L. Respighi on the Solar Protuberances. 



The development of the protuberances is ordinarily announ- 

 ced by bright points or patches standing out upon the chromo- 



bX fori 



) considerable elevations, and then fall back in para- 

 s upon the sun, or diffuse themselves in masses of 

 varymg and sometimes very singular conformation, and subject 

 to more or less rapid transformations. Prof. Eespighi has been 

 able now and then to be a witness of the development, in the 

 neighborhood of the spots, of enormous protuberances, produ- 

 ced by the eruption of groups of very slender and brilliant jets, 

 which in a short time spread into great cloudy masses, either 

 settling down upon the surface of the sun, or gradually vanish- 

 ing at a great height above it. An example of this kind ot 

 eruption is given in the plate, in the figure of the protuberance 

 No. 14, obser^^ed October 29, 1870. 



Respecting the duration of the spots, it is found that win e 

 some of them are developed in the space of a few minutes, and, 

 after undergoing rapid transformations, in a few minutes thin 

 out and disappear, others remain visible for a long toie, some- 

 times retaining in their forms some characteristic traits, inose 

 which are the most variable and evanescent, are produced m 

 the neighborhood of the spots. Outside the zone of spots, up 

 to about 70" in latitude, the protuberances commonly remain 

 visible for many days, so that it is possible to follow by ttien 

 the rotation of the sun ; and it has been possible, m the couije 

 of the observations, to observe the passage of some o 

 protuberances from one border of the sun to the other, an 

 also their return to the first border, after having "^^^^.^^^ 

 plete revolution. The time of the sun's rotation as ciea _ 

 by means of the protuberances agrees very^ closely witn , 

 obtained by observation of ' ' - ^^ ""+ 



shows that the retardation 

 spots distant from the equatoi 

 proper motion of the spots themselves. ^g 



In regard to the distribution of the Protuberances upon 

 solar surface. Prof Respighi finds the results deducea ^^^ 

 the eariier observations confirmed, namely, that m ttie ^^^ 

 polar regions, within a distance of 20° from the poie^, 



* This i3 doubtleaa the line observed by Mr. I'Ofkyer Oct 20 J868^^^ ^^ 



uces agrees very cioseij^ "" "v\r,\ 

 ' the spots near the equator ; wti cu 

 of this rotation observed m JJ^ 

 ator, is an appearance due to 



