ILLUSTRATIONS. 



Plate I. Spectra of various metals and of the sunlight taken with the grating 

 and quartz lens. The lines in the ultra-violet are obscured by repro- 

 duction. The print is given to show, approximately, what the 

 instrument will do, and a more complete series will be published in 

 another communication, when better results are obtained. 



TEXT FIGURE. 



Fig. 1. A. Lateral view of spectroscope; B. End view of slit and camera; C. 

 Grating; D. Quartz lens; E. Slit. 



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