82 The Astronomer 'Royal on the 



the side of the moon opposite to that at which the sun dis- 

 appeared. In the general decay and disease whicli seemed 

 to oppress all nature, 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 double ; it w^ould 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 composed of entangled thread ; in 

 some places, brushes or feathers of light proceeded from it. 

 One photometric estimate of the quantity of light in the 

 corona, cited by M. Arago, gave it equal to one-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 characterised the inquiry into the origin and 

 locality of this corona as one of the most interesting con- 

 nected with the eclipse. It had been specially indicated by 

 M. Arago (see the Annuaire du Bureau des Longitudes, 

 1842) as a very important subject of inquiry whether the 

 corona is concentric with the moon or with the sun ; but his 

 recommendation had received very limited 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 atmo- 

 sphere of the moon. 



But the most remarkable of all the appearances were the 

 red mountains or flames apparently projecting from the cir- 

 cumference 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 by other estimations. It was after- 

 wards discovered that these had been seen before by Vas- 

 senius, a Swedish astronomer, who observed the eclipse of 

 1733 at Goteborg (a place very favourable for the approach- 

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

 Transactions, vol. xxxviii. He terms them " subrubicundse 

 nonnuUse maculae, extra peripheriam disci lunaris conspectse, 



