XVI 



ATOMIC WEIGHTS OF THE MP:TALS 



363 



Their table shows : 



(1) The elements which they examined. 



(2) Their values for the heat-capacity of these elements, 

 compared with that of an equal weight of water. 



(3) The values which they selected for the atomic weights 

 of the elements, O= i. 



(4) The product of these numbers. 



A fifth column has been added which shows Dulong and 

 Petit's atomic weights reduced to the modern standard, 

 O=i6. 



ATOMIC HEATS (DULONG AND PETIT). 



1 The value Ii"i6 given in Dulong and Petit's paper appears to be 

 a misprint for 12 'i6 (Berzelius's number for the atomic weight) ; but 

 there is some further error in the table, as 12*16 x 0-0314=0-3818. 



In Dulong and Petit's table the atomic weights of the 

 metals were reduced to one-half of the values given by 

 Berzelius, whilst the value for silver was reduced to one- 

 quarter. The new values were ultimately accepted by 

 Berzelius, and are substantially the same as those employed 



