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phere about the sun. Laplace seems to have shown satisfactorily 

 that such an atmosphere, far from extending to the earth, would 

 not reach to even the orbit of Mercury- If this be so, we must 

 either adopt the theory of Von Humboldt, who supposes it to be 'a 

 luminous ring surrounding the sun, or conclude it is of terrestrial 

 origin. The preceding cut represents this beautiful phenom- 

 enon. It may he seen in our northern latitude in the spring months 

 after sunset, reaching up in the plane of the ecliptic towards the 

 Pleiades long after sunset; it gradually sets with the stars and may 

 again be seen in the morning before sunrise. According to Sir 

 John Leslie, the sun, shining upon the higher strata of the at- 

 mosphere, which he supposes phosphorescent, would form a large 

 luminous circle which we would see surrounding the sun at noon, 

 provided it was not eclipsed by his superior brilliancy; after sun- 

 set it would appear as a segment of a circle, did not the vapors of 

 the horizen obscure its extreme and faintest limits, hence it appears 

 lenticular, or lens shaped as represented in the engraving 



We shall conclude this chapter with a description of that well 

 known, but yet unexplained phenomenon the Aurora Borealis or 

 northern lights. In the high northern latitudes, beautiful dis- 

 plays of the aurora are witnessed, and they serve to enliven the 

 long winter nights with their bright coruscations. In our latitude 

 the exhibitions are of a less beautiful character, and rarer, but vet 

 so frequent that they are familiar to all. It generally appears 

 like a bank, or cloud of light, of a pale yellow color, resting upon 

 the northern horizon, occasionally emitting streamers which shoot 

 up towards the zenith, and then fade, revive again, and subdivide. 

 At other times It is seen as a luminous arch rising a short dis- 

 tance above the horizon, its highest altitude being in the magnet- 

 ic meridian ; from this, streamers ascend, and if the display is a 

 fine one, will appear to unite in a circle nearly in the zenith, called 

 the corona. It is a remarkable fact that great displays of the 

 aurora are always proceeded bv a disturbance of the magnetic 

 needle. Like the meteoric showers, there seems to be a periodi- 

 cal return of the auroral displays in unusual splendor, after defi- 

 nite intervals. One of these returns, which we well remember, 

 occurred at intervals from November 1835, to May 18.36. The 



