CHAP, i.] MIRRORS AND REFLECTING INSTRUMENTS. 205 



cations, amusing or useful, of reflection by plane mirrors combined 

 with each other in different ways : this class includes the magic 



FIG. 142. Street Reflectors. 



telescope and mirrors, the polemoscope and kaleidoscope ; for these 

 applications, therefore, we must refer the reader to that work. 



A 



Fa;. 143. Measuring lie vertical height of an object. 



