62 COSMOS. 



give the most general features, sufficiently applicable to the 

 it)tails of the phenomena upon the surface of the Sun, science 

 at present assumes the existence of three envelopes round the 

 dark solar sphere ; viz., one interior cloud-like vaiooroui en- 

 velope, next a lumi7ious inve?,tment (photosphere), and above 

 these, as appears to have been especially shovi^n by the solar 

 eclipse of the 8th of July, 1842, an external cloudy envelope^ 

 which is either dark or slightly luminous.* 



As felicitous presentiments and sports of fancj' — such sub- 

 sequently realized speculations as abound in Grecian antiqui- 

 ty — sometimes contain the germ of correct views long prior 

 to any actual observation, so we find in the writings of Car- 

 dinal Nicolaus de Cusa (in the second book De clocta Ig7io- 

 rantia), which belong to the middle of the fifteenth century, 

 the clearly expressed opinion that the body of the Sun itself 

 is only " an earth-like niocleus, surrounded by a circle of light 

 as by a delicate envelope ; that in the center (between the 

 dark nucleus and the luminous covering?) there is a mixture 

 of water-charged clouds and clear air, similar to our atmos- 



* "D'apres I'etat actnel de nos counaissances astronomiques le Soleil 

 86 compose, 1. d'un globe central Ei peu pres obscur; 2. d'uue immense 

 couche de nuages qui est suspendue a nne certaine distance de ce globe 

 et I'enveloppe de toutes parts ; 3. d'une photosphere ; en d'autres termes, 

 d'une sphere resplendissante qui enveloppe la couche nuageuse, comme 

 celle-ci, k son tour, enveloppe le noyau obscur. L'eclipse totale du 8 

 Juillet, 1842, nous a mis sur la trace d'une troisieme enveloppe, situee 

 au-dessus de la photosphere et forniee de nuages obscurs ou faiblement 

 lumineux. Ce seniles nvages de la troisieme enveloppe solaire, situes 

 en apparence, pendant l'eclipse totale, sur le contour de I'astre ou ini 

 peu en dehors, qui ont donne lieu k ces singulieres preeminences rou 

 ge^tres qui en 1842 ont si vivement excite I'attention du monde savant.'' 

 "According to the present condition of our astronomical knowledge, 

 the Sun is composed, 1st. of a central sphere which is nearly dark; 2d. 

 of a vast stratum of clouds, suspended at a certain distance from the 

 central body, which it surrounds on all sides; 3d. of a photosphere, or, 

 in other words, aluminous sphere inclosing the cloudy stratum, wliich 

 in its turn envelops the dark nucleus. The total eclipse of the 8th of 

 July, 1842, afforded indications of a third envelope, situated above the 

 photosphere, and formed of dark or faintly illumined clouds. These 

 clouds of the third solar envelope, apparently situated during the total 

 eclipse on the margin of the Sun, or even a little beyond it, gave rise 

 to those singular, rose-cc lored protuberances, which so powerfully ex- 

 cited the attention of the scientific world in 1842." — Arago, in the An- 

 nuaire du Burcmi des Longitudes pour Van 1846, p. 464, 471. Sir John 

 Herschel, in his Outlines of Astronomy, p. 234, § 39.5 (edition of 1849), 

 thus expresses himself*. "Above the luminous surface of the Sun, and 

 the region in which the spots reside, there are strorg indications of the 

 existence of a gaseous atmosphere, having a somewhat imperfect trana 

 parency." 



