GENERALIZATION OF PRINCIPLES. 91 



seen, rather led to by the general current of the 

 reasoning of mathematicians about the end of the 

 seventeenth century than discovered by any one. 

 Huyghens, Marriotte, the two Bernoullis, L'Hopital, 

 Taylor, and Hermann, have each of them their 

 name in the history of this advance ; but we cannot 

 ascribe to any of them any great real inductive 

 sagacity shown in what they thus contributed, ex- 

 cept to Huyghens, who first seized the principle 

 in such a form as to find the Center of Oscillation 

 by means of it. Indeed, in the steps taken by the 

 others, language itself had almost made the gene- 

 ralization for them at the time when they wrote; 

 and it required no small degree of acuteness and 

 care to distinguish the old cases, in which the law 

 had already been applied, from the new cases, in 

 which they had to apply it. 



