1826.] Perspective Aerial Light and Shade. 215 



I did from another journal, in which the experiment only was 

 described), I turned to the original place, and there, though I 

 found the experiment I had transferred, I also found another 

 which I had previously made on the same suhject, and which 

 M. Bellani had quoted. 



I very fully join in the regret which the ' Bulletin Universel' 

 expresses, that scientific men do not know more perfectly what 

 has been done, or what their companions are doing ; but I am 

 afraid the misfortune is inevitable. It is certainly impossible 

 for any person who wishes to devote a portion of his time to 

 chemical experiment, to read all the books and papers that are 

 published in connexion with his pursuit ; their number is im- 

 mense, and the labour of winnowing out the few experimental 

 and theoretical truths which in many of them are embarrassed 

 by a very large proportion of uninteresting matter, of imagination, 

 and of error, is such, that most persons who try the experiment 

 are quickly induced to make a selection in their reading, and 

 thus inadvertently, at times, pass by what is really good. 



On a peculiar Perspective Appearance of Aerial Light and 



Shade*. 



ONE evening last month (Aug. 19, 1826), a curious aerial phe- 

 nomenon was observed from the undercliffat the back of the 

 Isle of Wight, just above Puckaster Cove. The sky was clear, 

 the sun had just set to those who were standing where the ap- 

 pearance was observed, when several enormous rays of light and 

 shade were remarked towards the E., N.E., and S.E., all radi- 

 ating in strait lines from a spot rather south of east, and just 

 upon the horizon. They were ten or twelve in number, did not 

 join at the place from whence they appeared to originate, but 

 seemed to emerge from an obscure portion of surface of a convex 

 form 8 or 9 in horizontal extent, and about the third of that 

 in height. The rays extended from 30 to 40 on the right and 

 left from the centre, but were of less extent as they became 

 more vertical. They diminished gradually in intensity at the 

 extremities until they could be traced no further. The ap- 

 pearance slowly faded away, some of the rays disappearing 



* Quarterly Journal of Science, xxii. 81. 



