RECEPTION OF THE UNDULATORY THEORY. 479 



received from MM. Arago, De Laplace, or Biot, 

 never gave me so much pleasure as the discovery 

 of a theoretical truth, or the confirmation of a cal- 

 culation by experiment." 



Though Young and Fresnel were in years the 

 contemporaries of many who are now alive, we 

 must consider ourselves as standing towards them 

 in the relation of posterity. The Epoch of Induc- 

 tion in optics is past; we have now to trace the 

 Verification and Application of the true theory. 



