1813.] On the Cause of Chemical Proportions. 447 



The greatest number of spherical atoms of the same diameter, 

 capable of touching a single atom of the same diameter, is 12. 

 Hence it follows that A + 12 B contains the greatest number 

 of atoms which a compound atom of the first order can contain. 

 If, on the other hand, we pay attention to the electric polarity 

 of the atoms, an atom of A cannot combine with more than 9 

 atoms of B, if the atom A + i) B preserve any part of the 

 electric polarity originally belonging to A : for example, oxymu- 

 riatic acid, which is a compound of 1 atom cf muriatic radicle 

 and 8 atoms of oxygen, still preserves a part of the original 

 polarity of the radicle, by means of which it re-acts ; while the 

 supersulphuret of arsenic, of which I shall give an account in 

 the sequel, and which is composed of 1 atom of arsenic and 12 

 atoms of sulphur, has no other electro-chemical re-action than 

 that of sulphur. 



It is contrary to sound logic to represent a single compound 

 atom of the first order as composed of 2 or more atoms of A 

 combined with 2 or more atoms of B ; as, for example, 2 A + 

 2 B, 2 A + 3 B, 7 A + 7 B, &c. : for in such a case there is 

 no obstacle, either mechanical or chemical, to prevent such an 

 atom from being 1 divided, by means purely mechanical, into 2 or 

 more atoms of more simple composition. Besides, such a com- 

 position would almost totally destroy chemical proportions. 

 Hence it follows, that in stating the result of an analysis con- 

 formably to the views of the corpuscular theory, we must always 

 consider one of the constituents as unity, that is to say, as a 

 single atom. What I have stated here appears to me to be 

 necessary consequences, or reflections inseparable from the 

 theory of atoms, not one of which can be rejected without 

 committing what is called conlradidio in adje.Uo. 



1 shall now give an account of the difficulties to which I con- 

 ceive the corpuscular theory is liable. 



1. The first of these difficulties is, the circumstance that 

 tbeK are combustible bodies, iron, for example, which unite 

 only with two doses of oxygen, the second of which is only \X- 

 times greater than the first. This difficulty, however, is only 

 apparent : for 1 have already, in my former memoirs on this 

 subject, shown that, in all probability, it is owing to our being 

 still unacquainted with all the degrees of oxidation of which the 

 body in question is capable. The multiple H- implies the exist- 

 ence of an inferior degree of oxidation to that which we consider 

 as the minimum. 1 hope in this essay to prove the truth of this 

 opinion in a still more satisfactory manner. 



2. 1 think 1 have proved that when two oxides combine they 

 always unite in such proportions that each contains either an 

 equal quantity of oxygen, or the one contains a quantity which 

 is a multiple by a whole number of the oxygen in the other. 



