42 On Glucinum: its Atomic Weight and Specific Heat. 



soon to be in a position to continue these experiments with 

 the pure metal. 



It will, however, appear from the following considerations 

 that we may fairly regard the above determination of the 

 atomic heat of glucinum as being of such value as to enable 

 us, even at an early stage of the inquiry, to use it as a physical 

 control, and to fix the atomic weight of the metal, subject of 

 course to the probably small change in the numerical expression 

 which may prove to be necessary as the investigation proceeds. 



If we assume the atomic weight of glucinum to be 9*2, and 

 employ the value I have obtained for the atomic heat, i. e. 5*91, 

 we can calculate the specific heat of the metal by means of the 

 formula 



s=J (1) 



when S represents the specific heat, H the atomic heat, and A 

 the atomic weight of an element. The specific heat of gluci- 

 num thus calculated is *642. 



If now we substitute for H a constant, which in this case is 

 the product of the well-ascertained atomic weight of silver* 

 into its equally well-determined specific heat, AS = 6*157, the 

 expression becomes 



S= 6 -^- 7 ; (2) 



and with its aid we can calculate the specific heat of any solid 

 element, if its atomic weight is known or assumed. I have 

 thus calculated the specific heat of glucinum on the assumption 

 (a) that its atomic weight is 9*2, (b) that its atomic weight is 

 4*6, and (c) that it is 13*8. 



The results are compared in the following Table with the 

 specific heat obtained by calculation from the actual determi- 

 nation of the atomic heat of the metal: — 



Specific heat of glucinum calculated (1) from the result of 

 determination of atomic heat. 

 A=9*2 -642. 



Specific heat of glucinum calculated by (2). 

 WhenA= 9-2 . . -669 

 WhenA= 4-6 . . 1*338 

 When A= 13*8 . . *446. 



I am therefore justified in concluding that the atomic weight 

 of glucinum is nearly if not exactly 9*2. 



* We might obviously take any other product ; but that of silver is here 

 preferred because the atomic heat of that metal has been employed as the 

 standard for reference. 



