AND ON SOME SUBJECTS OF CHEMICAL THEORY. 319 



more powerful with oxygen and hydrogen ; but it differs in the 

 peculiarity, that the proportion of oxygen to the base in the 

 binary combination is considerably larger than in the ternary, 

 so that the addition of hydrogen converts the one into the 

 other ; and also in its combining apparently with more nume- 

 rous proportions of oxygen than any of the other acidifiable 

 bases, — two circumstances which, as well as the difficulty of 

 effecting its decomposition, probably depend on the same 

 cause, the strength of its attraction to oxygen. The fluoric are 

 similar to the muriatic compounds, except that the binary com- 

 pound of the radical with oxygen cannot be obtained in an in- 

 sulated form, and that its combinations with oxygen are less 

 numerous. The relations of iodine or its radical are similar to 

 those of the radical of muriatic acid, or perhaps rather to sul- 

 phur, except that its binary compound with oxygen does not 

 appear to have acidity, in which it approaches to the metals. 

 The metals usually combine with oxygen so as to form oxides j 

 some of them also form acids with oxygen, or with oxygen and 

 hydrogen ; and these last usually also combine with hydrogen 

 alone. This fact, of some of the metals forming acids, is so far 

 an anomaly, since their compounds with oxygen rather form 

 alkalis, and no other substances give rise to both results ; the 

 greater number of the substances, too, which form acids with 

 oxygen or hydrogen, are evidently, from the smallness of their 

 combining quantities, not of a metallic nature, Still the con- 

 nection between the two classes is in some measure establish- 

 ed on the one hand, by nitrogen, which with hydrogen forms 

 an alkali, and on the other by iodine, which has properties and 

 relations common to both. 



In some cases it is probable, that there is a variation in the 

 proportions of these ternary combinations, giving rise to a di- 

 versity of products, which exist only in combination with those 



bodies 



