MEMOIR IV.] CONDITION OF THE SUN'S SURFACE. 33 



Of such hypotheses we have given reasons for declining 

 the first. Prismatic analysis, which demonstrates no re- 

 semblance between the light of the sun and that of any 

 form of electric discharges with which we are familiar, 

 enables us in like manner to reject the second ; and, upon 

 the whole, facts seem most strongly to prepossess us in 

 favor of the third ; in artificial combustions similar fixed 

 lines being observed. If such is to be regarded as the 

 physical condition of the sun, we can no longer contem- 

 plate him as an immense mass slowly and tranquilly 

 cooling in the lapse of countless centuries by radiation 

 into space, as so many considerations drawn from other 

 branches of science have hitherto led us to suppose, but 

 he must be regarded as the seat of chemical changes 

 going on upon a prodigious scale, and with inconceiv- 

 able energy. 



If the law designated above, that the more energetic 

 the chemical action in combustion the more refrangible 

 the emitted light, be translated into the conceptions of the 

 undulatory theory, it not only puts us in possession of 

 a distinct idea of the manner in which the combustive 

 union of bodies is accomplished, the quickness of vibra- 

 tion increasing with the chemical energy, but it also en- 

 ables us to transfer for the use of chemistry some of the 

 most interesting numerical determinations of optics. 



UNIVERSITY OF NEW YORK, Dec. 10, 1857. 



NOTE. I have thus presented the four preceding 

 memoirs as early contributions to the history of spec- 

 trum analysis, and applications of spectroscopic researches 

 to solar physics or astronomical problems. I think that 

 perhaps they will not be less interesting to the scien- 

 tific reader from the circumstance of their imperfections. 



