1425 
on which there is no uncertainty, it assumes over its entire length 
the new temperature equilibrium of a thread carrying a current, which 
equilibrium is determined above the vanishing point in the usual way. 
In order to improve the comprehensive view that may be formed 
on the ground of Table IV combined with Table IL in which latter 
the different current densities do not refer to the same wire, further 
experiments were made in June 1912, which show how with the 
same thread the resistance disappears at different current densities. 
The thread had a section of about 0.003 mm*., at the boiling 
point of helium the resistance was 0.1287 2. The experiments were 
made with a falling temperature, with current densities of 1.8, 
cont ankem 
zE Keer Pe 
a he 
500.12 we Ok UM 
2 a ie 
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. L 7 voo 
400 Si 
fey 
/ 
/ 
/ > 300 
300 — ns ; 4 
Te gon tiny 2QUeAINE. 
[3 iS=quovang 
/ | e 200 
200 4 = 5 
100 4 we 109 
| 
0 1 0 0 79) 
’ 200 +100 ed 
eae ae toons 1001( 6-5) 
ss . 
Fig. 6. Fig. 7. 
18 and 130 amp. per mm’. (strength of current 4, 40 and 400 
milliamp.). The phenomena are shown in the accompanying figs., 
upon which the numerical values are distinct enough to make 
it unnecessary to print a table. Fig. 6 allows a comparison between 
the phenomena at 0.004 amp. and 0.04 amp., fig. 7 at 0.004 amp. 
and 0.4 amp. The ordinates represent the potential fall in mierovolts divi- 
ded by the strength of the current, expressed:in 0.004 amp., the 
abscissae the difference of the temp. 7’ with that of the boiling 
point 7, = 4°.25 K. in thousandths of a degree. The unit of the 
scale of the abscissae in fig. 7 is five times as large as in fig. 6. 
At 0.04 amp. the curve continues with diminishing values of the 
ordinate to lower temperatures than are shown on the fig.; at 
4°11 K., when the experiment had to be stopped, the resistance 
was not quite 0, we found 0.2.10-6 V. The intersection with the 
