SCIENCE. 



[Vol. I., No. 1. 



PnOrOGRAPIlTNG THE CORONA WITH- 

 OUT AN ECLIPSE. 



Perhaps the most important observation 

 since the discovery by Jannsen and Lockj'er 

 that the solar chromosphere could be studied 

 without an eclipse, has recentlj- been made by 

 Mr. Huggins,^ the well-known English as- 

 tronomer. 



When the spectroscope had been found ca- 

 pable of bringing this important region into 

 dailj' view, there still remained the corona, 

 whose feeble light and nearlj' continuous spec- 

 trum defied all attempts to see it through the 

 overpowering glare of our own atmosphere ; 

 which, even in the purest skj', acts as a lumi- 

 nous veil between us and the object. It is 

 very easy at all times to cut off the sun's di- 

 rect light by a screen : unless the screen be at 

 an enormous distance from the ej-e, however, 

 this glare is not diminished by its use. Mr. 

 Huggins's method is founded principally on 

 two considerations. 



The flrst is, that tlie principal coronal radia- 

 tion (as found in Egypt by Dr. Schuster in 

 the late eclipse) occupies a narrow part of 

 the spectrum between G and H, while the 

 atmospheric glare consists of light of all 

 refrangibilities. As this coronal radiation, 

 though occupying narrow limits of wave- 

 length, is not monochromatic in the sense in 

 which that of the chromosphere is, he has not 

 employed the prism to disperse the atmos- 

 pheric glare, but certain absorbent media to 

 shut it out ; choosing those, of course, most 

 transparent to this violet light alone. The 

 best isolating medium has been thus far found 

 to be potassic permanganate. 



The second consideration is, that since the 

 G — H region is near the limit of vision, 

 where, though the retina responds but feebly, 

 the photographic plate is active ; and since the 

 latter is sensitive to feeble distinctions of light, 

 and preserves a permanent record of them, it 

 is best to use it, rather than the eye. Dr. 

 Huggins has worked with a Newtonian tele- 

 scope having a mirror of six inches aperture 

 and three and one-half feet focus. By select- 

 ing fine days, he has obtained, between last 

 June and September, twenty plates, showing 

 what appear to be the rays and streamers of 

 the sun's inner corona. 



As at least one European observer of dis- 

 tinction deceived himself by the supposition 

 that he had obtained a naked-ej-e view of the 

 corona without an eclipse, and as the appear- 

 ances about the sun caused hy inequalities in 



' On 3 method of photographing the solar corona without an 

 eclipse. Paper read at the Royal society by William Huggins, 

 D.C.L.,LL.D.,F.R.S., Dec. 21. 



our own atmosphere are most perplexing, and 

 so corona-like as almost to ' deceive the very 

 elect,' the reader will be interested in perus- 

 ing the following letter to Mr. Huggins from 

 Captain Abney, the eminent photographer : — 



' ' A careful examination of j'our series of 

 sun-photographs, taken with absorbing media, 

 convinces me that your claim to having 

 secured photographs of the corona with an 

 uneclipsed sun is fully established. A com- 

 parison of your photographs with those obtained 

 during the eclipse which took place in May 

 last shows not only that the general features 

 are the same, but also that details, such as 

 rifts and streamers, have the same position 

 and form. If in your ease the coronal, appear- 

 ances be due to instrumental causes, I take it 

 that the eclipse photographs are eqnall3-untrust- 

 worthy, and that my lens and your reflector 

 have the same optical defects. I think that 

 evidence hj means of photography, of the exist- 

 ence of a corona at all, is as clearly shown in the 

 one case as in the other." 



This is a clear opinion from a master of 

 the subject ; but Dr. Huggins's own caution 

 in statement, as well as skill in research, are, 

 without it, sufficient to predispose us to be- 

 lieve, that, in spite of its difficulties, the problem 

 of securing the forms of the inner corona with- 

 out an echpse has been, in principle, solved. 

 What these difficulties are, only those few who 

 have experimented in this particular direction 

 know. As one of this number, the writer can 

 onlj' express his sense of the great consequence 

 of the result reached, and his admiration of the 

 skill employed in obtaining it. It is given to 

 few to crown such a scientific life as that of 

 Dr. Huggins, by a discovery of such impor- 

 tance. S. P. Langley. 



A SINGULAR METEORIC PHENOMENON. 

 We are indebted to the favor of the Bureau 

 of Navigation, for the privilege of publishing 

 the following verj' interesting letter of Captain 

 Belknap, addressed to Commodore John G. 

 Walker, United-States Navy, Chief of Bureau 

 of Navigation, Navy Department, Washington. 



U.S. S. Alaska, at Sea, 



lat. 37° 54' N., loug. 124° 25' W. 



Dec. 15, 1882. 



Sir, — I beg to report, that on the evening 

 of the 12th inst., a few minutes after sunset, 

 and in lat. 38° 21' N., long. 134° 07' W., a 

 remarkable phenomenon was witnessed in the 

 western horizon from the deck of this ship. 



