the 
protection of contacts against changes of temperature, and others which have 
reference to the special circumstances under which the resistance measurements 
were made 
(A 
1) In § 9 it is demonstrated that in repeating the experiments 
rot so many precautions would have been sufficient. 
*) In the distillation the mercury was not heated above 65° 
and 70° CG. while the cooling was effected with liquid air. In order 
not to have to wait too long to procure a sufficient quantity it 
was done in an apparatus shown in fig. 2 at 1/3 of the actual 
size. The mercury is brought into the double walled tube a & 
(with the reception beaker c), which was sealed off below at e. 
It is exhausted through tube d, while the mercury is warmed 
and then sealed off at f. 
The lowest part is immersed in warm water; in the hollow 
a liquid air is poured. In 3 hours about 2 em? goes over; the 
Fig. 2 condensed mercury in ¢ is afterwards poured out at £. 
