320 Intelligence and Miscellaneous Articles. 



from the lens reached a focus it was intercepted by the Rutherfurd 

 grating set at an angle of sixty degrees. This threw the beam on 

 one side and produced there three images — a central one of the sun 

 and on either side of it a spectrum ; these were received on three 

 separate sensitive plates. One of these spectra was dispersed 

 twice as much as the other — that is, gave a photograph twice as 

 long. This last photograph was actually about two inches long in 

 the actinic region. If, now, the light of the corona was from in- 

 candescent gas giving bright lines which lay in the actinic region of 

 the spectrum, I should have procured ring-shaped images, one ring 

 for each bright line. On the other hand, if the light of the corona 

 arose from incandescent solid or liquid bodies, or was reflected light 

 from the sun, I was certain to obtain a long band in my photo- 

 graph answering to the actinic region of the spectrum. If the 

 light was partly from gas and partly from reflected sunlight, a 

 result partly of rings and partly a band would have appeared. 



Immediately after the totality was over and on developing the 

 photographs, I found that the spectrum-photographs were con- 

 tinuous bands without the least trace of a ring. I was not sur- 

 prised at this result, because during the totality I had the oppor- 

 tunity of studying the corona through a telescope arranged in 

 substantially the same way as the phototelespectroscope, and saw 

 no sign of a ring. 



The plain photograph of the corona taken with my large equato- 

 rial on this occasion shows that the corona is not arranged centrally 

 with regard to the sun. The great mass of the matter lies in the 

 plane of the ecliptic, but not equally distributed. To the eye it 

 extended about a degree and a half from the sun towards the west, 

 while it was scarcely a degree in length towards the east. The 

 mass of meteors, if such be the construction of the corona, is there- 

 fore probably arranged in an elliptical form round the sun. — Silli- 

 man's American Journal, September 1878. 



WATSON S LNTKA-MERCUFJAL PLANET. 



To the Editors of the Philosophical Magazine and Journal. 



Haverforcl College, Pennsylvania, 

 Gentlemen, September 9, 1878. 



G-aillot's estimated orbit for "Watson's inner planet (C. E. 5 Aout 

 1878) accords closely with my predictions in 1873 (Proc. Soc. Phil. 

 Amer. xiii. pp. 238, 472). It appears to be the third of the har- 

 monically indicated intra-Mercurial planets. 



Mean distance. Time. 



Gaillot (computed) '164 24-25 days. 



Chase (predicted) -165 24-50 „ 



Yours truly, 



Pliny Eaele Chase. 



