50 



. 



/ 'I'lf'ums on 



observations, and the \r U continued for sometime after the 



experiments commenced. The value of these original calculations is, 

 however, prejudiced 1>y the fact that the results are affected by any 

 want of equality between the leads, unless this can be eliminated. I 

 have thus included in the following table only those observations in 

 which the difference between the leads was known and could lie allowed 

 for. The thermometers are arranged in descending order of Rj/Ro 

 during the last epoch. 



Table XIX. 



The last figure is retained mainly to give an idea of the concordance 

 between the several results for the same thermometer. Without 

 realising this, one is not in a position to judge of the weight to be 

 attached to the apparent differences between the different ther- 

 mometers. 



It will be observed that KI alone has altered its relative position 

 since September, 1897. Again, it will be noticed that the order of 

 R,/Ro is the same as that of Ri/Ro- But for this fact we should have 

 found larger differences between the values of pt t and 8 in the several 

 thermometers. 



48. The above table will, I think, be considered pretty conclusive 

 as to the reality of the differences between the different thermometers. 

 I shall, however, also give the results of the second method of attacking 

 the problem, as they possess an independent interest. 



If two platinum thermometers differ only in the absolute resistance 

 of their spirals, the difference may be ascribed to a definite portion of 

 the wire forming the spiral of higher resistance. Thus, in such a case, 

 the difference between the resistances should increase M'ith the 

 temperature in precisely the same way as the total resistance of 



