Figure 6 — Diagrammatic sketch showing the path of the light. L, source; K, 

 condenser; 8, slit; (', collimator; X, Y, Z. prism; R and G, double slit openings. 

 Behind R and G are to be found the system of total reflection prisms and 

 small lenses used in spacing, reversing and j^rojecting the monochromatic 

 bundles. M and L are speculum mirrors for receiving the projected beams. 

 The small diagram shows the path of the lieams after reflection from the mirror. 



