54^ ON THE ALKALINE METALLOIDS. 



Views of affinity, are the modified affinities of that sub- 

 stance to the elements of the coinpomid*. If the alkaline 

 metals be admitted to exert an attraction both to hidrogen 

 jind oxigen, but more energetic, as their chemical relations 

 evidently show, to the latter, it will follow, that the more 

 powerful affinity will tirst be exerted, or the metal will 

 combine with oxigen. But when thjs is diminished in force 

 by the approach to saturation, the weaker affinity, that 

 to hidrogen, will be capable of being exerted with equal 

 effect — the attraction therefore of the oxidated base or 

 alkali will now be exerted both to oxigen and hidrogen, in 

 other words to water, with which it wilj combine. If the 

 bases of barytes, strontites, and lime, be procured pure, 

 they may be expected also to contain a portion of hidrogen, 

 though perhaps lo a less extent than the alkaline metals, as 

 in their stale of earths they are less soluble in water than 

 the alkalis — indicating, according to this view, a less strong 

 attraction exerted to hidrogen. There may thus be a series, 

 through the other earths, to the common metallic oxides. 

 Source of the -^"^ if this speculation can be admitted, we have the satisfac- 

 properties that tion of being able to point out the source of the peculiar prp- 

 alkMi^eaJthr pe»'ties, by which the alkalis, earths, and metallic oxides are 

 $nd metallic distinguished as subordinate divisions of a class; and of 

 farther showing, that the cause giving rise to these peculi- 

 arities is the same as t)iat which is the cause of the ecjually 

 striking differences by which they are distinguished in their 

 simple or metallic for^n. The attraction of the real alkaline 

 metals to hidrogen gives rjse to their combination with it, 

 and this is the cause of the levity, and probably also of the 

 fusibility of potassium and sodium— the most striking pro- 

 perties by which they are distinguished from the common 

 roetals; and the same affinity to hidrogen is the cause of 

 the solubility of these substances, when oxidated, in water, 

 the property by which the alkalis and alkaline earths are 

 separated as an order from the common metallc oxides. 

 If this view be correct, it will ^Iso follow, that the metal- 

 loids obtained from the earths contaiuing only a small por* 



♦ I hate given at considerable length a view of this doctrine, which 

 affords so many refined explanations of m inure chemical phenomena, in 

 ihc Notd lo my System »f Chemistry, vol. J, p. 609. 



t}oi> 



oxides. 



