400 ZINC, CADMIUM, LEAD, &C. 



consequently, my estimate of the quantity of 

 oxygen in this oxide was too high. 



Berzelius dried the peroxide of lead in a tem- 

 perature at which tin melted. He found, that 

 5 parts of the Qxide thus dried, lost, when ex- 

 posed to a red heat, 0-325 parts ; the residue, 

 which weighed 4 '675 parts, being digested in 

 acetic acid, left 0-13 parts of sulphate of lead 

 and silica.* It follows from this experiment, 

 that peroxide of lead is composed of 



Protoxide of lead 4'545 or 14 

 Oxygen . 0-325 - 0-973 



4-87 



No doubt the true composition is 



Protoxide of lead . . 14 

 Oxygen .... i 



15 



The atomic weight is 15, and the oxide is a 

 compound of 1 atom lead =13, and 2 atoms 

 oxygen = 2. 



Thus, the constituents of the three oxides of 

 lead are as follows : 



LEAD. OXYGEN. ATOMIC WEIGHT. 



Protoxide 1 atom + 1 atom . . 14 

 Deutoxide 1 + 1J . . 14-5 



Peroxide 1 + 2 ... 15 



* Afhandlingar, III, 170., or Ann. de Chim. LXXVIII, 16. The 

 French translation is unintelligible, because a sentence is left out. 



