ELECTRICAL PROPERTIES OF HYDROGENISED PALLADIUM. 



175 



Table showing Resistances in Ohms at various Temperatures of Palladium and Hydrogenium. 



Temperature. 



Palladium. 



I. 



II. 



III. 



IV. 



V. 



VI. 



18° C. 



•927 



•991 



1-051 



1-175 



1-306 



1-402 



1-514 



28° 



•958 



1-027 



1-089 



1-207 



1-342 



1-430 



1-547 



38° 



•990 



1-062 



1-123 



1-242 



1-376 



1-464 



1-578 



48° 



1-022 



1-098 



1-157 



1-273 



1-410 



1-497 



1-611 



58° 



1-053 



1-134 



1-190 



1-309 





1-530 



1-645 



68° 



1-084 



1-171 



1-225 



1-346 





1-563 



1-677 



78° 



1-116 



1-208 



1-260 



1-381 





1-597 



1-712 



88° 



1-147 



1-244 



1-296 



1-418 





1-632 



1-746 



98° 



1-176 



1-279 





1-453 





1-669 



1-780 



108° 



1-206 







1-491 





1-700 



1-813 



118° 















1-847 



If a table of first differences is formed from these numbers, it will be found 

 that all the hydrogeniums have the first difference nearly constant throughout, 

 whereas in the palladium itself the first difference distinctly diminishes as the 

 temperature rises. 



The following table gives the mean of the successive differences for each 

 specimen : — 



Palladium. 



I. 



II. 



III. 



IV. 



V. 



VI 



•030 



•036 



•035 



•035 



•035' 



•033 



•033 



The gradual decrease in the values for the hydrogeniums as the charge of 

 hydrogen increases is so regular, that it is difficult to regard it as accidental. 

 Also the distinctly smaller value for the pure palladium is a significant fact ; 

 although it must be remembered that it is a mean of a series of steadily 

 diminishing values, whose greatest value is nearly -032. The others again are, 

 as already pointed out, means of values which must be regarded as practically 

 constant throughout the whole range. 



The quantity, however, which should receive our closest attention is, as I 

 have pointed out in my previous paper on the resistance of nickel at high 

 temperatures, not dKjdt, but 'R~ 1 dR/dt. It will be sufficient at present to 

 form this quantity from the series of first differences, by dividing each by the 

 mean of the resistances whose difference it is. The sanction for this simple 

 mode is the " straight-linedness " of the numbers throughout. The following 

 table shows these " logarithm-rates " arranged opposite the interpolated means 

 of the temperatures of former table of resistances : — 



