G ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



RESPIGHI ON SOLAR PROTUBERANCES. 



The April number of the American Journal of Science 

 contains an interesting account of observations upon the so- 

 lar protuberances, by Professor Respighi, translated for its 

 columns from the Italian by Professor Wright. The conclu- 

 sions arrived at are, in the main, similar to those of Professor 

 Zollner, of which an account is given elsewhere ; the essen- 

 tial idea seeming to be that the photosphere is an incandes- 

 cent liquid mass or stratum, by the weight of which various 

 gases, especially hydrogen, are confined and compressed in 

 the interior of the sun at an elevated temperature, and that 

 these occasionally rise toward the surface with great veloci- 

 ty, until they force themselves through with a rapidity great- 

 er or less according to the depth from which they emerge. 

 The Professor suggests that it is these agitations* and erup- 

 tions which constitute the protuberances, and that the hydro- 

 gen issuing from the body of the sun serves as an aliment to 

 the chromosphere, thus repairing the repeated losses of the 

 latter by its not improbable combination with the substance 

 of the photosphere ; and it is suggested, also, that possibly 

 this immense stratum of incandescent hydrogen to wit, the 

 chromosphere may be the principal source of heat radiated 

 from the sun. 



The solar spots, according to Professor Respighi, are nei- 

 ther cavities nor clouds, but are superficial modifications or 

 partial obscurations of the photosphere, produced by scoria? 

 or scum floating upon it ; or, as it were, solid masses of isl- 

 ands floating upon the liquid stratum. 4 D, April, 1871, 283. 



TEMPERATURE OF THE SUN. 



Dr. Zollner, whose graphic pictures of the phenomena of 

 the solar atmosphere are well known to many of our readers, 

 has lately discussed anew the question of the temperature 

 and physical condition of the sun. Assuming that the prom- 

 inences which presenfthe appearance of eruptions are really 

 produced by the action of explosive forces projecting vast 

 quantities of glowing hydrogen into the chromosphere, he 

 applies the principles of thermo-dynamics to determine the 

 heat and pressure in different portions of the sun's mass and 

 atmosphere. He obtains as a probable minimum value for 



