OTHER MODES OF FORCE. 177 



again glanced at in the margin of the new field of vision, 

 which in their turn have to be verified, and again lead to 

 new extensions ; thus the effort to establish one observation 

 leads to the imperfect perception of new and wider fields of 

 research ; and, instead of approaching finality, the more 

 we discover, the more infinite appears the range of the undis 

 covered ! 



