A N N A L S 



OF 



> 



PHILOSOPHY, 



APRIL, 1821. 



Article I, 



Experiments to determine the true Weight of the Atoms of Copper, 

 ZinCf Iron, Manganese, Nickel, and Cobalt. By Thomas 

 Thomson, MD. FRS. 



In two papers pubHshed in vol. xvi. of the Annals of Philo^ 

 sophy, p. 327, and in the first number of the New Series, I have^ 

 shown by experiments, which to me at least appear decisive^ 

 that the atomic weights of the 14 bodies which constitute the 

 subject of these papers are as follows : 



Oxygen = 1. Hydrogen = 1. 



Nitric acid 6-75 64 



Sulphuric acid 5*0 40 



Muriatic acid. 4-625 37 



Chromic acid Q'5 52 



Arsenic acid 7-75 ...... 62 



Phosphoric acid 3*5 28 



Potash 6-0 ....... 48 



Soda 4-0 ...... 32 



Barytes 9-75 78 



Strontian 6*5 52 



Lime 3*5 28 



Magnesia 2-5 ...... 20 



Silver 13-75 110 



Lead 13-00 . 104 



The process which I followed succeeds also with the sulphates 

 New Series, yoL, I, q 



