308 
I. Bismuth. 
§ 2. Change in the resistance of a wire of electrolytic bismuth. 
This part of the investigation was made with a wire of electrolytic 
bismuth provided by HARTMANN and Braun 0,3 mm. thick, and iden- 
tically the same as that used by KAMERLINGH ONNEs and Cray in 
their determination of the change of resistance (Comm. N°. 99). The 
Konrrausen method of overlapping shunts was used. At ordinary 
temperature and at the boiling point of hydrogen the main current 
was + milliamps, but at — 259° C. it had to be reduced to 0.1 a 
0.2 milliamps on account of the effect of heating upon the resistance. 
In the following Table w’ represents the value of the resistance in 
ohms in a magnetic field of strength H, wr is the resistance with 
no field on, and w, is the resistance at 0° C. with no field. 
We may notice that we have not obtained the maximum in the 
isopedals observed by Brake. It will be seen from the forthcoming 
paper on the change of resistance with magnetic field at liquid air 
temperatures that BrAKE’s bismuth wires which showed the maximum 
exhibited a smaller change in the resistance than ours and were 
therefore probably not so pure. It is possible that as the purity in- 
creases the maximum in the isopedals is displaced towards the lower 
temperatures. 
TABLE 4. 
Resistance of Bjy 7 as a function of the temperature and of the 
field strength. 
Fi T = 290° T = 20°,3 T = 15° 
Gauss zi w ow w' PF: w 
| Wo | W) Wo 
o || 2.570 | 1.057 | 0.588 | 0.242 0.526 | 0.216 
2760 22710. old) ELS 4.73 
3850 As he AME a 19.9 | 8.185 
5540 3.110. | 15280 3208113250 34.9 | 14.35 
7370 3.473 | 1.388 54.7 | 22.50 55.9 | 23.00 
9200 3.635 | 1.495 16.7. «| 31-55 80.8 | 33.25 
11850 4.002 | 1.646 || 113.2 | 46.55 116.4 | 47.90 
13600 4.248 | 1.746 || 141.5 | 58.20 143.1 | 58.85 
15670 4.540 | 1.868 || 172 10.75 175.6 | 72.25 
17080 196.5 | 80.85 199.3 | 82.00 
