140 ANNUAL OF SCIENTIFIC DISCOVERY. 



these rosy tints cannot be assimulated to simple optical appearances, 

 and have, in truth, a real existence, that they are not real solar clouds, 

 it will then be necessary to add a new atmosphere to the two of which 

 we have spoken ; for these clouds cannot be sustained in vaccuo. The 

 existence of a third atmosphere is moreover established by phenomena 

 of quite another nature, namely, by the comparative intensity of the 

 border and the centre of the sun, and also in some respects by the 

 zodiacal light, so perceptible in our climate during the equinoxes. 



TRUE PLACE OF THE SUN IN THE UNIVERSE. 



IN addition to the remarks contained in the foregoing article on the 

 physical constitution of the sun, M. Arago submitted the following- 

 observations on the true place of the sun in the universe. 



Archelaus, who lived in the year 448, B. C., was the last philoso- 

 pher of the Ionian Sect ; he said, regarding the sun, "It is a star, 

 only it surpasses in size all other stars." The conjecture, for what is 

 not based upon any measurement, or any observation, deserves no 

 other name, was certainly very bold and very beautiful. Let us pass 

 over an interval of more than two thousand years, and we shall find 

 the relation of the sun and the stars established by the labors of the 

 moderns, upon a basis which defies all criticism. During nearly a 

 century and a half, astronomers endeavored to determine the distance 

 between the stars and the earth ; the repeated failures with which 

 their researches were attended, seemed to prove that the problem was 

 insolvable. But what obstacles will not genius, united to perseverance, 

 overcome ? We have discovered within a very few years the distance 

 which separates us from the nearest stars. This distance is about 

 206,000 times the distance of the sun from the earth, more than 

 206,000 times 95,000,000 of miles. The product of 206,000 by 

 95,000,000, would be too much above the numbers we are in the habit 

 of considering, to warrant its annunciation. This product will still 

 more strike the imagination, when I refer to the rapidity with which 

 light travels. Alpha, in the constellation of the Centaur, is the star 

 nearest to the earth, if it be allowable to apply the word near to such 

 distances as those of which I am about to speak. The light of Alpha, 

 of the Centaur, takes more than three years to reach us, so that were 

 the star annihilated, we should still see it for three years after its 

 destruction. Recall to your recollection that light travels at the rate 

 of 192,000 miles in a second ; that the day is composed of 86,400 sec- 

 onds, and the year of 365 days, and you will feel as thunderstruck 

 before the immensity of these numbers. Furnished with these data, 

 let us transport the sun to the place of this, the nearest star, and the 

 vast circular disc, which in the morning rises majestically above the 

 horizon, and in the evening occupies a considerable time in descend- 

 ing entirely below the same line, would have dimensions almost imper- 

 ceptible, even with the aid of the most powerful telescopes, and its 

 brilliancy would range among the stars of the third magnitude, you 

 will thus see what has become of the conjecture of Archelaus. One 



