£30 



ON ACETIC ACID AND ACETATES. 



the afnnity of 

 its parts, un- 

 less one of 

 these is de- 

 structible. 



MetaJlic ox- 

 ides. 



Circumstances 

 to be attended 

 to. 



State of the 

 oxide before 

 the process. 



Acetates of 

 silver and 

 manganese. 



Composition 

 of the salts. 



for its base. But if the acid, or base, be decomposable at 

 a lower temperature than would separate them were it not 

 for this destructibility, the affinity that unites them is a 

 function of that on which their composition depends. The 

 phosphate of lime does not lose its acid at a temperature, at 

 which sulphate of lime parts with its acid, because the lat- 

 ter is decomposed. 



Let us take then for bases the metallic oxides ; but let us 

 first unite them with one particular acid, so that all the 

 differences in the results of the decomposition of the sails 

 they form may depend on the variation of one substance 

 alone. 



It is true, that each base is accompanied with fresh cir- 

 cumstances, independently of the facility with which it is 

 decomposed. The proportions too of water, of base, and 

 of acid, are not to be neglected. 



Another essential consideration is the state of the oxide 

 before the process, and that to which it has a tendency dur- 

 ing its taking place. Metallic silver, for example, is not 

 soluble in any acid : manganese oxided at O'Gfc is equally 

 insoluble; but after adding oxi gen to the one, and abstract- 

 ing oxigen from the other, saline combinations of these me- 

 tals may be formed. Chemists speak of the gray oxide of 

 silver with 10 per cent of oxigen, and the white oxide of 

 manganese with 20 per cent, as those of their respective 

 metals that are most soluble. But this gray oxide of iilver 

 is reducible by a gentle heat, and the white oxide of man- 

 ganese is liable to be superoxided by taking up 46 per cent 

 Miore of oxigen. We must pay attention therefore to the 

 0*10 that one gives out, and the 0*46 that the other may 

 absorb. 



The acetates formed by these two oxides may be consi- 

 dered, in this point of view, as the extremes of a series, the 

 intermediate terms of which are to be found among the 

 other oxides. Let us then examine in detail the acetates of 

 filver, copper, nickel, lead, iron, and manganese. 



To compound these salts in a uniform manner, I prepared 

 the oxides of the different metals by the most appropriate 

 means the art of chemistry teaches us ; and I always satis- 

 fied myself of their purity, before I. made use of them. I 

 ..»; then 



