154 ON THE OEIGIN OF THE PLANETARY SYSTEM. 



under investigation can be allowed to enter. It then 

 passes through the telescope B, afterwards through the 



Fio. 6. 



four prisms, and finally through the telescope A, from 

 which it reaches the eye of the observer. Figs. 7, 8, 

 Fie. ?. FIG. 8. 



