On the Atomic Weight of Glucinum. D 



Fig. 3. 



Curve showing specific heat of glucinnm at varying temperatures. 



A curve showing the true specific heat at varying temperatures is 

 given in fig. 3. According to the above expression the specific heat 

 reaches a maximum at about 470°, and then falls. But it is doubtful 

 whether this expression would correctly represent the specific heat at 

 temperatures above 500°. Weber's experiments with diamond and 

 graphite tend to confirm this doubt. His results between —79° and 

 4- 280° show a rapid increase in the specific heat, and give a para- 

 bolic curve similar to that obtained for glucinum. But in the other 

 experiments which he made between 600° and 1000° the increase in 

 the specific heat is much less rapid, and the curve takes another 

 form. However this may be, my results show that the specific heat 

 of glucinum rapidly increases up to about 400°, and that between 

 400° and 500° it remains practically constant at the approximate 

 value of 0'62. If this number is multiplied by the atomic weight 

 taken as 9*1, the atomic heat becomes 5 '64. It is therefore clear that 

 this number represents the true atomic weight, and not 13'6, as was 

 previously deduced from the specific heat between 100° and 10°. 

 Glucinum is thus to be classed with those elements of which the 

 specific heat increases rapidly with the temperature,, and, like most 

 elements with low atomic weights, its atomic heat is considerably 

 below the average. 



The expression for the true specific heat of the metal given by 

 Nilson's results is similar to that obtained from mine. His values 

 for the constants, as calculated by me, are : & = 0-3710, a =0-00058, 

 and ^— —0*00000044, which closely agree with those derived from 

 my experiments. 



