o26 ANNTTAL OF SCIENTIFIC DISCOVEUY. 



Dr. Winnecke, at Carlsruhe, Oct. 17 ; and a third at Leipzig, Oct. 



23: — 



Perihelioa Passage, 18G9. 



October 8.4421 Greenwich M. T. 



Longitude of Perihelion, . . . 124° 41' 1 ") From apparent 

 Longitude of Ascending Node, . 3 IP 24 ' 4" > Eiiuino-x. 



Inclination to Ecliptic, G8>* 48' 8'^' 



Log perihelion distance, 0°08D85 



Ileliocentrio motion retrograde. 



The above orbit does not resemble that of any comet previously 

 computed, — J. II. Hind, Observatory, Twickenham, Nov. 8. 



SPECTRUM OF THE AURORA, ZODIACAL LIGHT, ETC. 



In connection with the observation of Prof. Youn":, during the 

 late eclipse, the following translation from a few paragraphs in the 

 text accompanying Angstrom's chart of the solar spectrum may be 

 of interest. On page 42, he says, after some introductory re- 

 marks : — 



" In fact, during the winter of 18G7-8, I have been able to ob- 

 serve, repeatedly, the si)ectrum of the luminous arc bordering the 

 obscure sci^ment, and alwavs seen during the feeble auroras. Its 

 light is almost monochromatic, and consists of a single brilliant 

 ray, situated to the left of the well-known group of calcium lines. 

 By measuring the distance from this group, I have determined 

 the wave-length of this ray, which is found equal to a z= 5567. 

 Beside this ray, of which the intensity is relatively great, I have 

 deserved, also, by widening the slit of the spectroscope, traces of 

 three lines extending almost as far as F. On a single occasion, 

 when the luminous arc was agitated by undulations which changed 

 its shape, 1 saw regions momentarily illuminated by certain feeble 

 spectral rays; but, taking into account the intensity of these rays, 

 I would, nevertheless, say tliat the light of the luminous arc is 

 sensiblv monochromatic. There is a circumstance whith gives to 

 this observation of the aurora spectrum a mucii greater impor- 

 tance, and, indeed, a cosmical character. During one week of 

 ^larch, 1867, I succeeded in observing this same spectral ray in 

 the zodiacal light, which then presented itself with an intensity 

 truly extraordinary for the latitude of Upsal. Finally, when, dur- 

 ing a starlight night, all the sky wa-^, in a certain sense, phosjjho- 

 rescent, I found traces of it in the feeble light emitted by all parts 

 of the firmament. A very notable fact is, that this remarkable 

 ray does not correspond with any of the known rays of simple or 

 compound gases, so far, at least, as I have studied them up to 

 this time. It follows, fnun what I have said, that an intense au- 

 rora, such as may be seen above the polar circle, would probably 

 give a more complicated spectrum than that which I have found. 

 Granting this, we may hope that an opportunity will be atforded 

 of explaining the origin of the rays already found, and the nature 

 of the phenomenon itself. Not being able to give this explana- 

 tion at present, I propose to return to it another time." — Journal 

 of Franklin Inst., Nov., 1869. 



