512 Roi/al Itistituiio/i. 



the moon, called the corona. The Lecturer described the magical 



change, from the state of a very narrow lune of solar light (the 



contour of the moon being totally invisible) to the state of an entire 



dark moon surrounded by a ring of faint light, as most curious and 



striking. The progress of the formation of the ring was seen by 



his companion, and by some other persons ; it commenced on the 



side of the moon opposite to that at which the sun disappeared. 



In the general decay and disease which seemed to oppress all nature, 



,1 the moon and corona appeared almost like a local disease in that 



part of the sky. In some places, the corona was seen as distinctly 



ov double ; it would appear that the ring which the Lecturer saw 



(whose breadth, by estimate of repeated duplication, he found to be 



. about one-eighth part of the moon's diameter, or four minutes of arc 



nearly) was the inner of the two rings seen by M. Arago and others. 



; The texture of the corona appeared in some places as if fibrous, or 



ii: composed of entangled thread ; in some places, brushes or feathers 



i> of light proceeded from it. One photometric estimate of the quantity 



tf of light in the corona, cited by M. Arago, gave it equal to one- 



tr seventh part of full moonlight. From a chromatic analysis of its 



- light by means of an ordinary prism, it appeared to be deficient in 



green rays. 



The Lecturer characterized the inquiry into the origin and locality 



of this corona as one of the most interesting connected with the 



eclipse. It had been specially indicated by M. Arago (see the 



Annuaire du Bureau des Longitudes, 1842) as a very important 



ir subject of inquiry whether the corona is concentric with the moon 



or with the sun ; but his recommendation had received very limited 



t, attention. The general tenor of the evidence went to prove that 



\( the corona belongs to the sun. This, however, was not the opinion 



. of more ancient writers, who tacitly consider it as the atmosphere of 



the moon. 



But the most remarkable of all the appearances were the red 

 mountains or flames apparently projecting from the circumference 

 of the moon into the inner ring of the corona, to the height of one 

 minute of arc at the smallest estimation, or a much greater height 

 v; by other estimations. It was afterwards discovered that these had 

 f been seen before by Vassenius, a Swedish astronomer, who observed 

 the echpse of 1733 at Goteborg (a place very favourable for the ap- 

 proaching eclipse), and whose account is given in the Philosophical 

 ,,j Transactions, vol. xxxviii. He terms them " subrubicundae non- 

 , nullse macula2, extra peripheriam disci lunaris conspectte, numero 

 ,, tres aut quatuor." This observation, however, was not known to 

 any of the observers in 1842, and all were therefore taken by sur- 

 , prise. Drawings were exhibited of these red mountains as seen at 

 ;, Perpignan, Narbonne, Vienna, Pavia, Superga, and Lipetsk. It was 

 shown that, by a trace still visiljle on the engraving, the drawing first 

 made at Vienna had coincided very exactly with that made at Pavia ; 

 that the Narbonne observations would be very exactly reconciled with 

 them by supposing the error (very likely to occur to unpractised 

 astronomers) of taking the north limb to be the upper limb ; that at 



