485 



TABLE I. Resistance of ^«-3 



NO. 



W 



Standard- 

 thermometer 



27 Febr. '15 II 



III 



I 



25 Febr. '15 II 

 III 

 IV 

 V 

 VI 



1 



30 April '15 II 



IV 



III 



1 



12 May '15 II 



111 



IV 



I 



V 



H2 vapour pressure 

 apparatus 



Ptp 



Pt,, ') 



Pti' with changed 

 zero resistance, cal- 

 culated from the 

 resistance of P/| o at 

 points 111 and IV. 



W 

 f^iVlay '14 



1.0034 

 34 

 33 



[1.0033] 2) 

 1.0010 



0.9999 



1.0023 

 25 

 24 

 15 



[1.0027] 2) 

 1.0004 

 0.9997 

 0.9999 



This was done for the measurements treated in this pa[)er by 

 determining for each series of measnrenienls in liquid hydrogen a 

 point of tlie scale of Auci with tlie aid of the temperature derived 

 from the pressure of the licpiid hydrogen bath'). 



1) Checked by comparison with tlie temperatures calculated from the pressure 

 of the bath. 



-) It has appeared since that at Ihis temperature the calibration of the auxiliary 

 thermometers used in the measurement of May '14 was less accurate. 



') In table I it appears from the measurements of April 30 '15 that even in a 

 single series of measurements at hydrogen temperatures small changes in AucZ 

 may occur. With a view to this fact we intend in future measurements to deter- 

 mine each time at least two points of the scale of Aucz, viz. one at the boiling 

 point and one at the melting point of hydrogen. 



