Reflexibility ofLiglit. 177 



sequently rectified. A little consideration on 

 this subject, applying the principles which have 

 been laid down in the course of this lecture, will 

 easily enable you to see the theory on which 

 these mirrors act, particularly if you have the 

 objects before you : without which, indeed, an 

 infinity of words must be expended in describing 

 and explaining them. 



