320 M. Arago on Kcbulcp. 



Examination of the difficulties which these ideas of transforma* 

 tion have raised. — It has been enough for us to group conve- 

 niently the diverse forms which diifused nebulae affect, in order 

 to arrive at the most important cosmogonical conclusion. By 

 means of the natural and sober combination of observation 

 and reasoning, we have established, with a high degree of 

 probability, that a gradual condensation of the phosphorescent 

 matter leads as the last term to sideral appearances ; that we 

 at last arrive at the formation of true stars. 



This bold idea is not so new as is imagined. I can, for 

 example, trace it back as far as Tycho-Brahe.* 



This astronomer, in fact, regarded the new star of 1572 as 

 the result of the recent agglomeration of a portion of the dif- 

 fused matter, disseminated throughout the whole universe, 

 which he called celestial matter. 



According to him, celestial matter existed in the Milky Way 

 in much greater abundance than elsewhere Must we then be 

 surprised, he says, that the star should have made its appear- 

 ance in the midst of this luminous band ? Tycho even saw an 

 obscure space., as large as the half of the moon's disc, in the 

 very place where the star appeared. He had no remembrance 

 of having observed it before. 



Kepler, in his turn, composed the new star of 1604, of 

 the agglomerated matter of ether. This matter, when in a 

 less complete state of condensation, seemed to him the physi- 

 cal cause of the atmosphere with which the sun is enveloped, 

 and which shews itself under the appearance of a feeble lumi- 

 nous crown during the whole continuance of total eclipses of 

 the sun. The new star of 1572 was formed in the Milky Way ; 

 the new star of 1604 was not far distant from it. Kepler saw 

 in this coincidence a plausible reason for assigning to the two 

 stars the same origin ; only he added : if the milky matter con- 



* I purposely put aside the idea of the Brahmin philosophers, that there 

 exists, besides the four terrestrial elements, a jiflh element, the Akasck, of 

 which the heaven and stars arc formed. The Akasch may undoubtedly be 

 legitimately likened to the nebulous matter of modern astronomers ; but no- 

 thing, I believe, would authorize the supposition that the Indians imagined 

 that new stars were engendered, in our own times, and under our eyes, at 

 the expense of the Akasch. 



