496 PHILOSOPHICAL TRANSACTIONS. [aNNO 1779- 



there was in keeping the solar image and a part of that of the moon within the 

 field of the telescope ; the object vanished every instant, and it was not till after 

 several fruitless trials that he could get it again. Besides this, the arms grew 

 tired of holding up the telescope and smoked glass, which could not be rested on 

 any thing from the necessity there was of moving the telescope in a contrary 

 direction to that of the ship. He had no calculations but those to be met with 

 in the Connoissance des Tems, which he did not find very exact, owing either 

 to some error in the calculations themselves, or to the longitude of the ship's 

 place, not having been accurately determined in that book: he found a pretty 

 sensible difference in the hour set down for the beginning of the eclipse. He 

 observed the total obscurity of the sun's disc at 3^ 44"*, the beginning of the 

 emersion at 3'^ 48'", the end of the eclipse at 4^ 48"^; consequently the middle 

 of it must have been at about 3*^ 46™: the total obscurity lasted 4 minutes, a 

 sufficient time for observing the ring which was formed round the moon. 



Five or 6 seconds after the immersion he began to observe round the moon a 

 very brilliant circle of light, which seemed to have a rapid circular motion, 

 something similar to that of a rocket turning about its centre. This light 

 became livelier and more dazzling in proportion as the centre of the moon 

 approached to that of the sun; and about the middle of the eclipse it was of 

 the breadth of about a 6th of the moon's diameter. Out of this luminous 

 circle there issued forth rays of light, that reached to the distance of a diameter 

 of the moon, sometimes more, sometimes less, which made him think they 

 were parts of a weaker light reflected in an atmosphere more subtle than that in 

 which the ring was formed. When the centres of the two planets began to 

 separate, the diminution began, and took place gradually, in the same order 

 which had been observed at its beginning and during the progress of it. It 

 disappeared entirely 4 or 5 seconds before the emersion. The colour of the 

 light was not the same every where; the part immediately joining the disc of the 

 moon was of a reddish cast, from which it changed towards a pale )ellow, which 

 about the middle began to clear till, at the external extremity, it ended in an 

 almost entire white. It was equally brilliant throughout, and the whirling 

 motion, connnon to all the parts of it, seemed to change the form and position 

 of the rays which appeared to the eye sometimes larger, sometimes shorter, at 

 the same time that there was no change either in the colours of the ring them- 

 selves, or in the arrangement of them, both which continued as above 

 described. 



For 4 or 5 seconds before the appearance of the shining ring, and during as 

 many after it had disappeared, they could see the stars of the 1st and 2d mag- 

 nitude, as at the entrance of the night; but when it was in its greatest degree 

 of brilliancy, only those of the 1st magnitude could be discovereti. The dark- 



