otfjer heavenly Boiles, have Atmofpheres. 175 



One of the lateft inftances of fuch a ring around the mooa 

 Is that Aen on the 34th of June 1778, by Don Antonio de 

 Ulloa, between Tercera and Cape St. Vincent *. Five or 

 fix feconds after the fun was completely covered, a very- 

 bright ring began to be feen around the moon; and this 

 ring feemed to be in a continual and violent motion round 

 the moon's circumference. The nearer the moon approached 

 to the centre of the fun, it always became brighter and more 

 luminous. Its colour was not every where the fame : next 

 to the moon's limb it was reddifh ; then of a pale or goI(J- 

 yellow colour ; and towards the exterior edge it always be- 

 came whiter: but it was every where equally luminous and 

 beautiful. All the parts of the ring feemed to be carried 

 round the moon with the fame velocity, without the order of 

 the colours being confounded. Every thing before obferved, 

 in regard to this luminous ring, might be explained from re- 

 fraftion ; but the circumftance, never obferved on any other 

 cccafion, of its moving with a continual and uniform motion 

 around its centre, if this was a6lually the cafe, and if it did 

 not arife from fome deception in the organs of fight, makes 

 a new, and, according to every appearance,- an almoft infu- 

 perable difficulty in the explanation. It is much to be la- 

 mented that we are likely to remain in this uncertainty a 

 confiderable time ; for, according to a calculation of M. Du 

 Vaucel t, a total eclipfe of the fun, vifible at Paris, will not 

 take place for 120 years, and none can occur vifible in any 

 part of Europe till the year 1816 J. From the above obfer- 

 vation Don Antonio de Ulloa docs not hefitate to conclude 

 that the moon has an atmofphere. 



I ihall now proceed to the fecond point, adduced as a proof 



• See his Qbfewntion de I' Eclipfe du Soleil totcde du 24 Jidn 1778, in 

 Rozier's "Journal de Pbvfique,Yo\. XXV. part 1. April 1780, p-3i9; alf* 

 Mem. dc l Acad. Rovale des Sciences a Paris 1778, Paris 1781, p. 64 j and 

 Don Antonio dc UUoa's Obfervations on the total Eclipfe of the Sun on 

 the 24th of June 1775, in ^^^ SwedifliTranfaCtions, Vol. XL. Lciffic 1783, 

 p. 225. 



t Vol. W Dcs Memoircs preftntes. 



\ See Peter VVargentin's Paper on the luminous Ring with which the 

 ^loon ffcms to be furrounded when (he entirely covtri the Sun, in the 

 gwediJh Tranfadtions for 1778, Vol, XL. p-2j', 



of 



