CADMIUM. 387 



after it in the title of the chapter, but none of 

 those that are placed before it. 



Iron has likewise the property of throwing 

 down all the metals belonging to this chapter, 

 except zinc, in the metallic state. When a plate 

 of zinc is put into a solution of iron, the iron 

 falls very slowly in the state of peroxide. Cop. 

 per is a good precipitant of mercury and silver ; 

 zinc precipitates cadmium, tin, and copper very 

 well from muriatic acid, and lead very well from 

 acetic acid. 



The reader will recollect that the atomic 

 weight of zinc was established in the first sec- 

 tion of the first chapter of this work. The know- 

 ledge of it was necessary in order to enable us 

 to determine the specific gravities of oxygen 

 and hydrogen gases, upon which the whole doc- 

 trine of atomic proportions ultimately depend. 

 The weight of an atom of zinc is 4-'&5 ; it com- 4 tom of 

 bines with only one proportion of oxygen, and 

 forms one oxide, the atomic weight of which is 

 5-25. 



SECT. I. 



OF THE ATOMIC WEIGHT OF CADMIUM. 



CADMIUM is still a very scarce metal ; but by 

 the kindness of Mr. Harepath, I was favoured 



Bb2 



