L. Respighi on the Solar Protuberances. 



Art. XLIIL—Oji the Solar Protuberances ; Abstract of a Note read 

 by Prof. L. Kespighi, before the Accademia de' Nuovi Linctt] 

 Dec 4, 1870.* With a plate. 



This note is founded upon spectroscopic observations of tlio 

 border and protuberances of the sun regularly made by Proi: 

 Respighi, at the Campidoglio observatory in Eome, from On. 

 1869, to Nov., 1870. The author deduces some important fa. 

 relative to the forms, size, development, and transfonnatioii 

 the protuberances; to their duration, and the manner of tin r 

 distribution over the solar disk ; and to their connection wirn 

 the other solar phenomena, namely, the spots and the faculse. 



Among the surprisingly various and singular forms of tiic 

 protuberances, he finds those that have the appearance of gaseo);s 

 masses issuing from the sun's surface to be so marked and con- 

 stant, that it is necessary to conclude that they are really pro- 

 duced by gaseous eruptions from within the body of the sun, 

 taking place with more or less energy, and on a varying scale 

 of grandeur. 



Not being able to explain the various modes according to 

 which the erupted masses are ramified and diifased, by refer- 

 ring them to the simple velocity of eruption combined with the 

 action of gravitation, and with the natural expansion of the jets, 

 or by the resistance of the solar atmosphere, or on the supposi- 

 tion of powerful currents in the latter, he finds it necessary to 

 admit the concurrence of other forces acting within the erupted 

 masses, and between these and the body of the sun. 



In regard to the dimensions of the protuberances, spectro- 

 scopic obsei-vations show that they may vary between the most 

 remote limits, from jets which are very small and low, to those 

 of enormous section and of immense altitude. Among the 

 protuberances sketched by Prof Eespighi, which exceed 4,000, 

 there are more than 700 not less than 1' high, that is, more than 

 three times the diameter of the earth in altitude, and among 

 these some not less than 6', that is, more than 20 times the 

 earth's diameter in height , 



lo these immense altitudes of the protuberances, correspond, 

 ^ery often, expansions or ramifications in a horizontal direc- 

 tion, which are truly astounding, and in which the hydrogen dif- 

 ti^ses iteelf in vast volumes, or stretches out in branches 

 ^ore or less subtile and of enormous length. 



Prof Respighi observes that the loftiest protuberances 

 Observed by him show, besides the i 



5 the spectral line C, which i: 



s Journal, by Prof. AETUi 

 lass., from Secchi's BuU. 1 



