COMBINING EQUIVALENTS. 273 



tricity, or determine its composition by direct chemical 

 analysis, we shall find it consists of two volumes of hydro- 

 gen gas, united to one volume of oxygen, or, by weight, of 

 one part of hydrogen combined with eight of oxygen. 

 In 100 parts, therefore, we should find 



Oxygen <^ s ' 



Hydrogeu ll'O 



It is found in the same way that the theoretical weight 

 of the atom of carbon is 6, and that of nitrogen 14 ; 

 whilst the atom of iron, is 28, that of silver 108, of gold 

 199, and that of platinum and iridium each 98.* Now, 

 as these are the relative weights of the ultimate in- 

 divisible atom, it follows that all combinations must be 

 either atom to atom, or one to two, three, or four ; but 

 that in no case should combination take place in any 

 other than a multiple proportion of the equivalent or 

 atomic number. This is found to be the case. Oxy- 

 gen, for instance, combines as one, two, or three 

 atoms its combination presenting some multiple of its 

 equivalent number 8, as 16, or 24 : and in like manner 

 ' the combining quantity of carbon is 6, or some multiple 

 of that number. Where this law is not found strictly 

 to agree with analytical results, of which some ex- 

 amples are afforded by the sesquioxides, it may be 

 attributed, without doubt, to some error of analysis or 

 in the method of calculation. 



Nothing can be more perfect than the manner in 

 which nature regulates the order of combination. We 

 have no uncertain arrangement ; but, however great the 

 number of the atoms of one element may be, over those 

 of another, those only combine which are required, 

 according to this great natural law, to form the com- 

 pound, all the others still remaining free and uncom- 



* Graham's Elements of Chemistry ; and Brando's Manual. 



T 



