Smithsonian Report, 1907.—Hale. PLATE V. 
SLIT AND PLATE-HOLDER END OF SIMPLE WOODEN SPECTROGRAPH OF LITTROW OR 
AUTO-COLLIMATING TYPE (18 FEET FOCAL LENGTH), USED IN THE SPECTRO- 
SCOPIC LABORATORY ON MOUNT WILSON. 
[Not the instrument referred to in the lecture, but a similar one, suitable for use in an open 
room. | 
GRATING AND LENS SUPPORTS FOR MODERN SPECTROGRAPH (18 FEET FOCAL LENGTH), 
USED IN THE SPECTROSCOPIC LABORATORY ON MOUNT WILSON. 
The bar for cutting off reflections from the lens is shown. 
