730 PRELIMINARY OBSERVATIONS. 



1. That the basic or positive element or elements are in imme- 

 diate combination with the chlorous element or elements placed 

 above them in the formulae. 



2. That these binary compounds again are associated together 

 so as to form the compound molecule, from an attraction of all 

 the basic elements for each other, and of all the chlorous ele- 

 ments for each other, of such a nature as retains together the 

 3 atoms of the same kind which form a single equivalent of 

 nitrogen or phosphorus, the 3 atoms of cyanogen in cya- 

 nuric acid, the various multiples of C 2 H 2 grouped together in 

 the molecule of olefiant gas and hydrocarbons isomeric with it, 

 or the multiples ofC 5 H 4 in the molecule of oil of turpentine- 

 and a large class of essential oils. A complex organic mole- 

 cules is thus represented as an association of two or more binary 

 compounds, comparatively simple in constitution, often isolable 

 substances and possessed of considerable stability. 



In the superior or chlorous portion of the formulae of organic- 

 compounds we may generally expect to find chlorine, oxygen, 

 nitrogen, hydrogen ; and in the inferior or basic portion, car- 

 bon, or carbon and hydrogen. The former elements appear to 

 be chlorous in the order in which they are enumerated : 



Chlorine 



Oxygen 



Sulphur 



Nitrogen 



Hydrogen. 



We find in substitutions, those in the lower part of the table 

 replaced by those above them, hydrogen at the bottom of the 

 table eminently so by chlorine at the top, and hydrogen also by 

 oxygen. Nitrogen less frequently interferes, but it appears in 

 certain cases more chlorous than oxygen and to replace that 

 element ; only, however, in certain double decompositions as an 

 element of ammonia, which are not sufficient to determine its 

 place, as oxygen might be placed above chlorine from similar 

 indications, as the conversion of chloroform FoCl 3 into for- 

 mic acid FoO 3 by potash. 



. Compounds of the same type. These are bodies which have 

 the same number of elementary atoms, and the same numbers 

 of them chlorous and zincous. As : 



