74 



Intelligence and Miscellaneous Articles. 



pendently of the measurements of which I shall afterwards speak, I 

 fixed in the evening the slit of the micrometer which I used in 

 measuring Saturn's rays, and I left the instrument until morning ; 

 I then observed our atmosphere at the horizon. I constantly saw 

 that the slit did not coincide with any of the telluric bands. The 

 nearest was the atmospheric band marked C 6 by Brewster ; but 

 generally the band of Saturn remained near the middle, between C 6 

 and C. 



To compare Saturn with Jupiter, I used the same method. 

 Having fixed the micrometric slit on Saturn's ray, I waited until 

 Jupiter rose as much as Saturn, and I then saw that the slit coin- 

 cided sensibly with the black band of Jupiter which corresponds to 

 the same part of the red. Yet Jupiter shows a brighter and more 

 extended red, and he has towards the extreme red a pretty feeble 

 band, at a distance of l r, 85 of my micrometer. In Saturn the band 

 is really not seen sharply in this place ; but very near it the light of 

 the spectrum diminishes pretty perceptibly, and it appeared sepa- 

 rated at 2 r *17 ; beyond that there is only a very feeble light. Yet 

 spite of the difficulty of taking these measures we can say that the 

 bands are identical. 



We have, then, here a new analogy common to the two largest 

 stars of our planetary system, that is, an identity in their atmo- 

 spheres. 



To give an idea of the precision which we can hope to obtain in 

 measurements taken with my instruments, and then to give starting- 

 points for calculating the position of the planetary as compared with 

 the solar rays, I shall adduce here the measures of the principal 

 solar rays seen in our atmosphere at two different points in the 

 horizon, between which the zero of the screw of the micrometer had 

 been completely changed. 



Solar Rays. 





B. 



C. 



C 6 . 



D. 



b. 



F. 



22nd May, morning. 

 24th „ 



r. 



3-95 



2-51 



r. 



5-24 

 3-83 • 



r. 

 617 



4-98 



r. 



7-94 



6-51 



14-97 

 13-64 



19-83 

 18-22 



Difference 



1-44 



1-41 



119 



1-43 



1-33 



1-61 





Excluding the ray C 6 , which from its feebleness was uncertain on 

 the 24th ; the others give the mean 1*44, which shows the accord- 

 ance of the partial measurements. 



For Saturn we have obtained the following: values : — 



