Kimirudogmphic Demonstration of Eeflcctcd Ware-fronts. 289 



Fi&. 9. 



\cvOOO 



Tig. 10. 



W VQ^ O O 



O Q 



^ ^ w 



w w w w v_y 

 w w w w 



through Mr. Paul's animatograph, will give us a very vivid representa- 

 tion of the motion of the wave-front. 



The series illustrating reflection inside of a complete sphere was the 



