VOL, LXIX.] PHILOSOPHICAL TRANSACTIONS. 497 



ness was such, that persons who were asleep, and happened to awake, thought 

 that fhey had slept the whole evening, and only waked when the night was pretty 

 far advanced. The fowls, birds, and other animals on board took their usual 

 position for sleeping, as if it had been night. Before the edge of the sun's disc 

 emerged from that of the moon, there was discovered near that of the latter a 

 very small point of that of the sun ; it was imuerceptible to the naked eye, but 

 having looked at it with the glass Don U. estimated it at first to be about the 

 magnitude of a star of the 4th order; after which it seemed to increase to that 

 of one of the 3d. Its first appearance lasted about a minute and a quarter, 

 the luminous circle was still visible, though already much weaker than it had 

 been. 



The reddish colour of the ring towards the lunar disc, its deep yellow towards 

 the middle, its clear and very pale yellow at the external extremity, its uniform 

 circumference, and the rays issuing from it to the distance above noticed, con- 

 vinced him that the whole is the effect of the lunar atmosphere, which is of a 

 substance different from that of the earth, that is, more transparent, more 

 homogeneous, more uniform, and fitter for reflecting the rays of light, since 

 otherwise the ring would not have been equally clear, shining, and coloured 

 throughout the whole circumference of the lunar disc. It cannot be said, he 

 thinks, that this luminous ring is the effect of the rays of the sun reflected by 

 the atmosphere of the earth, because the apparent diameter of the sun is 

 smaller than that of the moon, whose disc entirely hid that of the sun. Besides, 

 if the luminous circle had been made by the atmosphere of the earth, its colours 

 would have been like those of the rainbow, and it would have appeared fixed 

 without motion, instead of which, that which was seen is the same as that 

 which is seen by the naked eye on the sun when it is just above the horizon a 

 little after sun-rise or before sun-set, so that one may conclude, that this lumi- 

 nous circle is a part of the disc of the sun seen after refraction through the 

 moon's atmosphere. 



The point of the sun's disc, which was seen before its limb began to emerge 

 from that of the moon, is a very extraordinary phenomenon, which he was not 

 acquainted with before. It was noticed by 3 different observers. This point 

 gradually increased, and when it became of the size of a star of the 2d mag- 

 nitude, the edge of the sun emerged from that of the moon. The interval 

 between the first discovery of this point and the beginning of the emersion, was 

 about a minute and a quarter. The apparition of the sun, before the beginning of 

 the emersion, can only have taken place through some crevice or inequality on the 

 limb of the moon, not perceivable at the full moon, by reason of the reflected rays 

 which cross each other, and confuse it; whereas at the time of the eclipse, the 

 moon's body being entirely obscured, the light of the sun is behind, and comes 



VOL. XIV. 3 S 



