682 



1000 windings (resistance at ordinary temperature, 290° K., 773 £^) 

 insulated bv silk soaked in liqnid helinm. We found: (See table XII 

 p. 681). 



Judging by this we may perhaps estimate that the lower limit of 



-4 



P 



Q 



\^ 



h S M 10 20 3Ö 



Fig. 10. -Pig- li- 



the threshold value at 4°.25 K. given above cannot be raised much, 

 and that the vanishing point for lead lies at about 6° K. 



