44? 



in this field of temperature ilicillinin is in the same condition as is 

 shown for mercury in Comm. N". 133(2 p. 24, fig. 6. At a current 



0,001 



opoo 



O TLiznr. /9/6. 

 □Ti.Dx:./a76. 



(!5H3- 



3 



Fig. 2. 



strength of 3,1 m.A. tfiroiigh the resistances the resistance falls, thus, 

 within a smaller temperature range than in mercury; a similar 

 difference had been found earlier between mercury and tin. ') At 

 T=z 2°. 32 K. all measurable resistance has disappeared. 



^ 4. Highest limit of a microresidual resistance. This limit is found 



from the quotient of the smallest observable potential difference and 



the threshold value of the current, it being assumed that Ohm's law 



still holds. We found : 



W 

 15 April 1919, for T/-VIII .^^^ < 14.10-^0 at p=r2. 3 m.m. Hg and 



27 May 1919, for TUX 



w 



< 24.10-10 at p=2.Q m.m. Hg. 



^273«.K. 



The difference in the results may be due to the inequality of 



temperature, but more to the difference of current threshold value 



W 

 of the two wires (see further § 5). If the value ^^^ for thallium 



W, 



273<>K. 



^) This comparison is defective, for as yet the fall of resistance in mercury, tin 

 and thallium not has observed on wires of the same diameter by using the same 

 strength of measuring current. [Note added in the translation.] 



29 



Proceedings Royal Acad. Amsterdam Vol. XXV. 



