ON THE RELATION OF THE LAWS OF 



DECREMENT TO THE DIFFERENT 



CLASSES OF MODIFICATIONS. 



THE following tables, which exhibit these relations, 

 will illustrate fully the uses of the symbols we have 

 just described. 



It may be remarked, that the letters placed on the 

 figures of the primary forms contained in these tables, 

 differ from those which stand on the corresponding 

 primary forms placed at the heads of the several 

 tables of modifications; and that some new letters 

 have also been added to them. 



These changes have been introduced for the pur- 

 pose of indicating more explicitly, by means of sym- 

 bols, the changes of figure which any modified pri- 

 mary form may have undergone. 



The letters p, q, r, s, are used as the general indices 

 of the different classes of modifying planes, and thus 

 represent any numbers whatever ; but they will re- 

 present different numbers, in relation to the different 

 individual planes belonging to each of the classes. 



When these letters are used as the indices of the 

 modifying planes produced by intermediary decre- 

 ments, they represent whole numbers only. But when 

 p denotes the law of a simple or mixed decrement, it 

 may represent any whole number or fraction. 



