82 Mr Potter on the Specific Heats of Metal. 



to have shown the probability that such a law did exist in na- 

 ture. 



The proposition may be placed in view under the algebraic 



c d 

 formula — — 1, where c denotes the capacity for heat, taken 



with respect to some received standard, d is the relative atomic 

 weight similarly considered, and m is a constant, whose value 

 depends on the scales we adopt for the atomic weights and the 

 capacities. 



Taking, in the scale of capacities, that of water, for unity, 

 and in that of the atoms the weights of hydrogen as unity, and 

 oxygen 7, I find the value of m to be very nearly 2.75, and 

 on these data I have calculated the weights of the atoms of 

 the metals in the table below, where will be seen, in the re- 

 spective columns, the numbers deduced from chemical ana- 

 lyses by Mr Dalton, Berzelius, and Dr lire, and also those 

 used by MM. Dulong and Petit, but the last, as well as those 

 of Berzelius, I have reduced to the hydrogen scale, taking 

 oxygen at 7. In Dr Ure's, 1-I5th part must be allowed, as 

 he adopts 7.5 as the weight of the atom of oxygen. 



,, , . Weights of 



^ncc licit s 



""£ ', atoms for Weights of the atoms according to Weights used 



• \ . the formula 



we,g d =5 Dalton - 



c 



25. 

 29. 

 56 or 28 ? 

 90. 

 52. 



60. ± 

 62. 

 90. 



There is not here any more difference between the weights 

 of the atoms deduced from the specific heats, and those de- 

 duced from analyses according to Mr Dalton, than must be 

 allowed for the limit of error in either way, excepting in those 

 for copper and silver, where the number from analyses is dou- 

 ble the other. But in the analysis of the oxides and salts of 

 the former metal, I see nothing which militates against the 



c 



