44 Dr. C. Chree. Invatiffations on 



liy lining so, observational errors should be rendered less important. 

 Also there was no reason for preferring one to the other. The R, ;m<l 

 KI of K have IR-CH multiplied by 0*4 to reduce them to approximate 

 equality with the corresponding quantities in the other thermometers; 

 and in this instance the data given are limited to the cases where the 

 leads were interchanged. The reason for this is that the value of RO 

 in K is affected by a given inequality in the leads by no more than the 

 K in K 3 or K. ( , so that inequality in the leads would influence such a 

 quantity as 



0-4 RO (in K ) - (mean RO of K 3 and K 4 ). 



The differences between the RO, RI, and R of K 3 and K 4 are also given, 

 so that the differences of any thermometer from K 3 and K 4 separately 

 could be at once obtained from the table. Such a heading as K 3 - K 4 

 means that the RO, RI, or R* as the case may be of K 4 , when sub- 

 tracted from that of K 3 gives the results in the columns of Table XV 

 (p. 45). 



The data enclosed in the [ ] brackets are, I have reason to think, 

 affected by experimented error, while those in the ( ) brackets are, I 

 believe, correct but due to exceptional circumstances. These data are 

 not taken into account in the mean values. Data in the brackets { } refer 

 to two independent observations during the same month. The blanks 

 in the case of K_> and Kj arise from the absence of these thermometers 

 At Sevres and from the changes in the former thermometer during 

 1896. 



42. Table XV shows that if any relative change has occurred 

 between K 3 and KI since 1895 it must be very small. The figures are 

 not, however, absolutely inconsistent with a slight reduction in the 

 difference between the two resistances. 



There is the clearest evidence of a gradual fall in the RO and RI of 

 KI relative to the corresponding quantities in K 3 and K 4 , the change 

 being greatest in the case of RI. On the other hand, the R* of KI has 

 apparently risen during the last two years relative to the mean R, of 

 K 3 and Kj. As the resistance of KI at C. is intermediate between 

 the resistances of K 3 and K 4 , it is impossible to attribute the phenomena 

 to changes in the proportional arms, or in the coils, or to any other 

 external cause. I thus see no alternative to the conclusion that in KI 

 there has been a diminution in the resistance in ice and in the funda- 

 mental interval, accompanied by an increase in the ice-sulphur and 

 steam-sulphur intervals. 



In its early days KI was several times exposed to the temperature of 

 molten silver, but the last exposure preceded 1897. Table XV shows 

 no other certain example of relative change except in the case of KS 

 when quite new. The first experiment made with this thermometer was 

 on February 12, 1896, by which time the observers had become fairly 





