32 THE POPULAR SCIENCE MONTHLY. 



in Switzerland, and since then at the Cape of Good Hope. So far 

 nothing has been obtained, however, much in advance of Dr. Hug- 

 gins's own first results. But since September, 1883, until very re- 

 cently, the air, as every one knows, has been full of a fine haze, 

 probably composed in the main of dust and vapor from Krakatoa, 

 which has greatly interfered with all such operations. It is now fast 

 clearing away, and, if Dr. Muggins's views are correct, it is reasonable 

 to expect that a much greater measure of success will be reached next 

 winter at the Cape, and perhaps during the present summer in England 

 and Switzerland. 



About the same time that Dr. Huggins was photographing in Eng- 

 land, Professor Wright, of New Haven, was experimenting on the 

 same subject in a different way. He reflected the sun's rays into a 

 darkened room by a heliostat, cut out all but the blue and violet 

 rays by a suitable absorbing-cell, and then formed an image of the 

 sun and its surroundings upon a sensitive fluorescent screen, stopping 

 out the sun's disk itself. He obtained on the screen, on more than 

 one occasion, what he then believed and still believes to be a true 

 image of the corona. But the aerial haze soon intervened to put an 

 end to all such operations ; for of course it is evident that success, 

 whether by photography or by fluorescence, is possible only under 

 conditions of unexceptionable atmospheric purity. 



Both Professor Wright and Dr. Huggins base their hopes upon 

 the belief, which seems to be warranted by the spectrum-photographs 

 obtained during the Egyptian eclipse of May, 1882, that the light of 

 the corona and of the upper regions of the sun's " atmosphere " is pe- 

 culiarly rich in violet and ultra-violet rays — that the corona is far more 

 brilliant to the photographic plate and to the fluorescent screen than 

 to the eye. 



Probably it must be admitted that at present the predominant 

 opinion among astronomers and photographers is against the practi- 

 cability of reaching the corona without an eclipse, by any such meth- 

 ods ; at the same time, to the writer at least, the case appears by no 

 means hopeless, and success is certainly most devoutly to be desired. 



P. S. — The reports from the recent eclipse of August 29th, ob- 

 served by British and American parties on the Island of Grenada, in 

 the Southern West Indies, have just come to hand, and are strongly 

 unfavorable to the reality of the coronal appearances obtained by 

 Huggins and Wright in their attempts to render the corona visible 

 without an eclipse. 



Plates furnished by Mr. Huggins, and precisely similar to those 

 which he has employed in his photographic experiments, were exposed 

 by Captain Darwin during the totality (as well as before and after it), 

 in an apparatus like Mr. Huggins's, with a time of exposure the same 

 that he has been using, and were treated and developed according to 

 his directions. The plates exposed during the totality shoic no corona 





