134 ANNUAL OF SCIENTIFIC DISCOVERY. 



stars owe their light in part to the luminosity of their gaseous 

 envelopes, and notably to the presence of burning hydrogen. 



M. Jansen, of Paris, has ascertained, after Secchi, that the in- 

 tensity of certain lines seen in the solar spectrum varies with the 

 amount of moisture present in the atmosphere ; by transmitting 

 the light of 16 gas-burners through a tube filled with steam, 

 he reproduced all these lines. Quarterly Journal of Science, 1867. 



Stellar Spectra. Father Secchi divides the spectra of the stars 

 into three types. 1. The first and most dominant type is that 

 exhibited by white stars, like Sirius ; their characteristic is a Mack 

 band in the green-blue, and a second band in the violet ; half the 

 visible stars belong to this type. The two remarkable excep- 

 tions, f Cassiopeiae and /5 Lyrse, are perfectly complimentary to 

 the type, and have a luminous band instead of a dark ray in the 

 green. Another modification is presented by the constellation 

 Orion (a excepted), which has no large bands, and in which the 

 violet lines are very difficult to see. 2. Stars having colored 

 bands in the red and orange ; the most remarkable and typical is 

 a Herculis ; the spectrum of which has the appearance of a series 

 of columns illuminated from one side ; the stereoscopic effect of 

 the convexity of these bands is surprising. 3. Stars giving fine 

 lines, as Arcturus, Capella, Pollux, and our own Sun ; the spectra 

 of these stars perfectly resemble that of the sun, with fine lines in 

 the same places ; in them may be seen the principal solar rays, 

 B, D, 6, E, F, G, and many secondary rays. 



Iron in the Solar Atmosphere. M. A. J. Angstrom has com- 

 pared the solar spectrum with one formed by two iron.electrodes, 

 with a battery of 50 elements, and has found more than 460 rays 

 corresponding to the lines of iron. He has proved the existence 

 of manganese in the sun by the coincidence of nearly 30 lines. 

 He has also discovered a new ray of hydrogen, nearly half way 

 between G and H, which he calls h. 



Spectrum of Iron Flame. M. Secchi has recently communicated 

 to the Italian Society of Modena some curious observations on the 

 spectrum of a flame closely resembling that of certain yellow and 

 red stars. The flame is that proceeding from a converter in which 

 Bessemer steel is being made, and at the time when the iron is 

 completely decarbonized. The spectrum presents a series of 

 very fine and very numerous lines, similar to those of a Orionis 

 and a Herculis, only reversed. This results from the great num- 

 ber of metals burning in the flame, and is the only flame compar- 

 able with that of the colored stars. 



Spectrum of Light through Ice. He had previously ascertained 

 that the spectrum of the color of sea-water is deprived successively 

 of its red, yellow, and green as the depth increased, at the great- 

 est depths appearing violet-blue. To ascertain if the same fact 

 held true in the case of glaciers, he made experiments in an 

 artificial grotto, about 400 feet deep, in the glacier of Grinden- 

 wald. The ice wall was nearly 50 feet thick; the solar light that 

 penetrated through was of a fine blue tint, giving to the human 

 countenance an alarming cadaverous aspect. On looking toward 

 the entrance at a certain distance, the cavern appeared to be 



