24 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES. 



The New Spectrograph of the Lowe Observatory 



The cut shows a photograph of the spectroscopic apparatus 

 now in the observatory. The new spectrograph is not here — 

 probablj' will be in April. The two instruments to the right are 

 Nos. I, 2, 3, the heliostat, and 4 is another mirror to reflect the 

 band of light elsewhere if desired. The axis (2) of the heliostat 

 is parallel to the axis of the earth, the brass box (i) contains a 

 double clock which turns the mirror 3 upon which the sunshines, 

 to keep up with the rotation of the earth. This keeps the light 

 as long as required on a straight line entering the slit of the 

 spectroscope (5). The rays pass through the collimator (6) to the 

 defraction grating (7), which disperses the band into a magnificent 

 spectrum of gorgeous colors, crossed with over 4200 Fraunhofer 

 lines. These lines can be read as a telegraphic dispatch and 

 constitute the language or alphabet of the universe. The grating, 

 ruled with a diamond 14,438 lines to the inch, reflects the light 

 throuoh the lens (8) to another lens (at 9), where the eye is 

 placed. But the telescope (8), (9), is to be replaced bj' the new 

 spectrograph, which will take photographs of all that appears on 

 the grating. The entire instrument will rank with the finest in 

 the world. The other instruments shown cannot be explained 

 here for want of space. 



