134 ANNUAL OF SCIENTIFIC DISCOVERY. 



recognized in Saturn and Mars. No addition or change of linos has 

 been seen to indicate that the liuht ha> undergone any change by re- 

 flection from them. It is probable that, with the exception of the 

 moon, we receive the light reflected from clouds or vapor in the at- 

 mosphere of the planets, and not from the true planetary surface. The 

 light would not, under these circumstances, pass through so great a 

 length of planetary atmosphere, and in the same proportion would it 

 be less liable to have any modification impressed iq>on it. 



At a recent meeting of the Astronomical Society, Prof. Airy, in an 

 account of the observations on stellar spectra made at the Royal Ob- 

 servatory, stated that the line F of Fraiinhofer indicating iron was 

 seen in most stars, the sodium line 1) in two stars; and a line near- 

 Iv, but not quite coinciding with G in many. The star a Orionis ap- 

 peared most like our sun, but generally the stars seemed not to be so 

 complex in constitution. 



7 '< iit/H 'future of the Sun and Stars. Besides the light of the sun, 

 which, when spread out, forms the visible spectrum, the sun sheds 

 upon us a large amount of energy invisible as light. Professor Stoko's 

 investigations have shown that this invisible energy, when passed 

 through a prism of quart/, is spread out like light, and contains lines 

 or spaces where this energy is absent, similar to the dark lines in the 

 visible speetrum. By the substitution of a collodion plate for the eve, 

 Professor Miller has investigated the invisible spectra of metallic flames. 

 These are as distinct and characteristic of each metal as is the light 

 spectrum of each. Observation has shown that the length of these spec- 

 tra of invisible energy and their lines are closely connected with the 

 temperature of the source of heat. Thus, when photographs of the re- 

 frangible portion of the solar spectrum and that of- the metal magne- 

 sium were compared, it was observed that that of the magnesium ex- 

 tended much beyond the solar, and it was especially noticeable, that 

 there was a strong band in the magnesium spectrum just beyond the 

 limits ol'th" solar. Yet no metal has been proved to be present in the 

 sun with more certainty than magnesium. Professor Miller regards 

 this difference as an indication of the solar temperature. The magne- 

 sium -peeirurn was obtained by the electric spark. If, in place of this 

 intensely high temperature, the o\ y-hydrogen flame of only 15,000 F. 

 be substituted, the magnesium spectrum is shortened, and does not ex- 

 tend be\ ond that of the sun. From this, Professor Miller infers that 

 " the temperature of the sun may be approximately estimated to be 

 not higher than that of the oxy-hydrogen flame. It certainly appears 

 to be far below that of the electric spark." This seems to be scarcely 

 in accordance -with the known law of the decrease of radiant heat. 

 This decreasing, inversely as the square of the distance, gives an in- 

 tense amount of heat to the solar surface. Waterston, in a communica- 

 tion to the Royal Astronomical Society, in February, 1860, states that 

 his experiment.-, founded upon the supposition that the difference 

 tween the temperature in the sun and the temperature in the shade 



is a function of the sun's absolute temperature, give above "ten mil- 

 lion degrees, probably twelve million, Fahrenheit," to the solar sur- 

 face. 



Is it not possible that vapors may exist in the solar atmosphere 

 which, as Professor Miller shows to be the case with sulphuretted hy- 



