164 Foreign and Miscellaneous Intelligence. 



which has disappeared in the revolution their eyes being atten- 

 tively fixed on the sky. Inquiring 1 of one of them what was the 

 matter, he pointed with his finger to the object of their attention, 

 at the same time saying, " A star on the moon !" and, in fact, I saw 

 a star of considerable brilliancy on the edge of the enlightened part 

 of the moon's disk. According to the position of the star relative 

 to the sun, which was still far from setting, this should have hap- 

 pened in the spring or autumn, near the first quarter. I remained 

 some instants considering the phenomenon, which gradually dis- 

 appeared. I cannot now say positively whether the star disappeared 

 behind the moon, or whether it separated from it. 



* Although I was not at that time much versed in astronomy, I 

 did not doubt that the supposed star was Venus, which I had some- 

 times observed in full daylight ; and as I also knew that Venus was 

 placed in the heavens as to us far beyond the moon, the phenomenon 

 appeared very surprising to me ; and hence, doubtless, the reason 

 why I have preserved the recollection of it. 



* This particular fact would have nothing more remarkable than 

 many others which had been cited, if it did not establish, i. That 

 the phenomenon may be seen in full day-light; ii. That it may be 

 well observed with the naked eye, and that, consequently, the ex- 

 plication is not to be found in any action of the telescopes ; iii. That 

 it does not depend upon such a condition of the eye as, being purely 

 accidental or exclusively proper to such and such persons, would 

 prevent its uniformly affecting several persons collected together 

 accidentally ; iv. That its duration may much exceed that of some 

 seconds, for on this occasion it certainly lasted above a minute. 

 Such a prolonged effect should necessarily happen each time that 

 the motion of the occulted star is, with respect to the moon, nearly 

 a tangent to its disk ; and if I had at hand the volumes of the 

 Connaissance des Terns for that time, I should, without doubt, find 

 that the occultation which I have described, and which I should 

 then be able to refer precisely to the year and day, would be in this 

 condition. It is also to occultation of this kind that the preference 

 should be given, that leisure may be obtained for the correct ob- 

 servation of the appearances.' This letter is signed J. D. Gergonne, 

 editor of the Annales des Mathematiques, and in a note to it, it is 

 stated that in the Connaissance des Terns for 1788, p. 43, may be 

 found mention of an occultation of Venus on the 9th April, 1788, 

 about three hours fifty-four minutes afternoon, which might be seen 

 from many parts of the earth, but not at Paris*. 



8. ON THE PRODUCTION OF COLOURED BANDS BY PLANE 

 MIRRORS. 



If a person stand before a silvered mirror and observe the re- 

 flected image of a candle, he will see at its sides several verv 



* Bib. Univ., 1830, 345. 



